If you keep them at about 50% and avoid temperature extremes, it doesn't take a PhD in electrochemistry. The thing is, fancy battery packs usually do contain ac

If you keep them at about 50% and avoid temperature extremes, it doesn't take a PhD in electrochemistry. The thing is, fancy battery packs usually do contain active electronics that drain the cells slowly in storage, so it's necessary to charge them a little a couple times a year.