SOLARTECHDIY,INC

DIYSolarPanels

YouCANBuildThem!ByPatrickJ.MinnsMBA

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PatrickJ.Minns

IndexSheet–VQRBarCodesinChronologicalOrder

5:36How-Tomaintainsoldertips

0.29How-Torecognizedamagedsoldertip

11:43How-Toestablishlengthoftabbingwirestrip

5:33How-Todeterminetensionbendlocation

16:30How-Tocreatea“Pair”ofsolarcells

3:28How-Totestsolarpairindoors

16:21How-ToConnect“PAIRS”tocreateSTRINGS

8:53How-Toaddthe9thsolarcelltoastring

0.27How-TomoveaSTRINGontosubstrate

8:13How-ToconnectSTRINGSbytheend-runs

1:03howtoproperlyopencaulkingtubeandgun”

10:19“howtoapplyclearsiliconecaulkingtotabbingwire

8:21How-tobuildthe1stlegofPOSITIVEoutboundlead

2:30How-TosetupoutgoingNEGATIVEleadtobattery

5:14How-Tode-airsolarpanelencapsulantviavacuum

14:14HowtopourSolar-Tite384encapsulant

11:55How-ToremovetrappedairunderSTRINGS

1:29HowtoinstallTedlarBacksheet

10:01HowtosealTedlarBacksheet

10:11How-torepairsolarcells,BUSBARSthatwon’tadhere

1:18Howtotestsolarcellsrepairedwithconductivepaint

WWW.SolarTechDIY.com

Forcommentsandinquires:

Patrick@solartechdiy.com714-598-8881

TableofContents

Introduction……………………………………………..…..….11

Section#1Choosingaworkspace,securing“WIP”……...13

Section#2A)Hand-CraftedSolarPanel,JustBeforeYouGo“WIP”..18

B)SafetyISaPrimaryConcernatEveryStage….…..….26

C)KnowWhentoAskforHelp…………….………………29

Section#3

NowtoCreateYour“WIP” ……………………………….….31

WhataretheComponents?…………………………………….…..31

Section#4

Step1-Creatingthe“PAIRS”…………………………….…41

Step2-Combining“PAIRS”intoSTRINGS…………….…62

Step3-ConnectingSTRINGSviaEnd-Runs……………...72

Substrates–WeNeedToSlipThisInNow…………….….75

ThreetypesofSubstrates ………………………………..…76

TemperedGlass,PolycarbonateorAcrylicCovers………79

NowtoConnecttheSTRINGSasPromised……………….83

PlacingtheFirstSTRINGontoASubstrate……………..…85

PlacingtheSecondSTRINGontoASubstrate…..………..86

PlacingtheThirdandFourthSTRINGSontoaSubstrate..88

NowWeWillConnecttheEnd-Runs……………….……….88

CreatingthePOSITIVEOutboundLead…………………….95

AddingtheBlockingDiode…………………………………....96

CreatingtheNEGATIVEOutboundLead….……..………...97

Step4-Encapsulatingyour“WIP”……………………….…99

Removingairbubles,or“de-airing”………………………..101

PreparingtoPourEncapsulant…………………………….…104

PouringtheEncapsulant……………………………106

CuringProcessandFinalBubbleRemoval………106

InstallingTedlarBacksheet………………………...110

InstallingtheProjectBox…………………………...113

AWordAboutWireSizing………………………………….…115

WireSizingMathFormulas……………………………………118

SealingtheTedlar,ProjectBoxandConnectingLeads……121

Nowthatyouhaveitbuilt,whatnow?……………………….…...125

BatteryBanks,ChargeControllers,andInverters………..…127

Batteries………………………………………………………..129

Primarybatteires………………………………………………130

Secondarybatteries…………………………………………..131

Inverters……………………………………………………….134

FinalSafetyBriefing……………………………..…………….136

RepairingDamagedSolarCells……………………………...139

Aspecialworkofthanksmustgoouttomywifeandchildrenwhosupportedmethroughalloftheworkrequiredtoproducethisbook.Further,thisworkwouldnothavebeenpossiblewithoutthesupportofNitzaandIzharShyPh.D.,forwhomabriefmentionhereinishardlysufficienttoconveymyheartfeltandsincerethanks.

Introduction

Haveyoueverseensolarpanelsinusesomewhereandthought,“That’sagreatidea.Iamgoingtodothat”?However,afterpricingthesolarpanels,didyougiveuponyourideabecauseofthehighcostofthosesolarpanels?Perhapsyouhaverecognizedtheusefulnessofsmallersolarchargersforthingslikechargingcellphones,poweringsecuritycameras,orsecuritylighting,butyoudiscoverthesmallersolarpanelsarenearlyasexpensiveasthelargerones?

MyexperiencewaswithanRVownedbyaclosefriendwhohadpaidasmallfortunetohavehisRVoutfittedwithsolarpanelsanddeepcyclebatteriesthatgavehimunlimiteddrycampingrange.Whilehecouldcampvirtuallyanywhereintheopendesert,IwastetheredtotheKOAcampground,dependentonaccesstotheelectricutilitiesatthecampgroundtoenjoyalltheamenitiesandappliancesinmyownRV.

IhavealwaysbeenaDIY(Do-it-Yourself)enthusiast,andIviewedmyfriend’sRVthroughthose“DIY”eyes.AfterexamininghissolarpanelsIthought,“ThesesolarpanelswerebuiltbysomeprocessthatIamgoingtolearn.”Iresearchedsolarpanelconstructiontechniques,andIdiscoveredamethodologythatcouldbedoneathomeusingtoolsIalreadyowned.Ibeganhandcraftingsolarpanels,andwhiletheearlierversionswereprimitive,theyperformedreliablyforseveralyearsbeforebeingtakenoutofservice,replacedbyunitsbenefittingfrommyimprovingskillset.

InmyquesttofindtheknowledgeIneededtohandcraftsolarpanels,IreadeverybookavailableonthetopicandwatchedeveryYouTubevideoaswell.WhatIfoundwasapatchworkofinformationthatoftenleftmeconfusedinthefaceofdifferingopinions,andwidelyvaryingmethodsforhandcraftingDIYsolarpanels.Afrequentandmostcommoncauseoffrustrationwastheobstacleoftechnicaljargon.Demonstratorsofwhatappearedtobehighlyeffectivemethodswerecateringtoanaudiencealreadywellversedinphotovoltaics.

Inordertomakesenseofthevarioussourcesofinformation,Iconductedexperiments,andthroughtrialanderrorwasabletoeliminatemethodsthatdidnotworkwhileadoptingthosethatdid.IattendedelectricianschoolinordertolearnbasicelectricaltheorysoIcouldevaluateinformationthroughatrainedeye,sotospeak.

Idiscoveredthatpeoplewereveryinterestedinmysolarpanelbuildingactivities.NeighborswouldcomewatchmeworkwhileIwashandcraftingsolarpanels;mostbeingintriguedbythepossibilityofthemparticipatingintheactivity.In2011apoweroutagestruckSouthernCalifornia,largeswathsofArizona,andintoMexico.AtthetimeIhadanarray(collectionofsolarpanelsworkinginconcerttogenerateelectricity)containingadozenDIYsolarpanels.Ialsohadalargebankofdeepcyclebatteries;asaresult,ourhousehadlights,Internet,andhotwater.

Theeffectofonehousehavinglightwhenallaroundmyneighborsdidnot,lentforaverydramaticvisualstatement.Ihadtheentirecul-de-sacatmyhouseexaminingmy

solarpanels,anditoccurredtomethatIamontosomething.IwasontothenotionthatIcouldpassontheknowledgeIhavegainedinalanguagethatisstraightforward,butstillteachestheprinciplesnecessaryforsuccessfulhandcraftingofsolarpanels.Iwoulddoawaywiththetechnicaljargonthatconfusedme;aswellas,theassumptionoftechnicalproficiency.Iwouldpresentthematerialinastraightforwardmannergraduallyexposingandintroducingtermsandconcepts.ThereaderwillcomeawaywithadeeperunderstandingwithoutneedingtoGooglesearchtermsencounteredwhilereadingthiseBook.

Theonlyreaderswhomayhaveanissuearethosewithmoreadvancedknowledgeonthesubject.TheywillnoticethatIwrotetoreadersthathaveneverbuiltanything,certainlyneversolderedbefore,andthedescriptionsofactionsareinminutedetail.Thisisintentional.ReaderswhotrulyhavenopreviousexperiencewillbeabletodigestwhatIhavewritten,andactuallyunderstandtheinstructions.Moreimportantly,theinstructionsaresupportedbyillustrations,andthemajortasksaredemonstratedonvideo.

Squarebarcodesknownas“VQR”(VisualQuickResponse)barcodeshavebeenprovidedtolinkthereaderdirectlytomyYouTubechannel.EachVQRbarcodeislinkedtoauniqueandexclusivehow-tovideothatpertainstoaspecifictasknecessarytohandcraftasolarpanel.Eachvideoisnarrated,andrecordedfromtheperspectiveofapersoncompletingthetask.InordertowatchthevideosyoumustdownloadafreeAppfromtheAppStoreonyoursmartphone,thespecificAppIamusingis“Visualead”,afreeAppthatIusedtocreatethebarcodes.

IamconfidentthatuponcompletionofthiseBookyouwillbereadytohandcraftyourownsolarpanelevenifthisisatotallynewcompetencytoyou!Moreover,thisbookappliestoabroadagerange.Withparentaloversightthereisamplereasontobelieveyoungstersaroundtheageoftwelvearecapable,andtheupperagelimitisboundonlybythephysicallimitationsoftheparticipant.Theinformationcontainedhereinwilllaythefoundationuponwhichyoumaystartontheroadtoenergyindependence.WiththiseBook,youhaveknowledge,andastheysay,knowledgeispower.Sowhetheryouarelookingtohandcraftsmallsolarpanelstochargecellphones,orbuildlargesolarpanelsforanoff-gridcabin,thisistheidealsourceofinformationtokickoffyourentryintotheworldofphotovoltaics.Goodluck!

Section#1ChoosingaWorkspace,Securing“WIP”,andPatience

The first step must be to find a reasonably secure work area because it can mean thedifference betweensatisfactionwhenworkingona solarpanel,orghastly frustrationwhensomeoneorsomethingbreaksyourwork-in-progress.Ispeakfromexperience.I learned thehardway thatdelicate solar cellsbreakabout as easilyasPringles.Asyouprogress in thesteps required to complete your solar panel, you will gradually and temporarily need toenlargeyour“secure”workspacetoencompassanareaatleastaslong,andwideastheprojectyouarecurrentlyworking.Whatdoes“secure”mean?Iwillanswerthatquestionbelow,butIwant to touch on a vocabulary matter you may encounter very quickly. I refer to theconstructionofyoursolarpanelas“handcrafted”becauseyouare indeedbuildingausefulsurvivaltoolwithyourwits,hands,andtools.Thereistremendoussatisfactionconnectedtothisactivitybecauseeveryaspectofwhatyouaredoingispositive.Itishealthyforyou,yourwallet, the environment, and as a positive example for family, friends, neighbors, and co-workers.Youaredisplayingasenseofstewardshipforthisplanetonwhichwedependforourownlives,yetaredepletingatalarmingrates.Ialsorefertothisactivityasa“trade”,becauseinasense,youarelearningaskillsetwhichmaybecomeasourceofincomeforyouatsomepointinthefuture.AttheveryleastyouareemployingtheskillstoSAVEmoneyifdirectedtowardsoffsettingyourgrid-suppliedelectricity.Everywattyougenerateforfreeisawatttheelectricutilityproviderwon’tchargeyoufor.

SecuremeansaworkspacethatcanprovideprotectionforyourWIP(workinprogress)fromaccidentaldamageofalltypesthroughoutthelifeoftheproject.Icannotstressenoughhowfrustratingitistodiscoverthatacarelessincidenthasshatteredastringofsolarcellsnearingcompletion,orworse,theentiresolarpanel.Thewasteoftimeandmoneynotwithstanding,itisdemoralizingtoseetheresultsofyourlovingattentiondestroyedbyrandomcarelessness.Itisthetypeofthingthatmakesonewanttothrowinthetowel,sodon’tletithappentoyou.ThevulnerabilityincreasesonceyouwalkawayfromyourworkareabecauseyourWIPwillbelayingout,unprotected,foralltoseeand,well,dropthingson.Itisaphenomenonexperiencedbymanyinthetrade,thephysics-defyingabilityofsensitiveandfragilesolarcellstoattractforeignobjectstofallonthemalmostasiftheyaremagnetic!Ijokeofcourse,butthepointisthatthestatisticalprobabilityofdamagebyforeignobjectisdirectlyproportionaltothefrailtyoftheobjects

indanger.Imadethatupeventhoughitsuredoessoundscientific,butoddly,itseemstoholdsignificantvalidity.Ihaveawholepictureworthofproofonthenextpagetosupportmytheoryonthematterthatsolarcellsbreakeasilywhenimpactedbyanythingmoresolidthansay,afewgrainsofsanddroppedfromabout2mm.

OneofthemostimportantconsiderationswhenselectingaworkareawillbetoprovidephysicalprotectionfortheWIPfromthemomentthesolarcellsgetexposed;tothedayyoutransitionthefinishedproducttousegeneratingclean,freeelectricity.Theinitialworkareawillrequireasmallfootprint,approximatelythesizeoftwosolarcellswide(whichevertypesolarcellyouareusing)forsolderingpairs,thefirstcomponentneededtostartputtingSTRINGStogether.SinceanysizeablesolarpanelwillcontainmultipleSTRINGSofsolarcellssolderedtogetherinordertoformthecompleteunit,buildingtherequisitenumberofSTRINGStakesafewdays.ThecompletedSTRINGSwillrequireaverysafeplacetositwhiletheremainingSTRINGSarehand-crafted,somewheresafefromaccidentalcontactwithforeignobjects,dust,orliquid.Isuggestusingthoseplasticstoragetubsthataredesignedtoholdwrappingpaperandnarrowenoughtofitunderabed.Theyarelong,flat,andcanindeedbeusedtoshieldthewaitingsolarpanelcomponentsuntilbeingmatedwithasubstrateandprotectivecover.Therearesomanyoptionsthatyouarelimitedonlybytheboundariesofimagination.

Iwarnyouinthemosturgenttermsavoidthefoolishnotionthatbecauseyoulivealone,oronlywithotheradults,orwithfellowhobbyenthusiasts,thatnothingcouldhappentoyourWIP.Please,don’ttemptfate,yoursiblings,yourrivals,yourchildren,in-laws;Ithinkyougettheidea.Ioncewatchedinseeminglyslow-motionasmysonabsentmindedlytossedahardcoverbookontoadeskwhereIhadleftmyprojectunprotected.Thebooklandedsquarelyontopofanewlysoldered4-cellmini-STRINGshatteringthemallandwhileangry,Ihadonlymyselftoblame.Fromthemomentyouopentheprotectivewrappingaroundthebundleofsolarcellsuntiltheyrestundertheprotectionoftheirfinalcoveringtheyarevulnerable.BreakageisthefirstthreatbecauseasIhintedearlier,theyareindeedveryfragileandtheydobreakeasilyifhandledroughlyorifimpactedbyfallingobjects.Ihavemanyexamplesasyoucanseebelow.

FIGURE1.1Thisisacollectionofbrokencellsfromadecadeofhandcraftingsolarpanels,andwhileitmayseemdaunting,itisjustpartoftheterritorywhenpracticingthistrade.Thegoalhereistolearnfrommymistakessoyoudon’tendupwithacollectionsuchasthis.IfyouDOhappentobreaksolarcells,itisnotaproblem,youwillgetthefeelforhowtohandletheminshortorder,butitwillsaveyoulotsofgriefbypayingheedtomywarningsaboutsecuringyourworkareas.

Patience:IwouldberemissifIfailedtotouchontheissueofpatience.Thereisalearning

curveassociatedwithanynewactivity,nomatterifitislearningtoplaysoccer,orlearningthisfinetradeofhandcraftingsolarpanels.Thereisnosuchthingasanestablishedtimelinetogaining total proficiency in all aspects related to handcrafting solar panels because everypersonhasauniquelearningability.IrecallvividlythefirsttimeIhadsolarcellslaidouttosolderforthefirsttime,neverevenhavingsolderedwirebefore,handsshaking;confidentIhadgatheredasmuchinformationaboutdoingitashumanlypossible.Allthatwasleftwastodivein,andtobehonest,itwasn’tprettyinthebeginning.Ibrokemanysolarcellsasyouseeabove,butasIhonedmyskills,theoccurrenceofbrokencellsbecamelessfrequent.Youwillalsoachieveproficiency inyourown time, sokeep theoccurrenceofbrokensolarcells inperspectiveandremember,itispartofthelearningcurve.

TheprojectisNOTafootrace;youarenotinacontestmeasuringyourspeedagainstanyoneelse.Takeyourtime,focusonthetaskathand,andrecognizethatthereisnothinggainedbyworking too quickly, perhaps outstripping your skill level. I like to refer to the old adage,“measure twice, cutonce” takingextra time toverifymymeasurements,wire lengths, cellpositioning, etc., before committing permanently via solder, bolting, or encapsulating.Hurryingaprojectwillonlyincreasethelikelihoodthatamistakewillbemade,asolarcellortwobroken,andthepossibilitythatyoursolarpanelwillnotgenerateelectricity.Ifyouhavemadeanerrorduetoimpatience,itisnotlikelythatyouwillcatchtheerroruntilthepointatwhichyouare testing it in the sun, atwhich time it is too late tomakeadjustments to theproject,andyouwillbefrustratedbeyondwords.Ofcourseitisfarbettertoavoidthemistakeinthefirstplace,butmistakesdohappen,Imakethem,aswillyou,thetrickistolearnfromthemandmoveon.Generally,ifyouareabletorecognizeanerrorearlyon,thereisnothingthatcannotberepairedorredone,butONLYifyoucatchtheerrorbeforeencapsulatingthesolar panel. After that, the chances for repair are slim at best; such is the nature ofencapsulants,sincetheyprovidepermanentprotectionagainsttheelementsaswellashumanfingers attempting repairs. If you cover the solar cell with Plexiglas instead of usingencapsulants,theremightbeachanceofrepairbutdoyoureallywanttobetearingapartasolarpanelatthepointwhereyouwouldotherwisebeputtingittowork?Letmeanswerthatforyou,No!Timeisbetterspentdoingitcorrectlythefirsttimearound.

Frustration:Onoccasionyouwillrunintosituationsthatfindyourpatiencestretchedtothelimit.Ifyouarelearningthistradefromthegroundfloor,youmayencountersituationsthatyou are unfamiliar and perhaps uncertain how to proceed.That is normal in any learningsituation, it is howyou react to sticking points thatwill determinewhether you canmoveforwardandovercometheobstacle.Gettingmadandlettingyourangerget thebestofyouwillonlysetyoubackandpossiblythwartfurtherdevelopment.Unfortunatelywhenwegetfrustrated and angry, the things our bodies do to prepare us for either fight, or flight, arecounterproductivetothetaskathand.Adrenalincoursingthroughourveinsdoesnothingforhandstability,somethingabsolutelynecessaryforsolderingandkeepingthesolarcellsin-tact.Nordoesit leadtorationalproblemsolving,againanothercriticalingredientforsuccess.Ithappens,itisnatural,anditcanbeadestructiveforceifitgetsawayfromyou.Oncethatpointisreachedwherebyvilecursesarerollingoffyournormallymildmanneredtongueandyouarelookingaroundwild-eyedforsomelessercreaturetogotakeoutfrustrationon(don’tdothat!!),allislostforthemoment.Oncetothatpointofbroilingfrustrationitistimetopushawayfromtheprojectandgotakeabreak.

RelateddirectlytothispointisasetofinstructionsIoncereadinamanualabouttheuseoflock picking tools.Themanual stated that the readerwill encounter locks that defy initialattempts todefeatduring the learningprocess,and thengoeson to reassure the reader thatfrustrationwasnormal,andthatitisperfectlyfinetotakeafive-minutebreak.WhatcaughtmyinterestwasthenextlinewhichInowparaphraseandoffertoyouasadvice,andthatistoreturntotheprojectaftercoolingoff!Veryimportantthatyoureturntotheprojectandgetapositivesuccessforthesessiontomaintainyourenthusiasm.Likeanythingelseinlifeworthdoing,ittakestimetolearnproficiency.Ifwegaveuponnewthingssimplyoverfrustration,lifewouldbeaverynarrowtunnelindeed.LikethesayingaboutridingbicyclesorbuckingBronco’s,ifyoufalloff,takeadeepbreath,steadyyourselfandgetrightbackon.Theysaythatifyoudon’t,itwillbealongtimeifeverbeforeyouscrewupthecourageagain.Besides,you have an advantage over the hapless bicycle or Bronco riders in our example becauseunlike them,youaren’t thrownfromtheabruptlystoppedorviolentlybuckingBroncoandhence, don’t have to suckwind back into your impact-deflated lungs or pick pebbles andsticks out of your bicycle road-rash.TheWIP is therewaiting for you once the calm hasreturnedandyouarereadytofacetheobstacleandwintheday.Oncecalm,IhavealwaysfoundtheresolutionlaughablysimpleandnothingIshouldhavebecomeexcitedaboutinthefirstplace.ItrustyouwillfindthesameconditiontobetrueandIwilltakeitfartherandstatewith confidence that when you look back after completing the project, the sense ofaccomplishment will far outweigh any frustration along the way. The ensuing solar panelprojects will be smoother, quicker, and you will not likely be held up by the same typeobstaclesbecauseyouwillbedevelopingproficiency.

Timing: I find this to be a very relaxing activity, the process of soldering and creatingsomethingwithmyhands. Ienjoysolderingsolarcellpairswhile listening to talk radioorpodcast, and you may find other ways to make the experience not just enjoyable, buttherapeutic.Trytomakeadailyroutineyouspendperhapsjustthirtyminutessolderingpairsof solar cells together, working steadily towards the completion of another solar panel. Itshouldnotbeachoretohandcraftasolarpanelbecauseifyouseeitassuch,youwillavoiddoing it.Always return to the core reasons you chose to get involvedwhether founded inenvironmentalconcerns,orpurelyeconomicreasons;thenslowlyandsteadilyworktowardsyourpersonalgoals.

Section#2

A)Hand-CraftedSolarPanel,JustBeforeYouGo“WIP”

JustsomebackgroundsoIamnothummingtheStarSpangledBannerwhileyouhumMyCountryTisofThee.Iamtryingtofillineveryblankthatleftmescratchingmyheadwhen

IfirststartedbecauseIcouldn’tfindanswersanywhere.

ToolsoftheTrade:Thereareafewtoolsonemusthaveinordertohandcraftsolarpanels.Thegoodnewsisthatthecostassociatedwith“gearing-up”isnotextreme;infact,Iwouldhavetosayitisveryinexpensivetoenterthistrade.

Solderinggunoriron-minimumof45-watt,withthewidetip.Awordtothewiseonequipmentsuchasthis,stickwithbrandnameswithprovenreliability.MypreferenceistheWellerSolderingGun8100-B,100-wattbutthereareseveralmodelsavailablefromthistrustedbrand.

Sparesolderingtips-atleastonepaironhandatall times.Youshouldalsohaveacollectionof toolsneeded tokeep thesoldering toolsclean to includeasponge,wiremeshdippingtray,andastandtorestthesolderinggun/irononduringuse.

Rosincoresolder-iron-free-99.3%Tin,.07%Copper.Itdoesn’tneedtobethisexactmix,butmeltingpointsshouldbeapproximately350°F.

FluxPen-Kesterbrand,#186-neededtobondtherosincoresoldertothesurfacesbeingjoined.Anybrandpenwillsuffice.

ProbesandPokers–(Picturedonthenextpage)toolswithwhichtoholddowndelicatetabbingwire or tomove partswithout having to use potentially oily fingers (whichmightcompromise thesolder).Also,whenusing thesoldergun the temperaturescanexceed400°F, capableof inflicting seriousburns to flesh, so theuseofprobeshelpkeepfleshoffthehotparts.

Weights-toaidinpositioningofsolarcellsandtabbingwirepriortosolderingbecausethingstendtomovewhencontactedbythesoldertip.Socketsfromatoolkitworkwellbutvirtuallyanydense,heavyandappropriatelysizedobject.Itisagoodideatoapplyasoftnon-slipcoatingtothebottomofthemetalsockets,preferablysomethingthatwillprovideprotectionagainst scratchingof thesolarcells likea rubberplumbinggasketmaterial.Simplycutoutapieceofrubberandattachwithtwo-sidedtape(soyoucantearitoffifyouneedtousethesocket).Alwaysusegreatcarewhensettingtheweightsdownontoasolarcell!Gentlylowertheweightontothetargetandsetitdowneversolightly.

SafetyGlasses–toprotecteyesagainstforeignobjects.

WireCutting-youcanusesmallscissorsorsmallwirecuttingtools.

Magnifying Glass- for close inspection of solder joints, inspecting solar cells forcracks,orifyouhavequestionableeyesight,ahat-likedevicewithamagnificationlensthatcanberotateddownforhands-freemagnification.

Measuring Tape- or ruler, yardstick, or flexible-softmeasuring tape.A three footyardstickisuseful.

Yardstick-athickwoodmodelispreferablebecauseyouwilluseittodrawstraightlinesonthesubstrate(thesurfacethatyoumountthestringsofsolarcellsinthefinalstages of assembly). Straight lines are essential in solar panel construction whetherphysicallydrawingoutthesolarcellpairplacementonyourworksurface,ortracingtheoutlinepriortocuttingyourPlexiglascovers.

T-Square-typicallyatoolusedinthedraftingtrade,thisisavaluabletoolforensuringwith100%certaintyyourlinesareattrueanglessuchaswhentracingyoursubstratecutoutpattern.Throughoutyourdesignandconstructionphasesaccuracyisabsolutelycritical!Cornershavetobe90°orthingssimplywillnotfitmakingitlookamateurishanddifficulttoweatherseal.Icanlivewithamateurishbutunfortunatelythelifeofthesolarpaneldependsonamoisturefreeenvironment.IusethesameT-squareIboughtin1982forahighschooldraftingclassinvirtuallyeveryprojectIhaveeverdoneasanadult.

Combination Square- because it is such an accurate tool for giving you thePERFECTLY sized template for the tabbing wire strips you will be cutting, or fordrawing outlines on a smaller scale. An excellent all-around measuring tool withlevelingcapabilitieswhichyouwillneedlater.

WeareDIYpeople,otherwiseyouwouldn’tbereadingthis,norwouldIbewritingit.Thereis justsomethingaboutthatfeelingofpride,offist-pumping,back-slapping,youjustpriedyourdogfromthejawsofanalligatortypeprimalfeelingofvictorywhenthe______(fill in theblanks)actuallyworks!!!Likethatfeelingyougetwhenyouplugyourownflattireafteryouhadpriceditatthelocaltireretailerat$120installed,withapatchkitthatcostunder$5.Theexamplesgoonandon,andIbeteachofyouhasagreatsuccessstorytoshare.IamconfidentyouknowthefeelingsofjoyIdescribe.

Thefunnythingisthatinallthatback-slappingwetendtoglossoverthemoreunpleasantobstaclesweovercametofinallyachievesuccess.Thebestwaytoavoidanegativeoutcomewhilehandcraftingasolarpanelistomaintainaclean,organized,andclutter-freeworkarea.No,Ididn’tjustlandonthisplanetfromMars.Ilivehereaswell,andhavethesamespacerestrictionsasmost.Unlessyouarefabulouslywealthy,andhaveafewextrahobbyroomsora seven-cargarage,youwill have to carveout spaceperhapsusingminingequipment andexplosives.Iwillgiveyouthebulletpoints,andyoufindwhatworksforyou.Thefollowingisalistofwhatisinvolvedintheidentificationofasuitableareatoplyyourtrade.Youwillneed…

SturdySurface-youwon’tbepoundinghorseshoesonananvilbutyouneedasurfacethatwillbelevel,andsteady.Youwillbeperformingdelicateworkrequiringasteadyhand,soawobbly tablewon’twork. Itcanbeaplankofwood laidacrossadozencinderblocks if that is all youhave, justmake it steadyenough to leanonwithoutresultinginvibration.

Project Surface- the surface that youwill be soldering on, staging your pre-cuttabbingwire,recentlysolderedsingleandpairedsolarcells,solderingsupportsponge,andpoking/holdingtoolsforthedurationofyourproject.Itshouldbesturdyenoughtobecarriedasyoutransitionfromactivework,tosecuringyourWIPbetweensessions.Glassisidealforsolderingonbecauseitdissipatesheatefficientlythusreducingthe

occurrenceofheatrelatedsolarcellfractures.Ceramicisalsogoodsuchasthetypeusedindecorativetilewalkwaysorindustrialwalls,thetrickistofindasinglepiecelargeenoughtoworkonwhilejoiningsolarcellpairs.

Light-hastobesufficienttoclearlyilluminatetheprojectsurfacementionedabove.Ifyouareinafixedareawhereyouwillregularlywork,LEDlightingisexcellentforproducinghighlumensoutputaswellasbrightness.LEDfixturesarecurrentlyveryexpensive;atypicalfourfootLEDstylefixtureis$100atbigboxhomeimprovementstores.AmoreeconomicalwayofgettingLEDlightfromanexisting48”fluorescentlightfixtureistopurchasespecial48”LEDbulbsthatfitexactlyintotheexistingtwo-prongslots.Youmustdosomesimplerewiringofthefixture,basicallybypassingtheballast,andfor$40youget thefullbenefitofLEDlighting.Onecouldalsosimplyinstall anLED lightbulb intoa standardclamp-onwork lightandhaveverystronglightforunder$20.Enoughaboutlight,yousimplyneedqualityillumination.

AirCirculation-becausetoxicfumesarecreatedduringthesolderingprocess,thereneedstobeasourceoffreshairtoevacuateanylingeringsmokeorfumes.

Organization- is a very important trait to have in this trade.Keeping yourworksurface clear of trash, clutter,wire clippings, anything that is foreign to the projectshouldbeputawayimmediatelyafteruse.Thingstendtogetbrokenwhentoomuchclutterstartstoencroachontheworkarea.Youcontrolthespacesothereneedstobetight discipline regarding the sanitation and organization of the work area. If youmaintainstrictstandardsovertheorganizationofyourworkarea,gettingcooperationfrompeoplewithwhomyoucohabitatewillbeeasier.Iftheyseeapileofgoo,theywon’tfeeloverlyhesitantabouttossingonafewmoretrinketsortrash,andindoingsobeing totally unaware they just smashed your newly completed string of cells.Converselyiftheworkareaisclean,orderly,andfreefromclutter,otherswillbelesslikelytodepositforeignmatterbecauseitwillbeslightlymoreobviouswhostartedthetrashpile?

SecureStoragefortheWIP-asItouchedonatsomelengthearlier,nothingismoredisheartening than to shut downworking on your solar panel for the night only todiscoverthatsomeoneinthefamilymissedthememoaboutrandomlytossingsporting

gearintothegarageuponopeningthedoor,orsomesimilarmishap.Isuggestedplasticstoragetotesearlier,thetypethatslidesunderabedasanoptionbutthereareplentyofchoicesavailableinthestoragecategoryofproducts.Yousimplyneedtofindwhatfitsintoyourbudgetandyourenvironment.Ifyouareindustrious,shelvesbuiltalongthewall in thegarage,orhighupalong theperimeterof some least-used room inyourdwelling; just anything to get them up and out of the hands of curious siblings,children,and/orguests.

Dust-won’tbefoundanywhereontheproductionfloorinfactoriesproducingsolarpanels.Insuchenvironmentstheairispurified,filtered,andaircurtainshelptokeepnewparticulate frombeing introduced into theproductionareas.Mostofuswillbeworking in our garages, bedrooms, living rooms, and weather permitting, evenoutdoors.Itisunrealistictoexpecttocreatedust-freeworkspacewhenhandcraftingyoursolarpanelinanyoftheseenvironmentsbutyouneedtotakereasonablestepstokeepthesolarcellsascleanaspossible.Thenatureofthistypeprojectmeansitwilltakepossiblyacoupledaystocompleteasolarpanel.Duringthistime,someofthecompleted solar cell pairs, and completed strings will have to sit idle while youcompletetheremainderofthecomponents.Dustwillaccumulateonthesurfacesofthesolarcells,thelongertheysit,theheavierthecoating.ThisiswhyitissoimportanttohaveasealablecontainerinwhichtostoretheWIPduringtheseperiods.Evencoveredandinsideacontainer,somedustwillaccumulateovertheupwardfacingsurfaces.Nottoworry, a layerofdust at thispointcanbedealtwith successfully,yousimplydoNOTwanttoencapsulateorinstallthefinalcoveringuntilthedusthasbeenremoved.How you ask?Gently brush the dusty surfaceswith a soft paint brush; I use artistbrushesmadebyPlaid,softnylonandnaturalfiberbristlesthatgentlypushawaythedustwithout the riskof scratching thedelicate surfaces.Theysayyoushouldavoidusingcannedairforfearofstaticelectricity,notsomethingweareconcernedaboutitthisapplication.YoumayalsouseaShop-Vacinconjunctionwiththehobbynozzles(picturedon thenextpage) togiveyoupin-point precisionwhen cleaning theWIP.Whyisdustaconcernatall?Itiswellknowninthefieldofelectronicsthatdustactslike an insulating blanket because it traps heat underneath the layers. Heat is auniversalenemytoelectronicequipmenttotheextentIamwillingtobetatleastoneofushaslostadesktopcomputertotheill-effectsfromdust.Heatcausescomputerstoslowdownastheirinternalself-defenseprotocolsreacttoheatbyshuttingdowninaprocess known as “Throttling”. This process acts on a computer CPU (centralprocessingunit) like“shock”does to thehumanbodywhenfacingsomesignificantinjury to include those resulting fromexcessiveheat.Shockpreservesbloodforuseexclusivelybyvitalorganslikethebrain,cuttingoffthebloodsupplytootherorgansbecause the body sees them with lesser priority in terms of the developing crisis.Throttling helps reduce heat in the computer by shutting down functions that arecontributing to the heat which is manifest by slow performance and at worst, acompletely blue screen while the computer tries to cool itself. Dust should beeliminatedespecially in the final stageswhere the long“strings”arebeing installedontothesubstrate,andcertainlyjustbeforeaddingencapsulants.Dustmayreducethecuringeffectivenessofencapsulants,compounds,siliconesealants,soasyousee,thereis nothing positive about dustmaking it onto your final product.The dust removalshouldbedoneeachtimeyoupullanewsolarcellouttosolderthetabbingwirestrips,

dustingwithabrushbothsidesofthesolarcellpriortosolderingaswellastheglasssolderingsurface.

Gloves,orNot-ifyouhavewatchedafewYouTubevideosonthesubjectofDIYsolar panels, youwill have seen everypossible combinationofwork environments,work surfaces, andof course, someglove supporters.Gloves are tools used tohelpprevent certain contaminants from being introduced onto the solar cell surfaces.Humanhands transmitgrease,sweat,andoils fromourbodiesonto thesurfaceswesubsequently touch aswe proceed through daily life. Surfaceswe touch collect allmannerofcontaminantsthatgobeyondthescopeofthisbook,buttheissueisofgreatimportancetothetaskathand.Sufficeittosaythatwetouchawidevarietyofobjectsin our travels to include our own bodies. Even if we washed our hands beforecommencingwork,humannaturewillhaveustouchingourfaces,hair,clothing,andeachtimeourfingerscomeawaywithdetritusofseveraldescriptions.IcanuniversallyguaranteethatnothingonthosefingersIjustmentionedwillhaveanypositiveeffectonyoursolarpanel.Infact,thecontraryistruewhenyouconsiderthatbodilyfluidsaresometimesveryoilyorgreasyincomposition.DareIsuggestanexperimentdearreader?CouldIrequestthatyouwipeonefingeracrossyourcheekandforeheadandthentakenoteofanysheenonthefinger?Iamsurethereisastudysomewhereonthenumber of times we touch our face, head, etc. throughout the day because we allscratch,wipe,orswipeatourselvesallthetime,probablyabsentmindedly.Eitherway,formerlycleanhandshaveawayofpickingupforeignmatterasdohandscoveredinaglove.Gloves cangive a false sense of security because thewearer knows that thesolarcellsarenowsafefromoilyhumanskin,buttheyperhapsdon’trealizehowoftenthoseglovedfingersaretouchingfaces,beards,hair,andthelike.Afterthegloveitselfbecomes contaminated the point of wearing them is lost, so I feel it is best to beeducatedabouttheneedtohavecleanhands,cleanworkarea,andifyouworkclean,

yourfinalproductwillbeclean.

SoYouSpilledSodaon…orsomeothermishapwherebysomethingsplashesontoasolarcellorastringalreadycompleted.Youcancleantheliquidsoffwithaverygentledabbingmotionusingasoft,absorbentcloth,or tissue.Once theoffending liquid isremoved,theresiduecanbecleanedfromthesolarcellbysaturatingasmallportionofaverysoftrag,orQ-tipandgentlydabbingtheareasinneedofattentionwithrubbingalcohol(isopropylalcohol).

Residue-Thereasonforusingisopropylalcoholisthatitdissolvesmostoils,alkaloids,gums, and other things I cannot pronounce, but best of all, it evaporates withoutleavingbehindoilyresidue.Theoccasionalfingerprintwillcomerightoffwiththismethod.IcannotresisttheurgetoreiteratethewarningaboutleavingyourWIPoutinthe open when you are not actively working on it. It is one thing for you, thecraftspersontoslopaglobofchiliontoyoursolarcell,butquiteanothertocomeoutand discover some unrecognizable, formerly liquid, silver dollar-sized glob ofsomethingonyourWIP.

SafetyIsAPrimaryConcernAtEveryStageIdonotknowtheskillleveleachofyouhaswithregardtoworkingsafelyaroundelectricalcomponents.Thereisnoquestionthatelectricitycanbedeadly,forexample,areviewoftheU.S.DepartmentofLaborwebsiterevealedthatin2013,71peoplewerekilledbyelectrocutionwhileworkinginconstructionjobs.ThisisanOSHAreportandthuswecanextrapolatethatthesewerejobsitesfilledwithhazards.HomeownersfarelittlebetteraccordingtotheFloridalawfirmLeesfieldLeightonRubioMahfood,whoadvertisethatoveraquartermillionAmericansarehospitalizedannuallyafteranelectricalshockofwhichasmanyas14%willdiefromtheirinjuries.WhenyouputthesetwosetsofstatisticsintotheperspectiveofourlifelongpursuitofDoing-it-Ourselves,westraddlethefenceontheissueofinjurystatistics.Idon’tmeanweareconfusedaboutwhichsideofthefencetofall;weareexposedinsteadtobothcategoriesofhazard,constructiontradeandthatofthehomeowner.

Handcraftingsolarpanelsrepresentsrisksyouneedtoknowaboutespeciallyifyouareaparentwhowillbesupervisingayoungerpersonperformingthisactivity.Oncethesolarpaneliscompletedyouwillundoubtedlywanttoputittowork,andwhywouldn’tyou?Itisanexcitingdaytolookforwardto!Thesolarpanelitselfislive,electricitygeneratingunitthemomentsunlightstrikesitattheappropriateanglewhetheryouarereadyornot.Connectingthesolarpaneltoadeepcyclebatteryrepresentsanewsetofrisksanddangers,ifmishandledbecauseofabattery’shighdischargecurrentcapacity,andthepresenceofcausticcompounds.Inadvertentlyconnectingcablestothewrongpolarityoraccidentalcontactwithbatteryterminalsbytoolsorjewelrycancauseanarc,asuddenreleaseofenergycapableofmeltingsteelwrenchesuponcontact.Batterycharginggenerateshydrogenwhichiscombustibleat4%concentration,especiallyhazardouswithoutventilation.Ifyouintendtomountyoursolararrayonaroof,therisknowincludesfallsfromtheroofortheladderusedtogetthere.TheladderinquestionmustNOTbemadefromaluminumsincethatmaterialconductselectricityifalivewirecomesintocontactwithit.Onceyourarray(multiplesolarpanelsormodulesjoinedtogether)isupandprovidingpower,ifnotgroundedproperly(ornotatall),thereisashockriskwhichalsomightescalateintoafireifconditionsareright.

