WAIT! You don’t have to buy a new battery for your drill just because the old one won’t hold a charge anymore! There are some great companies who will rebuild those batteries for you… AND some great companies that will sell you the parts you need to rebuild batteries yourself. As ever I take my initial inspiration for this post from Woodnet: Batteries and Drills….

2 Companies that Rebuild Rechargeable Batteries
Building/Refurbishing Rechargeable Batteries Yourself
Battery Forums
Battery Pack Theory Pages
Information from Battery Rebuilding DIYers
Battery Rebuilding Videos
Other Battery Rebuilding Resources

Companies that Rebuild Rechargeable Batteries
First and foremost I have to mention Jason Abel of MTOBattery who posts regularly at both WoodNet AND SawmillCreek. I know from experience that WoodNet can be a tough crowd. If several members there openly and eagerly endorse Mr. Abel then I think you’d do well to have him rebuild your batteries.
Jason Abel of MTOBattery >>

Secondly I’d like to point out the folks over at VoltmanBatteries.com Now they didn’t have any forum recommendations I saw but they seem like they have a good time repairing batteries. Plus they made a funny video that I embedded below in the video section. They’re worth checking out if Mr. Abel can’t get to you ;)

Building/Refurbishing Rechargeable Batteries Yourself
Every battery pack is different, and most of them connect to your cordless power tools using proprietary systems. Most of the smaller batteries inside your battery pack are NOT proprietary. If you decide to rebuild your batteries yourself then you should definitely do some searches on your particular make and model of power tool. There could very well be a tutorial out there already written. I also want to scare you a little if you’re planning to DIY… this is from the excellent forum at BatterySpace:
“OK, I got all inspired by this and rebuilt my 14.4 Dewalt battery with 4200mAH NiMH bats…. It has not gone well.

Battery Forums
Your first and foremost resources should be the forums at the rechargeable battery suppliers sites – they don’t sell the whole battery packs, but rather the pieces and parts that go into the battery packs. I found two such forums and you will need to spend some time there as well as in the stores that relate to each one.

Battery Space Forums >>
All Battery Forums >>

Battery Pack Theory Pages:
Both links here probably fall into the “too much information” category. If I was about to start this project I wouldn’t want to bog my head down with theory. Then again, that’s probably why I would mess up the first couple of times. Anyways, if you’re the theory type who prefers to understand what’s going on rather than following direction I suggest both of these pages.

Engineering Guidelines for Designing Battery Packs
Assembling your own battery packs

Information from Battery Rebuilding DIYers:
how to build the Milwaukee SuperTough 12V Battery pack (PDF)
This *should* be the only guide you need for rebuilding your batteries. It’s 11 PDF pages long and full of great pictures and thorough explanation. Again you should search for your particular make and model first, but this is a great place to start (I was an english major in college though, not electrical engineering so I can’t vouch for if he’s right or not – also I cannot vouch for my grammar, so there you go).

Rebuilding a Craftsman 18 Volt Pwer Tool Battery
This is a good write up that should extend beyond just the Craftsman. The original author includes his email address so I assume you could write him with questions if the forum fails you. Here’s the author: “The project took about 2 hours and the total cost was really just the cost of the batteries – around $30. A genuine Craftsman replacement battery would run about $80 with clones costing around $50.”

Battery Rebuild DIY Projects
Here is a list of DIY projects that Battery Space paid to have written… Some are better than others. You may or may not be able to ask questions of the writers. You will get a response from someone, but English is not likely to be a first language for them.

Ni-Cad Rebuilding
This has one of the best write ups of the pitfalls of battery rebuilding that I found. It’s very straightforward. It’s from the This Old House forums.

Rebuilding the Makita Battery Pack
This write up is more of a warning than anything, as the writer was unable to fix his battery pack for less than the cost of a new battery pack. That happens.

DIY Cordless Drill Battery Improvement This brief how-to shows breaking open and rebuilding the battery pack on a DEWALT drill.

Homemade Spot Welders: Apparently most battery cells come with tabs pre-soldered to them so you don’t really need a spot welder. Plus they are expensive. Plus, if you’re crazy enough you just might want to build your own even though batteries come with pre-soldered tabs: The Home-Brew Spot Welder Also see: Homemade Spot Welder.

Battery Rebuilding Videos
Video from Voltman Batteries:
This is mostly a long advertisement for them, but it does show some of the basics of battery building about 2/3 through. Be patient and enjoy the incredible special effects they brought George Lucas in for ;)

Batterypack Repair Demo for Battery House:
Again, this is more of an ad than anything, but there are little clues that could help you in your particular situation.

DIY battery pack making:
An excellent video – I think it’s more targeted towards remote control applications but they appear to cross over nicely with power tools.

Other Battery Rebuilding Resources
Find a Drop Off Location Near You for Recycling Dead Batteries
BatterySpace forums Frequently Asked Questions & Answers (FAQ’s)
10 Battery Hacks
Rebuilding a Roomba Battery for Less
Battery Recharger Repair
HOW-TO: Rebuild your laptop battery