>>267677614
All of that mostly appealed to older battery types like NiMH or NiCd. Devices nowadays have LiFe or LiPo, and basically you don't have to worry about anything but physically damaging them, on-board electronics should take care of everything, and if they won't you'll be sure to hear about it like those exploding samsung phones.
There's a storage mode for LiPo batteries, which is holding it charged at roughly 70%, but I've heard that on airsoft forums, and airsoftters are fucking autistic and pretend they're shitty plastic toys are state-of-art weapons, people using same LiPo packets in RC cars and drones don't give a fuck and probably give those batteries more workout in a single week than airshitters do in their whole lifetime.
TL;DR just don't be stupid.