First, this has nothing to do with vapor, so if that’s a no-no, sorry Breaktru, please delete.
I’ve used Ryobi 18 volt cordless tools for long enough that I have several of the old ni-cad packs, dead, of course.
Some info on the Ryobi 18 volt system. There are newer 18 volt li-ion packs that are compatible with the old tools. They just require the newer chargers. I have a few of these too. The battery pack has three contacts, on the old ni-cads that third contact is a thermal switch connected to the negative post. I haven’t been inside a li-ion pack, but they have some brains in them. They won’t over discharge, just shut off. The tools are dumb, just connect to the positive and negative posts.
So my thought is to mount a 5s li-po pack in an old ni-cad case, with no connection to the third contact so that if someone stuck it on a Ryobi charger nothing would happen (as best as I can tell, the charger has to see continuity between the third contact and the negative contact, or no output). I would put plenty of padding around it and run the balance plug to the side of the case and use that to charge it. Of course I would have to be aware of discharge state myself.
I’m thinking this should be fairly safe, but the more eyes looking for safety flaws, the better. Thanks for letting me use up your time.
