Our 21 cuft Whirlpool draws 8 amps DC measured before the inverter…96 watts or 1 amp AC. It runs less than 50% of the time or 1.3 KW/day. One good 12V battery will run it 12-16 hours before needing recharged. A properly installed residential should come with a 1000W inverter and 2 extra batteries and Yes, your tuck shouldn’t have any problems beeping the batteries up, even with the small 12V charging wires.
OMG, a second alternator or a dc-dc converter to charge 8 amps part of the time…stay on the porch.
PS: we dry camp most of the summer and a residential refrigerator is my best mod ever.