6OPzV 420 maintenance-free stationary sealed lead-acid battery 6OPzV 420 Rechargeable lead-acid stationary hermetically sealed maintenance-free battery 20OPzV 2500 Rechargeable lead-acid stationary hermetically sealed maintenance-free 12OPzV 1500 battery Rechargeable lead-acid stationary hermetically sealed maintenance-free battery 12OPzV 1200 Rechargeable lead-acid stationary hermetically sealed maintenance-free battery 5OPzV 250 Rechargeable lead-acid stationary hermetically sealed maintenance-free battery 11OPzV 770 Lead-acid stationary hermetically sealed maintenance-free rechargeable battery 7OPzV 490 Rechargeable lead-acid stationary hermetically sealed maintenance-free battery 24OPzV 3000