Hello all, I am not exactly sure if this bit of info is suitable but I will put it out there just in case. While I haven't had anything to do with inverters or caravans as yet (ours is on order), I do have a camper and I run 4 batteries in total. 1 for starting, a second under the bonnet for the winch and fridge in veh and 2 for the camper. I run a "Rotronics" system which is a battery managment system. Basiclly it takes control of the output from the alternator and directs it to the various batteries. It gives "full" charge to all the batteries via a computer managment system unlike 99.9% of other duel battery systems which only trickle charge the extra batteries. It is an "off the shelf" product and is extremly robust as we are avide 4X4 drivers. The owner of the company will not deal with most of the 4x4 accessary places like ARB & TJM. He seems to deal with the independant stores however I purchased mine through Opposite Lock. The system is very impressive and I have been using it now for 11 years with out any faults. I hope this is helpful