Realistic expectations on what you can do with 100 watts and storage. A big battery bank can store the energy but depending on usage how long will it take to top the batteries off with 100 watts.
What do you want to run would be the starting point in determining just how much or how big your system needs to be.
I run 1000 watts on my bus and it is way more than I need but with that 1000 watts I have never needed to run my gen set.
I plan to install 1000 watts on my house this summer with a way to piggy back the 1000 watts from my parked my bus to the house storage. That additional 1000 watts giving my house system 2000 watts and the added battery bank of 4 T105's for storage will be a huge boost, and still give me a portable 1000 watts when we use the bus.