Originally Posted by lowcountry
Not sure of the age, as it came with the boat, but it looks like it has the Danfoss style compressor.
If it still has the AC controls, it is not likely that the DC is Danfoss style. The old Norcold system was to use only AC compressors and invert from DC to AC when running supposedly on DC. This results in being able to continue using the fridge while away from AC power, but losses in the inversion process cost several amps to invert to AC.
My own experience was a saving by replacing those AC compressors (2) with a single Danfoss. Amperage drawn while on AC dropped from over 10 to under 3. I was able to reduce my house batteries by 1/2 and also carry a Danfoss powered freezer.
Now you have the opportunity to do the same.