Charge the large-capacity lithium batteries fully after every use and frequently when not in use. If you’re not going to use the vehicle for several months, store the battery when it's fully charged and then charge it once a month. For longer periods, store the fully charged battery and vehicle separately and charge the battery once every three to six months. If you store the vehicle when it’s not fully charged; e.g., at 50% capacity, it may discharge excessively within 15 days.