I have a 2018 22E, the same overall dimensions as the 22B but no slide.
Due to this being Thor's smallest Class C, I think the most you would be able to mount on the roof is 3-4 100 watt panels.
Also extra battery storage space could be an issue.
I added a 100 watt panel, but I mainly use it for storage, and only plug the motorhome in a day before a trip
A 100 watt panel works great for keeping my 2, 12v batteries topped off, I rarely if ever have discharged them more then 70%.
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