I have some cordless power tools which all require a certain 12V nickel-cadmium battery pack.
My battery packs are dead, but the good news is they're held together with screws, so I took them apart to have a look. The bad news is the cells inside are all shot; they have the little crystals on the outside telling me they're done.
So, the dead cells are going to the official hazardous waste drop-off site.
- What should I replace them with?
I've wired up battery packs for RC cars and stuff before, and I'm confident I can put it back together properly. The problem is I'm having a hard time finding the nicad cells now. did they stop making them? I see a few for sale and they're like $3-5 per cell now (I need like 50 of them). - Is it possible to salvage the good cells from several different dead ni-cad packs to create one working battery?
Best Answer
Nickel-Cadmium (NiCd) cells are falling out of favor, because Cadmium is environmentally unfriendly and usually not compliant with RoHS. Nickel-metal hydride (NiMH) are replacing NiCd. NiMH and NiCd have similar characteristics (more thorough comparison of NiMH and NiCd here).
You can buy both NiCd and NiMH cells from industrial electronics distributors. Here, for example.
It depends on the actual packs and how you're planning to charge. In a general case, I wouldn't mix and match used cells of unknown pedigree. It wouldn't produce the best results, probably. I would buy a uniform batch of new cells.
p.s. Of course, when you say "power tools battery pack", most folks knows what you're talking about. However, a photo of your tool's battery pack would help this question a lot, especially if you've already disassembled it. Please post it if you can.