Charge the battery with the provided charger for 12-18 hours or until green indicator light is on to ensure there is sufficient battery life. If the battery does not charge, turn off the Swiffer. The Swiffer cannot recharge if it is on. If after 12 hours of charging the battery is still incapable of powering the device, it will most likely need a replacement unit. When purchased new, the Swiffer SweeperVac can operate on battery power for approximately 10-12 minutes after 16 hours of charging. Ensure you are charging it for at least 12 hours to maintain optimal battery life. If the battery still will not hold a charge, it will need to be replaced.