The TRE Series batteries are pure lead and are of new and unique bi-polar technology. They are designated for small to medium size renewable energy applications that require prolonged cycling at Partial State Of Charge (PSOC). They have excellent cyclic life at PSOC and can be re-charged in a very short time thus making the back-up available. The TRE batteries are especially effective in cyclic applications where the batteries are likely to function at PSOC and therefore are ideal for multiple types of renewable energy systems.