HopefullyIhaven’tshockedorfrightenedanyoneaway!Imentionthethingsabovesothatyouareawareoftheriskinherentinworkingwithelectricity.Thingsdohappenonoccasion

thatareunusualandthatdefylogic,likewhenyouhavedoneeverythingright,yetyouarehitbyanotherdriverwhowasdoingeverythingwrong.Outsideofyourcontrolis,well,outsideofyourcontrol,whichiswhyyouneedtobeincontrolofthosethingsthatyoucan.Theideais to prevent accidents that result from carelessness, working too fast, a sloppy workenvironment,takingshortcuts,oranyoftheotherbehaviorsthatarefairlycertaintohavebeenresponsibleforpreviousaccidentssomewhere.Thereisareasonfortheabsurdwarningsweseeoneverydayproducts suchas thoseon firearms instructionmanuals that specifynot topointaweaponatoneself.Seemsprettyself-explanatoryandawfullybigoncommonsenseyet,ifyousearchonYouTubeIpromiseyouthatyouwillfindfootageofpeoplewhonotonlyshotthemselveswhilelookingintoagunbarrel,butthenpostedthefilm!ThereforeImustplace graphicwarnings ofwhat could happen to you should you take shortcuts, or act onimpulsewhenyoureallydon’tknowwhattodonext.Ifyourunintoasituationwhereyouabsolutelydonotknowwhatthenextstepis,STOP,getyourinstructionsout,double-check,goonline,emailme,butdonotsimplyguess.Ifyoudo,thereisanevenchancethatwhateverthestepiswillcomeoutincorrectlyandtheresultingerrorcouldbecostlyintermsofwastedtimeandeffort,nottomentioncost.

Extension/PowerCords-mustalwayshaveallprongspresent;neveruseonethathasanyvisibledamagetotheplugorsurroundings.Neveruseacordthatiscrimped,torn,cut,orhaswiresshowingthroughtheoutercover.Inspectthepowercordforthesoldergun,lights;aswellasanythingthatyouplugintoanoutlettocompleteyourproject.Don’toverloadawalloutlet,extensioncord,orsurgesuppressorby“piggybacking”inordertopluginyoursolderingironorsolderinggun.Piggybackingiswhenyouincreasethenumberofoutletsavailablebyaddingoutletextensionsontopofoutletextension(seephotoexampleonthenextpage).Thecumulativedrawonsuchamassofclusteredoutletsresultsinconcentratedheatsufficienttostartafire.Youneedtobeabletoextractelectricitysafely,withafreshsurgesuppressorthatispluggeddirectlyintoawalloutletorreceptacle.Thatwillensureasteadysupplyofconsistentpowerwithoutplacingtheentirestructureinmortaljeopardy.Ifyouareaparentwithverysmallchildren,perhapstoddlers,youareawarethatchewingonextensionorpowercordsisacommonbehavior.AccordingtoLyndaLiuwithParentsMagazine,in1997(Iknow,ataddated)morethan6,000childrenweretreatedinhospitalemergencyroomsforelectricityrelatedinjuries.Seventypercentofthemwereundertheageoffiveandhadeitherchewedthroughapowercord,orstuckaforeignobjectintoawallreceptacle.Justbeawarethatwhenyoupluginthesolderingironitwouldbeagoodideatotriple-checkthatyouhavedevisedsomemethodforkeepingthatcordoutofharm’sway.Lastly,whenchangingsoldertipsoneithertheironorgunmodels,unplugthemwhileperformingthechange-out.Youcanimaginewhy…

Heat-isafactorwithsolderingequipmentsincethetipmustachieveatemperaturesufficienttoliquefysolder.Forexample,thespecificsolderIusehasameltingtemperatureof350°.Atsuchtemperaturesskinisnomatchandseriousburnscanoccurifcontactismeasuredinfractionsofasecond.Norationalpersonwouldintentionallyexposethemselvestosuchintenseheatbutifperhapsanunsecuredsolderingiron(theroundcylindricaltype),notsittinginarackbecomesairborneandlandsinyourlapbecauseapasserbytrippedoverthepowercord.Thehumanbrainisgoingtorespondtothiswithrespectableelasticitybutithastorelyonourclumsylimbstoaffectourrescue.Reactingwithlightningspeedwewouldsnatchtheoffendingsolderingironfromourlapbutinthosefewsecondsaveryseriousburnwillhaveoccurred,onerequiringimmediatemedicalattention.ALWAYSUSEASTANDinconjunctionwithasolderingironbecausetheyarehotallthewhiletheyarepluggedin,evenwhennotinyourhand.Thatmakesthemaverywilyriskwhichdemandsyourrespect!

IliketousethesolderinggunbecauseIcontroltheheat.Whenactivelysoldering,notonlydoestheareadirectlyunderthesoldertipgetextremelyhot,prettymuchtheentiresolarcellbecomestoohottotouch.Youwillnotbeabletoholddowntabbingwireagainstthesolarcellforalignmentpriortosolderingbecauseyourfingerswouldreceivethird-degreeburns.Thus,thereasonforthe“ProbesandPokers”ontheequipmentlist.Theyaretheinstrumentsusedtoholdtabbingwiredownwhilesoldering.SoimportantisthistoolthatIstronglyrecommendthistoolineveryenthusiast’toolkit.Theywillsafelyallowyoutomanipulatethetabbingwireandholditgentlyinpositionwhilesoldering.Thesurfaceyouaresolderingonwillalsobecomeveryhotforabrieftimeasyousolder.Thatmeansyoucannotsolderonasurfacethatwillcombust,ormeltfromthesolderingiron.SoanytablethatisplasticMUSThaveyourglassworksurfacebetweenthesolderactivity,andthetable.

Fumes-arepresentwhenthesolderreachesthetemperaturenecessarytoliquefyit.TheneedforventilationisparamountastheresultingsmokefromsoldershouldNOTbeinhaleddirectly.Afanmaybeusedtopushtheoffendingsmokeaway,perhapsadesktopmodelthatisbatterypowered(rechargeablebatteriesofcourse)oranactualsmokeextractorwhichpullsthesmokeawayfromtheworkareaandfiltersitincasethereareimpurities.Ifyouhavesensitivitiestotheodorsorfumes,suchadevicemightmakeyoursolderingactivitiesworry-freeandworththeexpense.Wewillbeusinglead-freesolderwhichsparesusfromexposuretothetoxinsmostnotoriousforcausingillnessnamelylead.YoucantakecomfortinthefactthattheMSDS(MaterialDataSafetySheet)informationfortheencapsulatingmaterialsweofferforsaleisNOThazardousmaterialandthisfactisconfirmedbytheU.S.DepartmentofTransportation.

D)KnowWhentoAskforHelpIhadaninstructorwhousedtotelltheclass,“Theonlyfoolishquestionistheoneyoudon’task”.

Hereiswherethemalesofourspecies,yourstrulyincluded,inviteallsortsofgrieftocomecrashingdownonourheadsbecausesometimeswearejusttooproudtoadmitwhenwedon’treallyknowwhattodonext.Iknow,someofyouarechucklingwhileothersmaywanttopunchmeintheteethforputtingsomethingsosacrilegiousintothisbook.Iadmitthatinthefardistantpast,therewasatimewhenIwouldchargeaheadonaproject,andifIencounteredobstacles(translatesintothefactthatIdidn’treallyknowwhattodonext)IwoulddowhatIthoughtwascommonsenseorfitwithwhatIthoughtIknewingeneral.Thosearethetypeofprojectsthatmayhavehadtobedoneover,butdoneproperlytheSECONDtime.YouwillnotencountermanyobstaclesafterreadingthiseBookifanyatallbecauseItriedtoanticipateyourobstaclesbaseduponthoseIexperiencedearlyon.Betweenthewritteninstruction,stillphotographsinthemarginsofthisdocument,andtheexclusiveHow-Tovideolibrarytherewillnotbeaquestionunansweredregardingthishandcraftingprocess.

Ihavecoveredsomeofthehazardsonemightencounterwhilehandcraftingasolarpanelbutmylistisnotall-inclusive.Therearemanysituationsandcombinationsoffactorsthatcouldleadtoinjuriesoraccidentsandthus,anall-encompassinglistwouldrequiremultiplevolumes.Wetakeriskseveryday,someweareawareofwhileotherscatchuscompletelybysurprise.Ifyouarenewtotheexcitingfieldofphotovoltaics,youwillprobablynotstopwithonesolarpanel,youwillgoontobuildyourcustomarray.Yourparticipationinphotovoltaicsplacesyouincontactwithelectricitygeneratingequipment,powerstoragedevices,grounding,andsomebasicwiringtasks.Itwouldbeextremelywisetoexploremethodsforlearningbasicelectricaltheoryinasystematicandcomprehensiveapproach.Thereissomuchinformationonlinehowever,IfearthatsometimeswelearnjustenoughaboutatopictoposeathreattoourselvesifwebaseourresearchONLYthroughInternetsources.Booktitlesonresidentialelectricalsystems,solarpower,photovoltaics,andvirtuallyeveryaspectoftheelectricaltradecanberesearched,butyouhavetodothereading.WhatIstronglyrecommendistoenrollinaformaltrainingcourse,somethingyoutakeatyourownpace,perhapsanonlinecourse,ofthecalibersuchthatuponcompletionyoucouldpasstherelevantstatecontractortestportion.IamreferringtoMikeHoltEnterpriseswhereyoucanfindafulllineofcoursesrangingfromtopic-specifictocompleteelectricalcontractortestpreparation.Theyaregoodpeoplewhowillhelpyouachieveyoureducationgoalsanddon’thard-sellyouforanythingyoudon’twant.Theycanbefoundonlineatwww.MIKEHOLT.comorbyphoneat888-632-2633.(Unsolicitedendorsement)

Section#3

NowtoCreateYour“WIP”

WhataretheComponents?SolarCells-arethecoreelementofasolarpanelandtheseinstructionsapplytopolycrystalline,monocrystalline,ormulticrystalinesolarcellsuniversallyaseacharemechanicallysimilar.Theonlydifferenceofanykindyouwillexperienceduringassembly,whetheryouareworkingwithmono,poly,ormulti-crystallinesolarcellsisthelengthoftabbingwireusedtoconnectapairofthesolarcells.Inordertoconnecttwo

cellstogether,tabbingwireisusednotonlytophysicallybondthem,italsoconductstheexcitedelectrons(orcurrent)ontheirpaththroughthesolarpanel.

Whatelectronsyouask?Abriefrefresherorintroductionsasitwere,toexplainhowasolarcellgenerateselectricitywhenexposedtosunlightisinorder.Itallbeginsabout93-millionmilesawayontheSunwhichhasasurfacetemperatureofover5,000°Candacoretemperaturesome2,700timesthesurfacetemperature.Thecoreisintenselyradioactiveandproduceslight-energyknownasphotonsthathavenomass,onlyhugeamountsofenergyandmomentum.ItmaytakeamillionyearsforasinglephotontotravelfromtheSun’score,tothesurfacewhereitispropelledintoouterspacewithanapproximatespeedof670,000milesper-hour².Inabouteightminutesthephotonscoverthenearly93-millionmilesofspacetoreachEarthbutsomephotonswillbedeflectedinouter-space,theremaindermakecontactwiththeatmosphereandontotheplanet’ssurface.WhenthesunwarmsyourskinonasunnydayyouarefeelingthephotonsstrikeyourexposedskincreatingthewarmththatisthesourceformuchofthelifehereonEarth.Whenphotonsstrikeasolarcellasillustratedinthegraphiconthepreviouspage,theycanglanceoff,passthrough,ormakeaperpendicular,head-onimpact.Itistheperpendicularimpact,oranythingreasonablyclosetoitthatcreatestheexcitedelectronsleadingeventuallytoelectricitygeneration.Howcanthephotonsgenerateelectricity?Thisisacomplicatedscientificprincipleknownasthe“photovoltaiceffect”whichIwillbrieflydescribe,onlyforfamiliarity.Idosuggestfurtherreadingfromothersourcesforgreaterdetail.

Refertothecrosssectionofasolarcellonpage31,andnotethebluesurfaceofthesolarcellbeingstruckbythephotonsasindicatedbytheredarrows.Photonswilldooneofthreethingswhenstrikingasolarcell;theycanbounceoff,aglancingshotsotospeak,theycanpenetratecompletely,passingthroughthesolarcellandstrikingthegroundorwhateverisbehindthesolarmodule,orlastly,canpassintothesolarcellcausingthedesiredchainreactionthatthesolarcellsarepoisedtoperform.Asolarcellisreallyasandwichmadefromtwolayersofsiliconservingasthebread,andahollowareainthemiddlewheretheelectricityiscreated.Thelayersofsiliconontheirownwillsimplyallowthephotonstopassthroughandso,eachofthelayersistreatedwithachemical,or“doped”asitiscalledinreferencematerial.Inessencethesiliconwafersmustbetreatedinordertoprovidethemwith“semiconducting”properties.AccordingtoWhatis.techtarget.comasemiconductorisanymaterialusuallyasolidchemicalorcompoundthatcanconductelectricityundersomeconditionsbutnotothers.Asyouwillsee,thetwohalvesofoursiliconsandwichwilleachbe“doped”withadifferentagenttoachieveaspecificresult.Asyouprobablyguessed,manydopingagentsareusedtoachievedifferentresultsgivingsiliconabroadapplicabilityinelectronics.Let’sgetintohowthesiliconis“doped”inordertoworkastheydo…

Thesideofthesolarcellfacingthesunisthe“negative”sideofthecellandiscalled,“n-layer”,or“n-type”inourgraphic.Thisnegativesideofthesolarcellis“doped”withphosphorusbecauseattheatomiclevel,phosphorushastheuniquetraitofcontaininganextraelectroninitsatomicstructure.Thisextraelectronsitsatrestintheatomsstructureinsidethe“doped”solarcelluntilsunshine-propelledphotonscollidewiththe“n-layer”attheproperangle.Photonsarecomprisedofenergyandmomentumfromthesun’sradiationandthus,uponcollidingwiththe“n-layer”,theyreleasethestoredenergyandmomentumofwhichtheyaremade.Inresponsetobeingbombardedwiththeseballsofenergy,theatomsbecomeexcitedfromthesuddenandvibrantradiationenergyandtheextranegativelychargedelectronsgetbouncedfreefromthephosphorus-dopedN-layerofsilicon.Thechainreactionstartsonthesun-facingsideofthesolarcellbutoncetheelectronscontainedwithinthissectionbecomeexcited,brokenfreefromthevalencethatpreviouslyheldthem,theythenperformthenextrequiredstepwhichispassingthroughtheP/NJunction.Thisjunctionistheareainthecenterofoursandwichexampleanditisdepictedinourgraphicassimplyawhiteline.However,itisaone-waystreetfortheelectronsbecauseoncefree,theflowofelectronsaroundthecircuitbeginsandrepresentstheformationof“current”,orelectricity.TheimportanceoftheP-layershouldnotbeunderstatedbecausewithoutthevacantelectronsintheboron-dopedsiliconmolecules,therewouldbenoflowofelectrons,hence,noelectricalgeneration.Oncetheflowofelectronsisstarted,apathismadeforthemtotravelfromcelltocellbywayofthetabbingwirewhichwewilldiscussnext.Ididnotwanttomakethisanoverlytechnicaldiscussionbecauseoncewestarttalkingaboutatomicstructures;Isuspectsomereadersmayhaveskippedafewpagesinhopesofbypassingasciencelecture.Ithinkwecoveredthemostpressingsciencebehindthephotovoltaiceffectwhichyouareprobablyinterestedinifyouhavethisinyourlineofsighteitherprintedorelectronicversions.Technologyisadvancinginphotovoltaicsonaquesttoachievegreaterefficiency,thehighestpossiblerateofconversionofsunlightintoelectricity.Experimentaldopingagentshave

showninterestingpromiseandthus,inordertofollowthedevelopments,mySolarTechDIYFacebookblogwillincludediscussionsaboutemergingtechnologiesinthefieldofPhotovoltaics.

Uponclosevisualinspectionyouwillnoticethatsolarcellslookdifferent,seeminglyallofthemhavesomedifferentvariationoncolorandlinepatterns,irregularshapesvisibleonthesurfacealthough,somedon’t,andsomearesolidincolor.Wetouchedonthereasonforthecolor differences earlier when discussing the origins of the monocrystalline versespolycrystalline solar cells. If you recall, monocrystalline solar cells are cut from a singlemonocrystalline silicon ingot as seen in the pagemargin to the left.The ingots are grownthrough theCzochralskiprocess,amethodofcreating largesinglecrystal ingots foruse insemiconducting. The silicon required for this process is very clean and pure and so theresultingsolarcellscutaswafersfromtheseingotswillhaveaconsistentcoloringshadeandappearance.

Contrasttheconsistentappearanceofmonocrystallinesolarcellswiththehaphazardandrandompatternsdiscernableonpolycrystallinesolarcells,thedifferenceisobviousinthephotoabove.

Inlightofthevisualdifference,itiseasytodistinguishbetweenthetwotypes.Therandompatternsofthepolycrystallinecomefromthemoltenoriginsthatmixedseveralsmallercrystalsorevencrystalliteswhichuponcoolingretainedsomeoftheirindividualityinappearanceanyhow.Whiletheresultingpolycrystallineingotcanbeasmuchas99.9%pure,thesolarcellscutfromtheseingotsareslightlylesscapablethantheirmonocrystallinecousins.Onevisualcueconsistentwithalltypesofsolarcellsisthepresenceoftinywiresrunninghorizontallyacrossthesun-facingsideaswellasapair,orevenatrioofwhitebandsrunningperpendiculartothetinywires.Asseeninthephotoaboveandtotheleft,thosewhitebandsareknownas“busbars”ontowhichyouwouldsolderthetabbingwirethatnotonlyconnectsthesolarcellstogether,butalsoservesastheconduitfortheflowingelectrons.Thebusbarsarealsoontheback,orpositivesideofthesolarcells,incertainversionsthe“bar”isreplacedbysmall“tabs”.Whetherbusbarorbustab,theyfunctionthesameandarejoinedtothesolarcellinthesameway.Thetinywiresthatappearasthinwhitelinesrunninghorizontallyacrossthenegative,sun-facingsideofthesolarcellarecalled“fingers”,andareaddedtothesiliconwaferduringthemanufacturingprocess.Theyarenecessaryfortheefficientmovementofelectronsthroughtheentiresurfacethesolarcelloncethesunisoutandspewingphotonsforthesolarcellstoabsorb.Toendtheconversationaboutsolarcells,I

wanttotouchonthecommonbluecolorpresentinagreatmanyversionsandtypesofsolarcells.ThetechnicaldetailsarebeyondthescopeofthiseBookbutsufficeittosaythatasiliconnitrideantireflectivecoatingproducesthatbluetintcommoninsolarcells.Thesiliconnitrideantireflectivecoatingispresenttooptimizespecificwavelengthsonthecolorspectrum,whichhelpscaptureasmuchlight-energyaspossible.

TabbingWire-isalsoknownasInterconnectWireanditprovidestwofunctions.First,itservestophysicallyjointhesolarcellstogetherthusprovidingstructureandsturdiness.Second,itprovidesthepathandconveyancefortheelectronssetinmotiononcephotonsbeginknockingthemintomotionwithinthesolarcell.Differentsizedtabbingwireisavailableandforthistypeofproject,Irecommend(.15x2mm)whichisanidealwidthformostofthesolarcelltypeswewillbeworkingwith.

Tabbingwireismadeoutofflatcopperwirethatisthencoatedwithtin,oratinalloythatwhenheatedbecomesliquidandhelpsthewirebondtothebusbar.Sometabbingwiresuppliersmaysuggestthatuseofrosincoresolderisunnecessaryduetothepresenceofthetincoatingoverthetabbingwire.Disregardsuchadvicesincethesolderguntipneedsrosincoresolderonitsimplytoconveyheat,itdoesn’tmatterifthetabbingwireispre-tinned.Whentheheatedsoldertip(thatislightlycoatedwithrosincoresolder)touchesthetabbingwire,thetincoatingliquefies.Heat,liquidtin,andacleanbusbarmakeagreatmatingsurfacefortabbingwiretobondontoasolarcell.Whenpreparingtosoldertabbingwire,pre-heatthesoldergunandapplyjustasmalldabofrosincoresolderwitheachapplicationofatabbingwire.Thiswillensureconsistentheatforeachtabbingwireportion,theresultbeingauniformperformancethroughouttheentirestringofsolarcells.

Heatdiscussionagain-thetemperatureinsideasolarpanelduringsummermonthscaneasilyexceed175°asIhavepersonallymeasured.Youwillexperiencehowquicklysolarcellsnotonlycollect,butretainheatasyougingerlyhandlenewlycompletedsolarcell“pairs”whiletestingtheminfullsun.Ittakesbutafewmomentstothoroughlytesta“pair”becauseyouareonlymeasuringvolts,andamps,requiringoneswitchturnandsimultaneouscableswap.Whensuccessful(whichwillbeincreasinglymoreconsistentasyoupractice,buthopefullyrightoffthebat)thereistheobligatoryself-celebration,acouplefist-pumps,anappreciativelooktowardstheheavens,followedbycurseswhenyouburnallofthefleshmakingcontactwiththesolarcellsyouwerejustfist-pumpingabout.Nowmultiplytheheat

bywhatevernumberoflittlecousin-solarcellsthatwillbeencapsulatedalongwiththetwothatjustcharredyourfleshinasolarpanel,underglass,perpendiculartothesun,alldaywhileyouarehunkereddownintherootcellarhopingthereisn’tanythingelsedowntheresimilarlyescapingtheheat.Unfortunatelytheheathasadampeningeffectonsolarpanelperformancebecauseofsomecomplicatedphenomenonthatexceedsthescopeofthismanual.Whilecomplicated,Icanprovideanoverviewingenerictermsonthenextcouplepages.

Solarpanelsgenerateelectricitybasicallybyreactingtostimulifromanexternalsource,thesun.Specifically,photonsfromthesunthatcollidewithourphosphorus-dopedN-layerofsiliconwafer,thetophalfofoursiliconsandwichexample.Photonsarecomprisedofenergyandthus,whentheycollidewithatomsinsidethesolarcellthathaveexcesselectrons,theyknocktheelectronslose.Thedislodgedelectronconductsafranticsearchforanewatomtocallhome,onethatisinneedofanelectron.Thisprocessisrepeatedmanymillionsoftimesoverwithintheconfinesofasolarcell.FreedelectronsbounceanddancedownthroughtheP/NJunctioninsideasolarcellandindoingsoarecreatetheelectricityattributedtosolarcells.

Vibrationiscreatedwhenphotonsstrikeatomsinsideasolarcell,butthereisanothersourceofvibration,heat.Mostofushaveseenwaterboil;wehaveseenevidenceofheatmakingmoleculesmovesofastthattheresultingcollisionsarevisibletothenakedeyeintheformofchurningwater.Solarpanelsneedtobeperpendiculartothesunforthebestefficiencywhichtranslatestoasignificantexposuretohighinternaltemperatures.Thinkofyoursunglassessittingonthedashboardwhileyoushopped,evenforthirtyminutes,thoseglassesaregoingtobetoohottoimmediatelyputonifthesunwasshiningdirectlyonthem.Asolarpanelthatismountedperpendiculartothesunandisfilledwithdarkcoloredsolarcellswillgeneratehighinternaltemperatures.Thebyproductofthisintenseheatisvibrationatthemolecularlevel,notvisibleliketheboilingwatermolecules,butpresentnonetheless.

Addtotheequationtriple-digitambientairtemperaturesandtheresultingtemperatureinsidethesolarpanelbecomesaproblem.Excessivevibrationwithinthesolarcellenvironment

causesaslowdownofelectronmovementastheymustnowstruggleagainstmoremovementthannormal.ThecumulativeeffectofthisaddedvibrationfromthevarioussourcesisthattheelectronsgetboggeddownandhavedifficultymovingfreelywithintheP/NJunction.Ifmovementisrestrictedtothepointwherebytheelectronscannotjointheflow,orcurrent,theydieouthavingexpendedenergyuselesslywhileattemptingtojointheflowofelectricity.Theheatmaynotstoptheflowentirelybutthedeclineinpoweroutputwillbenoticeable.

Statedanotherway,priortothesunraysstrikingasolarcellitisinastateofresttoincludetheelectronscontainedwithinthelayersofsiliconthatcompriseoursolarcell.Theelectronsatrestrepresentalow-energyexistenceatthetimeandthesun’sphotonsrepresenthigh-energy.Withoutoversimplifyingtheprocess,thedifferencebetweenenergylevelswhiletheelectronsareatrest,andtheenergycontainedwithintheinboundphotons,representtheelectricalpotentialwithinagivensolarcell.Itseemsunnaturalthatahot,desertenvironmentwithalotofsunshinemaynotproduceasmuchenergyasaclear,cold,butsunnydayinanenvironmentotherthanadesertbutasdescribeditistrue.Thisbringsuptheidealtimetosegueintoabriefconversationabouthowsolarpanelsareratedforperformanceoroutput.Theremustbeauniformstandardforestablishingthewattageperformanceonsolarmodules(anothernameforsolarpanels)andso,foruniformity,allsolarmodulesaretestedbythemanufacturersataconsistentairtemperatureof25°C/77°Ftosimulateexteriorconditions.Thenthemoduleorsolarcellisexposedtolampspowerfulenoughtomimicthe1,000Wattspermetersquared(1,000W/m²)typicalofnoontimesunandoutputismeasured.Manufacturedsolarmoduleshaveratingscalled“temperaturecoefficientofpower”thattellsthereaderhoweach1°Ctemperatureincreasewillnegativelyaffecttheperformanceofagivensolarmodule,forexample,thenumbermightbe0.5%.Thefirststepinthisprocessistoestablishthedifferencebetweenideallaboratorytestconditionsversesrealworldconditionswherethesolarmoduleisdeployed.Forexample,ifasolarmodulewasbeingobservedfortemperaturerelatedperformanceissuesat85°C/185°F,itwouldrepresent60°COVERthebaselineCelsiustestingfigureof25°C.Toquantifythedeclineinoutputweneedonlymultiply60°Cbythetemperaturecoefficientofpowerratingof0.5%toarriveat0.3(60x0.5=0.3).Thenextstepistomultiply0.3bytheDesignerWattageprovidedbythemanufacturer(100Wattsforthisexample)toarriveatthenumberofWattsthatwillNOTbegeneratedbecauseofexcessiveheat.

Thepotentiallossofgeneratingcapacityataninternaltemperatureof185°Fis30Watts,or30%oftotalgeneratingcapacity.

Ifwearelookingforanumbervaluethatreflectsapercentagewemustconvertouranswerintotheproperformat.Rememberfrommathlessonsthatinordertomultiplyanynumberbyapercentage,youmustfirstreducethepercentageintoawholenumber,onethatcanbemultiplied.Simplymovingthedecimalpointtotheleftbytwospacesistheequivalentofhavingmultipliedthepercentagenumberby1/100,therequiredstepinmathematicstoconvertapercentageintoawholenumber.Ournewmathematicallyacceptablenumberforthiscalculationis0.3(zerodoesn’tneedtobethere,justavisualplaceholdersoattentionisdrawntothedecimalpoint).

Ifyouaregoodatperformingmatchcalculationsinyourhead,the100-Wattsolarpanelisidealtoworkwithforthisexamplesinceweneedtofindanumericvalueforthe30%performancedeclinewehaveidentifiedduetoexcessheat.Ifwemultiply30%bythe“designerwattage”of100Watts,wewillrevealatthequantityofwattsthatwillNOTbegeneratedduetotheheat.Whenwemultiplythe100-Wattsolarpanelbythetemperaturecoefficientpowerratingnumberof0.3,itequals30-Watts,sotheexcessiveheatwilldeprivethesolarpanelof30-Wattsofgeneratingcapacity.

ThelastthingIwantyoutowalkawaythinkingisthatsolarmodules(solarpanels)uponyourroofwillsimplygettoohottoworkatall.ThisisNOTthecasebutknowledgeispower,andbeingawarethatheathasaneffectonsolarpanelpoweroutputcanassistyouintakingtheappropriatestepstomitigatesurpriseheatwaves.Simplyknowingheatreducestheamountofelectricityyoursolararraycangathershouldprepareyouforthiseventualitybecausethereareafewstepstotake.Firstandforemostistoconservetheexistingbatterypowerwhendaysareexceptionallyhot.Thismightprovedifficultinlightofthecomfortelectricfansbringtoahotroom,butifnotconservingfanuse,lookelsewherefordevicesthatcanaffordtobeshutdownuntilthenextdayinordertoconservepower.Addingsolarpanelstocompensateisoneoptionespeciallyifheatisaregularpresencewherepanelsaredeployed.

BusWire-isverysimilartotabbingwirewiththesamestructureandfunction;itissimplymuchheaviergauge.BuswirecarriesthecurrentgeneratedbythesolarcellSTRINGSanddeliversittothejunctionbox.Therewillalwaysbetwobuswireleadscomingoutofasolarpanel,onepositive,theothernegative,whichthenconnecttothecorrespondingoutputleadswithinthejunctionbox.InadditiontocarryingcurrentthebuswireprovidesinfrastructurefortheSTRINGSwithinagivensolarpaneluntilsuchtimeasencapsulationpermanentlysecurestheinternalcomponents.Thetypicalsolarpanelorsolarmoduleuponcloseinspectionhasfourrowsofsolarcellsrunningfromthebottomofthesolarmodule,tothetop.Ifyoulookattheendsofthefourrows,youwillseehowtherowsareconnectedtoeachotheratbothendsofthesolarpanel,Ihaveattachedaphotototheleft.Thephotodepictsonlytworowswhileatypicalsolarmodulewouldhavefourbutthephotoservesanexcellentexampleofwhatisknownasan“endrun”sinceyouguessedright,anditistheendofarunofsolarcells.

Whenyougettothestepwherebuswireisbeingused,thesolarmoduleisnearlycompleted.Youwillhaveutilizedtabbingwiretoconnecttheindividualsolarcells,andnowthebuswireisusedtoconnecttherows,orSTRINGSofsolarcellsphysicallytogether,butalsotoprovideaconduitthroughwhichtheelectrons(current)canflownotbetweensolarcellsasthetabbingwireprovides,butbetweenROWSofsolarcells.Theflowofcurrentfollowsapatharoundtherows,veryorderly,andthebusribbonisthepaththecurrentflowsthroughasitmakesitswayintothebatterybank.Wewillcovermoreonthespecificsofsolderingwithbuswirebutyouwillfinditoneoftheeasiestelementstoworkwithduetoitssize,sturdiness,andrigidity.Inadditiontoconnectingtherowsofsolarcellsinsidethestructureofthesolarmodule,onebusribbonforeach,thepositiveandnegativeleadsthatmustbeaccessibleonthebackofthesolarmodule.Itistheseleadsmadefrombusribbonthatphysicallyconnecteachsolarmoduletothephotovoltaiccablesthatallowforquickconnectingtoothersolarmodules,ortheleadsaretiedinto“projectboxes”orjunctionboxeswhereothertypesofcablingmaybeconnectedifnotutilizingspecialphotovoltaicconnectors.

RosinFlux-inapen,likeamagicmarker,usedtocoatthesilverBUSBARSonbothsidesofthesolarcellpriortosolderingthetabbingwiretothesolarcell.Youmayuseotherforms

offluxsuchasthegelthatcanbebrushedon,butthepenvariantissoefficientthatitishardtojustifyNOTusingaRosinFluxPenasdepictedonthe“tools”chapter.AccordingtoWikipedia,theword“flux”isderivedfromtheLatinword,“fluxus”andtranslatesintotheword“flow”intheEnglishlanguage,andindeedthatisoneofthefunctionsthefluxperformsafteritisappliedtotheBUSBAR.Infact,thefluxcleansoffanyimpuritiesthatmightotherwisehaveanegativeeffectonthebondbetweenthesolarcellandthetabbingBUSBAR.Additionally,thefluxaidsintheprocessofheattransferencefromthesolderingguntip,tothetabbingwireyouaresoldering.Itisnon-negotiable,youMUSTuseafluxofsometypeoryouwillhaveaverydifficulttimeachievingasolderthatismechanicallysoundandwillconductelectricity.

Section#4

TheHand-CraftingProcess:Nowforthehands-on,andifthisisyourfirstproject,takeyourtime,thisisnotaraceagainsttheclock.Thetasksthatseemunfamiliarnowwillberoutineandsimpleaftera

fewrepetitions.

STEP1-Creatingthe“Pairs”Mostofyouhaveheardthequestion,“HowdoyoueatandElephant?”,andhopefullyyourecalltheanswerbecauseitappliestothemethodforhandcraftingasolarmodule.Theanswertotheriddleis,“Onefork-fullatatime”,andinsolarpanelterminology,one“pair”atatime.Thestartingpointiscreatingthefirst“pair”ofsolarcells,whichleadstomore“pairs”,untilyouhavepairedthenumberofsolarcellsthatmatchthedesiredwattagefortheparticularsolarpanelyouarehandcrafting.Ifyouhavedecidedonbuildinga72Wattsolarpanelforexample,itwillrequire36-solarcellsthatwillrequire“pairing”(basedupon36polycrystalline3”x6”solarcells).Dividingthenumberofsolarcellsinour36-cellprojectby2(sincewearegoingtobemaking“pairs”),weknowthatwewillneedtomake18“pairs”ofsolarcellsinordertoarriveatthe36-solarcellsolarmodule.

1. Preparingthefirstsolarcell-Thestartingpointforpairingsolarcellsistopreparethefirstsolarcelltobejoinedbysolderingtabbingwireontothefront,or“negative”side(thesidethatfacesthesun)ofthesolarcell.

2. ApplicationofRosinFlux-Beforesoldering,opentheFluxPenandperformthe“wetting”ofthepentipbypushingthetipdownontoapieceofcardboard.Thiswillpushthepentipbackupintothepencasingwhichallowsittobecomesaturatedwiththeliquidfluxmaterial.Oncemoist,simplydrawlightlyoverthebusbaronthesideofthesolarcellthatwillbesolderedfirst.Thefluxmaterialdoesnotneedtobeflowingovertheboundariesofthebusbar,youareonlyplacingasmallamount,enoughtocoatthesurface,anythingmoreandyouwillhaveamessonyourhands.Usejustenoughtolightlycoverthewhiteportionofthebusbar,asmallamountofover-applicationisacceptable,butitneedstobeaverysmallamount.

3. Determinethelengthofthetabbingwire(seethedemonstrationvideobyscanningthebarcodeonthepreviouspage)thatwillaccomplishthetaskofcompletelycoveringthewhitebusbaronthefront,negativesideofthesolarcell.Thebusbarwillrunfromthetopofthecell,allthewaytothebottomandwillbeequalinmeasurementtothatofthesolarcell.Ifyouareusinga3”inchby6”inchpolycrystallinesolarcellasfeaturedinthemarginphoto,thetabbingwirewillsimplyneedtobetwiceaslongasthebusbar.Whytwiceaslong?Remember,thewaywesolderthetabbingwireisfromthefront,negativesideofthefirstsolarcell,underneaththenextsolarcellinthepair.Inadditiontobeingdoublethelength,anadditionalamountneedstobepresenttoaccommodateastressreliefpointwhichwillgiveslacktothesolarcellstoexpandorcontractcommensuratewiththeinternaltemperature.TheYouTube“How-To”videodemonstrateshowtodeterminethelengthoftabbingwire

needed.Therefore,thefirstsolarcellofeverypairwillhaveanoverhangingpairoftabbingwiresonceyoucompletetheinitialsolderingontothesun-facingsideofthesolarcell.Notethelastphotoonthepreviouspage;itdepictstheoverhangneededtoconnectwiththenextcellinline.

NOTE:SomeYouTubevideotutorialsthatdepictsolarcellsbeingpreparedforsolderingbyscuffingthebusbarsurfaceswithsandpaperorapencileraser.DON’TdothisUNLESStherewasaninitialfailureofaspecificportionofthebusbartogripthetabbingwire.FailuremeansyouhaveattemptedtosoldertabbingwireontosomeportionorallofabusbarbutitwillNOTstayaffixedtothebusbar.Occasionallyyouwillexperiencethisanditisn’tbecausethebusbarisdefective,youmayhaveomittedthestepofapplyingtheRosinFluxandsothetwosurfacesarehavingdifficultybonding.Therefore,BEFOREdoinganythingelsewhenencounteringanobstacle,verifythatyouhaveappliedtheRosinFluxtothebusbar.Ifyoudoresorttoattemptingarepair,anyscuffingorerasingonthebusbarmustbedonewithaverydelicatetouchandwithgentlepressure.YouaremerelytryingtoremoveimpuritiesbeforereapplyingathincoatofRosinFlux,thenattemptingtocompletethesolder.Typicallythiswouldbetheendofthelineforthiscellinquestionbecausewithoutallpre-designatedbusbarmakingexcellentcontact,thecellwouldbecompromised.Remember,asolarmodule(solarpanel)isonlyaspotentasitsweakestindividualsolarcell.Forexample,ifusingthepolycrystallinesolarcellspicturedonthepreviouspage,typicaloutputforsuchcellsis0.5Voltsand3.75Amps.Asolarmodulecontaining36-solarcellsofthisratingwouldthenproduce18-Volts,multipliedbytheamperage(averageof3.75Amps)givesusthe“designerwatts”forsuchapanel.Basedonthemathwewouldhaveasolarpanelcapableofproducing67.5Wattsunderidealconditions.However,ifoneindividualsolarcelliscompromisedbyacontactpoint(busbar)notcontributingtoelectronflow,theperformanceofthecellwillbeseverelycompromised.Forthesakeofexample,letussaythatoneoutofthesixbustabsonthebackorPOSITIVEsideofasolarcellisdefectiveandyouareunabletoachieveasolder.YouarealmostdonewiththisverylastSTRINGofyourfirstsolarpanel,andyouaskyourself,howbadcanoncelittledefecthaveontheWHOLEsolarpanel?ALOTistheanswer.Likeachainthatisonlyasstrongasitsweakestlink,theENTIREsolarpanelwillperformatthelevelofyouronedefectivesolarcell.Soifwedothemath,onecontactpointoutofsixmeansthateachpointcouldcarry16.6%oftheelectronflow(current)andifmissing,thatmuchoftheflowwouldbeidlebecausethe“bridge”iswashedout.Ifwemultiplytheaveragecurrent,oramperageexpectedfromourexamplesolarcellsof3.75Amps,timesthe16.6%outputdeficitresultingfromsaidmissingbridge,wedroptheENTIREsolarpaneltoareducednumberof3.15Amps.Againdoingthemath,multiplyingourrevisedsolarpanelamperagetothenewfigure,assumingthevoltagewillremainthesameforourdefectivesolarcell(itwouldn’tinreallife)andsowewillusetheestablishedsolarpaneltotalof18-Volts.Becauseofasingleshoddycontactpoint,apreviouslyacceptableperformancelevelof67.5designerwattsisreducedto56.7,andwhileitisonly10-Watts,itistheprincipleofthethingbecausethatlossistheresultofpoordecisionmakinginamomentofhastethatyouwillbepayingonforaverylongtime.Itismuchbettertojustswapoutthesolarcellbecauseitdoeshappenfromtime-to-time,notperhapsfrombeingdefectiveasIlabeledtheexample,buttherearemany

factorsthatcontributetoasolderobstacle.Temperaturefluctuations,impuritiesonsoldertip,soldersurfaces,moisturepresent,andon,soitisnotautomaticallygoingtobeafaultycell.

