We plug into mains when at home and usually every third or fourth day when on tour. This keeps the batteries topped up and allows the use of a 800W kettle and the Truma hot water and heater. We have three leads, 4m, 15m and 25m – the shorter ones are tidier and means less jumble. Both the longer ones can be joined by using this safe waterproof housing to reach a distant point. We keep the cables and a collection of adaptors in a pocket on the rear doors.