Designed for charging up to 25 Amp hours per day as well as long term battery storage. Will charge and maintain 12V batteries (10-250 Amp hours) for prolonged periods without boiling out battery electrolyte.  Prolongs battery life significantly.  Will not overcharge or damage batteries if left connected for extended periods. Just plug it into a standard 120V AC outlet and connect alligator clips to your battery. It is fully automatic and has reverse polarity protection. Features precise voltage regulation and an LED light signifies proper operation.  Is current limiting and has over temperature protection. Field adjustable for gel batteries.