Is the question "can I run an electric heater off my solar system?"
You can briefly but trying to build an off grid solar system to power electric resistance heating is impractical and expensive for a permanent home. It's an even worse proposition in an RV. The main problem is storage. That's what's hampering the whole solar industry right now. Battery technology is terribly inadequate for heating.
To give you a reference point, 2 golf cart batteries in series hold about 2,640 watt hours of electricity. A 20 pound propane tank with 4.7 gallons of propane holds the equivalent of 126,000 watt hours. So, you'd need 96 golf cart batteries to hold the energy in 20 lb LP tank.
