Digital controller links solar panels together and stabilizes incoming voltage to prevent 12V batteries from overcharge and discharge. Unit reduces overall system maintenance and prolongs battery life. Amps: 30, Watts: 500 Use to link solar panels Prevents overcharge and discharge of 12V batteries Reduces overall system maintenance Prolongs battery life LCD monitor displays charging current and voltage LED bar graph indicates battery charge level Handles up to 30 Amps of solar array current or up to 500 Watts solar power Maintenance free Works with Item#s 339615, 339617, 121125 and 121126