For storage of our Black & Decker Cordless Lawnmower (GRC models) and String Trimmers (GLC models) please refer to the following: If the area where the battery is stored would be above +5 degrees Centigrade at all times, the battery can be left on charge continuously. If the area's temperature would be below +5 degrees Centigrade, Black & Decker recommends fully charging the battery. Unplug the charger. Allow the battery to sit idle over the winter. Then, fully recharge the battery before the first use in the spring.