[. . . ] Insert the batteries into the battery compartment with correct polarity and position. [. . . ] For best performance and safety, charge only GP NiMH batteries with GP PowerBank. For brand new batteries, 2 to 3 times of charging and usage cycles are required to optimize the batteries' performance. If batteries are stored for more than one week, always recharge them before use. It is normal for batteries to become warm during charging and they will gradually cool down to room temperature after fully charged. Remove batteries from the electrical device if the device is not going to be used for a long time. Do not charge other types of batteries such as alkaline, rechargeable alkaline or any other kind of batteries not specified as they may leak or burst, causing personal injury and damage. Do not charge batteries with different stages of charge, brands or capacities at the same time. Never use an extension cord or any attachment not recommended by GP, otherwise may lead to a risk of fire, electric shock or personal injury. [. . . ] If electrical appliances are disposed of in landfills or dumps, hazardous substances can leak into the groundwater and get into the food chain, damaging your health and well-being. [. . . ]