SOLAR SEQUENCER WITHOUT SOLAR PANEL― JAMECO PART NO. 2161203

Experience Level: Intermediate | Time Required: 1 Hour

The Solar Sequencer kit enables a single 15 watt solar panel to charge multiple lead-acid batteries of different sizes and capacities, keeping them isolated from each other. An example is a truck, lawn mower and an ATV battery that can all be maintained with just the single solar panel. It is also possible to use a solar panel and battery to run a garage door opener in a building with no access to utility power. This kit uses the Parallax BASIC Stamp 1 microcontroller, which reads the batteries voltages by reading an ADC 0834 analog-to-digital converter. Using these readings, the solar sequencer can determine if a battery needs to be charged and can also load test the solar panel. Three power MOSFETs are used to switch on the charging current, one for each battery. The batteries all have a common ground connection to the solar panel. The battery voltages are divided by three in order to keep the voltages on the ADC 0834 below 5 volts, using an isolated single in-line package resistor network so that no adjustments are necessary. Power for the Stamp is supplied by the batteries through diodes so that as long as at least one battery is connected the Solar Sequencer will work. LEDs will indicate which battery is charging, whether there is enough solar capacity to charge, or if the batteries are fully charged. Required tools and parts: Soldering iron and solder Wire stripper/cutter and basic hand tools Digital multimeter Wire 18-14 AWG, length depending on setup Battery clamps or cigarette lighter plug Solar Panel 45W or less (Recommend P/N 2128569, P/N 2154003) Optional: enclosure or mounting board Kit Includes: BASIC Stamp 1 module 390Ω Carbon-film resistor BASIC Stamp 1 serial adapter 1kΩ Carbon-film resistor 1N4001 Diodes 2.2kΩ Carbon-film resistor Power Schottky Diodes 4.7kΩ Carbon-film resistor 1μF Capacitor 5.6kΩ Carbon-film resistor 10μF Capacitor Pushbutton switch 2N3904 NPN transistors IRF5305PBF P-channel MOSFET 2N3906 PNP transistor 8-pin IC socket T1-3/4 Yellow LEDs Heat sink mounting kit Automobile DC power plug with fuse 1N5817 Schottky diode 2-pole Terminal block 8-Pin, 10kΩ SIP resistor network 3-pole Terminal block 8-Bit, 14-pin ADC IC 3-pin header Printed circuit board Battery clamp for solar panel

Note: This kit does not include a solar panel. If you would like a solar panel included in the kit, please see P/N 2161211

Step 1 - Introduction If the PCB is going to be mounted in an enclosure or onto a piece of thin plywood, it is easier to mark the holes before the components are installed, or make a template out of a piece of cardboard. The board measures 3.8" x 2.5". The figure below shows the bare circuit board component side up. Install the components starting with the shortest, ending with the tallest. That way the components stay in the board when it is flipped over for soldering. Tip: when soldering parts with multiple leads, you can partially solder one lead to hold the part in place and then check its alignment. This works well for chips like the ADC0834 and the Blue Terminal Blocks. The rest of the images in the assembly instructions are on the mechanical drawing for the printed circuit board, and the components to be installed are outlined in red.

Step 2 - Installing the 1/4 watt resistors Bend the leads of the resistors and install them in the locations outlined in red on the diagram. The resistor values and color codes are as follows (from top of board to bottom): 2.2K – (red, red, red, gold) there are four 5.6K – (green, blue, red, gold) there are five 4.7K – (yellow, violet, red, gold) there are two 1K – (brown, black, red, gold) there is just one

Step 3 - Installing diodes and 390 ohm resistor Bend the leads of the diodes and resistor and insert them into the board in the locations shown in the diagram, and solder. The diodes and the 390 ohm resistor have heavy leads, trimming them about 1/16" from board prior to soldering makes it easier.

Step 4 - Single Inline Package Resistors Don't forget the ground connection at the very bottom, as part of a trace it is hard to see some of them.

Step 5 - Transistors There are five NPN 2N3904 transistors. Install them with the flat facing right. The one PNP 2N3906 transistor, with the double red rectangles, flat facing left.

