Revamping battery packs.....question

[Dennis Peacock]

I have 4 battery packs that simply won't hold a charge any longer. I have equipment to solder and such. Just wondering how difficult it would be to order new battery cells and rebuild my battery packs?

[Jim Koepke]

It isn't very difficult if you are good at soldering.

The biggest problem is many batteries have a material similar to stainless steel for the battery end caps. It helps to scuff the surface with sandpaper before soldering.

Otherwise an acid core flux might work well if you have a way to clean it up.

jtk

[John K Jordan]

I have 4 battery packs that simply won't hold a charge any longer. I have equipment to solder and such. Just wondering how difficult it would be to order new battery cells and rebuild my battery packs?

I assume you are referring to nicad packs, not lithium ion. Two things can be a challenge. One, some battery packs are potted in some type of resin and others use some pretty tough glue you have to cut away.

The second challenge is the conducting metal strips are often tack welded to the battery terminals. Battery stores used to tack weld tinned strips that could be soldered which made it easy but I don't know if they will still do that (I heard Batteries Plus quit that). I've soldered wires to plenty of alkaline battery cells but that was years ago - I don't know if the materials used for today's battery terminals are the same. Soldering then was a simple matter of cleaning, using a good flux, and having enough heat (but not too much).

Usually some individual cells go bad. I had success disassembling several battery packs, separating and test charging each cell, and combining the good cells into one pack.

I have had some success in regenerating nicad packs that would no longer take a charge. The idea is to zap the battery pack with a brief pulse of high current which will vaporize the "whiskers" that grow and short out the cells internally. This works some of the time but not always and when it does the rejuvenated batteries sometimes, but not always, go bad again before long. When my friend and I first zapped batteries decades ago we used the discharge from a bank of large electrolytic capacitors, then later used a suitable power supply. I read where someone used a quick strike from a welding machine and when I tried that it worked, but again, part of the time.

Lately, I've just bought cheaper off-brand batteries from Amazon.

JKJ

[Jim Becker]

I did it years ago for a DeWalt 14.4v setup. You need a heavy soldering gun to get enough heat to do the job, IMHO. That said, the replacements didn't last all that long and I eventually caught a couple of brand new batteries on close-out at HD and grabbed them so I could continue to use the tool for certain outside work where I didn't want to use my Festool stuff.