Sorry to ask such a mundane question but when I am driving our Compass avant-garde 120 low profile, does the engine charge the leisure battery as well as the vehicle battery ? and what position should the 3 way switch be in (aux..off..veh) I know I could connect a meter to the leisure batt to find out but its raining here in suffolk and I thought you folks would know. Thanks in anticipation. Mitch and Jenny.