Step 6 - Progress check This is what the board should look like at this point. Check your progress.

Step 7 - Capacitors Install the plus + (longer lead) to the square pad. You may need to use some tape to hold the smaller one in place. These must be installed with the correct polarity, the positive lead is marked with +++++.

Step 8 - Pushbutton switch Install the switch. It only fits one way.

Step 9 - LEDs Install the LEDs with the long lead to the square pad, flat to the left. There are four LEDs.

Step 10 - Progress check The board should look like this at this point. Inspect the board, making sure all solder joints have been made securely.

Step 11 - MOSFETs and diodes Install these, alternating as follows: MOSFET-Diode-MOSFET-Diode-MOSFET-Diode. Tip: insert all of them into the board and hold them in place with a ruler while flipping the board. Then lay the ruler next to the TO-220 package tabs and slide it to keep them in a nice straight row, and sticking straight up from the board ready to be soldered.

Step 12 - Programming pins Install the programming pins. Use tape to hold in place while soldering.

Step 13 - Analog-to-digital converter Install the ADC0834 analog-to-digital converter with the small half-circle notch facing to the left. There is also a dot at pin 1 which goes into the square pad.

Step 14 - Progress check The board should look like this at this point.

Step 15 - BS1 Stamp Install the BASIC Stamp with the components on the Stamp facing toward you.

Step 16 - Terminal blocks Install the blue terminal blocks Make sure they stay pressed against the board, and fill the hole around the post with solder. Also, make sure the opening on the blocks, where the wires will go, faces toward the edge of the board.

Step 17 - Finished board The finished board’s component side should look like this. Check your component orientation.

Step 18 - Solder side Inspect the solder joints. The solder joints should all be shiny with no gaps between the component and the hole, with a small fillet between the lead and the pad. There are some open holes in the board where no component is installed.

Step 19 - Programming This requires a Windows machine running Windows 95 or later, with a serial port or a USB to serial adapter, and a serial cable. Quick steps – (follow if you have programmed a Basic Stamp before) Download the SolarSequencer.zip from http://www.nutsvolts.com/magazine/downloads/, unzip it and save the three files. Open the

STAMP editor, find the SolarSequencer.bs1 file and open it. Connect a 9V battery, a 12V lead acid battery, or a power supply set to between 9 and 25 volts, to one of the battery connections. The bank of terminals on the right alternate +-+-+-. It doesn't matter which ones as long as the polarity is correct. Connect the programming adapter and cable, and download the program to the STAMP.

Disconnect the power supply or battery. More Detailed Steps – (follow if you have not programmed a Basic Stamp before) To download the stamp programming software, go to Parallax.com, click the Support tab, Downloads, then Basic Stamp Software.

Choose the editor for your operating system, and download it. Run the installer, which uses the Install Wizard, then click next until the installation starts. After it installs, the STAMP Editor is at start > All Programs > Parallax Inc > Basic Stamp Editor V2.5.2 > Basic Stamp Editor V2.5.2 Now download the SolarSequencer.zip software from http://www.nutsvolts.com/magazine/downloads, unzip it and save the three files in the My Documents folder. Run the Editor, click "yes" to file associations, then use file > open... > My Documents > SolarSequencer.bs1. It is a good idea to create a Stamp folder for your programs, especially if you plan to do any modifications. Now connect the STAMP programming adapter to a serial cable connected to the serial port on your computer. Connect a 9 volt battery, or a power supply set to between 9 and 25 volts, to one of the battery connections on the Solar Sequencer board. The bank of terminals on the right alternate + - + - + -. It doesn't matter which ones as long as the polarity is correct. Connect the programming adapter to the three pin header on the board with the >> symbol on the adapter to the left.

Download the program SolarSequencer.bs1 to the STAMP by clicking Run at the top left of the Editor and selecting Run. The Editor will detect the STAMP and download the program to it, showing a status display. Once the program downloads, disconnect the battery or power supply.

