Dometic have stated that the fridges have to be cooled first. The 12v should then retain the temperature. They state that the 12v will not cool down any fridge. The latter I got second hand from someone who had the same issue with the their fridge and contacted Dometic.
However I was told exactly the same thing by Thetford when I contacted Thetford. The Thetford fridge kept the fridge cool and food frozen . The 12v keeps the fridge at a constant temperature below the ambient temperature and will not cool down a fridge. In our case it is doing neither with our Dometic RM8551 fridge.
However I was told exactly the same thing by Thetford when I contacted Thetford. The Thetford fridge kept the fridge cool and food frozen . The 12v keeps the fridge at a constant temperature below the ambient temperature and will not cool down a fridge. In our case it is doing neither with our Dometic RM8551 fridge.