4.Layoutasolarcellonyourworksurfacethatwediscussedearlyon.WeighitdownontheouteredgesasinthephotototheleftafterGENTLYbrushingawayanydustparticlesfromthesolarcellsurface.

5.Preparethesoldergun/ironbycleaningthetipusingaspongesoakedindistilledwater.Ifyouhaveanelectronicsspecialtystore,spongesaresoldspecificallyforthispurposewithgrovesforcleaningaroundthetips.Manysolderstandshavespongesbuilt-inforconvenience.Cleaningthetiprequiresthesolderingguntobepluggedin,andthetriggerbeingpulledonthegunmodelsbecausetheyneedtobehotduringthecleaningprocess.Itwillsteamandsizzle,whichisnormal,andyourpurposeistoremovetheoldsolderandanyoxidationsincelastused.Finally,youneedtoperformastepknownas“tinning”ofthesoldertipwhichissimplyapplyingathincoatingoftherosincoresolderaroundthetipwhilethetipisclean,andhot.ItisaVERYgoodideatorepeatthisprocessfrequently,perhapsasoftenasaftereachpairofcellsthatyoumatetokeepthesoldercleanandsmooth.GoodsoldertipmaintenancepracticesWILLresultincleaner,smoother,andelectricallyconducivecontacts.Ifyoudon’tpracticeconsistentmaintenancehabitsyouwillnoticeanincreasinglevelofdifficultyachieving

cleantabbingwireacrossthesolarcelltopsthatarevisiblyobvious,evidentbylumpyuneventabbingwire.Thesolderinggunisprobablyhavingdifficultymaintainingthetemperatureconnectivityneededtobondtheliquefiedtinsurroundingthetabbingwiretothebusbar.Itthenleavesbehindanuneventrailofhalfmeltedclumpsofsolderwhichleavesabigquestionmarkoverthequalityofthesolderjoint.Beforeyoubegintosolder,ensureastandisavailableforthesolderingironifthisisyourtoolofchoiceandhavetheexhaustordesktopfansturnedonandpointedsuchthatanyfumeswouldbesweptawayfromyourface.

6.Lighting-needstobeonandsufficientinbrightnesstoseeyourworkclearly.Thiswouldbethetimetoputyourvisionenhancementdeviceonsuchaswasdescribedveryearlyon.

7.TabbingWirePreparationandPlacement-Iexplainedhowtoestablishthelengthofstripneededforanysizesolarcellearlierbutrecallthatthestripneedstodoublethelengthofthebusbaronthefaceofthefirstcelltobesolderedplusasmallexpansionfoldinthecenter.Youcanpre-cutenoughstripsfortheentireprojectorjustdoafewatatime,itisyourchoice,buteitherwayatemplateisagreattooltoensureconsistenttabbingstripsizeeverytime.Itcanbeapieceofwire,coathanger,evencardboard,firstmeasuredandthencuttotheexactsizeyouneed.Thisrigid,durableitemthenservesasareliableyardstickagainstwhichtomeasureandcutthetotalnumberofstripsneeded.Ifusingsolarcellsthathavetwobusbars,andifthepanelwillbecomprisedof36-cells,thenyouknowinadvancethat72-stripswillberequired.

Heatconversation-again!Aswehavediscussedalready,heatisamajorfactorinsidetheconfinesofthesolarmodule.SolarcellssitbehindglassorPlexiglas,intheprimesolarradiationhoursoftheday,sortoflikeyousittinginsideyourcarinaparkinglotwiththewindowsrolledupsomewherehot,likeDeathValley.Weknowforafactthatheatcausesmaterialstoexpand,forexample,lookatanyconcretedrivewayorsidewalkandnotetheexpansionjoints.Youhavebeensteppingonthemyourentirelifeperhapsnotknowingwhysidewalksallseemtohaveuniformlyspacedperpendiculargrooves,wellnowyouknowtheyareexpansionjoints.Failuretoallowforsomeminormovementwouldleadtocrackingoftheconcreteslabandsimilarly,weneedtomakesomeaccommodationtothetabbingwire.Theextremeheatduringthedayiscounteredbyextremecoldinsomeplacesandnotonlyatnight.Thetemperaturedifferencesarelikelytocausemovementofthesolarcellsinsideyoursolarpanel,perhapsonlyamillimeterorless,butenoughthatifnoslackhasbeenmadeavailableonthetabbingwirethesolarcellmayfracture.Thewayweaccommodatethetabbingwireforthesevariationsistocreateabendinthetabbingwireatthemid-pointsothereissparematerialthatcanexpandduringextremeheatwithoutplacingstressonanyparticulartabbingwiresection.ThephotoonthepreviouspagedepictsamethodIutilizeforprovidingtheexpansionslackrequiredfortabbingwire,nottheonlymethodbutoneIhaveusedmanyhundredsoftimessuccessfully.Itinvolvescreatingabendinthetabbingwirejustpasttheedgeofthenegativeorsun-facingsideofthesolarcelltoallowforexpansionshouldthesolarcellsexpandorcontractinreactiontotemperaturefluctuations.Thefollowingstepswillachievetheproperbendlocationonyourtabbingwirefortheexpansionrelief:

7a)Establishtheexactlengthofthebusbaronthesolarcell.ThatcombinationsquareIsuggestedyouaddtothetoolkitisidealforthistask.Youcanusethistooltosafelyandpreciselymeasurethebusbarsettingthesolarcellaspicturedtotheleft.Youcanthenslidetherulerportionofthetooloutuntilitisjustslightlyoverofthesolarcelledge.Tightentheadjustmentnutonceyouhavetherulersetintherightplacesothecombinationsquarecannowbeusedasanexacttemplateforwherethebendneedstobemadeinthetabbingwirestrip.Takeastripoftabbingwire,layitontotherulersurfaceandpushitasfarforwardasthestopperwillallow.Don’tapplyforce;youareonlytryingtoalignthetabbingwirestripagainsttheedgeoftherulerwhereitmeetsthecombinationsquarehandle.Remember,youaremeasuringwheretomakethebend,sonowtomakethat

bend,yousimplypushdownwardontheportionofthetabbingwirestripthatishangingovertheedgeoftheruler.Youwillhavecreatedthe“crease”neededtomakeacleanbend,whichyouwillnowdo,allthewayinhalf.Youwillnoticethatthesidesareuneveninlength,withgoodreason.Yousee,ifoneweretosimplyfoldatabbingwirestripinhalf,theresultingstripoftabbingwirewouldNOTfitacrossthefaceofthesolarcellthatissun-facing,ortheNEGATIVEside.WhattheywouldendupwithisthebendsittingonTOPofthesolarcellinsteadofbetweentwosolarcellsthatarejoinedtogether.Thecreasewouldneedtobepresseddownbythehotsoldertipinorderforthetabbingwirestriptorestsmoothlyontothebusbar.Failuretogetittolayflatonthesolarcellwouldlikelyrenderthecelluselessandthepressureneededtoflattenthecreasewiththehotsoldertipwouldcertainlyfracturethefragilesolarcell.Evenifitwaspossibletosmoothoutthecreaseformerlymarkingthemidpointofthetabbingwirestrip,indoingsotheexpansionreliefnowthereisnoexpansionreliefforthesolarcellswhichmayformmicro-fracturesfromtheresultingstressesshouldtemperaturesextremesofeithertypeappear.ItisbesttofollowwhatmygrandfatherusedtotellmeoverandoverwhichIdidnotunderstanduntilmymid-twenties,“measuretwicesoyouonlyhavetocutonce”.Youcould“eyeball”it,butyouwillbewastinganawfulamountoftimeandmoneyonbrokencellsbecauseyouwillmissmorethanhit.

Youmayhaveadifferentmethodforestablishingsuchmeasurementsandifso,pleasefeelfreetocontinuewhatworksbestforyou.Theimportantpointtotakeawayfromallofthisistofindatemplatesoyoucancreateconsistenttabbingwirestripsforthewholeproject.Itisanimportantissuebecausethehabitsformedearlywillbecomethefoundationforallofyourfuturehandcraftingprojectsofthissort.WhenthemeasurementistakenfortheTOTALlengthofthetabbingwirestrip,westartatthetipofthebusbaronthetopsun-facingside,totheundersideofthenext

solarcellinthepairwearecreating.Thereforewhendeterminingthelengthofstrips,thelengthofthebusbarsonthetopsandbottomsofthesolarcellneedtobeconsidered.IfthebusbarrunsthefulllengthofboththefrontANDbacksidesofthesolarcell,doublingthebusbarmeasurementandadding¼inchforthebendandcellpairgapwillsuffice.Somebusbarsdonotextendthefulllengthofthebackside;rathertheyappearassmallsquares.Thesebustabsperformthesamefunction;theyaresimplysmallerandassuchrequirelesstimeandefforttoworkwith.Themid-pointwherewewouldnaturallywanttomakeourcreaseisoflittlerelevanceinthiscaseeventhoughitmakessensetosimplymakeafoldinthemiddle.Thebustabsfallwell-shortoftheedgeofthecellandthus,allofthetabbingwireprotrudingafterthefinalsolderhasbeenmadeisservingtothrowoffthemid-pointofthestrip.Yourbendwillbetheonewementionedthatendsuponthetopofthecellputtingyourcellatrisk.

7b)Nowthatthebend-pointismarked,simplybendthestripoftabbingwireatthespotuntilthetwohalvesaretouching.Thisisagoodopportunitytostraightenthewireasmuchasyoucanusearulerasaguideperhaps.

7c)Pullthetwotabbingwirestriphalvesapartgentlyuntilthewiresarereasonablystraightandlevel.Placethestriponyourworksurfaceandgentlypullthetwohalvesapartwhichwillcausethecreasetoshrink.Refertothepictureonthenextpage.Oncethestripisstraightandyouhavepulledtautenoughtodropthecreasetoabout3mmofftheworksurface.Thiswillleaveasmallarchoftabbingwiretogive-wayshouldexpansionoccurinextremeheat.Likewise,shouldfreezingweatheroccur,thearchwillallowforthecellstomoveclosertogetherasthearchisidealforaccordiontypemovement.

8.ApplyRosinFluxtothebusbarpendingapplicationoftabbingwire.Performthe“wetting”processwiththepenbyremovingthecapandthenpushingthefelt-tipdown

ontoacleancardboardsurface.Thissaturatesthetipandensuresplentyofliquidispresenttodepositontothebusbar.Lightlyapplyacoatingtoeachbusbar,thickenoughtoreflectasheenthatwouldbeobvioustothenakedeye,butnotenoughforliquidtorunoutsidetheboundariesofthebusbar.YoudefinitelydoNOTwanttoapplythesamedownwardpressureontheRosinFluxpenduringapplicationtothebusbar;infactthetipshouldnotbemakingenoughdownwardpressureonthebusbartomovethetipupwardsintothepencylinderasthewettingprocesscallsfor.Justanice,soft,swipingmotionthatleavesasmooth,neattrailofliquidmaterial.Itisfineifthematerialappearstodryoutinthetimeittakesyoutoalignthetabbingwirestrip,aslongasyousolderwithinthehour,itwillmaintaintheintegrity.

9.Placecushionedweightsovertwocornersofthesolarcelltobesolderedtopreventslidingofthecellwhilebeingsoldered.Theweightsshouldbeplacedsuchthattheyarehalfonthecell,halfontheworksurface,sotherubbergasketmaterialservingasacushionwillprovidethegripneededtopreventsliding.Refertothephotoonthenextpage.

10.Applythetabbingwirestripoverthebusbar,onlyoneatatime,andgetitalignedwiththebusbarsothatthereisnoneofthewhitebusbarmaterialshowingaroundthesidesofthetabbingwire.Tabbingwireisapttosquirmandtwisteverywhereexceptwhereyouneedittostay.Itismalleableandsoyoucanveryeffectivelystraightenittoeliminateanycurvaturethatiscausingthedifficulty.Onceyouhaveitreasonablystraightandalignedwiththebusbar,youmayusesmallweightstoholdthetabbingwiredownjustpriortosoldering.Ideallythetabbingwirewillberestingneatlyonthebusbarpriortoapplyingtheheatedsolderingtipbecausethereisnotimeformakingplacementadjustmentswhilethesoldertipishotandmakingcontact.Youneedthattabbingwirestriptositstillwhilethesoldertipmovesacrossitssurface.Whileyouarenotapplyingdownwardpressure,thereisstillenoughfrictionfromthesolderingtiptocausemovementofthetabbingwire,averyfrustratingoccurrencetoreacttowhileholdingadangerouslyhotsolderingtip,whichcanbemademorefrustratingifthesolderhasbondedthetabbingwiretothebusbarcrookedly.Thiswouldrequirethetabbingwirestriptoberemovedandrepositioned,allthewhileplacingthecellinjeopardyofdamagefromtherepeatedexposuretohandlingandtohighheat.Therefore,itisimportanttohavethetabbingwirestrippositionedproperlybeforeapplyingheat.Theresultwillbeasmoothsolderingexperienceandgoodelectricalcontact.Itisalsoadvisabletoplaceaweightonthetabbingwireportionthathangsoverthecell,thepartthatwillbesolderedtotheundersideofthenextsolarcell.Thiswillaidinthecontinuedalignmentwhilesoldering.

11.Preparethesoldertipbyperformingthe“tinning”processbycleaningthehotsoldertiponthedistilledwatersoakedspongeandthenapplyingacoatingofsoldertothestill-hotsoldertip.Remember,thiswillallowforproperheattransferfromthesoldertipandintothemetalsbeingjoined,inourcase,tabbingwiretobusbar.Ifusingasolderingiron,pluggingitiswillresultinitheating,andstayinghot,soastandMUSTbeusedtokeepthatdangeroustipoutofharm’sway.Ifusingasolderinggun,youmustactivateitbydepressingthetriggerwhichwillheatthetipveryquickly.

12.Keepthetriggerdepressedthroughoutthetaskathand.Oncethetabbingwireisattachedthetriggerofthesolderinggunmaybereleasedandthesoldertipwillquicklycool.

12a)Withthetriggerdepressed(soldergun),brieflytouchthehotsoldertipagainstastrandofrosincoresolder,justenoughtolightlycoatthesolderingironorguntip.

12b)Triggerhelddown,startattheleftsideofthebusbarandpositionthesoldergunorirontipoverthetabbingwireabouthalfaninchbeforetheedgeofthesolarcell.Allowthesoldergunorirontiptomakecontactwiththetabbingwiretostartthesoldering,notpushingdownward,butinstead,allowingtheweightofthesolderingguntodothework.Yourjobistomakethemicro-adjustmentsincontactpressureasthesoldergunoriron’stipglidesacrossthetabbingwiresurface.Youhavethetaskofpreventingtoomuchdownwardpressurefrompushingthetabbingwireoffthebusbarwhichcanbemitigatedbycushionedweightsbeingusedasplaceholders.Thefirst

indicationthatthesolderingprocessisunderwaywillbeachangeintheappearanceofthetabbingwireonthesolarcell.Priortosolderingitwilllookexactlyasitdoesontheroll,orlayingthereonthesolarcell.Thesolderingtipwillcausethetincoatingthatsurroundsthetabbingwiretoliquefyandallowthetwosurfacestobondwhichwillgivethetabbingwireaflat,shiny,andsmoothappearance.Therecanbeminorroughtexturevisible,butthereshouldbenobulges,bumps,orobvioussectionsthatareliftedawayfromthebusbar.Itisidealtomakejustonepassoverthetabbingwirebeingsolderedtokeepthefragilesolarcellfromshatteringfromthehighheat.Repeatedpassesoverthealreadybondedsurfacewillonlyincreasetheriskofdamage,therewillbenobenefit,noaddedcontinuity,onegoodpass,perhapstwotosmoothoutanysolderpilesshouldbethemaximum.Isuggestwatchingmyvideoonthetaskforademonstrationonthistaskespeciallyifthisisyourfirsttimesoldering.Intermsofdifficultyacrossthespectrumofrequiredsteps,solderingisprobablyattheheadofthisshortlist.Havingsaidthathowever,solderingisaneasytasktomasterandproficiencydoesnottakelongtoachieveconsideringhowoftenyouwillbepracticingwhilejoiningsolarcell“pairs”.Don’tfrettheprocessthough,youCANdothissuccessfullyevenifyouhavetroubleinthebeginning,justdon’tgetfrustratedandgiveupifthetabbingwireisnotadheringoritismovingaroundonyou.Takeabreak,re-readtheportionofthisbookcoveringthestepyouarehungupon,orwatchthevideoatwww.aaroncake.net/electronicsforatutorial,butRIDyourmindofanynegativethoughtaboutnotbeingabletosolder.Itdoesn’tmatterifyouare85or15;thisisindeedaskillYOUcanmaster!

Oncethefirsttabbingwirestripissolderedyousimplyrepeatthesameprocessfortheremainingbusbarortwoassomesolarcellshavethreebusbarsforaddedelectron(current)flow.

13)Continuesolderingthetwo(orthree)tabbingwirestripstothenegative,sun-facingbusbarsuntilallofthecellsintendedforthespecificprojecthavetwo(orthreeifrequired)tabbingwiresprotrudingandreadytoacceptthesecondsolarcellneededtocreatethepairs.Forexample,ifhand-craftingasolarmodulecontaining36-solarcells,youwillneedtohave36-solarcellswiththetabbingwireextendingfromtheNEGATIVE,sun-facingside,hangingoverintoemptinessuntilweconnectthe“pairs”.Youmayjustperformthesameprocedure36-times,oryoumaydecideto

createpairsalongthewaysoastomixthingsup.Eitherway,youwillcometothenextstepwhichistomake“pairs”outofthesinglesolarcellsthatcurrentlyhavetabbingwireoverhangingtheirrespectiveedgesandarereadytobematedwithanothersolarcell.

14)Pairingthesolarcellsisnextandisdoneforaspecificreason.Itisaterriblewasteoftimetoassembleasolarmoduleonlytodiscoverabadsolarcellsomewhereinthemix.IdentifyingaweaksolarcellAFTERcompletingassemblywithalltherequiredsolderingmakesitacomplexprocesstoreplaceasolarcellsolateintheprocess.Itisfarbettertotestcell“pairs”BEFOREconnectingthemintoaSTRINGwithothersolarcellsforpermanentencapsulationbecausebythen,repairisnearlyimpossible.Testingtoensurethesolarcellsareviableiseasiertoaccomplishaftersolarcellshavebeen“paired”,anditisthebesttimetocatchanysub-parsolarcellsbeforecommittingthemtoaSTRING.Itisjustirresponsibletoputsomanyhoursintosomethingonlytohaveitsimplynotworkwhenplacedinthesunshine!Youshouldneverbesurprisedbyasolarmodulenotperformingatallwhenexposedtothesunforthefirsttime.Itisfarmoreefficienttotesteach“PAIR”ofsolarcellspriortoinsertingthemintoaSTRING,sowehandcraftthecellsinto“pairs”first,andthenlaterconnectthe“pairs”forassemblyonceweconfirmtheperformance.

Inordertoconnectasecondsolarcelltothefirst,wewillmakeuseofthetabbingwirethatextendsoffthesideofthefirstsolarcellsweprepared.Thosefirsttabbingwirestripsaresolderedtothenegative,orsun-facingsideofthefirsthalfofourfuturepair.Theoverhangingtabbingwirestripmustbesolderedtotheback,orpositivesideofthesecondsolarcellinthepair.Inordertoaccomplishthis,thesolarcellswilleitherhavefull-lengthbusbarsorsmallsquarebustabswhichareidenticalinphysicalstructureandpurposeasthebusbarsonthetopofthesolarcell.Theorderofstepsisasfollows:

14a)Turnthefirstsolarcellinthepairoversothatthenegative,sun-facingsideisfacingdown,towardsthetablethusexposingthebacksideofthissolarcell.TheresultwillbeanupsidedownsolarcellthathastabbingwiresprotrudingfromunderneathitmeaningtheyarecomingfromtheNEGATIVEsun-facingside.ThereshouldbeasmanystripsprotrudingfromunderthisinvertedsolarcellasthereareBUSBARSonthenowdownwardfacingsolarcellwhichwillbeusedtojointhenextsolarcell.

14b)Placecushionedweightsonthefirstsolarcellontherearmostportionofthesolarcell.Itisveryimportanttokeepthiscellasstableaspossibleandtheweightsneedtobeheavyenoughtopreventmovement,butnotsoheavythattheweightdamagesthesolarcell.Gentlyplacetheweightintopositionwithoutanyscrapingoftheweightagainstthesolarcellandtakingcarenottocrackthecellbythesuddenapplicationoftheweight.

14c)Placeanewsolarcellupsidedown,totherightofthecellitwillbeconnectedto.

Youdon’tneedtoweightitdownjustyet;youneedtoapplyRosinFlux(pen)tothebustabsonthenowupside-downsolarcellinpreparationforpairing.

14d)Movethesecondsolarcellintopositionsothatitcanreceivethetabbingwirefromthefirstsolarcellinsuchamannerthatthetabbingwirerestsacrossthebustabsforgeneralpositioning.Justasthefirstsoldertaskswithtabbingwirestrips,thesewillbejustaswiryandperhapswillnotberestingdirectlyontopofthebustabs.Thisiswherethe“probesandpoker”toolscomeintoplaythatImentionedintheearliersectiononthesubject.Myaffectionatelylabeled“sausagefingers”makemanipulationofsmallwiresdifficultbutthereinlaystheusefulnessofvariousfinemanipulationtoolsdesignedforsuchpurpose.Usingaflatbladedpokertomovethetabbingwireintothecorrectalignmentoverthebustab,youcanthenapplysmallweightstoholdthetabbingwireinpositionforsoldering.Thesolderingprocessisslightlydifferentforthepositivesidebustabswhicharesmallerthanthebusbarsonthefrontsideofsolarcells.YoustilladdtheRosinFlux,buttheapplicationofsolderisdifferent,andrequiresasofttouch.Thisistruesolderingwherethehotsoldertipmustrestonthetabbingwire,directlyontopofthebustab,withbarelyanyweightbehindit(thatmeansYOUneedtobesensitivetotheweightyouareallowingthesoldertiptoplaceonthesolarcell).

Theheatfromthesoldertippassesintothetin-coatedtabbingwire,bustab,andsolarcellallowingrosincoresoldertomeltuponcomingintocontactwiththetabbingwire.Leavingthesoldertiptoolongonthespotwillcertainlybreakthesolarcellsoyouneedtobeasbriefaspossible,butlongenoughtohavetherosincoresolderwiremeltuponcontactwiththetabbingwireandNOTfromcontactwiththesoldertip.Iftherosincoresolderwiremakescontactwiththehottipitwillindeedmeltandflowdownontothetopofthetabbingwire,BUT,therewillbepoorelectricalconductivity.Inorderforthesoldertoconducttheflowofelectrons,therosincoresolderwireneedstoreceivethefullheatofthesurroundingenvironmentsothatthecollectiveheatallowstheliquefiedsoldertoflowbetweenthesurfacesneedingtobebonded.IstronglyrecommendgoingtoYouTubeandwatchanexcellenttutorialonthesubjectofsolderingbecausethispersonhascapturedtheessenceofhowtosuccessfullyachievegoodconductivitysolders.Thetutoriallocationisgivenonthenextpage.

14e)Withthetriggerdepressedonyoursoldergun(assumingyoursolderingironispluggedin),cleanthesoldertipbywipingitseveraltimesacrossthespongesoakedindistilledwater.Nextapplyathincoatofrosincoresoldertothehotsoldertipotherwiseknownas“tinning”.Withthetabbingwirerestinginplaceabovethebusbarorbustab,gentlylowertheheatedsoldertipontothetabbingwireandgentlypressdownsothatitadherestothebusbarortab.Asitsitseversolightlyonthetabbingwireitistransferringheatintothetabbingwire,theRosinFlux,thesolarcell,andtheworksurface.Thisheatiswhatcausesthesoldertomelt(onthesolderguntip)andthenmixwiththetintoformtheelectricallyconductivebondbetweenthetwosurfaces.Thetincoatingontabbingwireshouldstartmeltinguponmakingcontactwiththesolderguntip.IstronglyurgeyoutowatchtheYouTubevideoORoneofminedepictingtheprocessIamdescribinghere.

Youwon’tuserosincoresolderwiredirectlyontotabbingwire,forthisprocedureonlythesoldergunorirontiprequire“tinning”.However,whenconnectingend-runsyouwillberequiredtoplacetherosincoresolderwiredirectlyontothebuswirewhereitshouldmeltasresultofcontactwiththesuper-heatedbuswire.Itisamistaketobelieve

thatthesolderguntipitselfishowtomelttherosincoresolder.IfyouDOtouchthesolderwireagainstthehotsoldertip,rosincoresolderwirewillindeedmeltandrunquitefreelyoverthebuswireandbustab.Problemisthatwhenitcoolsandsolidifies;chancesareitisnotbondedtothesurfacesrequiringsuchabond.Itwilllookreasonabletotheuntrainedeye,buttherewillbeobviousvisualcuesthataretooindepthtocoverhere,butsufficeittosaythesolderisnotgoingtoachievegoodelectricconductivity.Itmayworkwhentestedinitiallybutthelong-termoutlookisnotgood.So,neverrelyonsimplytouchingthehotsoldertiptodeployrosincoresolderoverthejoint!Takeyourtime,usemagnifyingglassesasIhavepicturedinthetoolslist,makesureyouhaveadequatelighttoseeyourtarget,andhaveasteadyhand.Itwillworkasyouneeditto,justbepatient,youwillbebondingtheselikeaproinnotime!ThereasonthejointmayfaildowntheroadisthetemperaturerelatedexpansionandcontractionIhavementionedpreviously.Ifthesolderjointissolid,doneproperly,itwillhavethestrengthtowithstandtheinternalmovementalbeittinyinmeasurement,butlackingthisstrength,theoutcomemightverywellbedifferentevenconsideringhowtinythemovementis.

15)TestingthepairyouhavejustjoinedisthenextstepasIhavepreviouslyindicated;thisisthetimetocatchaproblemasopposedtowhenthesolarmoduleiscompleted.Inordertoconductatestonthe“PAIR”ofsolarcellsyouwillneedyourmulti-meterwhichwillbeusedtomeasurethevoltsandamperesproducedbythepair.Bothmonocrystallineandpolycrystallinesolarcellsproduceaminimumofhalfofonevolt,soa“PAIR”ofeithertypeshouldslightlyexceed1-voltorthereisadefectsomewhere.Likewise,theamps(shortforamperes)willbemeasuredwithsimpleadjustmentstothemulti-metercablingandtoolsettings.Thevoltageperformanceisgenerallyconsistentacrossthefullspectrumofsolarcellsgenresincludingthemono,multi,andmonocrystallinesolarcellscontainedwithinourkits.WhatWILLbedifferentistheamperegeneratingcapabilitiesbetweenthevarioussolarcelltypes.Polycrystallinesolarcellsproducethesamevoltageasmonocrystallinesolarcells(0.5Volts)butthepurityinheritedfromthesingle-ingotoriginallowsmonocrystallinesolarcellstoachievedoubletheampereoutput.Monocrystallinecellsmeasuring5”squarearemyfavoritetoworkwithandproduceover4-amps,soa“PAIR”beingtestedcanachieve4.5-wattsandabove.Thelowampereperformanceofpolycrystallinesolarcellsmightbeseenasadrawbacktosome,Ifindthemtobedurable,consistentinperformance,andachieve18-voltsinasmallerfootprintthanmostothertypesofsolarcells.FYI:calculateWATTSbymultiplyingtheVOLTSxAMPS.

NOTE:thisiswhenyoureallygethands-onwithyourfragileproject.Imadereferencetothefragilenatureofsolarcellsearlier,butonceyoustarttheprocessofcreating“PAIRS”,thelevelofcarewhenhandlingyourcomponentsneedstoincrease.Apairofsolarcellsjoinedbywayoftabbingwireisreasonablysecurewhenlaidflatandundisturbed.Movingasolder-joined“PAIR”ofsolarcellsrequirestwohands,oneforeachofthecellsinthe“PAIR”.Whenmovingthe“PAIR”,itisbesttoslidethepairtotheedgeoftheworksurfacewherethe“PAIR”maythenbeslidovertheedgeandgrippedbythumbandforefinger.Onceinsuchapincer-typeholdyoumayeithertransitionthe“PAIR”ontothetestsurface,ortransportthe“PAIR”byholdingthemsuchthatthesolarcellshangdownnaturallywhilestillbeinggrippedinthepincertypegripwithbothhands.Whenmovingbetweentestsurfaceandstorage,takegreatcarethatthewinddoesnotsweepthe“PAIR”offthetestsurfaceorgetbroken.Ithashappenedtome,andnotonlywasitthegustofwind;itwasmyinstinctivegrabatwhathadbeensuddenlyliftedoutofmyhands.MyhandcollidedwiththatwhichIwastryingtosaveandinthecontestbetweenbonesandfleshverseswafer-thinsilicon,youcanguesswhatentitywon.Whenjoining“PAIRS”ofcellsintoSTRINGSofcellscontaininganywherefrom4,toasmanyas18,theresulting“STRING”canbe20”inchesallthewayupto7.5’feetlong(comparinga16-cell32-wattsolarmoduletoa72-cell150-wattsolarmodule).Iendorsethesmallersolarmodulesof100-wattrangebecausewecansafelyproducethesebutmoreimportantly,Icanmountthemwithoutneedingassistance.Whenyoustartmovinglarger,twiceasheavysolarmodulesupontosecondstoryevesorroof-tops,havingasecondpersonpresentismandatorybecauseofthesafetytopicswecoveredearlyoninthismanual.Therisksareincreasedacrosseveryactivitystartingfromtheladderwork,totheliftingofthemodule,toworkinghigh-upwithanobjectthatexceedstheweightthresholdyoucansafelymaneuver,totheriskofexceedingweightcapacityofDIYframestonameafewconcerns.

16a)Thebestmethodfortestingsolarcell“PAIRS”isintheactualsunshine,as

closetonoonaspossible,butyoucansafelytestupuntilabout3pmwhichwouldbethetailendoftheusablesolarirradiationformeasurementpurposes.YouwillneedanelectricalmeasuringdeviceknownasaMulti-meterthatcomesinawidevarietyofcapabilitiesandpriceranges.Therearemodelsavailablethatprovidedigitalreadoutsaswellasanalogversionsthathavemeterswiththetraditionalmovingwandtoreadresults,anyoneofthesewillsuffice.HavinganLEDscreenisaneasierwaytointerprettheresultsespeciallyifyoureyeshavedifficultyseeingsmallfiguresonadial.Thisisatoolthatcanbepurchasedfor$5,uptoseveralhundredbutthepriceisirrelevantbecauseyoucanhaveperfectsuccesswiththe$5unit.Therearetwomeasurementstakenduringtesting,oneforvoltageandanotherforamperageandtotransitionbetweentestsrequirestheswitchingofonecableandonechangeofadialpositionasdepictedinthephotographsonpage52(twopagesback).

16b)Movethe“PAIR”ofsolarcellstobetestedontoaflatpieceofmateriallargeenoughtosupportthejoined“PAIR”ofsolarcells.Itcanbeglass,cardboard,wood,justsolongasitissturdyenoughtosupporttheweightwithoutbendinginaslightbreeze.Oncethe“PAIR”isonthesurfaceandyouarereadytowalktothetestarea,placeafingerortwooverthetabbingwirestoholdthesolarcellpairontothesurface.Youcanexperienceagustofwindpickingthosecellsrightoffyourtestsurfacesothisstepisimportant.

16c)Onceintothesunlitareafortesting,placethesurfacecontainingthetest“PAIR”onthegroundortabletopwhereunobstructedsunisstrikingthesolarcells.Fortestingaswellasfinaldeployment,orientthetestsubjecttotheSouthifyouresideintheNorthernHemisphere,facingnorthifyouresideintheSouthernHemisphere.

16d)ConnecttheblackNEGATIVEleadcomingfromthemulti-metertoeitheroneofthetabbingwiresprotrudingfromthetop,sun-facingsideofthetestpairwhichistheNEGATIVEpolarityofasolarcell.ThisNEGATIVEtestleadshouldideallyhaveanalligatorclipwithwhichtogripthetabbingwireprotrudingfromthesun-facingsideofthesolarcell.Thesecondprobecomingfromthemulti-meteristheredPOSITIVEleadwhichmustbeplacedagainstthebottomofthetestpairatapointfarthestawayfromthealligatorclippednegativelead.ThisPOSITIVEtestleadshouldbethemetalprobewhichisidealforpositioningagainsttheundersideofthesolarcellbeingtested;itcanevenachieveagoodreadingwhiletouchingthetargetcellatanextremeangle.Theeasiestmethodtogivegoodaccesstothetestspotontheundersideofthelowersolarcellistoslidethe“PAIR”backwardsonthetestsurfaceuntilaninchofthetargetsolarcellisexposed,overhangingthetestingblock.Onceoverhangingyougentlyholdthetestleadagainsttheundersideoftheoverhangingsolarcell,towardsthebackofthecellnearesttowhereithangsover.ApplyenoughpressurewiththePOSITIVEtestleadtomaintaincontactbutnotenoughtoliftthesolarcelloffofthetestplatform.ContactwiththePOSITIVEtestleadisonlyrequiredforasecondasthemulti-meterinterpretsdatainstantly.ThedatawillbedepictedontheLEDscreenandyouwillhaveinstantmeasurementsforthedesiredtestparameters.Don’tbeconcernedifthenumberschangealotonthemeterduringthetestprocesssinceyourhandholdingtheprobetotheundersideofthecellistheweakestlinkinthetestingprocess.Asyounavigatethetestprocedure,balancingthepairattheendofthetestplatform,keepingeverythinginorder,youwillhavetheproclivitytoslipwiththehandholdingtheprobetothe

undersideofyourtestpair.Thiswillcausethemulti-metertoprovideawiderangeofnumericresultsmostofwhichwillbeoutsidetheacceptableperformancewindow.Ifyouencounterwildlyfluctuatingdata,simplystabilizethehandholdingthepositiveprobeandthenumberswillalsostabilize.

16e)Interpretingtheresultsareamatterofdeterminingwhethertheperformancefallswithintheexpectableparameters.Ingeneral,apolycrystallinesolarcell‘PAIR’comprisedof3”inchby6”inchcellsmustproduceaminimumof1-voltsinceeachcellwillcontributeaminimumof0.5-volts.Theamperagewillrangefrom1.7to3.5witheverythingin-between.Ifusingthe5”inchsquaremonocrystallinethevoltswillbethesame,aminimumof0.5-wattspercell,buttheamperagewillbenearlydoublethatofthepolycrystallinesolarcells.

16f)Ifwithintheacceptableperformanceparameterssetthe“PAIR”asideforlaterinclusionintoa“STRING”thatwillcomprisetheheartofthesolarmodule.Thisisthetimetoreallysecurethetested“PAIRS”inasafelocationwhileother“PAIRS”areeitherconstructed,ortesteduntiltherequisitenumberof“PAIRS”ismadetosupporttheproject.

16g)Iftheperformanceisnotwithintheguidelines,checkthefollowing:

a)Lookforanytabbingwireissuesbycloselyexaminingtheentiresurfaceofthebusbarsandbustabs.Youaresearchingforanyfailureofthetabbingwiretoadhere,perhapsasolderfailureduetothehandlingasyoutransportedthepairtothetestsite.

b)Examinethesolarcellsindividually,andclosely,perhapswithamagnifyingglassorajeweler’sloupebecausethemagnificationwillallowyoutoseecracksinthesolarcellthathadpreviouslyeludedyourinitialinspectionoroccurredduringthesolderingprocess.

c)Ifallofthetabbingwireappearssecureandtherearenovisiblecracksineithersolarcell,itmaybethemulti-meterprovidinginvaliddataduetosomefaultwiththedevice.Ensurethebatteryisfreshandthatthefuseisin-tactandhasnotbeenblown.Youwillknowafuseinblownwhenitisunabletogiveyouareadingontheamperageyouaretestingfor.Withoutthefuse,mostmulti-meterssimplywillNOTprovideanymeasurementofamperesandthedatayoureceivewillonlybethenumber“1”,oranerrorcode.Inordertoreplacethefuseyouwillneedtoremovefourscrewsvisiblefromthefrontofthedeviceorontheback,underthebatterycover.Itrequiresaverysmallsetofscrewdrivers,thetypethatcomeswitheyeglassrepairkitsthataresoldatmosthardwareandconveniencestores.Youcanpurchasethefusesfromanyautopartsstoresincevehiclesallrequirefusesofvarioussizesandtypes.Oncethefuseisreplaceditisagoodtimetocheckthebatteryhealthsincetheunitisopenandwillnotworkproperlywithadrainedbattery.Afterreplacingthefuseandbattery,inspectthecablesusedtoconnecttothesolarcellbeingtested.Pushthemintothe“inputjack”firmlytoensuresolidcontactwiththedeviceandalsocheckthecablesforfrayedspotsorlacerations.Ifyouhavereviewedallofthestepsoutlinedaboveandthereisnochangeuponfinalre-testing,considerthecellstobedefectiveandsetthemasidebeingcarefultosomehowmarkthemsoasnotto

accidentallyhavethemappearinaproject.Consideryourselfverywiseforpreventingyourprojectfromendingindisappointment.

STEP2-Combining“pairs”into“STRINGS”Keepingtruetoourexampleofeatinganelephant,wehavebeentakingtheequivalentofmanysmallbitesbyproducingthesolarcell“PAIRS”.Nowwearegaininggroundonthemonumentaltaskbeforeuswiththecompletionofenough“PAIRS”torepresentacompletesolarmodule.Intermsofthehypotheticalelephantcarcass,wewillhavemadeasizeabledentbutnowwearegoingtobetakingbitesthesizeequivalentthatofaKillerWhale(nowwhatpray-tellwouldanelephantbedoinganywherenearthehabitatofaKillerWhale?).Connecting“PAIRS”inordertobuildSTRINGisabenchmarkinthehandcraftingprocessthatmovesswiftlysinceitonlyrequiresfour“PAIRS”toequalaSTRING,fourSTRINGStocompriseasolarpanel.Ineedtoremindyounowthatfour“PAIR”ofsolarcellsequatestoaSTRINGcontainingeight(8)solarcellsbutweneedSTRINGScontainingnine(9).WeneedtoaddonesolarcelltoeitherendofthefourSTRINGS.Eachnewlyaddedsolarcellshouldhavetabbingwirestripsprotrudingfromtheendthatisnotgoingtobeconnectedwithanothersolarcell.Forexample,youwilladdasolarcelltoeithertheright,orleftsideoftheSTRING.Youwillthenneedtoestablishthepolaritysincethislastsolarcellbeingaddedwillserveasanend-runtobeconnectedwithbuswiretotheadjoiningSTRINGortheoutboundleadconnectingwithprojectorjunctionbox.TophysicallyestablishthepolarityforthefinalcelloftheSTRING,thetabbingstripsonthenewsolarcellshouldbeconnectedwiththebusbarorbustabsontheOPPOSITEsideofthesolarcellattheotherendoftheSTRINGyouareworkingon.Alignmentisimportanthereandshouldbeafocalpointeachtimeyouliea“pair”downtoaddontoaSTRINGthatisunderconstruction.ItisextremelydistressingtoreachthestageatwhichyouareabletoplacetheSTRINGSinsideasolarpanelframebutcannotfitthembecauseyoubuiltcrookedrows.Makingrepairsafterthefactistedious,difficult,andmightjustdiscourageyoufromproceedingtothenextstep,orevendroppingtheskillcompletely.Butyoucanavoidthisbyusingsomethingassimpleasastraightlinedrawnonyourworksurfacetouseasaguide.Asyousoldertabbingwireontothetop,NEGATIVEorthebottom,POSITIVEsideofasolarcellitiscommontorequiremultipleminoradjustmentstopositioningofcellsinordertomaintainthestraightlineorientation.Minormovementisincidentaltothecontactofthesolderingtip,yourhands,yourtools,andthesolarcellssimplyreactingtotheeversoslightpressurefromthesolderingtipwhichiscompletelynormal.Simplysetthesoldertooldownandrealignthepiecesinneedofadjustmentandcontinue.AstheSTRINGSgrowninlength,thesameprocessappliesforeach“PAIR”addedtotheSTRING.17)Joiningthetestedsolarcell“PAIRS”inordertobuildaSTRINGisthenextstepinthebuildingprocess.MostallsolarmoduleswillbecomprisedoffourSTRINGS;thedifferencebetweenthevarioussolarmoduleswillbethesize,thetype,andthenumberofsolarcells.However,differencesnotwithstanding,thelargermodules(70-wattsandlarger)allhavefourrowsorSTRINGSofsolarcellsconnectedbybuswireinsidetheirrespectivecasings.Youmaybuildcustomsolar

panelstomeetanyneedyoumighthave,certainlysmallersolarmodulesmaybeonlytwoSTRINGSofcellslikethosemadespecificallytorechargesmallhouseholdbatteries,butIamreferringtosolarpanelsseventywattsandabove.IprefertohandcrafttheselargermodulesbecauseIfeeltheyhavethemostapplicabilitytoRV,out-of-doorsactivities,off-gridliving,andarelightweightenoughtomountwherelargerpanelscouldnotpossiblyfit.However,havingadmittedmypreferenceforthelargersolarmodulesdoesnotdiminishmybedrockconvictionthateveryownerofacellphoneshouldhaveasolarmoduleofsufficientsizetochargetheircellphoneattheveryleast,aprojectthatiswithinthegraspofthemostnoviceofsolarpanelhandcrafters.ThemainreasonIamfondofthe70-100wattrangesolarmoduleisthatIcanmountthissizemoduleanywhereIneedtowithoutrequiringphysicalassistance.Thiscanbeamajorsafetyfactorifworkingonaroof,alone,orhangingthemodulesfromtheeveswhichhavelowerweighttolerance.Thisisthetremendousadvantageyouhaveinthatyouarenotboundbymodulesizesofferedbythebigmanufacturers;youcancustomizemodulestofitspecificopportunitylocationsortofitaspecificelectronicdevice.OnceyouareatthepointofcreatingtheSTRINGS,youhavegainedsomevaluableexperiencesoldering.Theremainderoftheassemblyissolderingthe“PAIRS”togetherbasically,ataskyouwillbecomemuchmoreproficientasyoucompletemoreSTRINGS.Anydifficultiesyouarehavingnowwillbeamerehiccupthenexttimeuntilthefollowingunitwhenyouwillbeaconfidenthandcraftinggenius.

