Not sure what you're referring to exactly. We had a small panel that mounted atop the forward air conditioner on a Diesel Bounder that worked OK to keep the house batteries up when we weren't using the coach in the summer. It was a very limited charge and needed full sun for as long as possible. If you're thinking of trying to use something that small in the winter (with short, grey, possibly snow covered days), I'd look for something better.
2013 Tiffin Allegro Bus 43QGP
2011 Chevy Silverado 1500 Toad