My 2015 Rockwood Freedom 232XRT has a Zamp Solarport presinstalled. The port is mounted on the frame just behind the propane tanks. Have not purchased a solar panel yet, but am looking at the Renogy 100W foldable and not sure if I need to buy one with a charger controller. My question: How do I know if a solar controller is already installed on the trailer? (Not sure what I am looking for or where to look)?