http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

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Convert old cordless tools to Lithium powerby Honus on August 6, 2016

Table of Contents

Convert old cordless tools to Lithium power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Intro:   Convert old cordless tools to Lithium power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 1:   Tools and materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Step 2:   Open the battery case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Step 3:   Solder the battery connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Step 4:   Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Step 5:   Finished! . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

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http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

Author:Honus    DIY AnimatronicsI'm a former bicycle industry designer turned professional jeweler. I like working with my hands and am happiest when I'm in the shop building my creations.If you need help with your project just let me know!

Intro:  Convert old cordless tools to Lithium powerI have several old cordless power tools and they're all in good working condition. The trouble is the batteries all need to be replaced and the batteries are obscenelyexpensive. I have a really hard time paying for batteries that cost almost as much as the tool and I didn't want to discard perfectly good tools.

One other issue I had with my old batteries as that every time I went to use them the batteries were dead as the NiMH batteries would self discharge rather quickly,especially in cold weather.

Most modern cordless tools use Lithium batteries and I happen to use LiPo battery packs all the time for other projects so I figured I'd convert my old cordless tools toLithium power using inexpensive LiPo battery packs.

This is a really simple conversion and the cost is a fraction of what power tool manufacturer replacement batteries cost.

Be sure to check out the FAQ section at the end as Lithium batteries do have to be treated in a particular manner!

Step 1: Tools and materialsThere are only a few tools needed:

Wire strippers

Wire cutters

Soldering iron

Dremel tool with cutoff wheel (a narrow bladed saw will also work)

Battery charger- I really like the Hitec X1 Multi-Charger as it's a smart charger can handle most any battery chemistry but any charger capable of charging multi cellLithium batteries will do

For materials you'll need the following:

Heat shrink tubing

Wire (14ga is best)

XT60 connectors

Battery monitor- I really like the inexpensive Hobby King low voltage battery alarm

3s (11.1V) or 4s (14.8V) LiPo R/C battery pack- Hobby King sells lots of different LiPo packs so pick the one that best matches your tool's voltage and available battery

http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

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Image Notes1. Wire strippers2. Wire- use 14ga.3. Low voltage battery alarm4. LiPo battery pack5. Wire cutters

Image Notes1. Trusty soldering iron!

Image Notes1. Hitec X1 charger- this is a great battery charger!

Step 2: Open the battery caseCut apart the old battery case.

A few cordless tools have battery packs that are bolted together but no such luck with my Makita tools- the battery packs are seam welded shut so they had to be cutopen.

To cut open the battery pack I carefully cut around the top edge of the casing with a Dremel tool cut off wheel. Once you get the top of the casing off remove the batterycells (properly recycle them) and keep the empty battery casing.

Measure the inside of the casing to determine how large a LiPo battery pack you can fit inside that closely matches the power tool voltage rating. For my Makita 14.4Vdrill I used a Turnigy 1300mAh 4S (14.8V) LiPo pack that measures 74mmx 34mm x 33mm and it fit the empty battery casing perfectly. You don't want the battery to useall of the available space as you'll need a bit of room for the wiring and low voltage alarm,

http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

Image Notes1. Cut open the battery casing with a Dremel tool and cutoff wheel or thin saw

Image Notes1. Save the top of the battery casing for later to check polarity

Image Notes1. Measure opening of battery casing to fit LiPo battery pack- leave a little room forwiring and battery alarm

Step 3: Solder the battery connectorNow it's time to do some wiring!

Take your power tool casing apart. For my drill I only had to remove a few screws to lift off one side of the drill housing. Once this was done I could insert the top of theold battery casing in order to correctly determine the battery polarity for the wiring.

Take a length of 14ga wire, strip the ends of the wire and solder to the battery contacts inside the power tool. Slide heat shrink tubing over the opposite ends of the wireand solder the wire ends to a XT60 battery connector (most 3S and 4S LiPo battery packs ship with XT60 connectors) and then slide the heat shrink tubing down toprotect the wire ends at the connector.

http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

Image Notes1. Drill with casing removed

Image Notes1. Here you can see how the original battery casing fit- watch the polarity!

