VDC Electronics Battery Maintenance Chargers are designed to both properly charge and maintain all type/size lead acid batteries, without ever overcharging, even after months of non-use. All BatteryMINDer models feature exclusive U.S. Patented PulseMode desulphation circuitry, designed to safely remove the #1 cause of early battery failure, Sulphation. Plus, all units are polarity reversal-short circuit-temperature protected. Never overcharges. Restores weak batteries. High-frequency pulses safely remove sulphate from battery's plates that prevent batteries from holding a full charge. For all batteries including gel and deep cycle. UL listed.