17a)Thefirst“PAIR”inaSTRINGwillstartoffwiththeNEGATIVEorsun-facingsidedownandthetwostripsoftabbingwirepointingtowardsanopenarealargeenoughtoaccommodatethesecond“PAIR”ofsolarcellstolienexttothefirst.Gentlysetcushionedweightsstrategicallyaroundthefirstsetor“anchor”inordertopreventmovementasyousetthesecond“PAIR”inplace.Atthistime,applytheRosinFluxpentothebustaborbusbaronthesecond“PAIR”thatyousetdownnexttothefirst(youmaygoeitherway,rightorleft,whicheveryouarecomfortablewith)inordertoprepareitforsoldering.Remember,somesolarcelltypeswillhavebustabs;somewillhavebusbarsrunningthefulllengthofthecellonthebackorPOSITIVEsideofthecell.

NOTE:aligningtheSTRINGsothatthefinishedproductwillsitstraightupanddowninsidethesolarpanelisimportant.AllfourSTRINGSofsolarcellsmustfitwithintheconfinesofyoursubstrate(solarpanelbackingmaterialthatthestringsofsolarcellsaremountedto)andthereisnotmuchroomforerror.Forexample,ifyoursolarpanelsubstrateis25”incheswideandyouareworkingwith6”inchwidepolycrystallinesolarcells,fourrowswillconsume24”inchesleaving¼”inchbetweentheSTRINGS.Therearemanywaystoachievestraight“PAIRS”rangingfromdrawingastraightline,toutilizingsmallrubberspacersoriginallydesignedforlayingceramictileinperfectsquarepatterns.Rubbertileguidesprovideamechanismforlayingsolarcellsor“PAIRS”ofcellsintoperfectlyalignedrows.Icautionyouifyoudecidetousethismethodbecausethetileguidessometimescatchthecornersofsolarcellsasyouattempttoliftyourcompletedsolarcell“PAIR”,orSTRINGofftheworksurface.Sometimesthesimplestmethodisgoingtoworkthebestinsteadofthefancytilespacers,somethingassimpleasdrawingtwolinesontheworksurfacetouseastheguidelinesforbuildingSTRINGSofsolarcells.InmydemonstrationvideosIusean8”inchwidepineboardthatIaffixedawoodenyardstickalongtheedgeonwhichIconnectthe“PAIRS”.Whichevermethodyouuse,theultimategoalistoarriveataSTRINGthatsitsinaverystraightline.Iliketousetheedgeofmyworksurface,halfofahallwaydressingmirrorwhichprovidesanexcellentstraight-edgedguideasIbuiltmySTRING.YoumayfindothermethodsthatsuityouasanindividualandIencourageyoutofindmethodsthatfityourneeds.Thereisnohardandfastconcretemethod,thisiswhereyougettoexperimentandfindwhatworksforyou.

17b)Withthefirst“PAIR”ofsolarcellsweighteddown,slidethe“PAIR”tobeconnectedsothatitrestsunderneaththeloosetabbingwiresthatwearegoingtosoldertothebusbarorbustabonthisnew“PAIR”wearejoiningwiththefirst.Positionthissecond“PAIR”sothatitisalignedandstraightusingamethodofyourchoicetoachievestraightlines.Theidealdistancebetweenthetwopairswillbeonlyapproximately1/8to1/4inches.Asaruleofthumb,yougenerallyonlyneedenoughspacebetweenthetwopairsofsolarcellstoallowroomforexpansionandcontraction,enoughspacefortheexpansionbendyoumadewiththetabbingwireconnectingsolarcellsinagiven“PAIR”.Takeamomentnowtogobackthroughthismanualandexaminethephotosthatincludepairsofsolarcellsoractualstringsandnotehowfarapartthesolarcellsarefromoneanother.You’llstarttonoticeconsistencyinthedistancebetweencellsintheexamplesIhaveprovidedinthephotographsthroughoutthisbook.Thephotographsinquestioncontainpolycrystallinesolarcellpairsthatutilize3”x6”cells,andyoucanseethespacingisminimalbecauseyoureallydon’tneedthatmuchspacebetweenthemoncetheyareinsidetheprotectivehousingofthesolarmodule.Thepresenceofthecreaseinthetabbingwirewillallowfortheminutemovementsrelatedtotemperaturevariations,andthespacingonlyneedstobesufficienttopreventcontactbetweencellsthroughouttheworkinglifeofthesolarmodule.Onceyouhavethesecondsolarcell“PAIR”intheproperposition,younowmustsetcushionedweightstopreventthis“PAIR”frommovingduringthesolderingprocess.Whensettingyourweightsdown,takegreatcarenottoimpedeyoursolderingonbustabsorbusbarsasobviouslyyoucannotplacethetabbingwireoverablockedbustaborbar.Youalsodonotwantthecushionedweightstointerferewiththemovementofthesoldertipasyouareworkingoveraparticularcell.Onceintoposition,alignthetabbingwiresthatarenowhangingoverthebackorpositivesideofthesolarcellinneedofbeingsolderedandpositioneddirectlyoverthebustab/bar.Usecushionedweightstokeepthetabbingwireinplacesoyoucanmoverightinwiththesoldertip.

17c)Nowthatitisalignedandthetabbingwireinpositionandreadytosolder,itisnowtimetojointhetwo“PAIRS”ofsolarcells.Beforestartingremembertocleanthesoldertipandperformthe“tinning”stepaswediscussedearlier.Justaswiththemethodusedpreviouslyontheback,orpositivesideofthesolarcell,carefullyplacethehotsoldertipontothefirstbusbartobesoldered,rememberingtoallowjustenoughweighttorestonthattiptotransferheatintothetabbingwiretomeltthetincoatingaroundthetabbingwirebutnomore.Afterafewsecondsofallowingthesolderguntiptoheatthesurroundingmaterial,touchthesolderwiretothetabbingwireanditwillmeltfairlyquickly.Releasethetriggeronthesoldergun,reapplyadabofsolderandmoveontothenextbuswire/tabuntiltheyareallcompletedonthe“PAIR”beingconnected.Oncethetabbingwireshavebeensolderedandthe“PAIRS”joined,itistimetoaddthenext“PAIR”,untilyouhavejoinedasufficient

numberof“PAIRS”tocompriseyourstring.Inthe“How-To”videosfilmedforthisbook,weliketofocusonthe36-solarcellpanelsforreasonsstatedearlierthatrevolvearoundsafety,easeofmounting,andthewiderangeofapplicability.

17d)Volt/Ampcheckuponcompletionofeachstring-youmayperformthesamevoltageandamperagetestingasdonefora“PAIR”.Youshouldnotfindanyfaultysolarcellssinceeach“PAIR”hasbeentestedpriortobeingaddedtoaSTRING.Youcanestimatetheoutcomebyperformingsomebasiccalculationsusingdatafromthevoltageandamperagetestingcompletedoneach“PAIR”beforeaddingthemtothestring.Forexample,ifthestringyoujustcompletedcontainsnine(9)monocrystallinesolarcells,eachproducing0.5-volts,andeach“PAIR”averaging4.4-amps,wecanexpectourstringtotestonthemulti-meterundernoon-timesunshinetoprovide4.5-voltsat4.4-Amps.Remember,VOLTSareadditivebecausewearesolderingourtabbingwireinseries,startingontheNEGATIVEortopofthesolarcellandsolderingittotheundersideorPOSITIVEsideofthenextsolarcell.Idonotanticipateyoutohaveanysurprisesheresinceyouhavebeentestingasyougo,right?Thatisthereasonwetestaswego,sotherearenounpleasantsurpriseswhenitcomestimetotestthelargerunitssuchasSTRINGSandultimately,thecompletedsolarmodule.

17e)Applyaprotectivecoatingofsilicone-tothetabbingwirealongthefulllengthoftheSTRINGthatyouhavejustcompleted.Toaccomplishthistask,ensurethatthesun-facingorNEGATIVEsideisfacingdownexposingthefulllengthofthetabbingwirethatissolderedtothesolarcells.Thepurposeofthisapplicationistoprovideprotectionagainsttheelements,namelyoxygenwhichservesasanacceleranttooxidation.Thethinlayerofsiliconealsoprovidesadditionalsupportfortheconnectedsolarcellsbydistributingtheweightevenlyacrosstheentiresurfaceofthesolarcell.ThisbecomesincreasinglyimportantastheSTRINGoccasionallywillneedtobeliftedbytheoverhangingtabbingwiresatbothendsoftheSTRING.LiftingaSTRINGofsolarcellsinthisfashionmightbenecessarywheninsertingtheSTRINGSintotheframeworkofthesolarmodule.Withoutthesiliconecalkingyourisktearingthesolderedtabbingwirefreefrombusbarsortabsevenifyouareasgentleashumanlypossible.TheaddedstrengthandweightdistributionqualitiesgivetheSTRINGSaddeddurabilityandsurvivabilityduringthefinalstagesofassembly.Placecushionedweightsat4locationsontheSTRINGincludingtwoateitherend,andtwosomewherenearthecenteroftheSTRING.TheweightsaretopreventmovementoftheSTRINGasyougentlybrushthesiliconecaulkingoverthetabbingwire.TakegreatcarewhenplacingthecushionedweightssotherearenofracturesorotherdamagetotheSTRING.

18a)Cutthetipoffatubeofsiliconecaulking,notthewholetip,justaboutaninchbelowthetipofthelid.Keepinmindthatthecutyouaremakingwilldirectly

controlthesizeofthesiliconecaulkbeadthatisemittedbythecaulkingapplicationtool.Thereforeonceyoumakethecut,youarecommittedtothatsizebeadforthelifeofthatparticulartubeofsilicone.Itisbettertocutasmallerholebecauseyoucanlateradjustthesizebymakinganotherangledcutandyourbeadsizewillincrease.ToolargeaninitialholeandyouwillhaveamessyWIP(work-in-progress).Ifyouareusingatraditionalcaulkingapplicationtool,aftersnippingtheapplicatortipoffatanangle,youmustthenpuncturetheinnersealattheendofthecaulkingtube.Thiscanbeaccomplishedbyusingthesmallmetalrodaffixedtomostcaulkingapplicationtools,ontheundersideoftheapplicatortoolthatisthereforthisspecificpurpose.Simplyrotatethisrodsothatitispointingstraightaheadofthecaulkingapplicationgunandthenusethisrodtopuncturethesealinsidethecaulkingtube.Ifthecaulkinggunyouareusingdoesnothaveabuilt-insealpiercingrodyoumayuseanylong,slenderobjectofsufficientlengthandrigidityThesiliconecaulkingtubeisnowreadyforuseandmaybeinsertedintotheappropriatechamberinthecaulkingapplicationtool.Thetoolwillthenneedtobeadjustedbypressingthetriggerinordertomovetheramforwardtomakecontactwiththebaseofthesiliconecaulkingtube.Oncetherammakescontact,continuetosqueezethetriggeracoupletimeswithyourgoalofbeingabletoseetheinitialflowofthesiliconecaulkingmaterialentertheapplicatortipthatyoupreviouslyhadcutopenataslightangle.ItisHUGELYimportantthatyouuseCLEARcaulking!Now,topreventapanicattackletmewarnyouinadvancethatwhenyouwatchinabstracthorrorasaWHITEbeadofcaulkingescapesthetubeclearlylabeledas,well,CLEAR.Asitcuresitbecomestransparent,Isuspectasamechanismtomakeiteasiertoworkwithduringapplicationsotakeitinstride.Forthisapplicationyouwillnotbeapplyingsiliconecaulkingdirectlyontothetabbingwirewiththecaulkinggun.Instead,usetheguntoapplyahealthyglob(scientifictermforaboutaplasticwaterbottlecapfull)ontoascrappieceofcardboardfromwhichyouwillapplyitbyhand.

Thecoatingoftabbingwireontheback,orPOSITIVEsideofthesolarcellsisdoneuponcompletionofeachSTRINGofcell“PAIRS”.ApplythiscoatingaseachSTRINGiscompleted,youwanttogetprotectioninplaceassoonaspossiblebecausethecorrosiveforcesareatworkonexposedsurfacesfairlyquickly.TheSTRINGSarefullyprotectedbyanencapsulatingmaterialwhenthepaneliscompleted,butuntilthen,itisbesttoprotectthemanywayyoucan.Thisprocessalsohelpsprotectlong-terminsidethesolarmoduleaswell.

18b)GentlypaintathincoatofthesiliconecaulkingoverthetabbingwiresurfacesONLY.Tobeabsolutelyclear,DONOTapplycaulkingoverthetabbingwiresurfacesrunningin-betweenthesolarcellsnorthebacksofthesolarcells.Youdonotwanttoaddanyresistancetothatportionofthetabbingwiresinceitistheshockabsorberallowingfortemperaturerelatedexpansionorcontraction.Ifyoupaintaparticularsectionanduponcompletioncanseeonlythewhitesiliconcaulkingontopoftabbingwire,andnoactualtabbingwire,thenyouhavesuccessfullycoatedthesurfacesinneedofassistance.Whenbrushingthesiliconecaulkingontothetabbingwiresurface,rememberyouarestillworkingwithverydelicatesurfaces.Itisnotunheardofforastraypaintbrushbristletocatchajunctionbetweentabbingwireandsolarcellwithenoughforcetodislodgethetabbingwireorfracturethesolarcell.Thisisthetypeoftaskwhereoneshouldbewearingthemagnifyinggogglesandpaintingwithverysmallbrushheads.

18d)StorethesiliconecaulkingcoatedSTRINGsafelyaswehavediscussedpreviouslyuntilthattimewhenyouincorporateitintothesolarmoduleassembly.Aplacewhereitissafefromjostling,objectsfallingonit,orundueexposuretotheelements.Assuggestedearlier,thisistheidealtimetoplacetheSTRINGintoastoragecontainerthatcanbeslidunderabedoroutofharm’sway.Oncesecured,

moveontotheassemblyofthenextSTRINGbyrepeatedthestepstakentopreparethisoneyouhavejustsecured.

NOTE:WhenaSTRINGiscompleted,thelastsolarcelloneitherendoftheSTRINGmustbeofoppositepolarityinorderfortheSTRINGStobeconnectedtogetherinseries.Inthreepagesyouwillencounterthedefinitionofserieswiring,butinshortitisachievedbyconnectingthesolarcellsfromthesun-facingNEGATIVEside,tothebottomofthenextsolarcellwhichisthePOSITIVEside.WhenconnectingSTRINGStogetherthesameprinciplesapplyaswhenconnectingindividualsolarcellstocreatethe“PAIRS”.Justasweconnectthesolarcellstogetherbysolderingtabbingwirefromthesun-facingside,tothePOSITIVEundersideofthenextsolarcell,wewanttocontinuemakingconnectionsinseries;wewillsimplybeconnectingSTRINGStogetherbyjoiningtheNEGATIVEtabbingwiresprotrudingoffoneSTRINGtothePOSITIVE,orbacksideoftheSTRINGnexttoit.ConnectingSTRINGSoccursastheylayside-by-sideonasubstratewiththelastsolarcellateitherendtrailingtabbingwirestripsthatwillbeusedtomaketheseriesconnections.ThetabbingwiresfromtherespectiveSTRINGSareconnectedtogetherbywayofbuswireasdepictedinthephotoonpage66.Thephotodepictstheseriesconnection,asyouexaminethephototakenoteofthetabbingwirestrailingoffthesolarcellontheright-mostSTRING.Itiscomingoffthetop,sun-facingsideofthesolarcellwhichweknowtobetheNEGATIVEpolarity.ThesolarcellitisconnectedtoattheendofthenextSTRINGhastabbingwiresprotrudingfromtheundersideorPOSITIVEpolarityandalsotakenoteofthebuswirethatconnectsthetwoSTRINGS.ThepicturealmostappearstodepicttwoSTRINGSconnectedbytabbingwirecomingfromthetopsofbothSTRINGSbutuponcloserinspectionyouwillindeedseethattheleft-mosttabbingwirestripsdocomefromundertheleftSTRING.

STEP3-ConnectingtheSTRINGSvia“EndRuns”A FTER TH I S BR I E F I NTRODUCT ION TO THE “ENDRUN” I AM GO ING TO TALK ABOUT SUBSTRATESBEFORE L I S T ING THE S TEPS TO CONNECT THE END RUNS . SUBSTRATES ARE THE SURFACES YOU

WILL MOUNT THE S TR INGS TO IN ORDER TO CONNECT THEM AND CREATE THE F LOWOF CURRENT(OR EXC I TED ELECTRONS )

Youarealreadyfamiliarwithan“end-run”becauseyouhavereadaboutitseveraltimesthusfarandIsimplyhadn’tyetprovidedtheterminologyuntilwewereatthisstageofassembly.Anend-runissimplythosetabbingwirestripsthatoverhangfrombothendsofaSTRING,oneend-runcomprisedoftheNEGATIVEleads,theotherendbeingthePOSITIVEleads.YoucannotuseaSTRINGthathasthesamepolarityonbothend-runs;itjustisnotgoingtoallowtheflowofelectronsorcurrenttobecomepartofacircuit,themostessentialfunctionoftheSTRING.Thepurposeforthewaytabbingwirerunsfromthetopofonecell,tothebottomofthenextistofacilitatethemovementofelectrons;wearebasicallyprovidingaroadwaybysolderingthetabbingwireontothecells.Asphotonsstrikethesolarcellsandtheelectronsstarttogetexcitedandultimatelybreakfree,iftheyhaveapathtotakethatallowsthemtofulfiltheirnewmission(tofindatomsinneedofelectrons,justsomewhereelse),they

willindeedmoveswiftly.Onceinmotion,providingtheyhaveapathfreefromobstruction(seetheend-rundescriptiononthenextpage)andcontinuedradiantenergyfromthesun,theelectronswilltraveltheroadwayswelayforthem.

Thepathtakenbytheelectronsbecomesaflowasmoregather,andwiththeircollective,frantic,single-mindedpurpose,theybecomethesourceofelectricalcurrent.Thepathmustbesimilartoanextremelybumpyrollercoasterridewithafewverysharpcornersthrowninforthefaintheartedelectrons.Theymustrapidlyfollowtheover-undercontoursofsolarcellswhicharevirtuallypumpingelectronsoutandintotheflowwhichmakesseveralsharp,90°turnsrightbackintoanotherSTRINGofsolarcellsatthespeedoflightorsomethingclosetoit.Thetabbingandbuswirehighwayyouwillhaveprovidedbecomeslikeaone-waysubwaysystemmovingelectronsatincrediblespeeds.Takeanotherexampleofahighway,thetypewedriveourcarson,whichserveasimilarpurpose,gettingmovingobjectsfromonepoint,toanother,inaone-wayflowoftraffic(atleastitworksthatwaymostofthetime)inappropriatelymarkedlanes.Toillustratetheconceptofobstaclesthatcauseinefficiency,anautomobiletravelingonafreewayisafairlyuniversalconceptforthoselivingindevelopedcountriesbecausewerelyonfreewaysregularlyandtheideaofblockagesareverysimilarwithsimilarresults.Justaselectronsmoverapidlythroughthetabbingwire,carsmoveswiftlyinlanesalongsideothervehiclesandbarringcollisions,movewithsteadyandrapidspeed.However,throwinthatcollisiononthefreeway,andweallknowwhatthatmeansright?Bumper-to-bumpertrafficwithnearwalkingspeedifyouarelucky,andthatisoneBIG“IF”becauseyouarejustaslikelytobesittingidle.Similarly,sloppysoldering,theabsenceofRosinFlux,coldsolders,andextremeheathavethesameeffectonelectronsasacaraccidenthasonafreeway.Thecaraccidentbasedtrafficjamistheequivalentofwhatisknownas“resistance”inelectricalterms.ResistancedescribesconditionswherebyelectronshavedifficultyflowingfreelythroughthesolarcellsandSTRINGSduetofactorssuchascoldsolders,anabsenceofrosinflux,orcrackedsolarcellstonameafewfactors.Carshelduponacloggedfreewaywouldbetheequivalentofelectronsrunningintothebacksofothersinthecurrentthathavereachedanobstacle,thusresistance,andlikeatrafficaccidenttheresistancestopsthefreeflowofenergyorattheveryleast,slowsitconsiderably.Iamnotsayingthere

canbenoerrorsatallandthatitmustbemachine-likeinperfection(yourperformanceImean),rather,youshouldbeawareoftheconceptbecauseitcanmanifestitselfthroughpoorperformanceoroutrightnon-functionalityofthesolarcellorSTRING.

Substrates-WeNeedToSlipThisInNow…THISISANECESSARYINSERTIONPOINTFORACONVERSATIONABOUTSUBSTRATESBUTONCEDONEWITHTHE

INTRODUCTIONINTOTHETOPICWEWILLREVERTTOTHESTEPSNEEDEDTOCONNECTTHESTRINGS.

MerriamWebsterisn’tmuchhelpinfiguringoutwhythewordsubstrateisusedconjunctionwithsolarpanels.“Thebaseonwhichanorganismlives”iswhatIsawwhenIwastryingtohandcraftmyfirstsolarpanelafterreadinganinstructionmanualthatwasawfullyshyoncriticaldetails.Bynowyouhavecaughtonthatmymissionistoover-stateeverydetailwhichcanbecometedioustotheveteranhandcrafterofsolarpanelssoIbegpardon,andpleaseunderstanditisforareason.Forthenewermembersofthiseliteclub,thesemightbenewconceptsandterms,andnoassumptionscanbemadeaboutfamiliarityotherthanthatthereiszerofamiliarity.Ivividlyrecalltheobstacleoftryingtofigureoutwhatthe@%$&isasubstratethefirsttimeIsetouttoconstructasolarpanel?NaturallyIfigureditoutandhavetriedavarietyofthemandbyperusingtheYouTubechannelsofferinginstructionsonthisprocessIseethatthereisindeedawidevarietyinuse.

Asubstrateistheobjectthatyoursolarcellstringsrestunder,oruponastheyperformtheirworkofcollectingphotonsinacompletedsolarpanel.Substratesthatserveasabase,wherethesolarcellSTRINGSaresetatopthesubstratewiththesun-facingsideup,aretypicallymadefrommaterialssuchaswood,aluminum,temperedglass,orthickersyntheticplastics.Regardlessofthematerialyouselect,itmustbe100%waterrepellant,andifitisnotsonaturallythenyoumusttreatitinordertomakeitso.Ifwoodisthesubstrateofchoice,paintingitwithwater-basedpaintalonewillnotsufficebecausewoodisporousandmoisturewillfindawaytosoakthroughfromtheoutside.Theresultwillbecondensationontheinsideofthesolarmoduleeventhoughforallpracticalpurposes,thesealisin-tact.Oncethewaterstartscondensingontheinterior,timeisshortforthatparticularmodulebecausetheelementswillerodetheperformanceandfranklymakeitadangerousfirehazard.Therefore,itrequiressomethinglikesiliconecaulkingtobepaintedontotheplywoodOVERthepaint,averylightcoat,butthickenoughtoensurethatawatertightbarrierispresent.TheremaybeotherwaterproofingproductsusedthatIamnotfamiliarwiththatwillsuffice,justmakecertaintheproductproducesnofumesandhasaguaranteedlifespanofatleastthreedecades.Evenifsiliconecaulkingisused,itmustbeallowedtocurecompletelybeforebeingenclosedbytemperedglassorsyntheticcoveringslikePlexiglas.Assiliconcaulkingcuresitemitsfumesthatmustbeallowedtoescapepriortosealingthesolarmodule.

Substratesgenerallycomeinthreetypes,the“box”type,“sandwich”,and“single-sheettemperedglass”andthenamesimplydirectlywhateachlookslike.Boxtypesubstrates-aresonamedbecausethesubstrateservesasthebaseonwhichthesolarSTRINGSaresitting,sun-facing(negative)sideupwards,andthebottom,positivesideofthesolarcellsfacingdownandactuallyrestingonthesubstrate.Thesubstrateperimeterislinedwiththinsquarewoodenrailsthatwillthensupportacovermadefromtemperedglass,polycarbonate,oracrylic.Thecoverprovidesthephysicalprotectionforthesolarcellsagainstrain,hail,birds,dirt,orforeignobjectsfromanysource.Typicallythesetypesubstrateswouldnotbeusedinconjunctionwithencapsulatingmaterialbecausetheweatherprotectionisprovidedbythecover.Inadditiontothecover,recallthattheinsideofthesubstrateispaintedwithsiliconecaulkingtopreventmoisturefromseepingthroughtheporouswoodsubstrate.Recallalsothatwepaintsiliconecaulkingontheback,POSITIVEsolarcelltabbingwiresthatareexposedasaprotectionagainstmoisture.Wemaytakeanadditionalstepofcoatingthefront,sun-facingsolarcellswithathincoatofGERTV615OpticallyClearSiliconemixedwithXylenesolventtothinitforpaintableconsistency.Thisverythincoatingofsiliconewouldprotectthesolarcellsandtabbingwireswithoutcompromisingtheperformanceofthesolarcells.Takingthisstepisveryexpensivebutwouldgivethistypeofsubstratetheseriousprotectionneededtogiveitacrediblelifespan.Asofthiswriting,GERTV615canbepurchasedoneBayforjustover$350fora1-lb,two-partkit.Onewouldneedtofairlyfondofthistypesubstratetoinvestthatmuchtoensurelongevityandmightbebetterservedlookingtoadifferentdesigntoachievethedesireddurability.BarringtheuseofGERTV615,thiswouldbetheleastexpensivemethodtomountthesolarSTRINGStocreateaworkingsolarmodule(panel).Manytimesthematerialyouwillusetoconstructtheboxwillalreadybeon-handsomewhereinyourgarageandtherefore,notmuchneedbepurchasedinadditiontowaterproofingandthecover.Theseboxescanbetrickytosealcompletelyandsothelifespanofthistypesubstrateislessthanotherdesignsbutcannotbeequaledforanaffordable,functionalsolarmodule.Myfirsthandcraftedsolarmodulesareofthisdesignandtheyservedmewellforanumberofyears.

Sandwichtypesubstrates-arenamedassuchbecausefranklythesolarcellSTRINGSareliterallysittingbetweentwopiecesoftemperedglass,polycarbonate,oracrylic.ThismakesforavisuallyinterestingsolarmodulebecauseyouwillhaveaclearviewofbothNEGATIVEandPOSITIVEsidessoitisagreatconversationpiece.Thedrawbackisheatretentionwithintheconfinesofthesandwichinterior.Thesemightbebestsuitedforclimatesrichinsunshinebutlightonthetemperatures.Don’tmisunderstand,ifyoudoexperienceunseasonablyhotweatherforashortspell,yoursolarmoduleswon’tself-destruct,theyjustwon’tperformaswellastheywouldinmildertemperatures.Iwouldnotrecommendthesetypesifyoulivewheretripledigittemperaturesarethenorm.TypicallythesolarSTRINGSareaffixedtothepolycarbonate,acrylic,ortemperedglassthatcomesintocontactwiththebottomorPOSITIVEsideofthesolarcells.AftersecuringtheSTRINGSandthenconnectingthemviabuswireandrunningthePOSITIVEandNEGATIVEleadsout,thesandwichiscompletedbyaddingencapsulantfollowedbythesecondpieceofsubstrateoverthetop.Heatwillcauseexpansionoftheglass,acrylic,orpolycarbonateaswellastheSTRINGS.Ifdelicateobjectsaresandwichedbetweenexpandingandcontractingsolidobjects,saiddelicateobjectsaregoingtogetshattered!TheSTRINGScanbeprotectedagainstthisbyplacingsmallplasticcraftringscalledPonyBeadsthataregluedintoplacebetweenSTRINGStoactassupportpillarsfortheupperandlowersubstrates.Iftemperaturerelatedexpansionorcontractionoccurs,thePonyBeadspreventthetwosubstratepiecesfromcomingintocontactwhichofcoursewouldshatterthesolarcellsrestingbetweenthem.Adrawbacktousingtwopiecesoftemperedglasswouldbethecost,doublethatofsimplyusingasinglepieceinconjunctionwithanencapsulatingmaterial.Butifthatiswhereyourmindisset,thengoforit!Justbeawarethatweightwillbeafactor,perhapsnotsomuchwithPlexiglas,buttherewillbenohandholdswithwhichtograbpurchasewhenhandlingunlessyouaddsomethingforsafetywhenmounting.

Single-SheetTemperedGlass Substrate-This ismypersonalchoiceafterexperimentingwith othermethods.A single piece of tempered glass is very strongwhenmarriedwith aframemade from 1.5” angled aluminum.When you examine commerciallymanufacturedsolarmodules,mostallhavetemperedglasssubstratessupportedbyanaluminumframe.Thiscombination provides excellent protection from the elements, light falling objects, and

providesoutstandingheatdissipation.Itisalsocomparativelylightmeaningitissafertohang,requires less framingmaterialbecause the solar arraywillbe lighter than thosewithwoodsubstrates.WhytemperedglassasopposedtoanormalpieceofglasslikethosesoldatHomeDepot?Generally theglass soldathome improvement stores are for replacementpurposeswhenwindowsorpictureframesbreak,thingsthatarefairlycommoninourhomes.Aswehavelearned,somethehardway,whenthosetypeglasssurfacesbreak,theresultingshardscanbeextremelydangerousandittakesbutataptoshattersuchglass.Infact,accordingtoMarkFord,fabricationdepartmentmanageratAFGIndustries,normalglassbreaksat6,000PSIbut temperedglassatasignificantlyhigher24,000PSI.With thiscomparisoninmind,imagineoneofyourworksofartisrestingstrategicallyonitsrackgeneratingahappythrongofexcitedelectronswhenacrowfliesoverheadandchoosestodropanacornfrom200feetinthe air ontoyour solarmodule.The resultingCRACK!And the familiar soundof tinklingglassisyoursolarmodulewreckage,becausethatiswhatyouwillbeleftwithifanythingbuttemperedglassisused.

The cost difference is notable, butwhen you consider that themoney saved buying thecheaperglassisnegatedbythelossofanentiresolarpanelifthatcheapglassisbroken!Thetimeinvestedontheprojectislost,thecostofthesolarcells,andthefactthatyoureallylostTWOsolarpanels.What? Ihaveonebrokenbyabird,howdoyoucomeupwithTWO?Well,ifyouarereadingthisandareintendingtohandcraftasolarpanel,yourintentionswillchangeuponcompletionof the firstofyour solarpanels.The fullbenefitofa solarpowergenerating system is that the energy must be gathered by several solar panels workingcollectivelytofillthebatterybank.Oncethefirstpaneliscomplete,mostpeople(yourstrulyincluded)willcontinuehandcraftingsolarpanelsuntilthearrayisbuilt,andyettherearesomanyapplicationsforsolarpanels,wetendtokeepbuildingthembecauseyoucanneverhave

enoughtofulfillalltheuses.However,sinceyouaremerelyreadingthisbook,Iwillattempttoexplainthatfeelingofliberation,ofprideinyouraccomplishment,thepurejoywatchingthebatterymeterrisingbecauseofthatsolarpanelyouJUSTBUILT!Oneisnotenoughtomakethekindofdifferenceanyofuswanttoseeandsothenaturalinclinationistocontinueproducingthemandasyoudo,eachtimebecomesquicker,easier,andofhighercaliberuntilyouarefillingyourfirstarray,orfillingtheroofoftheRV.Sothecrowtooknotjustthesolarpanelyou recently finishedanddeployed,but also thenextoneondeck is also a casualtybecauseitisNOTfulfillinganadditiverole.Ratheritisservingasareplacement,aprematureoneatthat,thefinaltallybeingonebrokensolarpanelandonea“lostopportunity”.Thedefinitionofan“opportunitycost”iswhenenergyorresourcesareexpendedoneway,andbydoingsoyouarepreventedfromdoingsomethingelse,perhapssomewhereelsethatwouldhavebeenmoreprofitable.Theoutcomeorresultsfromwhatever thatother thingisthatyouCOULDhaveexpendedenergyandresourcesonwillneverbeknownbecauseyouchosetofocuselsewhere.Itsoundslikeabunchofsmokeandmirrorsbutwhenyoureallybreakitdownintoacost/benefitdecision,itjustmakessensetoprotectyourhardworksoyoucankeep replicatingwhatworks insteadofwastingyour timeandmoneyby savinga fewdollarsupfrontbyusinginferiorglass.

Onecontributingfactorinthecostoftemperedglassisthatitmustbecuttothefinalsizeprior tobeingconvertedbecauseafter theprocess is complete, alterationsarenotpossible.Oncecut,welearnedfromMarkthat theglass is thensanded,washed, inspected,andthenheatedtoover600°C/1,112°F,afterwhichitisrapidlycooled.Thecoolingprocess isknownas“quenching”,wherebythereisrapidcoolingoftheouterlayerscausingtheinnerlayerstotrytopullfreeascoolsatamorenaturalpace.Theinnerlayerseventuallycooldownbutthetension createdby theunevencoolingbetweenlayers is thesourceofstrengthattributed totemperedglass.

TemperedGlass,PolycarbonateorAcrylicCovers,HowtoChoose?Twoprimarydriversinadecisionbetweentemperedglassversessyntheticcoverswillbeyourbudget,andthedesiredlifespanofthesolarpanel.Inanidealsituationtherewouldbeasubstratethatisbothinexpensiveandjusthappenstobeimpervioustotheravagesoflong-termexposuretoUVradiation.Unfortunatelythebestlong-termUVprotectionforasolarpanelsubstrateistemperedglass;theunfortunatepartistheexpense.Inspiteoftheexpense,commerciallymanufacturedsolarmodulesincludetemperedglassalmostexclusivelyforgoodreason,topmostissafety.Temperedglasswillshatterifstruckwithsufficientforcebutunliketypicalhouseholdglassitdoesnotbreakintopotentiallylethalshards.Instead,itshattersintoverysmallpiecesthatstayconfinedwithinthesyntheticlayersembeddedduringmanufacturingprocessforthatverypurpose.Temperedglassdoeshaveexcellentthermalproperties,andlowironforbetterlightspectrumpenetration.SincetemperedglassisnotinjeopardyofdiscolorationfromextendedUVexposurethereisnoneedforfilteringagentsasthereareinsyntheticcovers.Yellowingisanindicationthattheacrylicorpolycarbonateisbreakingdownatthemolecularlevelandisvisuallyobviousbythetrademarkyellowing.Thisyellowingreducestheamountofphotonsabletoaccessthesolarcellsandplacesthesolarmoduleatriskofshatteringbecausethesyntheticmaterialbecomesbrittleasitbreaksdown.ModernsyntheticproductshaveadvancedinUVfiltration

technologygivingthemlongerservicelife,butthatsamefiltrationblockssomeofthesunraysusefulforgeneratingelectricity.Thecostoftemperedglassishigherduetothespecializednatureoftheproductandtheinabilitytoalterthesizeoncethepiecehasbeencutandthenexposedtothetemperingprocess.Shippingcostsareexpensivewhetherpurchasedonlineoratalocalglassshopsincetheshopwilllikelyhavethetemperedglassmadeelsewhere.Packagingtoensurethegreatestpossibleprotectionrequiresanirregularlyshaped,bulkyboxthatrequiresfragilehandling.ThecombinedcostisgoingtobemorethanadrivetothelocalhardwarestoreforasheetofacrylicorpolycarbonatebuttheinvestmentintemperedglasswillpaydividendsfordecadestocomebecausethesolarpanelwillbeinserviceformanyyearsaftersyntheticshavesuccumbedtotheeffectsofUVradiation.

Idonotsuggestinanywaythatsyntheticmaterialsareinferiorasachoiceforsubstrates;infact,theproductdevelopmentscontinuetoimproveservicelife.Infact,someofthetop-tiermanufacturers are now offering a warranty against yellowing for a decade. There areadditional benefits to polycarbonate and acrylic such as the superior impact resistancecompared toglass.Whenheftingyoursolarmoduleupontoa rooftopsolararrayyouwillappreciatethe50%reductioninweightcomparedtotemperedglass.Ihaveusedbothacrylicandpolycarbonateforthecoversonsolarpanelsofvarioussizesandmyruleofthumbisthatfor rack-destined solar panels, tempered glass is used. Smaller battery charging type solarpanelshavesyntheticcoversbecausetheycanbecuttosizeeconomicallybymeathome.Iam not concerned about yellowing because the smaller solar modules used for batterycharging typically do not stay out in the direct sunlight longer than it takes to charge anindividual set of batteries. They are stored insidebetween useswhich can help extend theservicelifeindefinitelysincetheyarealsoshelteredfromtemperatureextremeswhenstoredindoors.Acrylic is more rigid than polycarbonate which makes it less likely to sag afterprolongedexposuretotheeffectsofweathering.Irrespectiveofwhichsyntheticcovertypeisused, it is still a goodpractice to use spacers like thePonyBeads discussed earlier. If thesaggingisseverethereisachanceitcouldactuallysaglowenoughtomakecontactwiththesolarcellswhichwouldnotbetolerantofsuchcontact.Minorsagisexpectedasthesyntheticmaterialsgetsofterwhenindirect,hotsunlight.Eventhemorerigidacryliccoverswillsag

eventuallyandtherefore,abracingsystemwhetherPonyBeadsorsomethingsimilarshouldbeusedtohelpprotectthesolarcells.Whateveryouuseshouldbedonesparingly,andwithobjectsthatwillNOTcastshadowsontothesolarcells.

