Engine starting battery being charged while parked?

J-Rooster wrote:
I have a solar panel on the roof of my coach that trickle charges to my battery. This solar panel works even when the sun isn't shining. Good Question Happy Holidays to you.

Could you tell us more about the solar panel that charges even when the sun in not shining? I would like to acquire an array of these, unless it is the "rotary type of solar panel", but I have never heard of one installed on a MH roof. lol!