Its a cheap china charger. I don't own a good charger and probably wont have one anytime soon. But this cheap charger seems to have known what to do? I didn't test the battery when it was discharged because I dont own a tester. I tried to test it on my provari and it was so drained that my provari wouldn't even tell me the voltage. I'm guessing it was around 3.2v because I couldn't of let it get down further than that.
Gotcha. Well, if the battery voltage went below about 2.7 I believe it would have needed a very low charge for a while to get it back above that. Below about 2.5 V and they are toast. Wherever your batteries ended up the charger handled them successfully. Each time this happens the batts are stressed and damaged somewhat. Life is lost and internal resistance probably goes up some making them a little less safe. IMO, unless you are pushing these batteries with very low resistance coils (close to their power ratings), it's safe to continue to use them. If they ever warm up during charge or use, toss them.
Once discharge reaches about 3.7 volts, the lower the voltage gets the faster the voltage drops. So, if it takes 3 hours to go from 3.7 volts to 3.6, it may take something like 1 hour to go to 3.5 volts, 30 minutes to go to 3.4, 15 minutes to go to 3.3, etc. This makes it really hard to take batteries out for recharge at say 3 volts. I try to pull my batts at 3.7 to 3.6, but have gone down to a bit below 2.7 a couple of times. My Xtar WP2 charger handled that just fine and those batteries are still powering my mechanical mods.
I do use a $10 digital multi meter. I would feel lost without it. I recommend this for anyone using mechanical mods. The ability to check the voltage of batteries and the ohms of coils without using a PV is extremely handy IMO.
HTH a bit and best of luck with it!