Opticscomesintoplaywhendiscussingsubstratesthatserveasacoveringoverthesolarcellstringswhethertemperedglass,acrylic,orpolycarbonate.Youwanttheleastamountofresistancebetweentheinboundphotonsfromthesun,andthehungrilywaitingSTRINGSofsolarcells.Thescienceofitisbeyondthescopeofthiswritingbutabriefoverviewisinorder.Thegeneralideaisthatphotonsoriginatingonthesunarecomprisedofenergyandmomentumsincetheyhavenomassoftheirown.Infact,weseesomeoftheenergyintheformofvisiblelight,buttherearealsobandsofenergywecannotseewiththenakedeyebecausetheyareemittedintheultravioletandinfraredlightspectrums.Nowitgetstechnicalaswegetintowhichwavelengthsareabsorbedandwhichareallowedtopassthrough,buttheunderlyingprincipleisthatsomeUVlightgetsthrough,somedoesnot.Ultravioletlightexposurecausesacrylicandpolycarbonatesheetsdamageoverlongperiodsoftime.Someofthisdamageisvisibleintheformofyellowingwhilesomeisnotsuchasthelossofelasticity,orinotherwords,theybecomebrittle.InordertostaveoffdamagefromprolongedUVradiation,someacrylicandpolycarbonatesheetingistreatedwithacoatingofUVrepellant.Thechemicalnatureoftherepellantisatradesecretbutthetopmanufacturer’swarrantyagainstyellowingforadecade,asignificantimprovementoverprevioustechnology.However,therehastobeabalancebetweentheUVprotectionsofferedbytherepellantwhilesimultaneouslyallowingamaximumnumberofphotonsthroughtomakecontactwiththesolarcells.Ihaveresearchedthistopicindepthandmyunderstandingisthatfromourperspective(theDIYsolarpanelhandcrafters),theUVprotectionthatisaddedtoacrylicorpolycarbonatesheetsisnotsufficienttonegativelyaffectthesolarpaneloutput.Oneauthorsuggestedthatkeepingthesolarpanelsclean,regularlywipingdustfromthecollectionsurfacesissufficienttooffsetanyhindrancetoperformanceresultingfromUVcoatings.

BynowitshouldbeobvioustoyouthatsubstrateseithersitunderthesolarcellssothatthePOSITIVE,orbackofthesolarcellsrestonit,orthesolarcellsareaffixedtotheundersideofthe substrate and the sun-facingNEGATIVE side gathers sunshine through it.When thesubstrateservesasabasethatthesolarcellsreston,wearenotconcernedasmuchwithopticqualitiesrather,wearemostinterestedinwaterproofing.However,whenthesunshinemustpass through the substrate made from tempered glass, acrylic, or polycarbonate, we areconcerned about three categories of properties: 1) Optical, 2) Thermal, and 3) Chemicalproperties.Iamcoveringthisinformationforfamiliarizationpurposes,NOTtosuggestyouneedtouseanyparticularcovertype,instead,youwillhaveenoughinformationtomakeaninformeddecisionwhenitcomestimetopurchasethesubstrateoracoverforthesolarpanel.Indeed, there are several other properties such asmechanical, and electrical to name two,however,sinceitisadisciplinealluntoitself,Iamfocusingonthepropertiesmostpertinenttous.Thepropertiesareasfollows:

ThermalProperties:Coefficient of Thermal Expansion - has to do with how much the product (glass,polycarbonate, or acrylic) will expand in extreme heat, or contract in extreme cold. Forexample,acrylicsheetsexpandupto8-timesmorethanapieceofglasswould.Thisneedstobekeptinmindwhenusingacrylicorpolycarbonatebecausetheywilldefinitelybemoving

onadailybasisasthesolarpanelheatsupinthedirectsunlight.Themethodsusedtosecurethecovertothesubstratebaseneedstoallowforminormovementasthecoverwillwanttoexpandandovertime,willstartsagging.ThePonyBeadsorothersupportobjectswillpreventsaggingfromcausingdamagetothesolarcellsifthesaggingbecomesextreme.Thisisalsowhyweplacethecrimpsinthetabbingwiresconnectingindividualsolarcellsinastring,sotheytoocanexpand.

OpticalProperties:RefractiveIndex-hastodowithhowmuchtheincomingsunlightis“bent”whenenteringthe glass or synthetic surfaces. For example, polycarbonate has a refractive index of 1.49whichmeansitfiltersUVlightatwavelengthsbelow300mm,almostthesameasstandardglass.Dispersion-isameasureoftheseparationofsunlightintoitscomponentcolorsinthelightspectrum.

Transmission-isameasurementofthelightpassingthroughthematerial.

Reflectivity-measurestheamountoflightreturnedoffthesurface.

Absorption - measures the amount of light energy that is converted into heat that is nottransmittednorreflected.

ChemicalProperties:Glasscontainssodiumoralkalimetalionsthatmigratetothesurfaceofglassafterexposuretoliquidsorwatervapor.ThiscausessaltorAlkalileachingwhichmanifestitselfbyacloudyorhazy appearance to the glass. Tempered glass made specifically for photovoltaics (solarpanels)isusuallycoatedwithsilicondioxidetoserveasabarrieragainstthissortofdecay.Thismechanismfordecay isabsent in thesyntheticcoveringmaterialsbut theyhave theirownvulnerabilities related toUVexposureaswellasprotections. Iwouldsurmise that theleachingprocesstakesaverylongtimemeasuredindecadesasallofushaveobservedglassthat has been exposed to direct sunlight for many decades that hasn’t started leachingirrespectiveoftheclimate.Byextension,IthinkitveryprudenttousetemperedglassandIam equally confident that if leaching did occur, it would be so far in the future as to beinconsequentialtousinthisapplication.

In Conclusion, it is really a matter of personal preference based upon cost and expectedlifespanofyoursolarmodule. Ifyouneed togetasolarpanelupandprovidingelectricityquickly,likeyesterday,thesyntheticcoversarereadilyavailable,comparativelyinexpensive,andthebestpartisthattheycanbecuttocustomsizes.Whenselectingsyntheticcoversorsubstrates,theyneedtobethickenoughtoprovidethesupportneededbythesolarcells,butnotthickenoughtoblockinboundphotons.Shoptheproductsbeforepurchasingbecauseyouwant at the very least, to examine the product for the properties we discussed above andcompareyourdecisionfinaliststofindthebestmatch.Usingtemperedglassismypersonalchoice for providing the highest level of longevity, yet I do employ both acrylic andpolycarbonateforcustomorbatteryrechargingsolarpanels.

NOWTOCONNECTTHESTRINGSASPROMISED… .

19a)therearetwopossiblescenesfacingyourightnow.

1. YouarelayingtheSTRINGSontoasubstrate,sun-facingorNEGATIVEsidesofthesolarcellsfacingupwards,whichthenwillbecoveredbytemperedglass,Plexiglas,oracrylicsheeting.Noencapsulatingmaterialused.

Or…

2. Youareusingasinglepieceof temperedglass,acrylic,orpolycarbonateand thatsinglepieceISthesubstrate.Inthiscaseyoumustlaythestringsdownsothatthefront,sun-facingsideofthesolarcellsisfacingdownwardandyouarelookingdownattheback side, or POSITIVE side of the solar cell STRINGS.Remember,when you aredonewiththeconnectingandencapsulating,thesolarpanelwillbeflippedoverandthesidethatiscurrentlyfacingdownwardtowardsthefloorwillbethesidefacingthesun.

19b)sizingtheSubstrate-nomatterthematerial,thesubstratemustprovideaplatformsufficientinsizetoholdhowevermanySTRINGSyouareinstallingintothesubstrate.Youcanpre-measurethesubstratewidthbymultiplyingthewidthofasinglesolarcellononeoftheSTRINGS,bythenumberofSTRINGSbeingplacedside-by-sideonthesubstrate.Forexample,ifyoucreatedfourSTRINGSusing3”inchx6”inchpolycrystallinesolarcells,yourcalculationswouldlooklikethis:6”inchwidthx4-STRINGS=24”incheswide.AddsomeroomforslightlyimperfectlyalignedSTRINGSandtemperaturerelatedexpansion;twoinchesonallsidesshouldsuffice.Thiswouldgiveyouasubstratewidthof24”inches+2”inchesforexpansion=26”inch-widesubstrate.ThecalculationforthelengthisthesamealthoughnowthatyouhaveSTRINGSreadytomount,youcanbasicallytakethelengthofanySTRING,addthreeinchesonthetop,sameforthebottom,andyounowhaveasubstrateoutlinethatcanbecutoutofthesubstratesheet(ifusingsynthetic).Examinethephotosatthepagebottom;themiddlephotodepictstheplacementofthebuswiresinrelationtotabbingwiresandtheendofthesolarpanel.ThepicturetotheleftdepictsasubstratewhichhashadtheSTRINGSinstalledandissimplywaitingforacovertobeinstalled.Remember,weareNOTusingencapsulatingmaterialsothewaterproofingofthatbottomsubstrateisveryimportant,sofollowthestepsIoutlinedearlierinvolvingpaintingacoatofsiliconcaulkingallaroundthesubstrateevenifitisprimedandpainted.Notealsointhatleftphoto,thesidesofthesubstratehaverailsofwoodonwhichwesecurethecover.ThesiderailsmustbewideenoughtoprovideagoodpurchaseforthecoveryouselectsinceyouwillbebothgluingANDscrewingthecoverdown.TherailscannotbetootallortheywillcastashadowovertheSTRINGSastheysitinsidethesubstratecollectingphotonslaterintheday.TherailsneedonlyprovideenoughclearancesothatIFacovershouldsag,itwon’tmakecontactwithyoursolarcellsastheywouldfractureforcertain.PlacingthespacerssuchasthePonyBeadsisabsolutelycriticalinthesetypeboxesbecausethesyntheticcoverswillsagtosomedegreeafteracertainamountoftime.Thisisnormalsodon’tpaniconedaywhenyounoticetheformerlyflatsheetofacryliccoveringyourpanelnowlooksmorelikeawavywatersurface,itisfinesolongasyouhavethe

spacersinplace.

SizingTemperedGlassSubstrates-mustbedoneatthemanufacturingfacilityproducingtheglass.Unlikeacrylicorpolycarbonatesheetswhichcanbecustomcuteasily,temperedglasscannotbecutafterundergoingthetemperingprocess.Thisiswhereplanningisimportant;youmustknowexactlythetypeandnumberofsolarcellsthatwillbeusedintheconstructionofthesolarpanelneedingasubstrate.Mostpeoplesellingtemperedglassforuseinsolarpanelconstructionwillknowexactlywhatyouneedifyouprovidethetwoitems,numberofcellsandthemeasurementofthespecifictypeofsolarcellyouareusing.Yourrequestwhetherinpersonoronlinewillbemetwithfamiliarityandtheywillrecommendthesizecommensuratewithyoursolarpanelsoyouwon’thavetomeasure.Ifyoudidneedtomeasureyouwouldfollowthesameprocessasfornon-glasssubstratestoderivethemeasurements.

19c)FORSCENERIO“A”-FirstSTRINGONTOSUBSTRATE

**Thisappliestotheboxtypesubstrateswherethesun-facingnegativesideistowardsyouasyouinstalltheSTRINGSontothesubstrate.

Set the substrate onto a stable,well illuminated surface that is tall enough for you to sitcomfortably while soldering without needing to bend uncomfortably. Retrieve the firstSTRINGfromwhereyouhavebeensafelystoringitawayfromdanger.SettheSTRINGontoaflatsurfaceOTHERthanthesubstratebecauseyouaregoingtocleantheSTRING.Usingthequalitybrushesyoupurchased,gentlybrushthesun-facingsideofthesolarcellswithaside-to-sidemotionandremoveanydustthathassettledduringstorage.Oncedusted,pickuptheSTRINGandsetitgentlyontothesubstrateoneithertheleftorrightsideofthesubstrate.YoucanpickupaSTRINGbythetabbingwiresateitherendifyouhavelargeenoughhands.Ifnot,itmightbeeasiertomovetheSTRINGmuchlikemovingarowofcookiesoffacookiesheet.YoucangingerlyslidetheentireSTRINGontoalong,thinpieceofcardboardsothatyou aremoving theSTRINGon a solid surface.Whenyou deposit theSTRINGonto thesubstrate, simply lineup thecardboardwith the substrateand tilt thecardboardat agentleangle.Whiletilting,gentlyvibratethecardboardtoassistgravityingettingtheSTRINGtoslidedownontothesubstrate.YoucantakecomfortinthedurabilityofyourSTRINGbecauseyou took the time to paint silicon caulking over the tabbing wire connections giving theSTRINGmuchgreatersurvivability.OncetheSTRINGisonthesubstrate,positionitbyhalflifting, half pulling the STRING in whichever direction needed to align it to one side oranother.

NOTE:Takenoticeofthe“endruns”,oneitherendoftheSTRINGyoujustsetinplace.One sidewill have tabbingwire strips coming fromunderneath the last solar cell in theSTRINGwhicharethePOSITIVEleads.Theothersidewillhavetwotabbingwirestripshangingover,buttheseoriginateonthetop,sun-facingsideofthelastsolarcellonthatend of the STRING and are theNEGATIVE leads.Every STRINGmust have oppositepolaritiesateachendandifnot,somethingwasdonewrongwhencreatingtheSTRING.This firstSTRINGon the substrate sets thepattern for thenextSTRINGplacedon thesubstrate as they will alternate polarity. For example, if the first STRING has placedPOSITIVEleadsatthetopofthesubstrate,theSTRINGplacedrightnexttothefirstonewould haveNEGATIVE leads at the top. Think of it in terms of bunks in a militarybarracks, for us veteranswho attended that friendly college-like environment known asBootCamp.Recall that the barrackswere absurdlywide, longsingle rooms thathousedseveral rowsof lockersandbunks. If youalso recall that thebunkswerearranged inahead-to-footpatterndowneachrow,andforagoodreason.Unfortunatelyforourexample,notforthesamereason,itwasforpreventionofairborneillnessesandbystaggeringtheheadsofthemen,thereislesschanceofspreadingsickness.InasolarpanelweneedthatPOSITIVE toNEGATIVE flow of current or electrons because it allows the volts to

combineandcollectasitflowsinthat“series”configuration.

19c)FORSCENERIO“B”FirstSTRINGONTOSUBSTRATE

Ifusingasinglesheetoftemperedglass,acrylic,orpolycarbonate,theframemustbefirmlysecuredinplacewithclearsiliconcaulkingbetweentheglassedgesthatrestonthealuminumframe.ThemostnotabledifferencebetweenlayingSTRINGSdownontoglasssurfacescomparedtowoodistheeaseofmovementonthecomparativelyslipperysurfaceoftheglass.WhilethismakesforeasypositioningoftheSTRING,plentyofheadachesfollowbecauseaftermakingveryminorpositioningadjustments,youdon’tWANTthoseSTRINGSmovingaroundATALL!Thereisaremedy,wejustcannotemployituntilthelastSTRINGhasbeenlaidinplaceandnofurtheradjustmentsneedtobemade.ThefixisadabofclearsiliconcaulkingonthecornersofalternatingsolarcellsdowneachSTRINGtopreventslippagewhileencapsulating.Thatnotwithstanding,aseconddifferenceisthatwelaytheseSTRINGSwiththesun-facing,orNEGATIVEsideDOWNanddirectlyontothetemperedglasssurface.SonowpickupthefirstSTRINGtobeinstalledeitherbythetabbingwirestripsontheendsorbyothermeans,andgentlysettheSTRINGontothesubstrate.YouwillbeabletoeasilyslidetheSTRINGintopositiononcesafelydownontothesurface,andbeingthefirstoffourSTRINGS,youwillneedtopositionittothefarthestleft,orrightonthesubstrate.Notethepolarity,whichsidethetabbingwirestripsareprotruding,fromunderorontopofthelastsolarcellintheSTRING.ThiswillhelpwhenplacingthenextSTRINGbecausethe“end-runs”mustbeofoppositepolarity.

19d)FORSCENERIO“A”-SecondSTRINGONTOSUBSTRATEYounowhavebeforeyouasubstratecontainingasingleSTRINGthatissun-facingorNEGATIVEsideisfacingupwardsandyouarenowaddingasecondSTRINGimmediatelynexttoit.ExaminethepolarityaswrittenatthetopofthesubstrateabovethefirstSTRING,noteitandplacetheoppositepolaritynexttoitasyouinsertthissecondSTRING.TheendresultshouldbeaPOSITIVEpairoftabbingwiresnexttoaNEGATIVEpaircomingfromunderthelastcellintheSTRING.Oncedown,carefullyhalf-lift,half-pulltheSTRINGintopositionparallelingthefirstSTRINGandabout¼inchapart,thewidthofa#2pencileraser.NowthatyouhavetwoSTRINGSinplace,youhaveagoodideaofhowthespacingwillbewhentheremainingtwo,orevenpossiblyasingleSTRINGisadded.YouwillneedalittlespaceinwhichtoworkwhilesecuringtheSTRINGSinplacewithclearsiliconcaulking.Withapencilorfinepointballpen,traceafaintoutlineonthesubstrateatthecornersofthesolarcellsinthefirstandsecondSTRINGSasthesitonthesubstrate.Writingdirectlyonthesubstrateisperfectlyfine,justmakeyourlineslighter,justenoughtomakeouttheoutlineforguidingyourplacementofsiliconcaulkingdabsthatwillbeusedtoaffixtheSTRINGStothesubstrate.UsetheopenspaceonthesubstratewheretheremainingtwoSTRINGSwillbegoing,totemporarilyholdthetwoSTRINGSyoujusttracedtheedgesaround.Gentlymovethemasidebythesamemethodusedtotransportthemintopositionandgograbyourcaulkingapplicationgunandmakecertainitisloadedwithatubeoffresh,clearsiliconecaulking.Usethecaulkingapplicatorguntoapplypencilerasersizeddabsonfourplacesoneachsolarcellposition,keepinginmindthatthedabswillbeservingasanadhesiveanddonotneedtobeverylarge.Remember,thesearedelicatewafersandwillnottolerateheavydownwardpressureappliedinaneffortto“mash”downanoverlygenerouscaulkingdab.WhengentlysettingtheSTRINGinplaceoverthecaulkingdabs,theweightoftheSTRINGplusaVERY

gentlemassagingmotionisallthepressurerequiredtobondthecaulkingwiththeSTRING.So,afterplacingtheappropriatequantityofproperlysized“dabs”ofcaulkingdirectlyontothesubstrate,pickupthefirstSTRINGandgentlysetitintopositionineithertheleft,orright-mostsideoftheframecorrespondingtowhereyouhavedepositedthecaulkingdabs.Asindicated,therecanbeonlythesoftestofpressureappliedtotheindividualsolarcellsintheSTRINGthatyoujustsetinplace,soifthereneedstobesomeminormanipulationofthecellsitshouldbedonewithasoftpaintbrush.IfyougototheexclusiveHow-Tovideolibrary,watchthevideorelatedtoworkingtheencapsulantintothesubstrateentitled,“How-ToRemoveAirBubblesfromEncapsulants”.Thisdemonstrationvideowillteachyouamethodforusingastandard2”inchpaintbrushtoapplydownwardpressuredirectlyontosolarcellswithoutexposingtheSTRINGorsolarcellscontainedthereintoriskofdestruction.ItwillrequireverygentlemassagingwiththepaintbrushtoflattenoutthecaulkingdabsundertheSTRING,butjustenoughtogivethecaulkingareasonablegrasptothePOSITIVEsideoftheSTRING.

19d)FORSCENERIO“B”-SecondSTRINGONTOSUBSTRATEItistimetoplacethesecondSTRINGnexttothefirst,takingnoteofthepolarityatthetopofthefirstSTRING.PlacetheendcontainingtheoppositepolaritynexttothefirstSTRINGsuchthattheorderisPOSITIVE,thenNEGATIVE,orinreverseorder,yousimplyCANNOThavelike-polaritiesnexttoeachother.Oncedownontothesurface,gentlyslideitintopositionabout¼inchapart,visuallyuniform,andverifyingthepolaritiesareoppositeastheysitside-by-side.ThisisagoodtimetouseacoupleofyourcushionedweightstosteadythesetwoSTRINGSasyoucontinuetowork.Iamgoingtosaveyoutimereadingfurtherstepsthatmirrorthesetwo.

In order to complete the placement of the remaining two STRINGS, simply repeat the

alternationofpolarityattheendrunsasyouinstalltheSTRINGS.TrytoaligntheSTRINGSasclosetoperfectasyoucanbeforethenextstep.

19e)FORSCENERIO“A”–Third&FourthSTRINGSONTOSUBSTRATE With two STRINGS already secured in place, you are now ready to place the third byfollowingthealternatingpolarityprocess.SinceyouhavetwoSTRINGSfirmlyinplace, itdoesn’ttakeamassivestretchoftheimaginationtoestimatewherethenextSTRINGwillbesetting to include the fairly precise positionof individual solar cells. If not, you canuse apenciltodrawoutfeintlinestouseasguidesbecauseyouaregoingtobedroppingthedabsofsiliconcaulking.Thedabsshouldbeplacedasbefore,inseveralrandomplacesoneachsolarcell’sposition,aboutthesizeofa#2pencileraser.Verifythepolarityoftheexistingendruns,place the new STRING over the silicon dabs and massage it into position. You will beeyeballing this STRING unless you had previously drawn guidelines, but once you areconfidentitissecurelyintheproperposition,repeattheprocessandinstallthefinalSTRING.WiththisfinalSTRING,makecertainthepolarityiscorrectbeforeplacingitontothesilicondabs.Whendone,youshouldhavefourSTRINGSlaidinstraight,parallellinesinrelationtoone another, and eight (8) tabbing wire strips protruding from the each end of the solarmodule.

20)Nowwewillconnectthe“end-runs”-andatthisstagethesubstratetypedoesmatterastheconnectionprocessisthesameregardless.Thisisthetimetodiscussthewayelectricityflowsinacircuitbecauseyouneedtounderstandtheone-waytravelofelectronflowtoappreciatewhyweroutethetabbingwiresthewaywedo.Afterreviewingtheinformationonthenextpageaboutelectriccircuits,considerthewayyouplacedthestringsontothesubstrate,alternatingpolaritywitheachstring.YoulaidthePOSITIVEpolarityofthefirststringnexttotheNEGATIVEpolarityofthenextinline,andsoon.Nowthinkaboutthewayyouplace“AA”batteriesintoanyelectronicitemrequiringmorethanonebattery.YoulaythemintothedeviceinthesamefashionastheSTRINGSwerelaidontothesubstrate.Examinethephotoonthenextpagedepictingauniversalbatterycompartmentandspecificallytakenoteofthealternatingpolarityoftheslotsthebatteriesrestin.JustlikeourSTRINGS,thesebatterieslayside-by-sidewithpolaritiesneedingtobeoppositewheretheyrestinthecompartment.Thiscanalsobesupportedbythealternatinglocationofthespringsinthebatterychargingcompartment(nextpage);becausethespringcanalwaysbecorrelatedwiththeNEGATIVEpolarityonabattery.ItisauniversaltruththatthespringwillalwayspushthebatteriesupwardfromtheNEGATIVE,orbottomofthebattery.Whenlookingatthebatterycompartmentphoto,trytoimaginewiththeminds’eye,theimageofabatterysuperimposedoverthesolarcellSTRINGwiththepolaritiesaligned.WhetherbatteriesorsolarcellSTRINGS,theyfollowtheexactsameprinciplesfortheflowofelectrons,fromtheNEGATIVEterminalonthefirstbatteryintothePOSITIVEterminalofthebatterynexttoit,throughthebattery,andoutthroughthebottom,orNEGATIVEterminal.

Infact,wecouldusecomputertrickery,ifIwassuper-slick,Icouldusegraphicstodepictthestringsfloatingupofftheglasssubstrateanddownintothebatterycompartment.Itworksexactlylikethat,sowhenyouarejoiningthestringsattheend-run,youcanpicturebatteriessittinginacompartmenteitherwaitingforacharge,ortoperformworkintheformofreleasingtheirstoredenergy.

Justasyouworkedfirstwithindividualsolarcellstocreate“PAIRS”,youwillagainbecreating“pairs”,thistimeyouarejoiningtwoSTRINGSbyconnectingtheirtabbingwire“end-runs”.ThemethodforjoiningtwoSTRINGSistoconnectthetabbingwirestripsprotrudingofftheendsofthefirstandsecondSTRINGSwhichMUSTbeofoppositepolarity.Asthestepstoassemblygo,thisisoneofthesimplerstepsbecausetheprocessinvolvessolderingalargebuswiretothetabbingwirestrips.YoursinglegreatestchanceforerroronthisstepisunplannedmovementoftheSTRINGSasyousoldertheend-runtabbingwirestripstothebuswirethatwillconnectthemtoeachother.ThisislessofanissuewiththeSTRINGSthatareheldinplacebythedabsofsiliconcaulking,anddefinitelyafactorwhenthesubstrateistemperedglassorsyntheticmaterial.Therefore,youmayusecushionedweightstosecuretheSTRINGSwhileworkingonend-runs,oryoumayuseclearsiliconcaulkingtosecuretheSTRINGStotheglassorsyntheticcovers.Remember,thesolarcellswillbefacedownonaglasssubstratesoyoucanbemoreliberalwiththeclearsiliconcaulkingsincethereislittlechanceofitbecomingintroducedintopathofsunshineandnegativelyaffectingthesolarmodule’soutput.SimplyapplyadabofclearsiliconcaulkingtothesidesorcornersofeachsolarcellinaSTRING,perhapsonesmall#2pencilerasersizedonatthetopofeachsolarcellandasimilardabonthebottomofeachcell.Youthenuseasmallcraftpaintbrushtospreadtheclearsiliconcaulkingovertheedgeofthesolarcellsothatitispartiallyonthesolarcell,andpartiallyontheglassorsyntheticsurface.AllowittodryforafewhourssothatitiscuredwithsufficientstrengthtogriptheSTRINGbythecombinedeffortofallthetinydabs.AdirectbenefitofusingthecaulkingdabstoholdtheSTRINGSinplaceisthatthecaulkingpreventsthesolarcellsfrombeingliftedupandawayfromthesubstrateoncetheencapsulantispouredoverandaroundtheSTRINGS.IftheSTRINGSfloattothetoplayerofencapsulant,theywon’tcompletelyliftoutofthestill-liquidencapsulantbuttheresultinglayeroverthePOSITIVEstringswillbeextremelythin

J

oncetheencapsulantcures.ThelopsidedthicknessoflayersbetweensidesoftheSTRINGSwillresultinanunevenlevelofprotectionbetweensidesoftheSTRINGS.ToomuchencapsulantbetweentheglassandtheSTRINGSprovidesnoaddedbenefitsincethebacksideoftheSTRINGSwillbemorevulnerabletothehazardsthatencapsulantsaresupposedtoprotectagainst.Rustwillmoreeasilyformonanyexposedtabbingwiresthuscompromisingthehealthandlongevityofthesolarmodule.Similarlythesolarcellswillnotbefullyprotectedagainstincidentalcontacttothevulnerablebacksideofthesolarpanelwhilebeinginstalled,orwhilemounting,perhapsduringextremewindconditionswheredebrisisbeingthrownaround.Conversely,thedabsofclearsiliconcaulkingwillpreventfloatingandallowtheencapsulatingmaterialtoenvelopetheSTRINGScompletelywhichisabsolutelycriticalforthelifespanofthesolarmodule.TherewillbeamoreeffectivemoistureandimpactbarrierifthesolarcellscanrestinacushionequallydistributedbetweenthetopandbottomsidesofthecollectiveSTRINGSwithinthesolarpanelframe.Nowletusgettotheheartofthematterandshowyouhowtoconnectthesestrings.

21)Visuallyconfirmthatend-runsareofoppositepolarity-onthetwoSTRINGSyouareabouttojointogether.YouwillconnectthembyusingastripofBUSWIREthatislongenoughtolayOVERbothsetsoftabbingwirestripsthatareknownasend-runs.WhenconnectingtwoSTRINGStherewillbetwo(2)end-runsneedingtobejoined,onefromeachoftheSTRINGSbeingmated.Remember,weare“series”wiring,fromoneNEGATIVEend-runtotheadjoiningPOSITIVEend-runattheendoftherespectiveSTRINGS.ApieceofBUSWIREapproximately9.5”incheslongwillmakethephysicalconnectionbetweenthetwoend-runs.TheBUSWIREisthethickermetalwirethatparallelstherulerandissittingontopofthetabbingwirestripsthatwillultimatelywraparoundtheBUSWIRE.AlsonotethepresenceofcushionedweightsonthelastsolarcellintheSTRINGS.ThesehelpkeeptheSTRINGSinplacewhileImanipulatethetabbingwiresinordertomaketheconnectionsandsolderingimmediatelythereafter.

22)Useyourpointedtoolstoassistyourfingers-insecuringtheBUSWIREintopositionwhereitwillbesolderedtothetabbingwirestrips.Startwiththetabbingwireclosesttotheedgeofthesolarpanelandwhilepressingthetabbingwiredowntopreventitfromfracturingthesolarcell,bendthetabbingwiresothatitwrapsaroundtheBUSWIREatleastonce,andthenallowtheremnantstofoldneatlybackoveron

itself,orsnipitwithwirecutters.Thisstepisdemonstrated,simplyscantheVQRbarcodeinthelowerrightcornertowatchour“How-To”videotogainfamiliaritybecauseitisdifficulttodescribeinwrittenformbuteasytovisuallyconveybyvideodemonstration.AfterwrappingthetabbingwirearoundtheBUSWIRE,feelfreetomoveontothenexttabbingwireinlineforthesameconnectionstepsofwrappingthethinnertabbingwirearoundthemuchwiderBUSWIRE.ThefoldingprocessofwrappingtabbingwirearoundtheBUSWIREprovidesstrengthandgrip,thesolderingprovidestheelectricconductivitysoimportantinphotovoltaics.

23)DrawalightcoatofRosinFluxPenoverthefourspots-ontheBUSWIREthatistobesolderedrememberingto“wet”theRosinFluxpenfirst.RemovethecapandpushtheRosinFluxpentipdownintoapieceofcardboardtogetthetipsoakedwiththefluxmaterial.ThenlightlyapplyacoatoftheRosinFluxoverthefourplacesyouareabouttosolderinordertojointhestrings.ThismeanspressingthetipagainsttheBUSWIREwhereitwillbemakingcontactwiththetabbingwire.YouwantaslightlyvisiblesheenfromtheRosinFluxpen,takinggreatcaretoensureitdoesnotflowoutsidetheimmediateareawherethesolderingwilltakeplace.RosinFluxisstickyandmakesamessifitflowsalloverandaroundatabbingwire,somethingthatislesslikelyto

happenifthetiphasbeenfirst“wet”priortoapplication.

24)Preparethesoldergunorironby“tinning”thesoldertip-bytouchingtherosincoresolderwireagainsttheheatedtipofthesolderingtool.Thesmallamountofsolderthatcoolsonthetiphelpstoconveyheatfromthesoldertip,intothesurfaceinneedofbonding.Oncetinned,itisnowreadytosoldertheBUSWIREtothetabbingwire.

25)Withthesoldertiphot,andfreshly“tinned”-holdthetiplightlyontopofthefirstsectionofwrappedtabbingwirethathasbeencoatedwithRosinFlux.Youwillseethetincoatingaroundthetabbingwiremelt,whereyouthenlightlytouchthetabbingwirewith a strand of rosin core solder wirewhichwill liquefy and flow around the buswire/tabbingwirecombination.

26)TurnnowtothebottomoftheSTRINGSthathavejustbeenjoined.YouDONOTconnectthesetwoatthebottomexactlyasyoujustdidwiththetop.Instead,youarenowgoingtoconnectthebottomofthesecondSTRING,tothebottomofthethirdSTRINGwhichshouldbeoppositepolarityofeachother.Thisisaccomplishedbyrepeatingthestepfromstep#25whereyoujoinedthetwoSTRINGSatthetopofthesolarmodule.AstripofBUSWIREapproximately9.5”incheslonglaidoverthetwosetsofoverhangingtabbingwirestripsfollowedbywrappingthetabbingwireovertheBUSWIREasyoujustcompletedinstep#25.

27)MovingontotheTOPofthethirdSTRING-whereyouwillconnectthethirdSTRING,tothetopofthefourthSTRING.Again,verifyingthepolarityisoppositeforthesetwofinalconnections,measurethefinalstripofBUSWIREneededtoconnectthesetwofinalstrips.RepeatthestepspreviouslytakentosoldertheBUSWIREtothetabbingwireanduponcompletion,youhavesucceededinconnectingalloftheSTRINGS.

28)AfterconnectingtheSTRINGSontheentiresolarpanel-youwillbeleftwithtwo

STRINGSthatwilleachhaveanend-runnotattached,justtwotabbingstripsoverhanging.TypicallythesetwoSTRINGSthatbecometheanchorfortheoutboundleadaretheleftandrightouter-mostSTRINGS.IfyouhavethreeSTRINGS(itispossibleifyoumakethreeSTRINGSof12-solarcellseach)thesetwoun-occupiedend-runswillbeatoppositeendsofthesolarpanel,itjustcomesoutthatwaybecauseyouareworkingwithanoddnumberofconnections.Itwillmerelyrequireyoutorunawire(alsocalledaconduit)alongtheinsideofthesolarpanel,alongtheinsidewallofthesubstrate.Becauseofthelimiteddistancethewiremusttransporttheelectricalcurrent;thewiresizecanbesmallerthanthatusedtotransporttheenergyfromthesolararraytothebatterybank.Iusea12-guagestrandedcopperwirewhichisperfectforthepurpose,smallenoughtofiteasilyandeffectiveforbringingthePOSITIVEandNEGATIVEleadsintocloseenoughproximitytofitintoasingleprojectboxenclosurewhichwewilltalkaboutlater.

29)POSITIVEOutboundLeadConstruction-connectbuswiretothePOSITIVESTRINGjustmentionedinthepreviousstep.ThisBUSWIREstripwillbesolderedperpendicularacrossthePOSITIVEend-run,coveringthetwotabbingwirestripsprotrudingfromthelastsolarcelloftheSTRING.ThebuswirestripshouldbepointedtowardstheinsideofthesolarpanelsinceyourgoalistohavethebuswirestripsfromtheNEGATIVE,andPOSITIVEleadsmeetinthecenter,topofthesolarpanel.ThisisbecauseyouwillbeconnectingtheseBUSWIREstripstoajunctionorprojectbox.Heavierinsulatedwirewilldeliverthecurrenttowheretheworkneedstobedone,primarilydestinedfordeep-cyclebatteries.Thefirstoutboundlead,thePOSITIVE,requirestwopiecesofbuswireeachbeingfour(4)inches.Thefirstpiecewilllayacrosstheend-runcomingoffthePOSITIVEstring(withtabbingwirecomingfromthenon-sunfacingsideoftheSTRING).Youwillpositionthesmallbuswirestrip,holditinplacewithcushionedweights,andthensolderthisbuswiretothePOSITIVEend-run.TheblockingdiodeisinstalledattheendofthenewlysolderedPOSITIVEoutboundlead,towardsthemid-pointofthesolarpanelframe.AfterthediodeissolderedtothefirstpartofthePOSITIVEbuswire,asecondpieceneedstobeaddedinordertomeettheNEGATIVEoutboundleadatthesolarpanels’mid-point.

30) ConnectaBLOCKINGDIODEtothePOSITIVE buswirestrip installed to thePOSITIVE end run in the previous step. A blocking diode is a device (picturedimmediatelyabove)thatpreventstheelectricitystoredinthebatterybankfromleakingoutthroughthesamesolarpanelthatgeneratedtheelectricityinthefirstplace.Somejunctionboxescontainfactoryinstalledblockingdiodessobesuretocheckifyouarenotcertainbeforecommittingtothisstep.

NOTE:shadeistheuniversalenemyofsolarpanelsasitrobsasolarpanelofconsistentperformance.Infact,shadecanessentiallyneutralizeanarraythatisonlypartiallyshadedbecauseitcreatesaweaklinksotospeakinourchainofsolarcells.Thesolarpanel(s)thatareeitherpartially,ortotallyblockedfromdirectsunshinestopproducingcurrentbecausewithouttheenergyfilledphotonsfromtheSun,thereissimplynotenoughexcitementgoingonwithintoknockelectronsfromtheirrespectivevalencelayers.However,thoseshadedsolarcellsactlikeamagnetforthoseelectronsthathavebeenbrokenfreewithinsolarcellsthatAREinthesunlightthusdisruptingthecurrentflowforthewholesolararray.Justasoursolarpanelbenefitsfromtheadditivevalueofallthosesolarcellsworkingtogether,whenonefailstogeneratecurrentduetoshade,theyALLfail.Onceasolarcell,STRING,orevenasinglesolarpanelcontainedwithinanarraybecomesshaded,theelectronslackingsunshinebecomeunmovingandactasaspongethatabsorbselectronsthatareinboundfromothersolarpanelsinthesamecircuit.MichaelBoxwelldescribesexplicitlythemechanisminhisbookentitled“SolarElectricityHandbook”wherehepointsoutthatbyabsorbingalltheinboundcurrent,hotspotsarecreatedthatcanleadtofireinthesolarpanel.

AtthebottomofthepageIincludeanexampleofcleveringenuitybyahomeownerwhodealswithshadebyhanginghishandcraftedsolarpanelsfromtheevesofthehouse.Hewasabletoachievetheproperorientation(south)andthetiltangle(hisissettoanoptimumfixedyear-roundanglearrivedatbytheformula,“90°-hislatitude(33°)=atiltangleof57°)byusingPVCpipestoprovidethedesiredtiltangle.Heisabletoavoidtheshadingissuesandstillemploysolarpanelswithouthavingtomountthemonhisroof.Onesolutiontoshadingmightincludeusinglessshadesensitivetypesofsolarpanelnamelythosemadewithamorphouscelltechnology.

31)ConnectalengthofBUSWIREfromtheunoccupiedendoftheblockingdiode-thathasthegreycolorbandfacingthedirectionofthebatterybankorchargecontroller.ThisparticularstripofBUSWIREneednotbethesamelengthastheNEGATIVEbuswireleadbecausetheblockingdiodetakesupsomeofthespaceformerlyneedingtobecoveredbytheBUSWIRE.ThisBUSWIREstripwillrunfromwhereitissolderedtotheblockingdiode,tothemid-pointonthesolarpanelframe.Itthenmakesthe90°turntopositionthePOSITIVEleadtoconnectwiththejunctionorprojectbox.

32)CreatetheNEGATIVEoutboundleadthatoriginatesattheEND-RUN-(theonlyEND-RUNthatdoesNOThaveanythingconnectedtothetabbingwirestripsprotrudingfromthetopofthelastsolarcellinthatSTRING).ThelengthofthisparticularBUSWIREshouldbethefulldistancebetweentheEND-RUN,andthemid-pointofthesolarpanelframe(asmarkedintheHow-Tovideo).Itmustthenalsomakethe90°turnupwardstobeabletoconnectinsidetheprojectorjunctionbox.BuswireisusedforjoiningSTRINGSaswellasfortheoutboundleads,andtheycannevercomeintocontactwitheachotheratanytimeinsidethesolarmodule.Thereistheveryslightpossibilityofcreatingsuchcontactifwearenotcarefulwhencreatingtheoutboundleads.ThepaththesespecificbuswirestakeputsthemincloseproximitytotheSTRINGconnectionsalongthetopoftheframeontheinside.Noticeinthephoto

belowhowtheBUSWIREstripsdonottoucheachotherirrespectiveofthefunction.TheoutboundleadsrunabovethebuswiresegmentsjoiningSTRINGSbutareasfarawayfromthealuminumframeaspossible.Theframeismadefromaluminumandwillshort-circuitthesolarpanelifanycontactwasmadebetweenBUSWIRESofoppositepolarity.

