You can do and effective load study by removing the fuse on the 12vdc side and insert an amp meter 10amp. Do this for each one of the fuses. Log the data and total. Power P= I x E.
If you have a modern fridge you will find that you have a heater strip for condensation running. About 6.8 amps. Disconnect this circuit and you will be able to run low power. The heater strip is join connected at the fridge interior lamp. Just cut the large red wire and insulate. Retest to prove you got the right circuit.
