Sun Xtender pioneered renewable energy storage batteries for off-grid and grid-tied systems. This is a deep cycle VRLA-AGM valve regulated lead acid battery with absorbent glass mat manufactured by Concorde Battery Corporation—the same design that has been proven and adopted by worldwide commercial and military users. The sealed, maintenance-free design means no spilling or spewing, no watering, and the option to operate upright, on its side or on its end. Deep cycle unique, high-density plate and grid technology with PolyGuard protection provides superior reliability, power, and extended cycle life. Sun Xtender features a low-impedance design, including Copper alloy, corrosion-free terminals that allow for maximum conductivity. There is no current limit with controlled voltage charging, and complete recharge is accomplished in a minimum of time.