InordertoensurethatcontactbetweenBUSWIREScannotoccurasresultoftemperaturerelatedexpansionorcontractioninsidethesolarpanel,alloftheBUSWIREScanbecoatedwithclearsiliconcaulking.AlightcoatingofthecaulkingwillprovideprotectionagainstmoistureandservetoanchortheBUSWIREtothesubstrateatkeypointswheremovementwouldbeproblematic.Justadabunderahalfdozenpointsoneachleadshouldsuffice.NoteinthephotobelowhowtheyellowcoatedNEGATIVEoutgoingleadisratherlanky,clearlyinneedofananchortopreventanyincidentalcontact.

33)YellowcoloringisnotapartoftheactualNEGATIVEoutboundlead;Imerely

placeditthereforeaseofvisualcomparisontoitssurroundings.Itwasremovedafterthephotographywascompleted.OncetheNEGATIVEleadissolderedtothe

respectiveEND-RUN,youwillneedtoextendthisbuswirenearlytotheendofits14”inchlengthsothatitmeetsthePOSITIVEoutboundleadwhereyouhavemarkedthemid-pointoftheframe.Onceinthecenteroftheframe,boththePOSITIVEandNEGATIVEleadsshouldbebentupwardsata90°.Aftermakingthesharpturnwiththebuswiretopointbothleadsstraightupintotheair,thereneedstobeatleastoneinchofwireremainingthatispointedupwardssotheconnectioncanbemadewiththeprojectorjunctionbox.Youhavetwochoicesonhowtoputyoursolarpanelintoservice,1)Connectwithothersolarpanelsonanarray(multiplesolarpanelsonarackingsystem)or2)Connectthesolarpaneltoachargecontrollerforusechargingbatterieseitherdeepcycle,orrechargeablebatteryconfigurationslikebatteryoperatedcordlesstools,laptopsorotherdevicesthatoperateoffdirectcurrentelectricity.Themoresolarpanelsyoubuildthemorepoweryouwillbeabletogenerate.

Step4

Encapsulatingyour“WIP”fortheUltimateLong-TermProtectionNotevery“WIP”willbeencapsulatedasthisisapersonalchoice;itjusthappenstobethemosteffectivemethodforreplicatingthetypeofprotectionaffordedsolarpanelsmanufacturedinautomatedfactories.ItisnotpossibletoidenticallyreplicatetheprocessesbecauseitiscarriedoutwithequipmentoutsidethefinancialrealmofthetypicalhomeownerorDIYenthusiast.Havingsaidthis,itisstillpossibletoachievethesamelevelofprotectioninourDIYhandcraftedsolarpanelprojects,providingthesamelevelofinsulationagainstmoisture,dirt,insects,rodents,birds,orotherexternalthreatstotheintegrityofthesolarpanel.Theprimarygoalofthisstageofsolarpanelassemblyistoprovidethebestprotectionagainstmoisturepossible.EncapsulantsdoanexcellentjobofencasingtheSTRINGSinasoft,gel-likesiliconeelastomercoatingthatprovidesoutstandinglong-termprotectionagainsttheelements.Encapsulantsprovideasoft,flexiblecushionforthesolarcellsthatallowsfortemperaturerelatedexpansionandcontractionanditprovidesaphysicalbarrierbetweenthesolarcellsandtheoutsideenvironment.Thereareavarietyofencapsulatingagentsonthemarket,somebetterthanothers,andbasedonmyexperience,thereareonlyacouplethatIwoulduseregularlyandthosearetheonlybrandsIuseformyDIYpanels,QSIL,Solar-Tite,andDowSylgard.

DuringthevideodemonstrationavailableinourSolarTechDIY“How-To”libraryIusedSolar-Tite384atamixratioof2-ouncesofSolar-Titecuringagentto16-ouncesoftheSolar-TiteElastomerBase.IamalsofondofQSIL214,216,and219whichhaveverysimilarpropertiesasSolar-Titeproductsbuttheycureinafractionofthetime.Infact,IhavepouredtheQSILencapsulatingcompoundovermy“WIP”intheearlymorninghoursandwasabletoinstallthesolarpanelthatverysameeveningontoarooftoparray.Deploymentofanewsolarmodulequicklyisadifficultambitiontofindfaultwith,whoisn’texcitedtoputthefruitsoftheirlaboroutintothesunshine?IhavehandcraftedagreatmanysolarpanelsyeteachcompletedpanelelicitsthesamelevelofexcitementasIfeltwiththefirstoneIeverfinished.Theuseofquick-curingencapsulatingproductsdefinitelywillgiveyouquickerdeployment,butyouneedtohaveeverythingreadyandcompletealloftheprocedureswithinaverytightwindowoftime.Whenthemanufacturestatesthecuretimewillbe28-minutes,theyarenotoffbymorethanafewsecondssoyoureallymusthaveproficiencytoavoidtheconsequencesofencapsulantshardeningbeforeyouarereadyforthattohappen.Theslowercuringencapsulatingagentswillallowyoumuchmoretimetoworkwithairbubbles(extractingthem)andtoinstallaTedlarBacksheetwellwithintheextendedcuretimewindow.Itisamatterofpreferenceandproficiency,twocriterionsyouwillpersonallybeinapositiontomakeafterjustalittleexperience.

34)PlumbersPutty-isusedinmydemonstrationvideoaroundtheperimeterofthesubstrate.Thisisdonefortheexpresspurposeofdenyingopenspaceforencapsulanttoflowwhereitservesnopurposeandisthereforeawasteofthevaluablematerial.Noteinthephotobelowhowtheputtyisusedlikeadam,rolledintoroundsectionsgenerallythediameterofapencilbutrolledsmallerorlargerdependingonthespecificareayouareworking.Oncethesectionsofputtyarelaidintoposition,useyourfingerstogentlypushdownontheputtyrollstomakeamoreseamlessbondbetweentheputty-rollandthetemperedglass.Thiswillhelppreventencapsulantfromflowingundertheputtyrollsandgoingtowaste.Takecarenottocrushtheputtyrollswhenpushingdown,youdon’twanttoaltertheirshapesuchthattheencapsulantmightflowOVERtheputtysections.Thereisanotherriskintheformofleakagefromthecornersofthealuminumframeontowhichthetemperedglasssubstrateisaffixed.Ifsiliconcaulkingisnotusedtosealthecorners,ANDifputtyisnotusedtostoptheflowofencapsulant,itwillliterallyleakoutfromallfourcornersoftheframelongbeforeithasthechancetocure.Typicallythemainbodyoftheframewillnotleakbecausesiliconcaulkingisusedtobondthealuminumframetothesubstratethus,preventingleakagealongthebody.CornerleakingcanbepreventedbycontinuingthecaulkingbeadallthewayUPthecornerswhenlayingtheinitialcaulkingbeadwheninstallingthesubstrateontotheframe.Oncetheencapsulatingmaterialiscured,gentlypulluptheplumbersputtyoutofthesolarpanelbyeitherextractingtheputtyrollsin-tactorgentlydiggingoutthecrumbledremnants.IhaveneverquantifiedthefiscalsavingsfromusingtheputtytocloseofftheareasitdoesbutIknowonethingforcertain,itallowsmoreofeachencapsulantbatchtobuildupwhereitismostneeded,surroundingthesolarcells.

35)Removingairbubblesor“de-airing”encapsulantsaftermixingcompounds,andhowthisprocessimpactsyourcuringtimetable.

Havingsaidallthatearlieraboutthesenseofprideandspeedyaccesstoyourfunctioningsolarpanel,therearesomethingsyouneedtoknowaboutthesuper-quickcuringencapsulatingproducts.WhenthemanufacturersuppliedTechnicalDataSheetindicatesthatcuringcommencestwenty-eightminutesafterthetwoingredientsaremixed,theyarenotoffbymuchmorethanafewseconds.Further,theypointoutthatthehotteritisoutside,thequickerQSILbrandencapsulantscure.Whiletheclockistickingdown,youmustfirstremovetheairbubblesusingthepumpIdemonstrateintheappropriatelyentitled“How-To”videoinourexclusiveYouTubevideolibrary.RemovalofairbubblesisspecifiedintheQSILinstructionsandsothisisnotanoptionalstep,thetechnicaldataspecifiestheneedfor“DE-AERATION”aftermixing(unlessthemixisdonebymachine,presumablyinsideavacuumchamber).The“How-ToDe-Air”encapsulatingproductsvideoavailableinourexclusivelibrarydepictsanearlyinvisiblejarthatseemedtocontainanequallyinvisibleliquid.ThetruthisthatIhadalreadypouredthetwocomponents,stirredthem,andthenusedthenegativevacuumpumpthreetimespriortoturningtherecordingdeviceon.Inreality,youwilllikelyintroduceairintothefirstofthetwo-partcompoundwhenyouaddthesecondpart.Remember,thisisextremelydenseliquidthatdoesnotbehavethesameasifaddingwatertocontainersofsimilarproportions.Airistrappedasthetwocomponentsinitiallycomeintocontactandfurtherwhenhand-mixingcommences.Inthedemonstrationvideo,whenIappear

topour“PARTA”followedby“PARTB”intothenearlyinvisiblyglassjarcontainerIamsimulatingtheactofpouring.Ihadalreadypoured,stirred,andde-airedthecontentsofmymiraculouslyinvisiblejar.Iwasnotattemptingtodeceiveasisevidencedbythesecouplesentences,quitesimplyitwouldhavebeentediousforyoutowatchmepumplikeafiend,thenpushthelevertoallowairbackintothejar,torepeatitthreetimesover.TheonlybenefitIsupposewouldhavebeentoseehowitlookswhentheairrisesthroughtheencapsulantundertheeffectsofnegativeairpressureintheun-filledportionofthejar.

WhenutilizingtheMityvachandpumpasdemonstratedinourvideo,eachsqueezeofthepumpisextractingasmallgulpofairfromwithinthejar.Anair-tightsealaroundthejarlidandthepumphoseconnectiononthatlidisessentialfortheMityvactoachieveavacuuminsidethejar.Airisgraduallyremovedfromtheportionofthejarnotoccupiedbyencapsulantuntiltheabsenceofairinthatemptychambercreatesapowerfuldrawonthetrappedairwithintheencapsulant(trappedairisvisibleintheformofbubbles).Eventuallytheairtrappeddeepestwillbedrawnupandoutintothechamberwhichmightrequirebetweenthreetofiveofthepump/releasecycles.Oncethejarisattachedtothelid/pumpdevice,manipulatethehandpumpuntilthegaugereadsapproximately-25Hgontheouterdial.Allowthenegativepressuretodrawthetrappedairupwardsthroughthedenseencapsulant,something

thatwillhappenfairlyquicklyfortheshallowbubbles.Iftherearemanybubblesrisingatthesametime,thebubbleswillformwhatlooksliketheworkofaverysmallbubbleblowingtoy.Bubbleswillbuildinnumbertothepointtheycanenterthevacuumintaketubethatprotrudesthroughthecenterofyourjarlid(ifyouusedasmalljarforsure).Thiswillruinthetubingifyoudon’tcleanitimmediately:however,thiscanbeavoidedbyreleasingtheleverandallowingairbackintothejarwhenthecollectiveassemblyofbubblesstartsgrowinginsize.Thispopsthecollectedairbubblesthathavebeenpulledupandoutoftheencapsulant,witheachreleaseofthevacuumyouwillnoticefewerremainingwithintheencapsulant.YouCANsignificantlyreducetheintroductionofbubbleswhilemixingbymovingslowly,carefully,andtryingnottoallowthemixingtooltobreakthesurfacesotospeak.Isaythatbecauseitmightseemnaturaltotreatthemixingofencapsulantthesameasyouwouldwhenmixingpancakebatter,whippingthethickliquidintofroth.MixingsuchasthiswouldrequireavacuumpumpthelikesofwhichmightbefoundontheInternationalSpaceStation,thetypetheymightusetosucksuspiciouslyOctopus-lookingspacealiensouttheescapepodhatchandintothedarkvoidofspace.

Thebestmixingisdonewithasteady,slow,swirlingmotionthatneedstobeexecutedatslow-motionmoviespeed.ItwillsaveyourforearmmusclesfromanexhaustinganddifficulttaskasthefewerbubblesintroducedwhenmixingmeansfewermaniacalpumpsoftheMityvactogetridofthem.Inconclusiononthetopic,whenusingthequick-cureencapsulantsyouhaveaverylimitedtimetocompletestepsyoupreviouslymayhavetakenyourtimeperformingwithslow-curingencapsulants.Theclockstartstickingthesecondpart“B”isaddedtothecanningjar,andwhiletheremustbeasenseofurgency,youractionsmustbegentle,controlled,andwithhyper-focusonlimitingairbubbleintroduction.Afterpouring,ittakestheviscousliquidafewminutestoself-level,aprocesswhereitslowlyexpandsuntilithasachievedauniformcoatingcommensuratewiththevolumeofencapsulationmaterialpresent.Youmustrealizehowquickly28-minuteswillpassandhowmuchofthistimewillbeconsumedduringthede-airingprocess.Theremustbeampletimefortheencapsulanttoself-levelsoitisinyourbestinteresttominimizethenumberoftimesyouwillbepumpingairoutofthecanningjar.Itispossibletohavetheencapsulantcurebeforeithashadenoughtimetoachieveanysemblanceofself–levelinginfact,itmaystillappearasitlookedafewsecondsafterhavingbeenpouredoverthesubstrate,permanently.Therefore,whenusingquick-curetypeproductsyoumustbeabletocompleteallpreparatoryandapplicationstepsandstillleavetimefortheself-levelingfeaturetowork.Tomakeitmorecomplicated,ifitisveryhotoutsidetheelevatedtemperatureswillshortenthat28-minutescuretimeandmakeitverydifficulttofitallthetasksintothecompressedtimeframe.

HINT:BenefitfromMYmistake,heedthewarningaboutairtemperatureinrelationtocurespeed.Inthenot-to-distantpastIwasabouttofinalizea“WIP”bypouringtheencapsulatingproductQSIL214whichhasanincrediblyfastcuretimeof28-minutes.Curingmeansthattheencapsulatingmaterialundergoesachemicalprocesstheresultofwhichisatransitionfromaliquidstateintogel-likesold.ThedayIhadmyexperienceitwasHOT,tripledigittemperatureinmy

shopwhichacceleratesthecuretime,afactIwasunawareasImixedmybatch.UnawareIwaspastthepointofnoreturnandshouldhavejusttossedthebatchoutandstartedover,Ipoured.Inoticedtwothingsimmediately,thejarwasalmosttoohottoholdwithbarehands,andtheencapsulantwasliterallyhardeninginmid-pourlikepicturesIhaveseenwheresmallwaterfallshavefrozeninmid-fallsomewhereintheArcticTundra.Horrified,ittookaboutanotherbillionthofasecondtorealizeIhadjustruineda“WIP”becauseIcoulddonothingabouttheglobsofunsightlyanderraticpatternsofcleartopographyIhadcreated.AtthesametimeIsuspectedthatwhileitlookedmessy,itwouldprobablyworkperfectlyandsoImixedanewbatchofQSIL.Notuntilafterresearchingwhathadgonewrongandwaitinguntilcoolereveningtemperatures,butthistimeitwassuccessful.Thatnextbatchperformedtheencapsulationintendedbythefirstbatchanduponcuring;itperformedflawlesslyandisinserviceatthistime.Thelasthinthastodowiththeencapsulantasitiscuringonthe“WIP”whetheritisthetraditional,orquick-curing.Thereissomethingaboutencapsulantthatattractsflyinginsectsduringthecuringprocess.Perhapstherearefumesthatinsectsareattractedtobutiftheylandanywhereontheencapsulanttheywillforeverremainapartofthesolarmodule.Youmayattempttoextractthembutusuallytheycomeoutinbits,ifatall,andsoitisfarpreferabletokeepthemfromlandingontheencapsulantatall.Afterpouringandde-airing,coverthe“WIP”withasturdypieceofwoodorglass,anythingthatcoversthemoduleandcansupportitsownweightsoitwon’tsag.IfyouareplanningoninstallingTedlarBacksheet,thatbecomesthepermanentanti-insectbarrier.Ifnotsimplyremovethewoodcovertocheckperiodicallyuntilcured.

35)PreparingtoPourEncapsulant35a)Thefirststepistopositionthe“WIP”insuchamannerthatyouwillbeabletopourthemixedandde-airedencapsulantovertheexposedsideofsolarcellSTRINGS,andafterpouring,beabletoobservetheundersideofthesolarcellSTRINGSwithunobstructedaccess.Youwillneed tovisuallymonitor theprogressof encapsulant as it self-levels in the spacebetweenthesolarcellsandtemperedglass.Thebestsolutionistocreateaworkplatformthatgivesyoufullaccesstothepourareafromabove,butalsotheabilitytoseetheundersidetogaugewhethertheself-levelingprocessisinneedofyourhelp.Themostadvantageousaccessposition to see the underside while simultaneously providing stable, level support for the“WIP”istouseeitheranoldunwantedtable,orapieceofwoodthathasbeencutwithaholemeasuringslightlysmaller than the“WIP”.Thenyousimplyprovidesupport for thewoodsurfacethatwillallowyoufreemovementUNDERthetableasyouvisuallyinspectforairpockets.Unlessyour skeleton ismadeofPlaydough, it is almost impossible toget agoodvisualinspectionunlessyouareabletolayonyourback,underthe“WIP”.So,ifyoucannotspareanoldtable,athickpieceoflevelplywoodwouldbeasuitablereplacement.Cutoutthe

same size hole as youwould have from the table, use a pair of sturdy saw-horses, cinderblocks,anythingthatwillallowyoutolayonyourbackandeasilylookthroughthe‘WIP”afterpouring theencapsulatingmaterial.OnthenextpageyouwillseeaphotographofthetableIusefortheencapsulatingprocess,anolddinnertablethathadserveditslastmealsometimeago.YouneedtotaketheappropriatestepstoensurethatthetableyoucutopenisNOTyourspouse’familyheirloom,orperhapsstillservingactivelyasthefamilyeatingplatformdueforserviceinitscustomaryrolethisveryday.Providingallisclear,andyouhavecutoutthehole,youneedonlyensurethetableislevel,andthatyouhavecutthepropersizehole.Thelastthingyouneedtohavehappenisforthe“WIP”tofallthroughtheover-sizedholebecauseIamnotfamiliarwithanysolarpanelcapableofsurvivingafallfromsuchaheight.

35b)Withthetablesetup,placethe“WIP”overthecut-outorontopoftheconfigurationyouhavedecidedtouse.Thesubstratemustbecompletelylevel,nottothenakedeye,butitmust be confirmed by use of traditional leveling devices that use an air bubble within atransparentwindow.Ifyoufailtolevelthesubstrate,thereistheverystrongpossibilitythattheencapsulantmaterialwillflowunevenlyandpoolatthelowestpointonthesubstrate.IfyouhaveNOTsecuredtheSTRINGStothesubstrate,itispossiblethattheentireSTRINGwill float out of position by literally floating on top of the shifting encapsulatingmaterial.Dependingonthetypeofencapsulatingmaterialused,thecuringtimemightbesoquickthattheshiftingSTRINGSmightbepermanentlybefrozen in theshiftedpositionandyouwillhavetoworkquicklytocorrecttheproblem.ThereareseverallevelingtoolsthatcanbeusedasdemonstratedintheHow-Todemonstrationvideo,whichshouldalsobeusedtomakesurethe tableyouare supporting the“WIP” is level. Inorder tomakesmalladjustments to the“WIP”,haveseveralpiecesofcardboardabouttwoinchessquarewithwhichtopropupanylowcornersofthe“WIP”toachievealevelstate.

PouringtheEncapsulantOncethesubstrateislevel,wellsupportedoveracut-outtableorboard,youcanmixthetwocomponentsof theencapsulatingmaterial.Watch thedemonstrationvideo toget thepropermixing techniqueaswellashowtoremoveairbubbles fromtheencapsulantonce the twoingredientshavebeenmixed.Onceappropriatelymixed,andde-aired,itistimetopourthematerialovertheexposedSTRINGS.Ifyouareusingaquick-curingencapsulant,setatimerofsomesort,perhapstheonethatcomesstandardontheAppleiPhone,orakitchentimer,anythingtokeepyouawareofelapsedtime.Ifyouareunabletoproceedtopouringwithinthefirstfewmoments,orifthede-airingprocesstakestoolong,bepreparedtomakethedecisiontoabortthepour.Youwouldaborttoavoidhavingtheencapsulantcurebeforeyouarereadyforthistohappen,notalightlymadedecisionbecausethemixedencapsulantbecomeswaste.Prematurehardeningdoesnotnecessarilymeanyouwillruintheproject,itonlymeansthatitwillrequireanotherbatchofencapsulanttocovertheareasnotprotectedbytheoverlyquick-curingencapsulant.Pouringisdonedirectlyoutofthejarusedinthede-airingprocesssothatyou don’t introduce air into the encapsulantAFTER already having completed de-airing.Pouringtheencapsulantisverydifferentthanpouringasimilarvolumeofwaterbecauseofthe density of encapsulating material. Water being poured from a pitcher will reactimmediatelytoanychangeinthepourangleaswecanallattest,butnotsowithencapsulants.Theypourslowly,andreactsluggishlytochangesinpour-angle,butoncethemomentumisbuiltup,gravitytakesoveranditwillflowoutquickly,moresothanyouwillbereadyfor.Justpourinaslow,steadystreamandmakepour-anglechangesslowlybecausethereactionwillbedelayed,butinevitable.

36a)PourtheencapsulantaroundtheoutsideoftheSTRINGSfollowingtheshapeoftheouter frame.Thiswill start the encapsulant flowingbetween theSTRINGS.ThePlumbersPutty“dams”made toeconomize theuseofencapsulantwill force theencapsulant toflowunderthesolarcellpairstheSTRINGSbecausetheencapsulantwillonlyhaveonedirectiontoflow,ontopoforundertheSTRINGS.

36b)PourtheencapsulantnextbetweentheSTRINGSontheinsideofthemainbodyofthesubstrate.Pourfromthetop,allthewaydowntothebottom,pouringaheavyenoughstreamtocoverthegapandleaveasmallamountofmaterialpiledupandreadytoflownaturallyundertheSTRINGS.

36c)Pourtheencapsulantnowbetweenthegapsbetweenindividualsolarcellsthatmakeup the STRINGS.The gaps I am referring to are the ones you used the pencil erasers toestablish, literally between the solar cell “pairs”. By pouring in this small space you areprovidingthemeansforencapsulanttoflowoverandundertheSTRINGSfromallfoursidesaroundeachandeverysolarcell.YouwillhavepouredaroundtheexterioroftheSTRINGS,the interior STRINGS, and finally between the individual solar cells. The self-levelingpropertieswillallowtheencapsulanttoflowundertheindividualsolarcellsandSTRINGStowhichtheyareattached.

CuringProcessandFinalBubbleRemoval Within approximately fifteen (15) minutes of pouring the encapsulant there will besignificantvisualevidenceofself-levelingbecausetheentiresurfaceofthesubstratewillbe

covered.Thiswillbeobviouswhilestandingoverthe“WIP”andlookingdownatthebacksidesoftheSTRINGSbutyouwillneedtoexaminetheothersideaswelltoverifyauniformcoatingofencapsulant.Pocketsoftrappedairarethebiggestconcernhence,thepurposeofthis inspection which can only be conducted from under the “WIP”. If you followed theadvicetobuildafunction-specifictablewiththecut-outthisinspectionwillbecomparativelystraightforward.Theremaybesmallpocketsofairundersomeofthesolarcellsthatareverylarge,perhapshalfthesizeofasolarcell,ordozensofsmallerpocketsthatlooklikebubbles.If you observe air pockets, don’t panic, many times the air will work itself out as theencapsulantself-levels.

Therewillbetimeswhentheself-levelingpropertyoftheencapsulantfailstopushtheairout and bubbles will be visibly present. Bubbles are unsightly and erode the professionalappearance of the solar module and for this sake alone we would want to take steps toeliminatethem.Theyalsorepresentalong-termthreattotheservicelifeofthesolarmoduleforacouplereasons.Oneconcernaboutairpocketsisthattheirpresencecanleadtosolarcelldamage as a result of temperature related expansion or contraction. Solar cells that aresurrounded by the soft, protective gel are protected from stress because the gel allowsmovement.Movementofthissortistiny,barelymeasurable,butifanairpockethasseparateda portion of a given solar cell from the protection afforded encapsulant it is vulnerable tomicro-cracks.Moisture isapossible threat toanyexposedportionof thesolarcellsandofparticularconcernwouldbeanyexposedtabbingorbuswire.Thesearehighlysusceptibletocorrosionshouldmoistureentertheenvironmentorperhapsbecomearegularlyintroducedbycondensation. Therefore, not all air bubbles represent the same risk, as a general rule ofthumb,ifthebubbleisoverasolarcellbutdoesnotinvolvetabbingorbuswire,thereisverylittlelong-termrisk.Ifthereisabusortabbingwireexposedtotheairbecauseitiswithinabubble, there is a greater risk of corrosion if moisture enters the air pocket and thencondensates.Thereisareasonablechancenomoisturewilleverenterthatvoid,butyouwillneedtocheckonthatspecificareaonaregularbasistoseeifthereisevidenceofmoisture.Ifso,therewillbecorrosionwithinaveryshorttimemeasuredperhapsinweeks.Corrosionwillleadtoresistance,meaningheat,soyoumaybeabletoseesignsofthisbythepresenceofcolorfulbandsradiatingoutwardfromthenowvisiblycorrodingtabbingwires.Thatisaboutthetimetopullitoutofserviceforthesafetyoflifeandlimb.IhavesolarpanelsinserviceonmyarraysthatdoindeedcontainexposedairpocketsexactlyasIamdescribing.Thefewunitsthathavetheseairpocketshavebeeninserviceinexcessoffiveyearswithnomeasurabledecline inoutputandIhaveneverobservedmoisturecondensingonthe insideof thesolarpanelsinquestion.Thepresenceofsuchanairpocketdoesnotautomaticallymeanthatwaterdropswill be forming on the inside of the substrate as onemight expect. Remember thatalthough there is a pocket of air, that air pocket is surrounded completely by a ring ofencapsulant thatwill prevent anymoisture to enter, therefore, nodropsofwater inside thesubstrate.

Ifyouareconstructing thewoodsubstrate inconjunctionwithaglassorsyntheticcover,moisturewillbeofparticularconcernbecausewoodissoporous.This iswhyit issoveryimportanttoliberallypaintthesubstratewithsiliconcaulkingbecausepaint,evenprimed,willnotprovideasufficientmoisturebarrier.Alittleoff-topicbutdefinitelyappliestothesubjectmatter.

37a)Helping the encapsulant self-level might be necessary if using a fast-cure product.

Onceyouhavepoured theencapsulantasoutlined instep#36, theself-levelingpropertieswillcausethedenseliquidtograduallyspreaduntiluniformlycoveringthesubstrate.Ifyouare using a fast curing product such asQSIL 214, the gradual pace of self-leveling couldpossiblyleadtotheencapsulantcuringbeforethesubstratehasachievedauniform,bubble-freecoating.Forexample,ifyouhavepoured16-ouncesofQSIL214overa“WIP”has36-solar cells; itmay take an hour for the encapsulant to achieve the desired uniformity andclarity.Itdoesn’trequireacomplicatedalgorithmtoarriveattheconclusionthatanhourtoachieveasatisfactoryconditionismorethandoublethemanufacturerstatedcuretime.Infact,theQSIL214willbegintosolidifylongbeforethesubstrateiscoveredsoyoumustassisttheprocessofself-leveling.Justasinthevideodemonstration,youmayneedtotiltthe“WIP”asameansofusinggravitytohelpspreadtheencapsulant.Tiltingeachsideofthesubstrateupapproximatelyeight(8)inchesofftheworksurface(yourcutouttable)asIdemonstrateinthevideo,youwillbeabletoobserveencapsulant

flowingcomparativelyquicklysincetherearenoobstacles.Infact,youwilltakeyourcueonwhentoreturnthe“WIP”toahorizontalpositionwhentheencapsulantsurgenearstheedgeoftheframe.Whileyouarewatchingtomakesurenothingiswastedbyfallingovertheedgeofthe“WIP”,theencapsulantunderneaththeSTRINGSwillbemovingaswell,justnotasquickly because the cramped quarters (between tempered glass and the solar cells). Thesudden increase in force behind the slow-flowing encapsulant usually does the trick andencapsulantwillflowoverthespotspreviouslyresistanttocoverage.Performthissametiltingactionaroundthefoursidesoftheframeapplyingthesamevisualcuesforwhentoreturnthe“WIP”totheflatposition.

37b)Aftertiltingthesubstratefourtimes,oneforeachsideoftheframe,youmayneedtoperformanadditionalsteptoremovesmallerpocketsoftrappedair.Thesesmallerairpocketswillappearasgreatconcentrations,numberingperhapsinthehundredsinagivenspotsincetheyaresotiny.Remember,wearetalkingaboutbubblestrappedbetweenthesubstrate,andthesun-facingorNEGATIVEsideofthesolarcells.Havingazillionairbubblesbetweenthebusiness-endofthesolarcell,andtheincomingphotonsfromthesunisaconditionyoumustattempttocorrect.WhenyouscantheVQRbarcodeonthebottomrightofthispage,youwillbedirectedtoourexclusiveYouTubelibrary,specificallyavideodemonstratinghowtofreeairpocketstrappedbetweentemperedglassandasolarcell.Idemonstratehowtomassagethetrappedairoutfrombeneaththedelicatesolarcellsbyapplyingdownwardpressurewithpaint

bushbristles.Idemonstratehowtocorral theairpockets towardstheedgeof thesolarcellunderwhichtheyaretrapped.Onceneartheedge,thebubblescanbegentlyproddedwiththepaintbrushbyapplyinggentledownwardpressure.Thepressureshouldstartinthemiddleoftheparticularsolarcellandthengraduallymovingthebristlestowardstheedgeofthesolarcellwheretheairwillrushfromunderthesolarcellandescapewithagratifying“POP(s)”asthebubblesburst.

Themethod involves the application of gentle downward pressurewith theSIDEof theBRISTLESasopposed to a straight downwardpressure. In fact, if thepaint brushbristleswerepointedexactlyperpendiculartothesolarcellsandthestraightnessofbristlesmaintainedwhilepressingthehandledown,onecouldeasilyshatterthesolarcellswithjustthebristlesmaking contact. It is surprising because we would expect the bristles to yield under thepressure,whichatsomepointtheydo,butwellafterthefragilesiliconwaferwouldfracture.WatchthedemonstrationvideoandtakenoteofmysmoothmotionwiththepaintbrushasIgentlymassage the trappedair pockets towards theouter edgesof the solar cells.Youcanactuallywitnessthetrappedairescapewhenthebubblesreachtheouteredgeandslipintotheopen.Thebubblesexpandandthenquicklypopwithasatisfyingfinality.TheonlywayyouaregoingtoidentifythepresenceofthesetrappedairpocketsisifyoucanphysicallySEEtheundersideofyoursubstrate.Remember,youCANNOTmovethe“WIP”offthetableorworksurfacebecausetheinstabilitymaycausethestill-in-liquidformencapsulanttoslosh(albeitaveryslowslosh,butsloshnonetheless)andwithit,theSTRINGSrestinginsidetheyet-to-be-curedencapsulant.Evenifyoucouldsafelymanage to lift itoveryourhead toperformaninspection,marking the locationof trappedair isa step thatcannotbeaccomplishedwhilesuspending the “WIP” overhead. Marking the location of trapped air is helpful becauseattemptingtorecallexactlywhichofthe36solarcellshasthetrappedairbeneathafteronlyabriefglimpse is adifficult feat atbest.Releasing trappedair requires frequent comparison,inspection, and adjustments, tasks whichmight require working fromUNDER the cutout

table.Reachingupandoverthesideof thecut-out tableisanidealpositionfromwhichtoaddress the pockets of trapped air. Looking up through the “WIP” from under the tableprovidesadirectlineofsighttotrackyourprogressonairpocketremovalanditmakestheprocessmoreefficientbecauseyouareabletofocusallofyourenergyonspecificpocketsofbubbles.Toenjoysuccessbyworkingfromunderthetableonemustpossessreasonablehand-eyecoordinationsince it isanuncommonangle tobeworking, likecuttingone’sownhairusingacombinationofmirrors.Itcanbedonebutitrequiresgoodhand-eyecoordinationduetotheanglesandthelimitedrangeofmotionavailabletoyou.YouwillbelookingdirectlyattheNEGATIVE,sun-facingsidewherethebubblesarevisible,andyoumustbeabletosetthepaintbrushdownonthecorrectsolarcellandapplytheappropriateamountofpressure.Itsoundsawkwardbutwithjustalittlepracticeitwillbecomeroutine.

OnefinalnoteaboutairpocketremovalsincethereisamethodIhaveyettomention.Somewill suggest the use of vibration to assist the self-leveling of encapsulating materials,somethingIhaveneverdonebutamcurrentlyinvestigating.

InstallingTedlarBacksheetTheinstallationprocessisstraightforwardespeciallyifyoupre-cutthepieceofTedlartofittheexactsizeofthesubstratesothatitfitsdirectlyintotheframe.Minormodificationsmightbe needed to accommodate unique attributes of an individual solar module. For example,smallcutoutswilllikelyneedtobemadeinordertoaccommodatecornerbracketsorclampsaddedtolockasubstrateontoaframe.The“WIP”shouldbeperfectlyrectangularasidefromthe objects mentioned above, so after minor trimming, the Tedlar Backsheet should laydirectly on to the still-curing, tacky encapsulant.Aftermaking the requisite adjustments toyour Tedlar Backsheet there will be a couple points that might appear higher than thesurrounding surfaces. For example, the blocking diodewill result in a bulge visible to thenaked eye butwill not affect the performance of theTedlar.Once theTedlarBacksheet isinstalledandencapsulantcured,itmayappearmildlylumpyasitreflectsthecontoursoftheSTRINGSitcovers.Donotbeconcerned, the lumpsarenotaproblemandwillnotaffectoutputinanyway.

38a) Unroll the Tedlar Backsheet and place it flat to smooth out any imperfections(wrinkles)whichshouldnotbepresent.Thesheetwill trytorollbackintotheshapeithasbeenrolledintowhilestoredintheshippingtube.Nothingyoudowilldefeatthemaddeningproclivity of this sheet to curl back into a tight roll, almost cartoonish in its maddeningpersistence.Itismorethananaggravatingexercisebecauseit

ispossiblefortheSTRINGStosufferdamageasadirectresultoftheself-rollingaction.Topreventthisfromhappeningtrytoopenthesheetupandhaveanassistantholdoneendwhileyoupositiontheother.HavingtwopeoplepositionthesheetwillpreventuncontrolledcontactbetweentheBacksheetandthesolarcellsresultinginfewerinstallationissues.

38b)OncetheTedlarsheetislyingflatonthesubstrate,beginsmoothing itout.Thisisbestdonewithaclean,DRYspongeorsoftpackingtypefoamwhichwillbeusedtogentlypresstheTedlarBacksheetdownagainstthe“WIP”.Uselightpressureandrememberthereare fragile solarcellsdown thereunder that shinywhiteTedlarBacksheet.Work theentiresheet in amethodical pattern, basically “wiping” the surfacewhichwill improve the bondbetweenencapsulantandBacksheet.

38c)NoadhesiveisrequiredwhenplacingtheTedlarBacksheetonbecauseitisinstalledwhiletheencapsulantistackytothetouch.TheTedlarBacksheetwillformabondwiththeencapsulating material prior to it drying such that glue is not required. In the event theencapsulanthascuredbeyondthepointofbeingabletoholdtheBacksheet,youmaymixasmallbatchofencapsulantspecificallytoserveasanadhesive.ThatisexactlywhatIdidforthedemonstrationvideoforthistopic.

38d)Once theencapsulantcures, theedgesof theTedlarBacksheet needs tobesealedagainstmoisture entering around theperimeter of theBacksheetwhere itmeets the frame.ThisisaccomplishedbyplacingabeadofsiliconecaulkingaroundtheedgesoftheBacksheetwhere it meets with the aluminum frame. In this case, instead of using CLEAR siliconcaulking, you can use WHITE since the Tedlar is that color and it will be much moreaestheticallypleasingtotheeye.AwidebeadcanbeusedtocontainthegaportobridgethedistancebetweentheedgeoftheframeandtheedgeoftheTedlarBacksheet.TheonlyportionthatyouwillNOTputwhitecaulkingonisthepairofoutboundleadsthatweputthroughthe

twoholes cut specifically for this purpose.Thosewill be sealed in thenext stepwhenweinstalltheprojectboxwhichhousesthedoubleterminalblock.

ThefinalstepinyourprojectistoprovidethesolarpanelwithawaytoconnecttoothersolarpanelsinyourarrayORdirectlytoachargecontroller.Thetwooutbound“lead”buswiresthatwerebroughtupandthroughthetwoholesintheTedlarBacksheet,onePOSITIVEtheotherNEGATIVEwillservetofacilitatethefirstlegoftherequiredconnectiontotheoutsideenvironment.Thetwobuswiresjustdescribedmustbeconnectedbysomemechanismthat“handsoff”thecurrentthatisgeneratedbythesolarpanel.Thetwobuswiresenteringtheprojectboxcarrythecurrent,orforourexample,the“baton”.Thecurrent,or“baton”,willneedsomemechanismforcontinuingonitsjourneyfromthesolarpanel,totheoutsideenvironmentwhereitcanbeputtowork.

The“hand-off”takesplaceonadevicecalledaterminalblockwhosepurposeistoprovidetheconnectionpointfromthesolarpanel,totheoutsideenvironment.Itdoessobyacceptingtheoutboundbuswires,bothNEGATIVEandPOSITIVE,whichcomefrominsidethesolarpanelandareconnectedtothescrewterminalsononehalfoftheterminalblock.Youthenconnectwirestotheremaininghalfthatareusedtoconnecteithertoanothersolarpanelsuchasonanarray,ordirectlytoachargecontrollerwherebatterychargingmaytakeplace.Justasyouneededtokeepthepolaritystraightwhenjoiningend-runsateachendoftheSTRINGS,keepingthesetwooutboundleadscorrectlyidentifiedisequallyimportant.Gettingthepolaritycrossedatthisstagewouldhaveunfortunateconsequenceswhenyoueventuallyconnectedthecompletedprojecttoaloadoradeepcyclebatterybank.Thisiswheremarkingthepolaritydirectlyonthesubstratecomesinhandyforeaseofensuringyoudonotgetitmixedupatthisimportanthand-offstage.

39a)Theprojectbox(photoonnextpage)mustbepreparedtoaccepttheoutboundleadscoming up through theTedlar Backsheet. The project boxwill rest directly on top of theTedlarBacksheetandtherefore,twosmallholesmustbedrilledintothebottomoftheprojectboxtoallowthetwoBUSWIREleadstobebroughtupthroughthebottomoftheprojectbox.Oncethroughthebottomoftheprojectbox,theBUSWIREleadswillneedtobeconnectedtotheterminalblock.Theterminalblockhastwopairsofscrews,onesetfortheleadscomingfrominside thesolarpanel, thentwoscrewstoaccommodate thewiringneededtoconnectthisparticularsolarpanelwithothersinanarray,ordirectlytoachargecontroller.Notetheplacementoftheholesforaccommodatingtheoutboundleadsoriginatinginsidethe“WIP”.Inthesecond,orbottom-mostphotoonthenextpage,notetheterminalblockhastheBUSWIRE leads coming up from inside the solar panel already secured to the terminal blockscrews.ThiswasaccomplishedbysimplyusingwirecutterstomakeasplitstraightdownthemiddleoftheBUSWIREwhereitconnectstotheterminalblock.Bycuttingstraightdown,perhapsafewmillimeters,youwillformasplitwhichfitsnicelyaroundthescrewsontheterminalblock.Whenyoufirsthandletheterminalblock,youmustbackthescrewsoutbyturningthemcounter-clockwiseinordertocreatethespacefortheBUSWIREsplittograspthescrew.OnceyoutightenthescrewsdownwithaPhillipsscrewdriver,theywillbefirmlyinplaceandwillstaysecure.

