[Carl n Susan]

OK, I will take a shot at answering this. Disclaimer: I don't have a residential refer so I have no experience with one. However I am somewhat familiar with inverters.

I believe Montana has installed a Magnum CWS 1012 inverter for the residential refer. This inverter only has connection to the 12V system for source power. It is totally unaware of the 120V power supply systems. Its only source is 12V and it outputs 120V. It always draws from the battery regardless of the existence of shore or generator power.

So to answer your question, Yes the refer will be driven by the batteries while your generator runs the AC (and other 120V appliances). Remember the converter will run when there is 120V power (unless you turn it off) and it will be charging the battery to replace the 12V used by the inverter.

I have attached the Magnum CWS inverter manual so you can see how it is connected to the 12V side and not the 120V source