Step 20 - Installation and testing The installation of the solar panel is a project itself. Pick a location that faces South with the least amount of shading as possible. There are web sites that can help find your latitude and longitude, and other sites that help you calculate the best angle from horizontal for the different seasons. I have been using a 45 watt solar panel kit from Harbor Freight (item 90599) that can cost as little as $149.00 with a coupon. The panels are mounted at 30 degree angles to each other in order to spread the capacity over as much of the day as possible, because if they are mounted as shown in the kit directions the current can be over 3 Amps at noon, but not much morning and evening. The mount was made out of 1" aluminum angle purchased from the hardware store. A single 15 watt panel, like the one Jameco carries, works fine for maintenance charging and is easier to mount. The solar panel is connected to the solar input, and a lead-acid battery is connected to one of the battery outputs as shown in the diagram, double checking the positive and negative connections. Connect wires to the Solar Sequencer blue terminal blocks first, then connect to the battery. If the battery voltage is less than 13V, the LED for that battery output will light. If the LED does not light, and the battery voltage is above 13V, connect a load such as an automotive light bulb to the battery. If the battery is in a vehicle, opening the door will load it when the interior lights turn on. This will usually lower the voltage enough that the LED will light. Close the door or remove the load, and once the battery voltage is above 14.2V, the LED will turn off. This will happen rather quickly if the battery is near full charge on a sunny day. This procedure is repeated for the other battery outputs. For operation connect the wires for the other batteries to the blue terminal block first, then to the battery. The Solar Sequencer will charge all of the batteries in sequence, starting with Battery 1. There is quite a bit of information about how this works in the software comments. Connect the battery for the garage door opener to the Battery 1 position, so it is the first to be charged every morning.

Step 21 - Solar panel mount Below is a picture of the solar panel mount I built. There are a lot of different ways to do this and everything is unique to a building and the way the sun shines on it. This is just an example.

Step 22 - Garage Door Opener This is where we connect the garage door opener and get it operating from the battery. My garage door opener is a Craftsman/Chamberlain belt drive with battery backup. It is designed to run on 12V DC and I usually run it from a car battery because my garage has no utility power. It comes with a 12 volt 5 A-Hr lead acid battery, but is only intended as a backup. Everything but the lights work with no AC power, and it draws about 40 mA when in standby. It does need AC power applied initially, but will work from the battery afterward. This garage door opener uses 4 amps DC to open the door, and 3.5 amps to close it. Both take about 20 seconds. The small battery included with the garage door opener is a 12 volt 5 A-Hr lead acid battery, but it only lasted about six months. It is only intended as a backup, not a primary power source. I replaced it with a lead acid battery that was still good, but out of warranty, removed from a Jeep Grand Cherokee. It is a size 26 battery, which has a standby power number of 150, meaning it can supply 25 amps for 150 minutes. I plan to add another opener, and this should be more than enough to power both. It also can run the lights that came with the solar panel kit. The Jeep's battery is on a shelf in the back of the garage and wired to the garage door opener with 14 gauge wire. To get the garage door opener working, connect its battery power leads to a 12 volt lead acid battery (it uses 1/4" female quick connectors), and the battery to the Solar Sequencer. It won't come on unless it is plugged in to AC power. Connect a power inverter to the battery, and plug the garage door opener into it, or use a long extension cord (or generator) to plug into AC power. I used a 400 watt inverter, but 100 watts is probably enough as long as it doesn't have to open the door. The garage door opener's LCD display will show "charging battery". Unplug it and it will continue to run on the battery. The display will still alternate between time and temperature, and the time can still be set. The only things I don't like are the display always scrolls "battery backup enabled" across the bottom; if the voltage drops below 12.5 it will beep every minute, and there is an orange LED on all of the time. The lights also don't work, they need AC power. I have been using the prototype version of this design for two years as a maintenance charger, and an additional year with the garage door opener, but only six months of that was with the Jeep's old battery. A 15 Watt solar Panel will maintain three batteries. With the garage door opener, the 15 Watt panel needs a while to make up for the 40 mA draw all night. Cloudy days and long nights in the winter make the 15 Watt panel not quite enough. This will depend on the location and how much direct sunlight the panel receives. In Maryland, the 15 Watt panel was not quite enough. Everyday use of the garage door opener will likely require a higher wattage solar panel. This has been a fun project, and a great way to use solar energy to power the garage.