Harness even more power from the sun with this nice big solar panel. We had these custom made for us when customers let us know they needed more than what our 2W panel could provide. This panel is a 12-cell (6V) assembly mounted onto a fiberglass PCB and covered with PET plastic which protects the cells without reducing efficiency. The back has two soldering spots to easily connect and is conformal coated. The panel is thus fairly strong and lightweight but isn't completely waterproof (since you'll have the exposed soldering on the back. However if you place this in a box or mount it so the back is encased, it'll be just fine.
We connected this up to our solar lipo charger and got over 550 mA to charge the battery with on a fairly sunny NYC day.