I have a 100w suitcase solar kit and I have had good luck with it
If the goal is to not run the generator as often, it works well. If the goal is to rarely run the generator, it is not enough.
In an unshaded site with sunny days, I rarely need to run the generator. If there are cloudy days, 100w doesn’t provide catch up ability.
Since I live in Michigan, with lots of clouds and lots of trees, I can’t really rely on solar, so I prefer to not put holes in my roof. With the portable panel I can put the panel where the sun is, away from trees. I changed the wire from the panel with a longer, thicker one.