Anytime when not in use (short term storage) - 3.85v / cell

For longterm storage (months) - Ziplock style freezer bag in the fridge


As soon as a lipo is fully charged it starts to degrade, its internal resistance slowly rises over time and the effect is cumulative

Charge them from storage voltage
Run them
Let them cool if using again
Charge them again
Run them again
Store them at storage voltage when finished for the day


3.85v / cell is roughly 50% capacity

Allthough discharge is not linear here is a handy table to remember (Resting voltage vs capacity)

4.2 - 100%
4.13 - 90%
4.06 - 80%
3.99 - 70%
3.92 - 60%
3.85 - 50%
3.78 - 40%
3.71 - 30%
3.64 - 20%
3.57 - 10%
3.5 - 0%


The storage value is arbitrary anywhere between 3.7 and 4.0v is fine in reality

Decent chargers will have a storage mode that leaves them at 3.85v / cell


Cheers