DC operation of fridge

Saskhunter wrote:
I am new to RVs and notice while driving my truck does not charge my Northern Lite truck camper battery. Is this normal? Within 4 hours the fridge kills my RV deep cycle Battery . . .

I assume you were running your fridge on DC (including the boiler) with one battery? If that's the case, your fridge was probably drawing ~20 amps of 12 vdc plus any current being used to power anything else you may have had on in your camper while driving. The wiring on many trucks are only capable of supplying 8-10 amps of current to the 7-pin connector on the camper. That leaves you with a 10+ amp deficit. That's enough current drain to run one 12 vdc 24/27 battery down to 50% in approx. 3-5 hours. Bottom line, your truck was very likely supplying 8-10 amps of current to your camper. However, that wasn't enough current to keep up with the ~20 amps the fridge was using---thus a discharged battery in ~4 hours.