The Serenity came with a GoPower GP-PWM-30 controller with a single GP-100W flex panel. In the spring of 2018 I noticed it underperformed and contacted the manufacturer of the Panel and Controller.
By the fall it was doing nothing, GoPower put me through the paces to ensure that it was really bad but did eventually replace the panel.
The flex panel is glued to the roof of the RV which seems like a good thing since no holes are made in the roof and it is low profile.
In reality it been found is that glue-on solar panels under perform when compared to rigid panels due to overheating and the glue can damage the fiberglass roof.
It is impossible to remove the panel without completely destroying it and what is found underneath is extremely difficult to remove.
I spent hours on my belly scrapping with a plastic kuchen scraper and lots of solvent, but I did eventually get it pretty clean, the only thing left was a bit of staining. I placed the panel off center because I was going to add another panel.
I would have liked to buy a matched GP panel, but the price was over $500, so I found a panel with matched specs on Amazon for about $180. I also did not want to use glue to put them back on so settled on using Industrial Velcro, hopefully when the time comes to remove them it will not be such a chore.
I connected the panels in parallel and the performance seems about 2X what the GoPower put out when it was new. So far so good.
