mrs sorento said:
hi, our van recently decided that the fridge wouldn't work on 12v, the van went for a service and the dealership said the fridge was working ok as they had tested it. There was a fuse in the car that kept going and then being replaced but that didn't do the trick. I took it to a car electrics place locally and they said the circuit was being overloaded. it then came to mind that the caravan dealership had said our van's battery was faulty. Then the lightbulb came on and I asked the electrics people if the faulty battery was to blame and they said yes, as the current would bypass the faulty battery and go to the car, then blow the fuse. We got a new battery for the van and hey presto it worked. Hope this might be of use to you.
Unfortunately this has nothing to do with the fridge tripping the mains electrics.
The fridge on 12v will only work when the van is connected to the car, with the engine running.
The fridge takes absolutely no power from the leisure battery at any time, it is fed by a separate circuit direct from the alternator.
If the wiring in the car is not the correct size it will overload the car system and blow the fuse.
The charging circuit for the leisure battery is also from the alternator and only comes into use when the engine is running.
The only time the relays that control the fridge pwer and battery charging activate is when the output from the car reaches 14v.