Car battery automatic recharging device. when the leisure battery voltage exceeds 13.6v (battery charger and/or solar panel are charging), the device allows to recharge the car battery (through the leisure battery). Charging current is set to max 4a, according to the batteries condition. When the leisure battery voltage is lower than 12.5v, the car battery recharging system is deactivated. When the green led is on, it means that the csb-2 is ready to recharge the car battery if necessary. Dimensions: 80 x 50 x 50mm