Drill Battery Rebuild - NiCd to Lithium

Drill/ screwdriver battery rebuild to Lithium using battery holder for 18650 cells (so no spot welding needed) and BMS. After rebuild original charger can be used for charge.

Part list:

• Battery holder for 18650 size batteries
• 3x Sony VTC4 18650 2100mAh 30A batteries
• BMS to control charge/ discharge

Step 1: Soldering

At first I soldered wires to battery holder, after that soldered BMS board and battery pack plug

BMS was glued to battery holder using double sided tape

Step 2: Fitting

Little bit of cutting and now batteries fit battery pack case

Then secured using electrical tape

Check fit, done

Step 3: Charging

As BMS was used, original charger can be used for charging

Step 4: Finished

It was quick and simple battery pack rebuild

Screwdriver works as expected

Comments

[dvdljns]

What bms did you use.

[criggie]

I did somethign very similar with an old 7.2V ryobi.

Two 3.6V 18650 batteries was a perfect voltage, and the physical space was just right. However there was no BMS used. Instead I left the battery pack wide open and simply swap the cells out when they need charging.

Battery dropped from 342g to 143g so under half the weight, and the pack went from 2Ah rated to 9Ah rated (minus the usual chinese brown-number factor)

[aliasfox]

Question: Say I did this on a Craftsman 19.2 Drill battery, would a Craftsman Multi-Chemistry charger (for Lithium Ion and NiCd batteries) work for the modified battery (to revive a few "dead" ones I have but also to move to lithium). I was considering getting a kit that comes with 2 "real" lithium batteries and a multi-chemistry charger.. and "upgrading" several "dead" batteries I have but I also have 1 or 2 NiCd batteries that still work. Thanks

[Maker_exe]

So you want to use different types of batteries? It doesn't work like that because they can't be put in series as the higher voltage lithium ion batteries would pass current through the lower voltage ni cad's and discharge fully or if the current is high enough potentially burn

[russ_hensel]

Just a note to let you know I have added this to the collection: Cordless-Drill-Battery-Maintenance !

>> https://www.instructables.com/id/Cordless-Drill-Ba...

Take a look at a bunch of different/similar approaches to this project.

And for even more drill info:

>> https://www.instructables.com/id/Cordless-Drills-A...

[aliasfox]

That link on another instructable is actually how I got here. Great collection! Thanks.

[russ_hensel]

Thanks for noticing and thanking.

[carlozousa]

Congratulations for this awesome instructable. The only snag is that this only works when the drill charger is not intelligent ...

[tedjuuh19]

Never mind, just found it on the photo. thanks for this instructable btw!:)

[tedjuuh19]

Do you have a link or a part number of the BMS that you used?