Originally Posted by
rscamp
Use a hobby charger - then any batteries can be charged and their actual capacity and health monitored. Purchase some cheap 18650 chargers just to strip out the electronics and use the holder with a good charger. Or if you search electronics suppliers you can find 18650 cell battery holders
If you can solder to tiny rare earth magnets without ruining the magnet (I haven't tried, but I do know that enough heat will ruin a magnet) they'd make nice chargers -- just stick the magnet+wire on each end and charge.
I suspect that the cheap 18650 batteries they use for things like the Magicshine pack (the 2s2p packs) would really benefit from occasional balancing, if you were to solder in a plug for it and use it with your R/C charger. Or just buy a 4000+ mAh 2s pack from HobbyKing and add the right connector and use it instead of the packs they come with.