Hi, I'm brand new to the solar world and this discussion board. I will be installing a 42w Uni-solar panel with a Morningstar 10L charge controller. I'll be mounting the panel on the roof rack of a slide-in camper but will fasten it so that it can easily be removed to set up on the ground (that way I can move the panel and battery being charged into the sun and not have to camp in the full sun). My question relative to grounding the panel - do I ground the panel to the truck frame when it's mounted on the roof and do I need to ground the panel to the ground when it's sitting away from the truck, mounted on it's yet to be designed and built mounting frame. Any tips/advice would be appreciated.

You would need to ground to the RV frame. I do not own an RV but myself with a moble panel such as you are planing I would not ground it at all. Check out this link, they do not use a ground wire other than to the battery. http://www.rverscorner.com/solar/solar.html.

Thanx for the info. Is grounding the frame of the pv solely for lightning protection?

For lighting protection you would need to be grounded to the Earth. Autos are not likely to be hit by lighting because they are not Earth grounded. An auto is one of the safest places to be in a lighting storm. I would not worry with grounding the solar panel frame because your RV would come closer to taking the strike being a lager target. Unless you put that solar panel in a tree or on top of a pole, I would not worry with Earth grounding.

You can always place your question in at rvdoctor.com and see what they do. I think you will find very few whom bother with this.