Image Notes1. Strip the ends of the wire. 14ga wire is recommended.

http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

Image Notes1. Solder the wire ends to the drill's internal battery housing connectors

http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

Image Notes1. Slide heat shrink tubing over the wire ends

Image Notes1. Solder the wire ends to the battery's matching XT60 connector. Watch thepolarity!

Image Notes1. Slide the heat shrink tubing over the connector ends and secure to protect thewiring

http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

Image Notes1. Wiring complete!

Step 4: ReassemblyNow reassemble your power tool.

Once the tool is reassembled connect the LiPo battery pack. Now plug in the low voltage alarm- there are notations on the alarm as to how to connect it to the batterypack balancing connector. The alarm will beep rather loudly at first and then either three of four green LEDs will light up, showing that each cell in the battery pack isabove the cutoff voltage.

As the battery is drained, the LEDs will turn red and an alarm will sound, indicating it is time to charge the battery. Most LiPo cells have a cutoff voltage between 2.8 and3.0V and the cells can be damaged if they are drained below that level. The alarm is there to notify you when the cells have reached this level. The low voltage alarm willwork with 2S to 4S batteries.

Once everything is working properly you can clip the bottom of the battery casing back into the power tool and you're good to go!

Image Notes1. XT60 male/female battery connector2. 4S LiPo battery pack

http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

3. LiPo battery low voltage alarm

Image Notes1. Battery casing snaps back in place- just like before.

Step 5: Finished!Now experience the joy of Lithium power!

I have several drills that I've converted using this technique and they all work better than they did when they had NiMH batteries.

I really like the old robust Makita stick style drills- they can be found dirt cheap (or even free) and they hold a decent size battery as well. The beauty of these old styledrills is you don't even need to take apart the old battery case as the battery just slides right in the grip. The mini Makita stick drill is one my son found for $3 at a recyclingcenter. When he found it it didn't have a battery but I knew we could fix it up as soon as we got home so he bought it and he's been using it ever since for his ownprojects.

FAQs

Don't LiPo packs require special chargers/procedures?

They absolutely do. Here's a good guide to understanding LiPo packs and how to care for them- A Guide to Understanding LiPo Batteries. If you're not comfortablehandling LiPo batteries and going to the extra trouble of maintaining them properly then this instructable probably isn't for you. If they are treated properly they areperfectly safe for every day use, but it's not something I would recommend if you're using tools on a construction site as they're not really practical for that application. I'vebeen using these tools for quite some time now with absolutely no negative side effects.

What about Li-ion batteries?

Yep- you can use those too- that's what I used in my son's drill as I already had a spare Li-ion 2s (7.4V) battery pack at home. The advantage of these batteries is thatthey tend to be a bit more durable than LiPo packs but they can be a bit larger so they may not fit inside many power tools. If you can find a pack that fits then great- justbe sure to use a pack that either has a built in protection circuit or be sure to use a low voltage cut off alarm. Again, you will need a special charger for these batteries.

Isn't the battery capacity less than the original manufacturer's?

In the case of my 14.4V Makita drill- yes. But I don't really care as I found I'm rarely trying to drive 200+ decking screws from a single battery charge. Since the batteriesare so inexpensive I can also afford to keep several packs on hand.

What do I do if I have a tool that has a plug in battery but I don't have the original battery?

In this case you'll have to get creative. Two options are 3d print a suitable battery case or vacuum form one from plastic sheet.

http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

Image Notes1. Collection of converted drills. All work as good as new!

Image Notes1. Makita stick style drill with a 2200mAh 2S LiPo

Image Notes1. Makita mini stick drill with a 2S Li-ion battery

Image Notes1. Sam loves his $3 drill!

http://www.instructables.com/id/Convert-Old-Cordless-Tools-to-Lithium-Power/

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