39b)Apairofholesmustbedrilledinthesideoftheprojectboxinadditiontotheholesin the bottom to allow for the “connecting” wires (red for POSITIVE,black forNEGATIVE).Theholesshouldbepointingtowardsthebottomofthesolarpanelbecauseyouwanttheoutgoingwirespointingdown,protectedfromthesunbyrunningbeneaththesolarpanel.Thewiresshouldbeminimum12-gaugeAWG,strandedcopperwire,thewirecross-section diameter determined in advance using the wire sizing formula described in detailshortly.Youmayconnectthissolarpanelwithothersonyourarray,orperhapsthisisindeedyourFIRSTcompletedsolarpanelsoitwillbeconnectingtoyourchargecontroller,whichthenfeedsthepowertothedeepcyclebatteryorbatterybank.Theuseof12-gaugeAWGforshort distance connections is absolutely fine, but youmay also feel free to use a differentmethodaltogether.Forexample,junctionboxesaspicturedonthenextpagearedesignedtoallowyourDIYsolarpanel toconnectwithmanufacturedmodels.TheycontainMC4typeconnectors which have superior UV and weather protection and are designed to preventdamagetoinsulationandeventualdecaycausedbydailyexposuretoagruelingSun.Usingthis type of junction box saves some effort when constructing a solar panel because theblockingdiodewillNOTneedtobeincludedwithinthesolarpanelsotherewillbenovisible“lump”undertheTedlarBacksheet.ThisparticularjunctionboxcontainstheblockingdiodesnecessarytopreventthesolarpanelfromdrawingelectricitybackOUTofyourbatteries.

Terminal blocks are versatile in how connections can be made in conjunction with thePhillip’sscrewsthatholdtheconnectionfirm.Somepeoplesimplystriptheinsulationoffthewireabouttobeconnectedandaftertwistingthecopperstrands,wrapthebarewirearoundthescrew and then tighten them.Turning the screwhead clockwise until tight, the copperstrandsarecrushedbeneaththescrewhead.Thisseemsfairlysturdy,butIwoulddiscouragethispracticeinfavorofamethodbettersuitedforlong-termservice life.Theseconnectionscan be a source of electrical resistance which can be mitigated by ensuring that eachconnectionhasthehighestintegritypossible.Instep(39a)IdescribedtheconnectionwheretheBUSWIREScomingfromthesolarpanelinteriorarescreweddirectlyontotheterminalblock.Thisconnectionisanexampleofgoodelectricalintegritysothenextconnectiontotheoutgoing (outbound) wires should continue that integrity. Using a “Spade” terminal isrecommendedtomaketheremainingconnectionwiththeoutboundwire.Thespadeterminalideallyshouldbesolderedtotheoutboundwirewheretheconnectionismadetotheterminalblock.

AWORDABOUTWIRESIZING…

Wiringplaysanimportantroleinaphotovoltaicsystembecausethecurrent(electricity)mustbetransportedfromthepointatwhichitisgenerated,tosomeotherlocationwhereitistobeeitherstored,orputtoworkinsomemanner.Wirecomesinadizzyingarrayofsizes,types,andcomposition.Someareinsulated,somenot,othersmadewithsolidcopper,otherswithstrandedcopper,whileotherwiremaynotcontaincopperatallinsteadbeingcomprisedofaluminum.Somewiretypeswearefairlyfamiliarwithsuchasextensioncords,appliancepowercords,speakerwire,entertainmentsystemtypewiring,andcomputercablingtonamejustafew.Wiredesignedforaspecificpurposesuchasspeakerwireforexample,shouldonlybeusedforthelowwattagepurposeitwasdesigned.Wireneedstohavemanystrands,morethebettertocarrythecurrentandthegreaternumberofstrands,thegreatertheefficiency.

Youmayneedtoplacethesolarpanelsomedistanceawayfromthechargecontrollertoaccessdirectsunlight.Therearecertainpropertiesrelatedtoelectricaltheoryyoushouldbemadeawarepriortomakingdecisionsabouthowfaraparttoplacecomponents.Notmanypeoplehaveaneedtomeasuredistancesbetweenvariouspointsontheirhomesorpropertiesandsotheymightbesurprisedbythelengthofwireneededtoconnectagivensolarpaneltoadistantbatterybank.Unfortunately,lackofknowledgewillnotprotectyoufromtheeffectsof“voltagedrop”,thelossofvoltageinawireduetoresistancewithinthewireinwhichitistraveling.Stateddifferently,themoredifficultitisfortheelectricitytopassthroughawire,theLESSofitwillactuallygetthrough.Someoftheenergyislosttotheeffortofpushingthecurrentthroughthewire,butthelossbecomesdramaticifthewireusedistoosmalltoaccommodatethevolumeofenergyinneedoftransport.Similartoexcessiveheat,usingwirewiththeinsufficientsizewilldrasticallyreducetheoutputofyourentiresystemirrespectiveofhowmanysolarmodulesyouhavedeployed.Infact,theproblemisexacerbatedwitheachadditionalsolarpanelcontributingcurrenttotheundersizedwire.Toomuchtrafficthroughagivenwirewillcauseheattobuildandaswehavediscussedearlier,heatisaconditionthatcontributestoelectricalresistance.Aheavyvolumeofelectronssimultaneouslyrushingtowardsthebatterybankthatencounterstraffic(otherelectrons,lotsofthem)willcausetheelectronstoslowdownastheybunchupmuchlikevehicletrafficonafreewayduringrushhour.Asthetrafficbeginstoslowasresultofcongestion,theelectronsbegintolosesomeoftheircollectiveenergyastheyfighttomoveforward.Ifenoughresistanceispresentthesystemcangrindtoahaltsimplyunabletocopewiththeheatgeneratedbythetrafficjamat

whichtimeyourundersizedcablingcanpossiblyfail.ObviouslyitwouldrequireasignificantvolumeofelectricityandIamoversimplifyingtheprocess,buttheansweristousethickergaugewireifyouneedtogolongerdistances.Itcangetconfusingwhendiscussingwireorcablesizingbecauseifyouhaveneverhadtoexaminewiring,youmaynotknowthedifferences.InordertoremovethemysteryofhowtodeterminethecorrectwiresizeIhaveincludedthemathematicalformulasoverthenextfewpages.Additionally,youwilldiscovertheAWGwirecross-referencegridthatwillallowyoutoquicklyidentifytheAWGwiresizecorrespondingtothemathformulayouwillhavesolved.Wireisexpensiveandtherefore,onemaybetemptedtousesmallergaugewirethanwhatourformularesultscallfor.Thisisamistakeofthehighestorderforseveralreasons,firstofwhichisthesafetyofyourself,yourfamily,orthestructureonwhichyouhavemountedthesolarmodule.Heatistheimmediatebyproductandnotthetypethatmerelymakesoneuncomfortable;rather,wearetalkingaboutwirebecomingasourceofcombustion.

Fireistheultimatehazardwhichshouldbeenoughincentivetomaketherightchoice,butsoshouldthevalueplacedonyourinvestment.Imentionedearlierthatwireisexpensive,butthereisadifferencebetweenbeingfrugalbyshoppingforthebestpriceonwire,andbeingfoolishbytryingtosavemoneyupfrontbypurchasingawiregaugethatisknowinglytoosmall.Thereisapricedifferencebetweenthevariousgaugesofwireforobviousreasons;largergaugewirecontainsmorecopperstrandswithinthecross-sectiontohandlemoreelectricity.AsIcoverwiresizingingreaterdetaillater,Ineedtobrieflyinterjectanoteaboutwiresizingnumberstominimizeconfusion.WiresizenumbersfollowtheAWGorAmericanWireGaugesystem,auniversalmethodforwireidentificationacrossmultipledisciplines.AuniqueaspectyoumustgraspimmediatelyistheinverserelationshipbetweentheAWGsizenumbers,andthephysicaldiameterofthewirebeingmeasured.Asthewirebeingusedgetsfatter,containingagreaternumberofcopperstrandsthanskinnierwire,thenumberattributedtosizedecreases.SoifthickestwireusedonsolarpowergeneratingsystemsisAWG-0,onemightimagineaverytinywirebasedupontheAWGsizingnumber.Inreality,anAWGsize0isaverythickcable,thetypeusedtoconnectdeepcyclebatteries.Wewanttheheaviestgaugepossiblewhenconnectingbatteriesduetothelargeamountofenergyinvolved.Conversely,whenconnectingsolarpanelstogether,youwillseeinthewireformulasthatAWG-12gaugewireissufficient.Confusionnotwithstanding,thereisnoexcusetouseimproperlysizedcablingforanyportionofaphotovoltaicpowergeneratingsystembecauseIamabouttoteachtheformulatodeterminetheprecisewirediameterforANYportionofyourphotovoltaicsystem.Ifyoudotakeshortcutsonwiresizeused,anymoneysavedupfrontwillbespenteventuallywhenyoumustprematurelyreplaceallofthewirewhentheimpropersizeleadstounacceptablevoltagedrop.Insects,rodents,rot,andnottomentionUVdamageareever-presentforcesthatwillneedtobeconsideredlesttheyservetodeterioratetheperformancecapabilitiesofthewire.Naturallytheseforcesarepresentdailyanditdoestakemonthsifnotacoupleyears,buteventuallywillleadtoameasurabledeclineinsolaroutput.Thereforeitisnotonlysize,butthetypeofwirethatisinneedofconsideration.Morewillbesaidaboutthisshortly,thepointbeingthatlikeanyjob,therighttoolisneededandwiringisverymuchlikeatoolinthisinstance.

Inordertocalculatethesizeofwireneededtosafelyhandlethesystemyouarebuilding,youneed to have a couple pieces of information. With this information you will have theingredientstomakemathcalculationstheresultsofwhichdeterminewirediameterneedsfor

eachstageoftheproject.Remember,youaregoingtoneeddifferentwiresizesatsomepointin the development of your photovoltaic power generating system as it grows in size andcomplexity.Youmaybestartingyourveryfirstsolarpanel todayandthus,discussingwiregaugesizingmightseempremature.Youwouldberight,butIproposetoyouthatwhileyouarerighttoday,thatwillchangeuponcompletionofyourfirstDIYsolarpanelbecauseyouwillwant to put it into service immediately.By the second completed solar panel you areclearlygoingtoneedtobeeducatedaboutwiresizingsincethecombinedelectricityfromthispairofsolarmodulesmustbetransmittedelsewheretobestoredforlateruse.Typicallythereis somedistancebetween the solar panels and thebatterybank considering theprohibitiveweight of deep-cycle batteries verses the relativemobility of the solar panels. In order toexpose the solar panel(s) to direct sunlight, it might require rooftop mounting, a locationchoicethatwouldrequiresomeconsiderabledistancebetweenthesolarpanel,andthebatterybank.Theunderlyinggoalshouldbetomakeeveryefforttominimizethedistancebetweenthesolararray,andthebatterybank.Thelongerthedistancebetweenthesetwocomponents,thethickertheconnectingwiremustbeinorder topreventvoltagedrop.Thereisapairofmathformulasavailabletohelpyoumakeaninformeddecisionabouttheexactwiresizetouse,butthereareafewpiecesofinformationyouwillneedinordertocalculatethespecificwiresizeneededforyourprojectasfollows:

Youwillneedtoknowthedistancebetweenthetwopointsthewireneedstorunsuchasfromthelocationwherethesolarpanelsaredeployed,tothebatterybanklocatedincloseproximitytoyourinverter.Similarlyforaresidentialdeployment,fromthesolarpanelmount,alongtheeveofthehouse,downtheraingutter,thentothebatteryenclosure.Thefinalstepistoconvertthismeasurementintometersbecausethemathformulaisdesignedtocalculateusingmeters.

Youthenneedtoknowthesystemvoltage,inourcase,wearetypicallydiscussing12V(12-Volt)systemsbecauseweareusingadeep-cyclebatteryofthisvoltage.

Lastly,weneedtoknowthe“current”inamps,whichwillrequireaquickmathformulaorfindtheinformationrightoffthetopofyourdeepcyclebatteryorbatterybank.

Ifyouarepanickingbecauseyouseemath,gettingthoseoldfeelingsofwantingtorunoutoftheclassroom,welldon’t!Thisisverystraightforwardmaththatcanbecarriedoutonthecalculatorfunctiononyourcellphone.Thesearemathcalculationsthatprovideyouwithinformationcriticalforthesafetyofyourselfandyourproperty.Iamnotsugarcoatingtheconsequencesofusinginsufficientlythickorinsulatedcabling,yousimplywillNOTgetthefullpaybackonyoursystemandyouwillbecreatingadangeroussetofconditionsaswejustcovered.Inadditiontorisksattributableoverloading,youhavetokeepinmindhowgruelingthesunshineistoanysyntheticmaterialespeciallyifthematerialwasnotdesignedfordirectexposure.WirethatisnotproperlyinsulatedwillshedtheprotectiveplasticcoatingafterconstantexposuretoUVradiationthusexposingcopperstrandedwiretotheelementsandtothepossibilityofashort-circuit.Thebestwaytoavoidsuchconditionsistostartwiththecorrectsizecabletocarrytheloadsafely,andoncethecorrectsizeisdetermined,youmustprotectthecablebyeitherusingconduit

piping,oruseproperlyshieldedcable.Iamreferringtothecablesthatconnectsolarpanelswitheachother,andfromthesolarpanelstothechargecontrollerwhichtendtobelongerrunsthatsitfairlyexposedtotheelements.Iuse10-gaugeexterioroutdoorwellpumpwire.Theconsequencesofusinginsufficientlythickorinsulatedcabling,yousimplywillNOTgetthefullpaybackonyoursystemandyouwillbecreatingadangeroussetofconditionsaswejustcovered.Inadditiontorisksattributableoverloading,youhavetokeepinmindhowgruelingthesunshineistoanysyntheticmaterialespeciallyifthematerialwasnotdesignedfordirectexposure.WirethatisnotproperlyinsulatedwillshedtheprotectiveplasticcoatingafterconstantexposuretoUVradiationthusexposingcopperstrandedwiretotheelementsandtothepossibilityofashort-circuit.Thebestwaytoavoidsuchconditionsistostartwiththecorrectsizecabletocarrytheloadsafely,andoncethecorrectsizeisdetermined,youmustprotectthecablebyeitherusingconduitpiping,oruseproperlyshieldedcable.Iamreferringtothecablesthatconnectsolarpanelswitheachother,andfromthesolarpanelstothechargecontrollerwhichtendtobelongerrunsthatsitfairlyexposedtotheelements.Iuse10-gaugeexterioroutdoorwellpumpcablebecauseitisdesignedforbeingburiedbasicallyforeversoitisfullyweatherinsulated,waterproof,andtoughasnails.Itiseconomicalbecausewitheachstrandyoupurchaseyougetdoubletheuseablelinearfootagebecauseyouareabletosplitthewirerightdownthemiddleandusebothhalvesindependently.Itmayrequirethehelpofagoodsharpblade,butonceyouseparatethetwohalves,eachmaybeusedindependentoftheotherhalfasneededtocompleteyoursystem.Asyouwillseebytheresultsofourcalculationfortheexamplebaseduponatypical36cell,72wattsolarpanel,theAWGsizeisverymodestandwillresultinamodestcablinginvestment,soletustakealookattheformulas.Themathformulasaretodeterminethethicknessofwireneededtosafelytransporttheelectricitygeneratedbyyoursolarpanels.

Thefirstformulaafterthephotoofwellpumpcableistodeterminethe“current”orampsusingtheformulaatthetopofthebox.Weneedtoidentifythecurrent(oramps)inordertosolvethenextmathformulafromwhichwewilldiscoverthe“CT”,orcross-sectionofthewireneededforourproject.Onceyouhavethecross-sectionalsizeofthewire,youthensimplycomparethecross-sectionalareatotheclosestAWGwiresizeinthehorizontalchart.

Afterlearningthecurrentoramps,

youarenowsettoworkthesecondformula.

NextwecrossreferenceagainstourcharttofindtheAWGsizethatcorrespondswiththe

Cross-SectionalAreainmm²thatwecalculatedabove.Youcanseethischartbelowthewiresizephoto,whichwouldleadustothecolumnclosesttotheCrossSectionalAreanumberwecalculatedof3.28mm².Youcanseethehighlightedfigure3.31isimmediatelyadjacenttothesimilarlyhighlightednumber12.ThesmallernumberistheclosesttoourcalculatedCrossSectionalAreaandtherefore,itisthecolumnfromwhichwewillgettheAWGsize.

ItispossibleforyoutofindyourselfmakingajudgementcallifyourCross-SectionalAreafiguredoesnotfitneatly,youknow,doesn’tseemtobeclosetoanynumber.AsyousawintheformulaIprovidedasanexample,ouranswerwas3.28whichdidnotexactlymatchthenumbersintheCross-SectionalAreacolumn.Wechosethenumber(3.31)becauseitwasclosesttothenumberIcalculated.Itwascoincidencethatwewereonlyafewbasis-pointsofffromanumberappearingonthechart.Youmaycomeupwithfiguresthatarenotasclose,buttheprocessisthesameinthatyousimplyneedtofindanumberontheAWGthatisclosertothefigureyouarrivedat,insomecasesitwillbe50-basispointsofffromthechoicesofferedyouonthischart.Don’toverthinkthis

one.

Asthephotototheleftdepicts,12-AWGwireiscomparativelysmallinthescopeofpossiblewiresizestoemployinyourphotovoltaicsystem.Fortheconnectionsbetweensolarpanels(solarmodules),theAWG-12sizewirecanremainthesame,butonceyoubranchouttolinkthesolararraytoadistantbatterybank,performingthecalculationsonwireorcablesizebecomesnecessary.Thiswillensurethattheelectronshaveamplespacetomovefreelyandefficiently.Whenconsideringthetypeandsizeofcabletomaketheconnectionbetweensolarpanelsandthebatterybank,rememberitisnotONLYthesize,butyoumustfactorinexposuretotheelementsandchoseawirethatisappropriatelysizedANDprotected.

Protectionmaycomefromasolidstructurearoundthewireasitrunsbetweensolararrayandthebatterybank,apipeessentiallymadefromeitherPVCormetalthatphysicallyhousesthewire.YoucouldalsopurchasewirethatcomesalreadyencasedinaprotectivesleevedesignedtokeepthewiresdryandprotectedfromdecayrelatedtoUVexposure.Usingeithermethodwillallowthewiretoremaininservicefortimemeasuredindecadesasopposedtojustayearortwoifyouopttodeployanun-sheathedornon-insulatedwire.Itmaynotlastevenayeardependingonyourclimate,sothisisanareaofyourwiringthatyouwillwanttoinvestanappropriateamountoffocussothatyouarenotcreatingafuturemaintenanceheadache.Onceyoudeploythesolarpanel,typicallyyouwillnotneedtoperformmaintenancesincetherearenomovingparts.Cleaningtheglassregularlytomaximizeefficiencyisabouttheonlyattentionyoupaytothepanels;theywillsitupontheirmountsandabsorbthefreeenergyfromthesun.

The comparative lack of need formaintenance is one of themore attractive elements ofphotovoltaicelectricitygeneratingsystems.But,whilewemightnotpaymuchattentiontothesystemotherthanappreciatingtheresultingelectricity,theUVradiationdoespayattentiontothe photovoltaic system, day in and day out. The solar cells are specifically designed totolerate decades of exposure to UV radiation, but the same cannot be said for othercomponentsofthesystemsuchasthewiring.Repeatedexposuretosunlightwillbreakdowntheinsulationthatprotectswiringandovertime,thatinsulationwillcrackandultimatelyfailcompletely.Oncegone,thatcopperstrandedwirewillbesubjecttoalltheforcesnaturecanstackagainst it to includecorrosion,animal, insect,andbirdactivityrelateddamage(manycreatureswillattempt to takeportionsofwirefornestsandbedding),allofwhichserve toreducetheservicelifeofthewireorcableinquestion.Heavyprotectiveinsulationmustbeprovidedforanywireexposeddirectlytothesunortotheearthshouldyouburyyourcableruns.Oneexcellentwaytoprovidephysicalprotectionistouseconduit,theplasticPVCtypethatiseasytocut,inexpensive,andimpervioustoUVradiationsothereislong-termpeaceofmindforthesafetyofthecabling.YoumayelecttousecablethatisspecifictophotovoltaicsystemsinconjunctionwiththeMC4connectorsforjoiningthesolarmodules,theultimateinUVprotectionbut also themost expensiveoption.Connectingdeep-cycle batteries alwaysrequiresalargercablesizetypicallythetypeofbatterycablethatissoldatautopartsstoresspecificallyforthispurpose.Neverusealligatortypeclipsonbatteryterminals,andthecablesshouldhavefactoryinstalledterminalconnectionssinceunequallytightenedconnectionsonthebattery terminals is a sourceof electrical resistance.Eachof thebattery terminalsona

given battery bank needs to be tightened at as closely to each other as possible to reduceelectricalresistance.AsIindicatedearlier,batterybanksrequiretheheaviestcableyoucanfitsuchasAWG-0,or evenAWG-4becauseof thevolumeof electricitypresent.There isnopossible way you should even consider wiring of lesser gauge when making batteryconnections,thestandardmustbethetwosizesIindicated,anythingsmallerandIcanalmoststatewithcertaintywillleadtoseriousconsequences.Equallylargewire(Iuse4-gaugeAWG)isrequiredforconnectingthebatterybanktotheinverter,thedevicethatconvertstheDirectCurrent (DC) electricity toAlternatingCurrent (AC), the typewe get fromwall outlets inhomes, offices, etc.Depictedonpage105 is10-gaugewiredesignedfor usewithoutdoorwell pumps, no better protection is available when the only option is to bury the lineconnecting solar panels with the battery bank. The gauge depicted is outstanding for thepurposeoutlined, but you could alsouse a12-guagewireof similar construction, the typemadeforlow-voltageexteriorlightingcommonlyknownas“MalibuLighting”.Thiscableissimilarly insulated for extreme underground conditions and is designed to withstand theravagesofbeingburiedinwet,cold,anddifficultenvironmentsformanydecades.Iwouldhazard tobet thatmanyofushaveencounteredburied“MalibuLighting”cables thatwereplacedundergroundbypreviousownersofourhomesthathavebeenburiedinexcessoftwodecadesbutlookasgoodthedayweunburiedthemasthedaytheywereburied.

SealingtheTedlar,ProjectBoxandConnecting“Connective”Leads40a)SealingtheProjectBoxtotheTedlarisasimplematterofapplyingahealthydabofcaulkingunder theprojectboxwhichwill seal theholespunched in theTedlar for thebuswiresthatcomeupfromtheinteriorofthesolarpanel.Oncethedabisapplied,pushdowngentlyontheprojectboxtospreadoutthecaulkingandtoforceitoverandaroundtheholesintheTedlar.ThenrunabeadaroundtheprojectboxitselftosealittotheTedlar.Don’tpushtoohard,therearesolarcellsontheotherside.

40b) Connecting outboundred andblackwires to theopenports on the terminalblocklocatedinsidetheprojectbox.Thiswheretousethespadeterminals,onthesewiresyouwilluse toconnectyoursolarpanelwithothersor to thechargecontroller.Yousimplyneed topositionthespadeterminalssothattheycanbeplacedunderthescrewsontheterminalblockand then tightened (the screws that is).The POSITIVEwire should be red, and itwill beconnectedtotheterminalblockoppositethebuswireservingasthepositiveoutboundlead,theonewhichhastheblockingdiodeattached.RememberthatyouwillnotbeabletoseetheblockingdiodesincewehavecovereditundertheTedlarBacksheetbutitcanbeseenasalump in the upper right corner (or possibly the left depending on personal preference).KnowingwheretheblockingdiodeisimportantbecauseitservestoidentifythePOSITIVEpolarity.Notallblockingdiodesarelargeenoughtoprovidethe“lump”Idescribedinwhichcaseyouwilleitherhavetorelyonthepolaritymarkingsmadepreviouslyonthesubstrateand frame, or through visual inspection through the front of the solar panel. In order toidentify the POLARITY, turn the solar panel over andobserve the tops of the outer-mostSTRINGSon the insideofyour“WIP”.Younowknow that the topsandbottomsofeachSTRINGwillhaveoppositepolarity,andyoualsoknowhowtoidentifypolaritybaseduponwherethetabbingwire“end-runs”aresolderedtothesolarcellsfromwhichtheyprotrude.

Examinethe“WIP”andinparticular,theend-runsthatareatthesameendastheprojectorjunctionbox.TakenotetheexactSTRINGthathastabbingwireprotrudingfromthenon-sun

facing, or the POSITIVE side of the final solar cell on that STRING.Remember that theoutermostSTRINGSonthesubstratewillbewherethe“outboundleads”originatefrom,fromthe“end-runs”onthosetwoSTRINGSonthetophalfofthe“WIP”.ThesamehalfthatwillcontainthetwoholescutintheTedlarBacksheetoverwhichyouwillhaveplacedtheprojectorjunctionbox.Now,lookingthroughthefrontofthe“WIP”,followthepathofthetabbingwirewhereyouarelookingfortheend-runthatisbisectedbyashortstripofbuswire.Thisshort strip ofbus wire will have a blocking diode on it which is absolute proof of thePOSITIVEoutboundbuswire.Youwillseeasmallstripofbuswireaftertheblockingdiodethat will then protrude up through the Tedlar Backsheet and it then is screwed onto theblocking terminal. It is opposite this POSITIVE buswire that youwould insert the spadeterminalattheendoftheREDcableandtightenthescrews.Onceyouidentifythepolarityonone STRING, you will have by extension found the POLARITY on the other STRINGbecauseitcanONLYbetheoppositeofthefirstoneyouidentified.The“connecting”wireswilltrailoutoftheprojectboxandfacethebottomofthe“WIP”asdiscussedearlier.Youmayuseadabofthewhitecoloredcaulkingtosealtheholesintheprojectboxwheretheredandblackwiresexit thusdenyingmoistureandinsects’entry.Thenthelidcanbeaddedtotheprojectbox, screwed intoplace,butNOTsealed.Youmaywish to inspect theconnectionslatersousingcaulkingnowwouldmakethatdifficult.

DeployingyourSolarPanel

Uponcompletionofthatfinalstepofsealing,thesolarpanelitisreadytobeplacedintothedirectsunshinefortesting.Thetwowiresprotrudingfromtheprojectboxmaybeconnectedtoamulti-meterandtheoutputofthesolarpaneltested.Youwouldwanttofirsttestforvoltage,thenamperage,justtoensurethatthefinalproductisworkingtosatisfaction.Youhavebeentestingthe“PAIRS”allalongthehandcraftingprocesssothereshouldbenosurpriseshere.FollowthedemonstrationvideofortestingsolarcellpairsthatisavailableontheHow-Tovideolibraryifyouneedarefresheronhowtousethemulti-metertotestsolarpanels.Itistheexactsameprocedurefortestingthe“PAIRS”,saveforwherethetestleadsattachtothesolarpanel.Toattachthemulti-meteryousimplymatchcolorsonthetestcableswiththecoloredwirescomingoffthesolarpanel.Redmulti-metercableattachestotheredconnectionwirecomingoffthesolarpanel.Theblacktestleadconnectstotheblackconnectionwirecomingoutoftheprojectbox.Imightaddthatthiswouldbeaverygoodtimeforalligatorclipsfortestleadscomingoffthemulti-metersincethesewillprovideexcellentelectricalcontactandthisfreesyourhandsuptomakeadjustmentstopositioningoralteringthetiltangleduringthetestingprocess.Remember,themulti-metershouldnotbeheldwhileinuseformeasuringortestinganything,itissafertoplaceitonaclean,drysurfaceuntiltestingiscomplete.Naturallyyouwouldbeinthenoonhoursun,orclosetoit,facingsouth,andthesolarpaneltiltedtoacloseapproximationof60°.Thenicethingabouttestingthesolarpanelforthefirsttimeisthatusuallyyouwillnothavemountedityet.

Thisisanidealtimetolearnhowtheangleatwhichyousetthesolarpanelaffectstheoutputas you manipulate the angle of your solar panel in relationship to the sun. Tilt-angle isimportant because there is a direct relationship between output, and the angle of the solarpanelinrelationtothesunoverhead.Theidealsituationistohavethesunsitperpendiculartothe solar panel because this position provides a direct, head-on path for photons to passdirectlyintotheNEGATIVE,sun-facingsideofthesolarcells.Insuchacasethemaximumnumber of electronswill be exposed to the inbound photons resulting in a greater output.Similarly,ifthetilt-angleisoverlyaggressive,lessofthephotonswillpenetrateintothesolarcellsbecausesomewillbedeflectedbythetilt-anglesimilartohowslopingarmorprotectstanksfromdirectshotsatthem.

WearediscussingelectricalcurrentasopposedtoarmorpenetratingmunitionsbutIthinkyouseethepoint.Thegoalistofindatilt-anglethatwillprovideyouthehighestoutputforagivenseason,winterrequiringthesmallertilt-anglebecausethesunsitscomparativelylowonthehorizonduringtheshorterdays.Converselyduringthelongersummerdaysthesunwillcrosstheskyatamuchhigherangle,about25°higherdependingonyourspecificlocation.Thesunrestinghigherintheskywillrequireamuchmoreaggressivetilt-angle,butalsoyieldamuchhigheroutputprovidingheat isnotexcessive.Whenitcomestimetoconductyourtests,simplysetthesolarmoduleonasmallstripofcardboardthatisrestingdirectlyonthegroundforthedurationofthisperformanceassessment.Thetestleadcablesfromthemulti-meter are easily long enough to allow it to rest on theground (and for safety reasonsyou

shouldNEVERholdthemulti-meterwhileactivelytestingANYTHING)soyoumayusetwohandstocontrolthemovementofyourpanelduringtesting.Withthetestleadsattachedviaalligatorclips,youmaythenfacethesolarpanelintothedirectsunlightstartingperpendicularto theground.Note theLEDscreenonyourmulti-meter andmake amental note of yourvoltagereading.Nowslowlystarttiltingthetopofthesolarpanelback,awayfromthesunandtakenoteofthechangeinoutput.Asyouslowlytiltbacktherewillbeapointatwhichtheoutputnumberswill stop increasingand in fact,willbegindecreasing.Goback to the tilt-angle where you experienced the highest output and if you possess the appropriate gear,measurethisangle.Itwillbedifferentdependingonwhereyouresideontheglobe,butonefact isconstant irrespectiveofgeographyandthat is theconditionleadingtothehighsolaroutput.Inotherwords,nomatterwhereontheglobeyoulivetherewillbeanoptimal tilt-anglethatcanbeidentifiedusingthemethodIamdescribing.Notallsunshinewillprovidethesamesolaroutputeven if the tilt-anglenumbers (theactual tilt-angle stated indegrees)have proven to be productive in another geographic location. The sun’s rays must passthrough92-millionmilesofopenspacebeforestrikingourplanetandideally,haveadirectpathtothesolarpanels.Thedistanceisnotnecessarilyaproblemforthesephotonstravelingatnearlythespeedoflightrather;itistheclouds,fog,smog,andotherpollutantsthatobstructtheinboundphotons.Thefartherthesunshinemustpassacrossourloweratmospheretoreachasolararray,theweakerwillbetheresultingsolaroutput.

Onceyouhavetheidealtilt-angleestablished,removethePOSITIVEtestcablefromitsportonthemulti-meterandbeforepluggingitbackin,changethesettingonthemulti-metertotheamperetestposition.Plugthetestcableintothefarleftportasyouhavedonefortestingallofthe“PAIRS”andwritethenumberyouseeintheLEDscreen.Youmayalsoexperimentwithyour tilt-angleperhapsasaverificationof the resultsyouachievedwhileestablishingyouridealtilt-angle.Youshouldbeabletoreplicatetheoutputlevelattheangleyouhadpreviouslyestablished toconfirm theaccuracyofyourdecisionon theoptimal tilt-angle setting. TheEarthismovinginrelationtothesunandtherefore,evenaseeminglyinconsequentialthirtyminutedelaycan lead todifferent ampereandvoltagemeasurements.As theEarth rotates,everysecondthatticsbychangestheorientationofthesolarpanelsrelativetothesunsoameasurement takenatnoonwillbemuchstronger than those taken twohours later. In thattimethesunwillhavechangeditspositionintheskyrelativetothesolarpanelbeingtestedleading to lower output. I mention this to alleviate concerns youmight have after havingmeasuredoutputathigh-noonthatwillNOTbeashightwohourslaterintheday.Hereagainis a topic that exceeds the scope and purpose of this book but the concept needs to bediscussed as it directly affects the performance of your solar panel. I covered the formulaearlierinthebookforestablishingthe“OptimalYear-RoundTilt-Angle”forthosewhoarenotplanning on altering any angles after installing the solar modules. Naturally you want toachievethehighestoutputpossiblefromeverysolarpanelyoudeploybecauseifyoudonot,you will have to compensate for the reduced output by installing more solar panels at agrowingcostintimeandmoney.Justasyouwouldtuneacarenginetoensuremaximumfueleconomy,aproperlycalculatedtilt-angle improves theperformanceandinessence,ensuresmaximum“mileage”fromthesolarpanel(s).

Nowthatyouhaveitbuilt,whatnow? First and foremost, pat yourself on the back! Seriously, this is a magnificent

accomplishment!Youwillnaturallywant tobeshowing thisoff,not inaboastfulway,butwith pride of accomplishment ofwhat you have builtwith your own twohands.Youwillprobablybetheonlypersonthatyouknowwhocandothis,whichgivesyoutheopportunityto illustrate to friends and neighbors how committed you are to the pursuit of things youfirmlybelieve in.Whetheryouaremotivatedbyenergyconservation, climate change,youwanttoliveoff-grid,workinremoteareas,reduceourdependenceonforeignenergysources,oroutfitanRVorboat;younowhavetheskillstomakeithappen.Onceyoubegintoseethebenefitsofbeingable toconstructyoursolarpowergeneratingsystem, thefirstsolarpanelwillbefollowedbyseveralmoreasyouaddnewsolarpanelsasyoucompletethem.Eitherway,thisbookhasprovidedyouwiththesolutiontothehighcostofsolarpanelsthatwillfityourbudgetbecauseyoudecidewhentoinvestmoneyortime.

Theadventurousindividualswhomundertakethistypeofprojectareprobablygoingtobefairlycreativewhenitcomestimetodeploytheircompletedsolarpanel.Theapplicationsarejustaboutunlimitedintermsofwheresolarmodulescanbeputtousehowever,therearetwospecificsyoushouldknowinordertogetthehighestpossibleoutput.

1) FacethesolarpanelSOUTH(ifyouliveintheNorthernHemisphere)whereveritisdeployed. If you have an iPhone, they have a compass application pre-loaded as astandardfeaturevisibleasaniconresemblingacompass.

2)TiltthesolarpanelatanangletoimprovetheexposureofthesolarcellsinrelationtothepositionoftheSuninthesky.Thebesthoursforachievingamaximumchargearebetween9amand3pm,andthatdependsonwhereontheglobeonelives.Duringthewinter,youmayget4.5hoursinCaliforniabutalmost6hoursduringsummer.Atiltequaltoapproximately57°isgenerallyagoodyear-roundoptimaltilt-angleforthosethatdonotintendtoshifttheangleoftheirsolararraythroughouttheyear.Ifyoudonothaveequipmentfordeterminingwhatatiltangleof57°lookslike,trythismethod.Useatraditionalroundclock,thetypewithnumbersaroundtheperimeterofacirclewiththepointed“hands”indicatingthetimeinhoursandminutes.Drawanoutlineofthisclockon a sturdypieceof cardboard and then as accurately aspossible, draw in thenumbers indicating the hours of the day replicating the appearance as closely aspossible. If you have access to a computer and printer,Google Image has the exactclocktemplateyouseeinmyphotoexampleonthenextpage.

Next,usearuleranddrawastraightlineacrosstheentirecardboardstartingatapointbetweenthenumbers“10”and“11”,specificallythethird“tic”,runningstraightacrosstheclockfaceandthroughthethird“tic”betweenthenumbers“4”and“5”.Thatwasdifficult todescribesothepictureshouldclearitup.Gooutsideandplaceyoursolarpanelatastraightuprightpositionwiththecardboardclockperpendiculartotheframeofthesolarpanel.Nowslowlytiltthesolarpanelbackwardswhilekeepingyourclocktruelevelwiththenumbers“9”and“3”parallelwiththeground.Asyoursolarpanelcomesintoananglethatmatchesyourlinedrawnonthefaceofyourcardboardclockyouhaveachievedthecloseapproximationoftheoptimumpermanenttilt-angle.

Set the supportdevice to thisangleand thenmount thepanel toyourproperly tiltedrack.Ofcoursetherearemoreaccuratemethodsforestablishingtiltangle,toolsspecifictothatpurposehowever;IamspeakingtotheDIYspiritofthematterherewherewefindaway!IfyouareplacingthesolarpanelontheroofofanyvehiclesuchasaboatoranRV,makesureyouleavespacebetweenthemountingsurfaceandtheundersideofthesolarpanel.

Heathasbeenatopicwellcoveredthusfarsoyoushouldhaveahealthyappreciationforanymeasuresrequiredtokeepthesolarpanelsascoolaspossible.Maintainingairflowaroundthesolarpanel(s)istheonlysteprequiredgenerallywhenmountingsolarpanelsonthetopsideofvehiclesofalltypesandthisalsoappliestoresidentialrooftopmounting.Acouple inches are all youneed toprovide for air to circulateunder andaroundtoevacuateanystale,hotairthatmightotherwisenegativelyaffecttheoutput.Anysolarpanelrestingdirectlyonaroofofanytypewillcollectheatunderthesolarpanelsoalittlebreathingroomgoesaverylongwaytokeepingthesolarpanelscool.

BatteryBanks,ChargeControllers,andInverters

TheoriginalpurposeofthisbookwassimplytoprovidedetailedinstructionsonhandcraftingaDIYsolarpanel.However,IfeelcompelledtoaddressthenaturalquestionsthatmightfollowthecompletionofyourDIYsolarpanel.IamlimitedinhowmuchdetailIcanofferintermsofadvicebecausetherearesomanyvariationstovehicles,buildings,boats,andIthinkyougettheidea.IstrayedoffplanwhenIventuredintothelessonabout“Tilt-Angle”whichIwroteforthepersonwhohasneversetthetilt-angleonasolarpanelorsolararray,somewhommayhavesolarmodulesinservicecurrentlybutsettheanglebyestimation.Thebenefittosettingthepropertilt-angleisquitesimplyademonstrablyhigheroutput,somethingeveryoneofusshouldbeintentlyfocusedon.Ihaveheardpeopletalkaboutsimplyaddingmoresolarpanelstoincreasetheenergydepositedintothebatterybanksandthatthinkingreflectsalackofappreciationforthevalueofefficiency.Insteadofaddingmoresolarpanelsitisfarwisertofirstensurethesolarpanelsyoucurrentlyhavedeployedareprovidingthegreatestpossibleoutput.Forexample,ifonehadanarraycontainingeight(8),100-wattsolarpanelsmountedwithoutmeasuringtilt-angle,youmaygetreasonableperformancebutitwillNOTbeoptimal.Infact,letussayforthesakeofconversationthatwithaproperlymeasuredtilt-angle,eachsolarpanelmountedonthisarraycanincreaseoutputby10-watts,notanoverwhelmingnumber.However,ourexampleinvolveseight(8)solarpanelssowearenotimprovingasingleunitbythisnumberbutrather,thewholerackofthemimproveby10-watts.Nowourimprovementisindeedsignificantbecausewithamereadjustmentintilt-anglewegettoexperiencetheequivalentofaddinganothersolarpaneltotherackwithoutactuallyhavingdoneso.IhaveprovidedafictitiousexamplebutIassureyouthatitisnotfaroffthetrailofreality.Infact,thereisaruleofthumbinthephotovoltaicindustrythatitisfarmoreeconomicaltoconserve,thantoaddgeneratingcapacity.Theexactratioisprobablyimpossibletofirmlyquantifybutthegeneralfiguresarethatforevery$1savedthroughconservationsaves$3inphotovoltaicequipment.Itwouldtakesomefancycalculatorworkbutyoucanseethelogicandbesides,anyonepursuingphotovoltaicsisgoingtobeopentoconservation,theygohand-in-hand.Liketheruleofthumbimplies,reduceconsumptionandinturn,youneedlessequipmenttosupportthedemand.

