12 Volt Battery Back-Up Sump Pump System. No more flooded basement during a power outage. 12 volt sump pump removes up to 20 gpm using a 12 volt deep cycle battery as power. Built in charger maintains battery at full charge while home AC power available. Water level sensor turns unit on as needed, and alarm notifies you of water intrusion. Intended as a backup to your standard sump pump system.