not positive, but i think they are all 12v so they can run when you are underway. when at the dock and pluged into shore power, i think it gets converted down to 12v
I don't have shore power either. My 2005 frig is 12v. It doesn't draw much power. Since it runs off the 2 battery bank when plugged in, most on board chargers will run the frig and charge the batteries.