Today I purchased a GoalZero Boulder30 solar panel
to replace my big 3 panel 45W setup from Harbor Freight. The new panel is 21"x18" as opposed to about 36"x24" on the old model. New panel is also WAY lighter than the old beast. The GoalZero rep assured me that the new unit is plenty adequate to keep my Casita battery
charged. I bought it at Costco for $170 - msrp is $240. Additional panels can be purchased to link together.
Discover Solar Power - Buy the Boulder 30 Solar Panel | Goal Zero
Charge-Controller to trickle charge battery | Goal Zero