Rebuilding NiCd Batteries - Help!

[Adam Moore]

I have an old 14.4V Dewalt and 18V Craftsman drill that the batteries are starting to go on them. I was hoping to rebuild them in future, so my dad gave me his old 12V Dewalt that the batteries have been dead (won't take a charge at all) for years (over 5) for me to "learn" with.

So I ordered the sub-c batteries to completely rebuild the 12V Dewalt batteries with and it's turning out to be a little tougher than I thought. Really only because I'm a little stumped on how to reconnect this top connection piece to the first/last battery in this string.

In this first picture, the negative connection is on the right, and is spot welded to the negative side of the battery. I'm not real sure how to reconnect this piece. You can see in the second picture the positive "terminal" has a wire running between batteries and connecting to the positive side of the battery in the upper right side in the third picture. That's not really a big deal. I should be able to solder that pretty easily.








I also shouldn't have a hard time stringing these batteries together pos to neg. I'm just stumped on how to connect this negative terminal (or whatever it's called) to the negative side of a battery.

I did a quick search on the site here and have searched all over the internet, but can't find anything on this. Most of the stuff I've found is how to replace a couple/few batteries in a string. Not rebuild the entire thing.

So if there's anyone out there that's done this before or has a site that describes this it would be much appreciated.

[Paul Atkins]

I'd just use a wire and solder it to the battery and clip the connector off and solder to it. You might have to rout the wire a bit differently for space.

[David G Baker]

When I worked for the Air Force we used parts from an old iron and the carbon element from a AA battery to spot weld small fragile parts. The iron was disassembled and the surface that is used to iron the clothes acts as a large resistor. I don't recall how it was wired but you may be able to find a diagram on line. If you plan on rebuilding batteries in any quantity you may want to get a small spot welder designed for this type of work.
I have used solder to join batteries like Paul wrote.

[Steve Peterson]

I have a couple of 5-6 year old batteries that need re-building. You can buy Ni-cads with solder tabs. It is fairly easy to solder the tabs together without overheating the battery. This avoids the expense of buying a spot welder.

Steve