We have a small solar setup on our garage roof that charges car batteries, 3 can be done at a time. Carrying in a car battery and using an inverter with it is an easy way to use things when the power goes out. Solar set up was about $300. And then we bought the car batteries. And good to use when the propane runs out, but that'll be awhile. The generac runs on propane.
We have a Generac and then a backup, both on propane. Running out of propane would not be good, but we, like you, have a solar backup.