20w coleman solar panel

From his previous posts he has 1975 Scamper, probably does not use any 12 volt controls at that vintage. So with that, OP what is your battery for exactly which will help us help you with usefulness of a 20watt panel.

Sealant depends on the surface being sealed. What is your roof constructed of?

Why not using silicone on a rv?

So you dont think this will even charge the battery?

We have such small needs it is just to keep in going as we dont used it really at all in the day just nights.

So you think i should just bring the panel out when i need it?

I wouldn't even mount it, 20W is barely enough to maintain an unused battery.

Screwing it into a roof with gobs of silicone is a recipe for disaster. Maybe no one has told you---never use silicone on an RV. There are better sealants out there, purpose built for RV's.

Wire isn't crucial since you won't be moving much power and solar modules don't need a cover (if that's what you're asking?).