My coach had 150 watts of solar power at manufacture. I added another 110 watt panel This produced about 14 amps. The original solar controller maxed at 7.4 amps, so I needed a new controller. I installed the new 16 amp capacity controller on the shelf next to the refrigerator, so I could view the LED readout inside. I routed new 10 gauge wires down the refrigerator vent to the controller and from there to the batteries. The old controller is still in the bay, but no longer in service. That was about 5 years ago, and technology has changed. Search the internet for the latest equipment. You may want to use the BAC link to Amazon.
Larry