Separate battery for the generator? All coaches that I have owned have used the house of chassis batteries to start the generator. If the solar panel is wired in it should be providing a small charge to the house batteries. 1 100 watt panel does not provide much in the way of a charge especially if you are using the coach systems.
US Army (Ret)
2020 Entegra Accolade 37TS
2019 Jeep Grand Cherokee Trailhawk (Toad)
FMCA - F432054