This post may have little value, for what it is worth I will share my Norcold experience. My 40' Silverton came with a 7-7.5 Norcold, the type that uses two compressors; one for the freezer and one for the fridge section. It was NOISY!!! My hearing is challenged but that pig had no problems annoying me whenever it ran........and it ran often.
The high duty cycle did a job on my battery
bank forcing me to upgrade my charger
even of weekend use. The battery
bank consisted of 2 each group 8 huge storage
devices that were charged for 4 hours a day using the generator
Last summer, I found the #$%^ running almost 100% of the time. Checked it to find one of the compressors running hot as was the evaporator. Enough!
I purchased a Summit 8.5CU that has a much larger freezer, so quite that even Wifey with her good ear cannot hear it operate. The box even has a defrost cycle and an interior
light. Best of all, It was an almost perfect fit into the space where the Norcold resided. The Norcold's compressors were located on the back of the back of the box, the Summit is on the bottom so the usable depth of the Summit is greater.
OK, the Summit is a 120VAC machine. I installed a 1KW Xantrex sine wave inverter
along with a relay that I use for a transfer switch. When on dock
power, the fridge is directly powered from either of those sources. When AC is off, the relay switches the fridge to the inverter
. I let the inverter run all the time, loaded and unloaded.
I do recommend at least a 1KW inverter only because of the defrost WHICH I HIGHLY RECOMMEND. The defrost cycle only lasts for about 3-4 minutes at about 600W.
I purchased the fridge on line delivered for less than $500. The inverter was about $250. A replacement Norcold from WestMarine was about $1200 PLUS SHIPPING! No defrost, no interior
light and noisy.
Just sharing my experience.