November 19, 2011
How to rejuvenate rechargeable NiCd batteries
This post is about a method to restore (rejuvenate) NiCd (NiCad) battery packs that are failing to charge. I have 2 sets of cordless tools (drill, circular saw, reciprocating saw and more) that use rechargeable NiCd battery packs. Three of the battery packs were failing to charge. Having had some previous success with rejuvenating apparently expired NiCd cells, I decided to do some tinkering, and I was able to restore the packs such that they will now charge to a usable level. I’ve previously used the same procedure, at lower current, to rejuvenate NiCd cells for cordless phones.
These tool sets and battery packs are very common. Mine were MasterCraft brand purchased from Canadian Tire, but there are many similar ones on the market with other branding. I’d guess millions of similar cordless sets have been sold, so maybe someone else can benefit from this post and save a few $ on new batteries. Perhaps more significantly, maybe this will save some battery packs and even the tools themselves from adding to our garbage output; the Cd in the cells is very toxic, so the less of it we put into use and the less that goes into the waste stream, the better. (more…)
Amy, next steps in diagnosis might be using an ohmmeter to do some continuity checks from the relay pins outward,…