Quote Originally Posted by Coldcomfort View Post
I finished off the rear power socket to the second battery today. When the car engine is off the voltage at the second battery is 12.88v. Voltage at the socket in the rear is 12.12v. Not too bad but will see when its under load.
Something is definitely wrong here. With no load (except the voltmeter) there should be negligible voltage drop. Might pay to re-check your readings and re-do your wiring if those readings are repeated.
Both the positive and the earth need to be solid to run a fridge.
Check the voltage between positive at battery and positive at your fridge point, and also earth/negative at battery and at your fridge point to see which one is your issue. These should be zero.