I just got through replacing the norcold with a samsung RF18 residential. It pulls about 10Amps from the battery, through the MSW inverter, when it's running. I installed two Group 27 RV/Marine batteries in parallel to run it. They each have a reserve capacity (RC) of 180. The RC capacity is the number of minutes the battery will supply 25A of current. So 180 is 3 hours at 25A. Two of these batteries in parallel would equal about 360 minutes at 25A. Because the refrigerator only pulls 10A when it's running we can double the 360 minutes to 720 minutes of capacity. That's over 9 hours of run time even if the fridge runs constantly. I don't plan driving over 9 hours and I don't boondock so this is sufficient for me. As a precaution I installed two group 24D batteries in parallel and have them wired so that I can switch them into the circuit if needed. I keep these charged separately with an external battery charger. Hope this helps.
Lynn & Diana Wagoner
Three Boston Terriers
2011 Chevy 3500HD, DRW, 4X4
2014 Big Country 3650RL
Retired
