My single panel feeds a black box controller under the bed. So, if I wasn't getting what I thought I should get out of the panel, I would start by finding the make and model of the controller. Then I would look for an "owner's manual" on Google.
Even with two panels, I don't think you should expect much. Panels and controllers used by Monaco had very limited use.
The main purpose was not for us campers. Instead, it was intended for the dealer staff. There is supposed to be enough coming out of the panel on mine to keep the batteries charged IF the coach power switch by the door is turned off. That is great for the sales staff because, when the show multiple coaches, they can flip that switch as they enter and exit.
When our Beaver was nearly new I wanted to park it for a few weeks and fly to see the grandkids for Christmas. I thought I might leave the fridge on propane and leave everything else off. Turns out that the circuit boards on the fridge alone takes more than the solar panel can do.
