So I think you're referring to solar charging panels, not batteries - correct? (AFAIK there is no such thing as a "solar battery"). And you're looking to add a solar panel to your boat to trickle-charge your batteries? I have some solar industry experience, but not specifically for boats. My input would be: For a small size, flexible isn't that important - there's plenty of flat surface on a boat to lay one of these things down. My concern about flexible panels is how well the encapsulatoin keeps the panel sealed. In theory, fine. In practice - I don't know. Rugged corrosion protection IS important as you can imagine for all electronics in the marine environment. If the panels aren't made for marine application, I wouldn't trust the connectors to be sufficiently protected against corrosion.
I do think a solar panel to trickle charge a house or start battery is a good idea, particularly for a boat that sits for a long time between use, and isn't on shore power. Will be curious to see how this plays out.
