Re: Air conditioning question in 97 roadtrek, does it have to run on the generator?
A room air conditioner large enough to cool your RV will require about the same amount of power to operate as will the roof unit that you have now. I have never heard of any air conditioner that will operate from 12V-dc power. Even though the dash air conditioner does operate while traveling, it does so because the engine that pulls the RV also turns the compressor of the air conditioner.
To operate even a very small air conditioner will require at least 8A of 120V-ac power to work and that means at least 85A of 12V-dc power to the inverter large enough to supply it. To supply that much current you would need a bank of 8 or so batteries to last through the night if you operate nothing else from them. In the real world, it would be more likely to require more than that.
As far as solar, even the largest of RVs are not nearly large enough to support enough solar cells to operate the smallest of air conditioners, and you would need enough to also charge the batteries while the sun is up in order for them to last through the night. Air conditioners must have a source of power either from a generator set or from a power pedestal in an RV park.