The best way to store a LIPO, for > than 1 month anyway, is to charge/discharge to 3.8v/call and store them at 35 degrees F (fridge).
The two biggest risks of a LIPO are damage and cell imbalance.
Cell imbalance occurs when the voltage of at least one cell drops below another. This causes the entire pack to show a voltage that does not represent the cell with the highest voltage in the pack. A non-balancing charger will charge the pack as a whole until it reaches 4.2V/Cell, effectively overcharging the high cell and damaging or venting the pack. This is why it's so important to use a balancing charger, which will charge each cell individually.
Damage is another issue. It can be physically evident or not. If a cell is dented, some people just keep en eye on it. Maybe they mark it, maybe they store and charge it in a can; it depends. Internal damage can sometimes be evident by how the cell charges or discharges, or not. The most common causes of internal damage are overcharging or, more likely, letting a cell drop below 3.2V.
This is why low voltage cutoffs, balancing chargers and diligence are all important parts of LIPO safety.
This is really the only thing I have a clue about, by the way, and it comes from my years of using LIPOs on airplanes. I'm seriously clueless with everything else, so I'll really be appreciating your help as I start with a barrage of dumb questions.
