Storing your Bosch battery
If you won't be riding for a little bit, it's best to store the battery with the charge level between about 30% and 60%. Storing the battery at 100% charge can cause the battery to wear prematurely, and storing the battery at 0% charge can cause damage.
Store the battery indoors, and be sure it's not somewhere it will not encounter extreme temperatures (such as in direct sunlight).
If you'll be storing the battery for a few months, we'd recommend charging the battery up to around 70%— do not charge the battery fully to 100%. Remove the battery from the bike, and be sure to unplug the charger as well.