This unit works very well when plugged to shore power but not so great while motoring or on batterypower. I've had refrigerant leak issues with it before but I think I've remedied them as evidenced by this unit working great on shore power. I have the stock 50amp alternator that came with the universal 40hp and an 80 watt solar panel. Am I wrong I. Thinking this should be enough to get the voltage up enough to run this thing?
Check the wiring to the unit. Waeco suggests wiring direct from the battery bank, not through the main panel, with a 10 amp fuse in the line. Waeco also suggests larger wire size, 10 guage for up to a 13 foot run, larger for longer runs. Check with a multimeter that, when the fridge is running on DC, it is getting at least 12 volts and drawing about 5 or 6 amps.