The RANGER PA10 has been designed to provide a DIRECT Power Supply to the 12v Services in a caravan or boat when fed from a 220/240v mains supply. Its torroidal transformer made to BS3535 has an output of about 120watts. The RANGER'S 12v Output is sufficiently smoothed to enable it to operate fluorescent lights, water pump, and other 12v services efficiently. If a battery is installed, the RANGER will charge the battery at a variable rate depending on the power demand being required of the 12v system. It will not overcharge a battery in good condition. The RANGER will automatically reduce to a trickle charge, as the battery charges up.