The CT 500 fully automatic charger that can manage 1 or 2 batteries at once. In the case of 2 batteries the charger manages each battery separately. This computer SMART charger applies super efficient 3 step regulated charging and charges batteries quickly. When a full charge is reached, a float mode is maintained and the battery remains at full charge until it is ready to be used. The CT-500 can be used for single 12 volt, dual 12 volt and two 12 volt batteries in series as 24 volt system.