Portalac PE6V7.2 6V 7Ah Sealed Lead Acid Replacement Battery

Designed for use in a variety of high and low drain devices, including solar and wind devices, this Sealed Lead Acid 6V battery boasts a powerful 7.5Ah capacity. So why wait?. (6V 7.5Ah). For standby power this range has a nominal 5 - 8 year life.

eBay