ChargeControllers -regulatetheflowofenergythatabatteryreceivesfromthesolarmodules (solar panels). Solar panels begin generating current as soon as they are incontactwithdirectsunlighthowever,ifitislightoutside,therecanbecurrentgeneratedeventhroughcloudcover.Ifasolarpanelisconnecteddirectlytoabatterywithoutanyformofoverchargeprotection,thereisastronglikelihoodofdamagetothebatteryuptoandincludingthepossibilityofcatastrophicfailure.ThereasonforthisisthatthesolarpaneldoesNOTknowwhentostopsendingcurrenttothe“load”itissupporting.Itjustkeepssendingeverythingitgeneratesevenifthereceivingstoragedeviceisfullandindangerofexploding.Theend resultcouldbeameltedbatterycasewhichmeans thesulfuricacidthatWASinsidethebatteryisnowontheflooroftheRV,boat,orgaragefloor. I speak from experience; in my early “experimenting” phase I conducted anempiricalexercisebyremovingthechargecontrollertogaugethealterationinchargerate.As luckwouldhave it Iwasbeckonedawayfrommyproject forsomenationalemergencynodoubt,butwhenIreturned,Ifoundfourdeep-cyclebatteriesthatlookedmorelikeballoonimitationsofdeep-cyclebatteriesthan,well,batteries.ItdidnottakenearlyaslongasIhadeversuspected,butoncethatpointofnoreturnisreached,say

goodbye to those batteries.There are somany variations in charge controllers that Icannotevenbegin todescribe themall.Thegoalyoushouldhaveinmindwhenyouselectyourchargecontroller is toplanforfutureexpansion.Donotpurchaseasmallunit that is only capable of a couple hundred watts and under 10-amps if you areintendingtoaddmoresolarpanelsasyoucompletethem.Keepinmindthepaceyouhave in mind for handcrafting your panels and perhaps purchase a model that willaccommodatethenextsix-monthsofsolarpanelbuildingfollowedbydeploymentofthecompletedsolarpanels.Thenin that timeifyouhaveaddedmoresolarmodules,upgradetoonelargeenoughtoreallyaccommodateyourexpansion.

MPPTchargecontrollersarepreferabletostandardcontrollersbecausetheyallowthevoltagegeneratedbythesolarpanelstobehigherthanwhatwouldnormallybeneededtochargeagivenbatterybank.Voltageisnotanissuewithasingleorevenapairof72-wattsolarpanels.However,bythetimeyouget toyoursixth(6th)DIY72-wattsolarpanel,youwillneedaseriouschargecontroller.

Howarevoltsdeterminedfromanarrayofsolarpanels?

Ifanarrayiswiredin“series”(positive leadconnectedtonegative leadofthenextsolarpanel) thevoltsbeingsent to thebatteryisADDITIVE.Thismeansthatchargecontrollerreceivesthecombinedvoltagesfromthecollectivenumberofsolarpanelsonthearrayinquestion.Asolarpanelcontaining36-solarcellswillproduce18-voltssinceeach individual solar cell contributes 0.5volts. So if you have a deep-cycle 12-Voltbattery to charge andyouareusing six, 72-watt solarpanels, theywill provide108-volts,almost5-timestheVoltageneeded.Fivetimesyouask?Recallthatinorderforasolarpaneltochargeagivenbattery,thesolarpanelmustgenerate150%ofthebatterybeingcharged.Atwelvevoltbatterythenrequiresasolarpanelcapableofproducing18-volts, something possible with any solar panel made with 36 solar cells. In ourexampleweareusingsixsolarpanels,eachcapableof18-voltsforatotalof108-volts.Subtractthe18-voltsneededtochargea12-voltbatteryfromthe108-voltsprovidedbyour six solar panels andwe arrive at 96-volts difference.Divide 96 by the 18 voltsneededtochargethebatteryandtheanswerisslightlymorethan5,orfivetimesthe

volts needed. It doesn’t take long for the acid toboil in the absence of a chargecontrollerandthebatterywillnottoleratemuchofthiscondition.Infact,Firefightersnowreceivespecialtrainingtohandlestructurefiresthatarebeingfedelectricityfromsolarpanelsthatdon’tknowthestructuretheyareatopisonfire.Buildingcodecallsforclear labeling of emergency shut-off switches on photovoltaic systems for this veryreason, Fire Fighters need to knowwhere to shut the photovoltaic systemdown.Ofcourse,thesizeofagivensystemdictatesthehazardsassociated,soIdon’twanttogivetheimpressionathermonucleardetonationisimminentifyougeneratetoomanyvolts;rather,useachargecontrollerifyouareconnectedtoabatteryandyouwon’thavetoworry about such hazards. There are very small “trickle charge” solarmodules thatproducelessthan10-wattswhichcanbeusedtochargebatteriesofall typesbecausethatsmallmoduleisonlyprovidingenoughcurrenttokeepthebatterytoppedoff.SuchasmallchargecouldnotpossiblydamageabatterywithsofewWattsbeingdelivered.

Batteries- arenecessaryforstorageoftheenergygeneratedbythesolarpanelorsolararray (multiple solar panels on a rack). It is generally not possible to run electronicdevicesdirectlyofftheelectricitygeneratedfromthesolarpanelbecausetheelectricitysuppliedmightbeinconsistentandthuscauseproblemsforthedevice.Forexample,acloudbankmaypassoverheaddrasticallyreducingtheoutputofthesolarpanelorarraywhichwouldcertainlyinterrupttheoperationofyourrespectivedevice.Conversely,ifadeviceisbeingpoweredbythestoredenergywithinadeep-cyclebattery,thedeviceinquestion can operate irrespective of the occasional cloud passing overhead. SolargeneratedelectricityisDC(directcurrent),youwouldneedaninvertertoconverttheenergy intoAC ifpoweringa device isnormally plugged into a typicalwall socket.Whenusingsolarpanels tochargebatteriesyouaregeneratingDC,ordirectcurrentelectricitywhichisthesameastherechargeable(orsecondary)batteriesbeingchargedand therefore requires no conversion. The specific traits and underlying scientificprinciplesinregardtobothtypesofelectricalcurrentexceedsthescopeofthisbook,butasabasicpieceofknowledgeyoumusthaveistounderstandthereisadifferencebetween the typesofelectricityand theyareNOTinterchangeablewithoutassistancefromequipmentcapableofconvertingfromonetypeofcurrenttotheother.Generallyspeaking,anythingthatyouhavewhichrequiresachargefromapowercordandthencanoperate independent of the power cord after receiving a charge, is runningoff abatterymeaningitcanchargeoffa12-VoltDCpowersupply.Byextension,itmeansthat thechargecancomedirectlyfromasolarpanelbecausebatteriescomeinmanydifferentshapes,sizes,voltages,buttheyallhaveonethingincommonwhichistheycharge directly fromDC sources because THEY operate from energy stored in DCbatteriesthatarepermanentlyinstalledinsidethedevices.

Youshouldstronglyconsider theuseof rechargeablebatteries forallofyourbatteryneedssinceyouarehandcraftingthemostefficientbatterychargingtoolthereis,whichbytheway,chargesthebatteriesforFREEfromtheSun.Thefiscalsavingsfromusingrechargeablebatteriesismeasureableespeciallyifyouusemanydevicesthatrequire“AA”,“AAA”,“C”,“D”,or“9v”onadailybasisasIdoformymotion sensor operated security lights all around the interior and exterior of thehouseandyard.Purchasingrechargeablebatterieswillcostmoreinitially,especiallyforgoodquality batteries, but youwill save that purchase pricemany timesover as the

paybackperiodissurprisinglyswift.Notallrechargeablebatteriesareequal;youwillwant to inspect the storage capacity to select somethingwell above 1,000mAh forstarters.

Primarybatteriesare the typemost consumers purchase fromgrocery or hardwarestores.They convert chemical energy into electrical energy by a process of “redux”reactionswhicharebeyondthescopeofourreadingtodayotherthantospecifythatitisaone-wayprocessinprimarybatteries.Youguessedright,wemustthrowtheseawayoncetheyhavebeenexhausted.Landfillshaveuntoldmillionsoftonsofthistoxicscrapasusedbatteriesmaketheirwayintopubliclandfills.Usedbatteriesneedtobedisposedof properly, treated like hazardouswaste, butmost people simply toss them into thetrash receptacle. Not so with rechargeable batteries which can be used hundreds oftimesbeforetheabilitytoholdafullchargedegrades.

Secondary batteries are the rechargeable type I mentioned above which are farpreferabletotheprimarytypeforavarietyofreasons,thefinancialbenefitsbeingonly

partofit.ThegolfcartbatteriesIuseareagoodexampleofamuchlargersecondarybattery that has significantly more storage than its smaller “AAA” cousin but theyoperateessentiallythesameinthechemicalprocesssense.Thebatteryorbankofthemwill require careful attention to ensure you get the longest possible life from themespeciallyconsideringtheywillcostaround$100eachfortop-qualitybatteries.Thereisasignificantdifferencebetweenthedeep-cyclebatteryweuseinphotovoltaics,andthetraditionalautomotivebatteryeventhoughtheyarevirtuallyindistinguishableifrestingside-by-side.Automotivebatteriesgenerallyexistforonepurposeandthatistoprovidetheshortburstofenergyrequiredtoturnanengineoverwhentheignitionkeyisturned.Ofcourseitisacomplexprocessthatinvolvesothercomponentsintheautomobilesuchasanignitioncoilandstarterbuttheautomotivebatteryisdesignedtoprovidethesheerjolt of amps required to turn the engineover.Naturally thebatterywill hold enoughenergyforyoutolistentotheradiowiththeengineoff,forashortwhileanyhow,butifyoushouldhappentoleavetheheadlampsonwhileshoppingforatypicalgrocerystoretripyoumayhaveadeadbatteryuponreturningtoloadyourgroceriesintothetrunk.Theautobatterysimplyisnotdesignedtocontinuetofeeda“load”suchasheadlightswithoutgettingimmediaterechargingfromthealternatorastheengineidlesordrives.Itisdesignedwiththepurposeintendedandformanyyearsthetypicalleadacidbatteryhasdoneadecentjob.

Photovoltaicsrequireadifferentperformancestandardfromdeep-cyclebatteriesthatanautomotivebatterycannotprovide;astoragedevicecapableofholdingasignificantamountofenergy.Equallyimportantinthisequationistheabilitytoslowlyconvertthestoredchemicalenergyintoelectricalenergyandcontinuedoingsoformanyhundredsofhours(providingappropriatelysuppliedwithincomingcurrent).Golfcartbatteriesareexcellentexamplesofdeep-cycletechnologyastheyareabletoprovidefuelsufficientfordriving18-holesofgolfcompletewithgolfersandgear.Ifthegolfcartbatterieswereremovedandreplacedwithautomotivebatteries,thegolfcartmightgetthroughthefirsthole,maybe?Theycontinuetodeliverenergylongerthaneventhemostexpensiveautomotivebatterybecausetheinternalconstructionisvastlydifferent.Autobatteriestendtoemphasize“coldcrankingamps”,whichtranslatesintoamassiveburstofenergylastingabriefmomentasthedriveroftheautoturnstheignitionkeytostartthemotor.Thebatteryunleashesthestoredenergyinaburstthatwecanhearintheformoftheengineturningovermeaningthebatteryisprovingenergytoturnthestartermotor.Thatmotorcontainsagearwheelwithteeththatfitintoasimilargearattheendofacam-shaftlocatedinsidethebottomoftheengineblock.Whenthekeyisturnedintheignition,thestartermotorturnsthegearitisattachedto,whichcausesthecamshafttorotate,whichthencausesthepistonstoriseandfall.Fuelisinjectedintothecombustionchamberwhilethemotoristurningandthebatterythenprovidesasmallsparktothecombustionchamber.Thesparkignitesthefuel-airmixturethatisnowinsidethecombustionchambersoftheslowlyturningenginecausingchainreactionexplosions(controlledofcourse)commensuratewithangasolineenginerunningasitisdesigned.OncetheengineisrunningthereisnolongeraneedforenergytobetakenFROMthebatteryandinsteadtheenginestartstoreplacetheenergyexpendedtogettheenginestarted.Theshallowcycleoftheautobatterymeansthatitiscapableofdeliveringapowerful,butshort-livedburstofenergythatcanberepeatedbutafewtimesbeforedepletingthecharge.Thisshallowcycledesignisoppositeofwhatis

neededtostoreelectricitygeneratedbysolarmodules.Tomaintainoptimalhealthandachievefullservicelife,automotivebatteriesmustbefullyrechargedbythevehiclewhiledriving,backtoastateoffullcharge.Anythinglesswillresultinreducedamperageavailabilityforcold-crackingonthenexttripsothevehicleneedstohaveafullyfunctioningelectricalsystem.Iftheelectricalsystemiscompromisedandunabletoprovidetheneededrechargingaftereachuseitmayonlytakeasingledaytopermanentlydamagethebattery.Basedonthatlastsentencealonewecanseehowill-suitedautomotivebatteriesareforphotovoltaics.Weneedabatterywithverythickleadplatesastheyplayanimportantroleinhowthebatterystores,releases,andthenacceptacharge.Insteadofdelivering570-ampsforturninganengine,weneedfarfewerampsgoingoutsteadily,perhapsformanyhoursifnotmanydays.

Sincedeep-cyclebatteriesaresoexpensive,andsocriticaltothehealthandusefulnessof theentirephotovoltaic system theywarrant special attentionandcare.The typicallead-acid deep-cycle battery will require frequent inspection to ensure there is theproperwaterlevelinsidethebatterycase.WithoutenoughwaterthebatterywillNOTchargeproperlyandcanbecomepermanentlydamaged.Youneedtoremovethewatercaps in order to inspect the amount inside the battery,which is a simple process ofunsnapping the covers. Once open, peer inside to determine the level which shouldcome to thebottomof thevent capyouare looking through.Eachof themmustbecheckedas therewillbeapproximately8-fillcaps to inspect. Ifwater isneeded, takegreat carewhen pouring into the battery to prevent splashing of sulfuric acidwhilepouring.Distilled water is the only thing you should add because regular tapwatercontainsmineralsthatwillbuildupontheleadplatesinterferingwiththeperformanceand reducing the service life of the battery. Battery care and maintenance shouldbecomepartofyourweeklyroutine.Maintainingwaterlevelistheeasiestwaytohelpachieve full service life,but there isonemoreaspectyouneed to control.Depth-of-discharge is a term referring to how deeply depleted a battery gets before beingrecharged,somethingthatisgenerallywithinyoursphereofcontrol.Youshouldhavesomemethod ofmonitoring the level of charge in your battery bank on a real-timebasis.Whether using amulti-meter to take a voltage reading or hard-wiring amoresophisticatedbatterymonitoringsystem,youneedtokeepthebatteriesfrombeingrundownwithoutbeingrecharged.Ofcoursethebatterybankisgoingtogetdepletedasyoudrawenergyout,Idon’twanttocauseundoconcernaboutdrawingenergyfromyourbatteries.Byallmeans,usethestoredenergy!Thatiswhyit isthere,thesinglemostimportantthingforyoutotakeawayfromthisparagraphisthatitisBADforthedeep-cyclebatterytobeLEFTinastateofdischargeforanylengthoftime.Goaheadanddepletethebatteryby70%,justdon’tleaveitinthatconditionforverylong.Theycan take the depletion, just not the chemical condition within the case after beingdepleted.

KeepaboxofBakingSodahandyandconsideritasessentialsafetyequipment.Itneutralizessulfuricacidshoulditspillorsplatteronyourskin.ALWAYSwearprotectivegearwhencheckingwater,yes,evenwhilechecking!WhenaddingwatertoabatteryyouMUSTWEAREYEGOGGLESandRUBBERGLOVESthetypethatprotectagainstacidsotheymustberubber.Itisagreatideatoalsowearanapronmadefromamaterialthatisresistanttothesulfuricacidaseventinydropletsthatgetonyourclotheswillcausediscoloration.Itisagoodideatoremovejewelrysuchasrings,bracelets,oranythingthatdanglesorcanpossiblymakephysicalcontactwithanyportionofthebatteryyouareinspecting.Havingafireextinguishernearbyisnotabadideaaswell,butonceyouhavethepropergearon,youshouldalsonotifysomeonearoundyouofwhatyouaredoing.Intheunlikelyeventyoubecomesplashedwithacidorsomethinggoesterriblywrongandabatteryarcs,youwillwantassistancefromsomeoneclosebytoeitherrescueyourself,orcallforhelptodealwiththe

consequences.Nothingwouldbeworsethantosufferaninjurythataffectsyourabilitytoseeandhavenobodywithincloseenoughproximitytorenderimmediateaid.Nobodyexpectsaccidentstohappenandyettheyhappenateverystationinlife,everyoccupation,hobby,andpast-timethereinlaysthepossibilityofinjuryfromthemostinnocentofsources.Batteriesarenotexactlyinnocentsourcematerialbuttheydon’tneedbehorrificallydangerouseither.TheyshouldcommandyourrespectforthepotentialofseriousinjurybywearingtheprotectivegearImentioned,maintainingthebakingsodanearby,communicatingwhenworkingalone.

Inverters are necessary to convert the DC electricity stored inside the battery orbatterybankintoACelectricityforusewithyourappliances.Thereareagreatmanytypesofinvertersdesignedtofilldifferentroles.Forexample,virtuallyeveryautopartsstorewillcarrya fewsmall inverters in the80-200Watt rangewithbuilt-incigarettelighterplugswhichclearlyindicatethemobileapplication.Thosearelight-dutymodelsidealforusewithsmallerelectronicitemslikephones,orbookreadersliketheNook,andhaveabuilt-infusethatwillshuttheunitdownifover-stressedbytheload.Heavierdutymodelswill be required for electric items like construction related drills, smallelectricsaws,orelectronicgearthatdoesnotrequiresine-wavequalityelectricity.Whenwegetintotheinvertersofheaviercapacity,typicallyyouwillnotseeanyevidenceofquickandeasyapplicationidentifiablebyacigarettelighterplug.Theinvertersdestinedto serve heavier loads like what we would expect in a residential, RV, or boatapplication that are typically serviced bymultiple solar modules will NOT have anoptiontousewithacigaretteadaptedplug.Theyrequireamoresturdyconnectionwiththebatterybankincludingaheavyfusebetweenthetwo.Wiresizeiscriticalhereasthesecableswillcarryallthecurrentrequiredbytheloadspluggedintotheinverter.ThesizeshouldbenolessthanAWG-4andifspaceallows,golarger(remember,largerwirewillhaveasmallerAWGnumbertoidentifyit)becausethelargerthewire,themoreelectronsitcantransportefficiently.Ihavepersonalexperiencewiththis,havingusedwirevastlytoosmallforthejob,myinverterstartedtomeltwherethewireconnectedtothe unit. Luckily Iwas home at the time and could smell something burning, but itcertainly brings home the idea that bad things can happen if you don’t respect thelimitationsofwirecapacity.Theselarger inverterswillhavetwopowerrangeslisted,“Continuous”whichisthetoprangeofwattsitcansupportwhileworkingtosupportthe appliances plugged into it. Next is “Surge” which is a demand placed bymostappliancesastheyinitiallypowerupafterbeingturnedon.Typicallythisdemandforpoweratstart-upisconsiderablylargerthanwhattheappliancewillusewhileinnormaloperation. The inverter must be rated to handle the load you will ask it to supportbecauseifyoudon’t,theunitwillsimplyshutdownasameansofprotectingitselfandthe appliance. Most units will have two GFCI receptacles, low battery alarms andautomatic shutdown to protect the battery bank from total depletion.They alsowillauto-detectandshut-downwhenoverloadedorover-heated,capabilitiesnotavailableinthemuchsmallermobileunits.

Pure SineWave vs. Modified some of the electronic equipment operated off aninverter may be highly sophisticated computer or entertainment equipment. Thesepieces of equipment have higher sensitivity to variations in the frequency of theelectricitypowering them.Thesesensitiveelectronicsdetect that there isadifference

betweentheelectricitysuppliedbytheinverterversesa typicalresidentialwalloutletsupplied current. The specific appliance will turn on and operate, but there will beobviousandunacceptablefeedbackbothvisuallyandaudibly.SoundwillbeheardfromTVspeakersthatarelikeanawfullyirritatingCricketthatcannotbesilencedevenbymutingthevolume.ThisisanexcellentexampleofelectronicsensitivitywheretheTVisreactingtothedifferenceinwavelengthbetweengrid-utilitysuppliedelectricityat60Hz, and the inverter supplied60Hz.A“modified sine-wave” inverter isdesigned towork with household appliances to include some TV’s and computers as not allapplianceswill reactpoorly to this slightlydifferentwavelengthofelectricpower. Infact, small microwave ovens, food processors, small refrigerators,fluorescent lights,smallvacuumcleaners, sewingmachines, fans,drills, sanders,buffers,DVDplayers,stereos, satellite equipment,musical instruments, toname just a few items thatworkwithoutanynoticeabledifference.Theminordifferencebetweenthecycles,gridutilityverses inverter,don’t interferewithnormaloperationsunless theelectricappliance ishighly sensitive, usually translated to mean highly sophisticated. The higher thesophistication,the“cleaner”thesourceelectricitymustbe.Gridsuppliedelectricityisprecisely distributed inwavelengthsmeasuring 60 per-secondwithout any variation.Modifiedsine-waveinvertersarenotaspreciseastheelectricutilitygrid;itissimplynothowtheyaredesigned.Theyareverycapableandsuccessfullyprovidepowerforawide range of devices, but the devices that are sensitive require a “Pure SineWaveInverter”.This type inverter is able toperfectlymimic thewavelengthpresent in theutility service providers at 60Hz so the equipment requiring “clean” electricitywillfunctionwithoutanyperceptibledifference inperformance. It is ideal forcomputers,LED and Plasma TV’s, and other high-tech entertainment equipment whoseperformance capabilities require the precision and consistency. I personally use aSunForce Pro Series 650Watt Pure Sine Wave Inverter for my LED TV, satellitereceiver, Sony PlayStation, and surround sound system since each of these itemsperformpoorlyunlessprovidedcleanpowerfromthegridorpuresinewaveinverter.Whenyou select themodel thatwill serviceyour system,keep inmind the typesofequipmentyouhaveselectedandtherelativetechnicalsophistication.Purchaseaunitthat works best with the highest level of technology you intent to operate from thesystemyouaredesigning. Iam justwarningyounow thatPureSineWave Inverterscost more, and have a lowerWattage rating than do theModified SineWave unitsbecauseof the level of sophistication required tomimicutility providedwavelength.Thenaturaltendencyistotrytogetbywiththelesserpricedunitbecausethereissuchasizeablepricedifference.Youwillbedisappointedwith theperformanceoutrightandyouwillregretnothavingspenttheadditionalmoneyfortheappropriategearfortheintendedload.

FinalSafetyBriefing

Younowhavetheresourcestoengageinanactivitythatyoucantakegreatprideinasatrue“Do-It-Yourselfer”!Theconceptofdoing thingsforoneself isnotnew, infact,prior to theIndustrialRevolutionwhensomanyitemsbecamemassproduced,ifyoucouldnotrepairorevenbuildsomething,youwentwithout.Ofcourse inanycivilizedsociety therewillhavebeenspecializationoftradeswherecertainlyagreatmanyproductswereboughtandsold,butthe follow-upmaintenance and repairs would fall on the owner of the products. It was anecessitytohaveskillsrangingfromcarpentrytohusbandry,withsomebarteringthrowninbutthisfadedslightlywiththeintroductionofmassproduction.Theintroductionofconsumergoodsofeverydescriptionbeingmadeavailablecoupledwiththedevelopmentoftherailroadsystemmeant that cheapergoodswere available to replace anything thatbrokedown.TheGreat Depression again was cause for many to re-invent the pioneer spirit as the moneyneededforrepairsorreplacementofbrokenitemswasnotavailable.Necessityagainforcedareturn to the practice of self-repair until the post-WorldWar II influx of technology andproducts.Factoriesformerlyusedtomassproducemilitaryhardwareturnedtosatisfactionofconsumerdemandforgoodsmanyofwhichwillhavecomeaboutasbeneficiariesofthewar.SuchaconditionprevailedintheUnitedStatesuntilcomparativelyrecentlywheneconomiceventshavestrainedtheAmericanmiddle-class totheextent that theneedforDIYismorelikely to be practiced.Who among us feels comfortable simply taking our vehicle to the“shop” and accepting the quotedprice andpunch-list of problems listed in said quote?Orsimplygivethego-aheadtoaplumberwecalledoutbecauseofcloggedtoilettodigupwhattheplumberclaimstobeatree-rootrelatedsewerlineblockagewhichhewillgladlytakecareof at a cost of $3,000?No, I thinkwe aremore likely to thank the person giving us thisinformationandthenswiftlydismissthemwithoutauthorizinganyworksowecaninvestigatehowtoperformtherepairourselvestosavemoney.Forexample,Ihavepersonallyrebuiltourclothesdryerthatiscurrentlyinservicespendinglessthan$55whenIhadbeenquoted$150toreplacethepartNOTCOUNTINGTHETRIPCHARGE!BeforeIstartedtheprojectIhadnoclueastohowaclothesdryerworks,andcertainlynoexperiencerepairingsuchadevicebutthankstotheInternetandastubbornstreak,Ifigureditout.Iamsureyouhavethesameexperienceifnotwithadifferentapplianceorautomobile,thatisjustwhoweare.Thepointisthatyoucandothisactivity!Thereisnolimittowhathumanscanachievewhengiventheinformationneededtoproceed,andthewilltopushaheadinspiteofthefactwhateverthetaskis,itisNEWandunfamiliar.

Now,havingsaid thataboutwhatyouarecapableofdoing, Iwantyou toexercisegoodjudgmentwhenparticipatinginthisactivity.Therearegoingtobetimesnomatterwhatthe

activitywepursueasavidDIYpractitionerswhentheinnervoiceistellingusthat“wedon’tknow what we are doing”, a voice you should listen carefully for. There is a differencebetweenmovingforwardwhilebeinguncertainofexactlywhattodo,andbeingreckless,thedifferencebetweenthembeingaverygreyarea.WhatdoesthatmeanintermsofhandcraftingDIYsolarpanel(s)?Everystepoftheprocessdescribedhereinmightbetotallynewtomanyreaders.Thefirsttimetheysitdowntoperformastepinthe“How-To”manual;itislikelytocause a bit of trepidation, especially if new to this task. There is no need for trepidationbecause the contents of this book, the instructions, the “How-To” video demonstrations,combinedwiththeabilitytoaskmequestionsviaemailallservetoprovidetheantidotetotrepidationwhichisconfidence.Youmightbetreadingonunfamiliargroundfromthetimeyoulayouttherawingredients,butkeepthisinperspective,thinkofothertasksyoucurrentlyperformthatonceseemedoutlandishlyimpossiblewhenyoustarted.Maybeyoupersonallydon’t have an “outlandish” example on which to draw comparison but it need not be anoutlandishactivity.Takemoreroutineactivitiesasexamplesbecausethisisreallyaboutthemental perspective, themind convincing you that a given event or activity iswithin yourgrasp,ornot.Letussayforsakeofconversationthatyouareworriedbecauseyouhaveneverdone thisbefore and assuch,youmightmakeamistakeleadingtoahorrificconsequence.Perhapsyoufeelunder-qualifiedbecauseyouhavenopreviousexperiencesolderingwire,oryoudon’tcompletelyunderstandhowitallworks.Thenthereisthepossibilityofbeingafraidoffailure,meaningyoufollowtheinstructionstotheletterandthesolarpanelisnotproducinganythingbecausethatisjusthowthingsgowhenyouhaveattemptednewprojects.

Ianswerthefirstproposedconcernwithasuggestionthatyoulookinwardtoevaluateyourpersonallistofachievements.Iaskthissothatyoudon’tsellyourselfshortontheskillsetsrequiredforthehandcraftingprocess.Iwantyoutofirstexaminewhatyouaredoingthisverysecond.Youare reading abook about handcrafting solar panels startingwithonly the rawingredients.Thefactyouareonpage124meansthatyounowhaveasignificantknowledgebaseonthesubjectbutmoreimportantly,youaretakingactiononyourinterest.ThereisgreatcomfortinknowledgebecauseIguaranteethatbypage124ofthisdocumentyouhavebeenexposed to virtually every step thus eliminating any unknowns. Fear of the unknown is auniversal human condition that can bemitigated by knowledge.Themore you understandaboutthisprocess,thelessyouwillfearitandbypage124,youshouldbefeelingprettygoodaboutthepossibilitiesofasuccessfuloutcome.Thefirsttimeyoudroveacar(providingyouhave)theremayhavebeenfearsinceitwasanewactivity.Drivingisnotarisk-freeactivity,tensofthousandsofAmericanslosetheirlivesannuallybutwecantakestepstominimizeourpersonal risk and the safety technology built into our vehicles is making crashes moresurvivable. Plumbing is another great example of a category of DIY repairs that we nowregularlydelveintothankslargelytotheInternetwherewecaneasilyfinddetailedanswerstoquestions previously held close to the vest by those in the plumbing trade. Armed withknowledgewehavetheconfidencetomoveforwardandsuccessfullycompleterepairs thatwould formerly been unthinkable. For example, a decade ago I would have called aprofessionalplumbertorunasnakethroughthedrainsysteminmyhomebecausethattaskwasbeyondthescopeoftasksIfeltcomfortabletakingon,fearoftheunknown.TodayIcansay with pride that I have already tackled this activity successfully after experiencing acompleteblockageofasewerlinebytreeroots.AfterresearchingtheparticularsonlineIwasabletorenttheequipmentneededandaccomplishthetaskthanksdirectlytotheinformationavailable to me via Google. Once informed I felt confident to boldly attempt an activity

previouslyoutsidemycomfortzoneandasadirectresultIcanaddplumbingtomylistofskills.ThisformulaisrepeatableonsomanyfrontsthatitisdifficulttoidentifyarepairthatwouldNOT bewithin our grasp. Information, common sense, coupledwith and a can-doattitudewillseealmostanyprojectthroughtosuccess.Itfeelswonderfultocompletethetaskathandknowingthatfutureissuesofthatnaturecanbeaddressedin-house,foreverinsulatedfromcostsrelatedtothird-partyserviceproviders.Confidencebegetsconfidenceandsoonceempowered,continuewithyourlearningbecauseknowledgeISpower.

Letusdiscussover-confidence,theothersideoftheequationthatmighttendtoworkagainstcommon sense. Have you ever heard the expression, “you know just enough to bedangerous”?Itappliestosituationswhereanindividualdivesintosomeprojectafterarmingthemselveswithjustenoughinformationaboutthesubjecttoskirtthesurface,butnotenoughin-depth knowledge to make informed decisions while making forward progress. Thisconditionmightlendonetotakestepsthattheythinkarecorrectbasedupontheverylimitedknowledgetheypossessthatmightactuallyturnouttobeincorrect.Fromthatpointforwardtheerrorwilleithercauseproblems,ornot,buttheindividualwillnotknowbecauseheorshewillbeblissfullyunawareofanydangerousconditionstheymighthavecreated.Agameofchanceinessencewherebyonehasa50%chanceofhavingmadethecorrectdecisionwhilebeing equally likely to have erred. In the context of photovoltaics, at least during thehandcraftingphase, sucha50/50prospect for failurewill likely result ina solarpanel thatsimply will not generate any current.A fairly harmless outcome in terms of danger, butcatastrophic in terms of your resulting confidence becauseI can personally attest, nothingdashesenthusiasmlikestaringatabig,glaringZEROontheLEDmulti-meterscreenwhentestinganewlycompletedsolarpanel.Infact,asymbolicpunchinthegutsuchasthismightdampenyourenthusiasmpermanentlydependingonpersonaltemperamentAdeadsolarpanelresultingfromawiringerrorisaveryhigh-possibilityscenariothatneednotbeexperiencedbyanyonefollowingtheinstructionscontainedherein.YoushouldNEVERguessifyoureachapointwhereyouareuncertainofwhattodonextwhenfollowingthecourseofactionlaidoutforyouinthepagesofthisdocument.Guessingplacesyoudirectlyintoagameofchance,that50/50rollofthediceconditionwhereyouwilleitherperformthestepasindicatedintheinstructions,oryouwill perform the step asyour common sensedictatesbaseduponyourinstincts.Theoutcomeofyourmisstepmightbenothing,oritmightleadtoamalfunction,butwhyguess?Iftheoutcomemightpossibleleadtowastedtime,effort,anddashedenthusiasm,whydoit?

RepairingDamagedSolarCells

IfyoudoNOTknowhowtoproceedduringagivenstep!AllIamaskingyoutodoisSTOPif you are uncertain and go research the issue! Return to the relevant portion of theinstructions,readthematerial,watchtheHow-Tovideos,oremailus,butdonotassumethatyou are taking a harmless step by guessing. An inert solar panel is distressing enoughemotionally,andtheriskgenerallystopsthere,butthatmightnotalwaysbethecase.Guessingcanhavelethalconsequencesinotherareasofphotovoltaicsespeciallywhenwestarttalkingabout live solarmodules generating current and sending it to a battery bank.An improperconnectiononadeep-cyclebatterycouldleadtoanimmediateandviolentreaction,perhapstheresultofaguessaboutwirepolarityshouldcablesorwiresbeincorrectlylabeled,ornotatall.Theinformationavailableonlinecanempower,butalsodeceiveusintoafalsesenseofconfidence.ImustseemlikeIamtalkingoutofbothsidesofmymouth,ononesidetellingyouthatinformationisavailabletoempoweryoutotackleanytask,thenimmediatelysayingthatcanbedangerous.Awareofthe“double-speak”,Imerelywantyoutounderstandthatitisperfectlyfineforyoutochallengeyourboundaries,butrecognizewhenyouhavehitapointofuncertainty.Thatisit!Oncerecognized,STOP!

TheInternet resourcesofwhichIhavemadereferencemight includeGoogle,orperhapswebsitesspecifictothetopicunderreview.Foreverysubjectimaginabletherewillbemanysourcesonlineandthegreatestchallengewillbetoselecttheversionofinformationyoufindeasiesttofollow.Becarefulduringthesearchbecauseyoujustmightdiscoverthatthefieldisfullofseeminglyconflictinginformationaboutwhatthenextstepshouldbeleavingonemoreconfused.Likemanyotheraspectsoflifeinthedigitalage,wearedelugedwithdataandthechallengebecomesclearly identifyingwhich is thebestsourceof information tosatisfy thesituation. I suggestyou takenoteson thechoices that fitwithin theboundariesoutlined ingreatdetailwithinthisdocumenttocomparewithinformationyouhavelearnedduringyouronlineresearch.Ifthereisstillanareaofuncertainty,emailusandwecanweighindirectlyonthequestionthatpertainstotheprojectinquestion.Thetypeofquestionwecanfieldwillbelimitedtothehandcraftingprocessasthisisdirectlyrelatedtoourexpertisesoitisnaturalforyou to look towards us for assistance. It is assistance we are glad to render as you gainproficiencyonyourprojectandwethinkyouwillfindthatwehaveindeedcoveredall thebasesthuseliminatingyourneedtoseekoutadditionalguidancebutwearehereifyoudo.Questionsoutside the scopeofhandcraftingyour solarpanel are anothermatter aswecanexposeourselvestolegaljeopardyofferingtechnicaladvicesightunseenshouldsomethinggoawryonyoursystem.Havingsaidthis,wewilldoeverythingpossibletohelpyousecuretheinformationyou seek so that you canmake the best possible decisiononhow to continuemovingforward.Unfortunatelyweliveinalitigioussocietythatcanleadtocostlylawsuitswhenthingsgodifferentlythanexpected,particularlyifsomethingbadhappensasresultofourdirections.Thereforewewilldoourbesttoenlightenyou,educateyou,steeryoutothebestsourceofinformationthatwehavesothatyoucanmakeaninformeddecisionbasedoncurrent“bestpractices”.

Theoccasionalsolarcellwillcomealong

T wherebyeveryeffortyoumaketosoldertabbingwiretothebusbarorbustabwillfail.YouwillhavedoneeverythingcorrectstartingwithapplicationofRosinFlux,properlymeasuredtabbingwirestrips,asoldertipingoodworkingorder,goodlighting,andyet,whenyoupullthesoldergunawayafterthinkingyouhavejustdoneagreatjob,thetabbingwirepopsoffthebusbar.Noexplanation,nothingobviouslywrongwiththebusbar,soyouattemptthesecondsolderingwiththesameoutcomeandnowyouhaveanawkwardsituation.Perhapsonlyoneofthebusbarsisrespondingthisway,butoneisenoughtorenderthesolarcelluselessbecausewithoutallbusbarsurfacesmakingexcellentelectricalcontact,youwillhavejustcreatedtheproverbial“weaklink”intheSTRINGunderconstruction.Referbacktopage39andexaminetheempiricalexerciseIconductedwherebyIpurposelyomittedtabbingwirefromoneoutofsixbustabsontheback,POSITIVEsideofasolarcell“PAIR”.Thedirectresultofthemissingbustabsolderwasadiminishedoutputthatwouldlimitnotonlythefaulty“PAIR”,butwouldnegativelyaffecttheentiresolarpanelifallowedinclusionasis.Usuallyyouwillencounterthiskindofproblemwhileconstructing“PAIRS”butitcanhappenwhileconstructingSTRINGS.ItmostoftenoccurstothePOSITIVEbustabs,perhapsduetotheircomparativelysmallsize,exposuretointenseheatduringsolderingoftheoppositesideofthesolarcell,buteitherwaytheresultisthesame.OncethebustabfailstoacceptthesolderthereisagoodchancethatthespecificbustabwillNEVERacceptthesoldernomatterwhatactionsyoutake.

AbsentthethincoatingofsilverthatisappliedduringthemanufacturingprocessnoamountofRosinFluxorRosinSolderwillforcethebondtohold.Eachprogressiveattemptwillonlyserveincreasethedamagetootherpartsofthesolarcellasitisrepeatedlyexposedtoheatfromthesoldertipandpossibleroughhandlingasmoreaggressivemeasuresareemployed.Theonlyoptionwouldhavebeentosurgicallyremovetheproblematicsolarcellandreplaceit

withonethatisnotcompromised.UNLESSthatis,youuseconductivepaintasdemonstratedinour“How-Tovideo!AdamagedbusbarorbustabdoesnotnecessarilyorautomaticallyrequirereplacementoftheproblemsolarcellasIdemonstrateinthevideothatcanbeaccessedbyscanningtheQRBarcodeabovethisparagraphintheappropriatelylabeledbox.Youmayrepairbusbarsandbustabsin-placewithoutrequiringtime-consumingextractionthussavingtheforwardmomentumyouhaduntilencounteringtheissuewithuncooperativebusbar/tabsurfaces.Thenicepartabouttheconductivepaintisthatithelpsnotonlymaintainforwardmomentumbuthasafiscalbenefitbyreducingtheoccurrenceofdefectssoyoutossfewerwreckedsolarcells.Everytimeabustabhasfailed(priortodiscoveringconductivepaint)Iwouldhaveextracted,thentossedouttheoffendingsolarcell.IcansafelysaythatmyphotoofshatteredsolarcellswouldhavebeenmarkedlysmallerhadIknownofthispaintlongago.

Theend,goodluck!!