yeah, the 5000 Mermaid unit pulls less than 700 watts when running (compressor startup surge runs more till it is all going). The whole kit runs around $1,500 for the pieces.

A 1500 watt inverter with the Mermaid running will pull in the neighborhood of 60 amps. A group 29 battery is around 90 amp-hours meaning that one battery will run the AC for an hour and a half. Two grp 29s will run the AC for 3 hours, but will not leave enough juice to start the motors back up.

The Mermaid unit weighs less than 40# including all the stuff in the kit. A 1500 watt inverter will weigh around 20#.

You'd probably want to add a third battery, just for starting your motors. Your two "house" batteries could be wired to the same position on your switch ("A") and the starter batt could be ("B"). If both house batts were deep cycles then it won't hurt them to run low before recharging (the fishermen around here use rebuilt Hester Deep Cycle batteries for $35 each direct from the mfr - they claim they last as long as the $80 Interstates and such).

This is what I have been considering.

The 2000 watt Honda is a sweet generator, but you can't run it in an enclosed engine compartment. It won't cool properly and will not vent exhaust properly. For this reason, it can't be used when underway. I am thinking the inverter plus one batt is the best p[tion since you get three full hours of AC (actually more if you figure that the compressor will not run continuously if you keep the door and hatches closed).