With the increasing need of power in a motor home the necessity for having more battery capacity is expanding. Therefore the use of a second service battery can become neccessary. So far the old service battery had to be renewed too - the rules were that only batteries of the same type, same age and same category can be connected. NOW WITH THE POWER SWITCH TWO BATTERIES OF DIFFERENT TYPES CAN BE CONNECTED WITHOUT AFFECTING THE EFFICIENCY AND DURABILITY. The Power switch regulates microprocessor controlled the charging- and discharging process of both connected batteries and a battery controller as well as an overcurrent protection are integrated. Via the remote control one of the both batteries can be choosen manually. Operating voltage 12V, highest power 30A each battery entrance, own consumption 6 mA, operating temperature -15-60°C.