The Unit activates with any charge source eliminating sulfation buildup that occurs during prolong lack of use. It has proven to extend battery life for seasonal equipment by 5 X or better. Cold cranking amps (CCA) & volts stay strong. A single unit can be used with up to eight 12-volt automotive batteries in parallel or series in 24- volt configuration For use with both 12V & 24V vehicle electrical systems | Canadus Power Systems LLC Battery Desulfator