I have a nor cold tech 11 fridge where the cooler is located, but It is a DC unit , works great but hard on the batteries when overnighting, is there a way to convert to AC? & my boat has shore power but no inverter , has anyone done this?

You would have to check the specs on the compressor. If it is a dc compressor you would have to add a rectifier in line to change ac power to dc power. Also prolly a transformer to get correct ac voltage to rectifier

If you look at the draw on most 12V refrigerators they will flatten a group 27 battery in a day. Have you given any thought to a good marine battery charger that you could hard wire and then plug in while docking? This should do the trick for you as well as keeping your batteries topped off when you are not using the boat. I am surprised that Fountains do not have a "house battery." Mine has two starter batteries but no deep cycle for overnighting.

The fridge in my SCARAB would easily run overnight without draining the house battery. Does your fridge run nonstop or does the compressor cycle on and off to maintain temp? Maybe you have it set too low.