I started with a pair of 45 watt panels in 1994then added a 75 watt and a pair of 120 watt as well!
They are all working on the same controller.
I would recommend a roof mounted solar panel and it will keep the battery full while you have it in storage.
SunElec.comThey had 140 watt with aluminum frame and 12 volt nominal output for $229 a few weeks ago.
Good luck,
Ferd.