No sure what they have going on there. I only have 1 positive and 1 negative going through the wall into the camper. I'm in the process of installing a master cutoff switch at the battery along with a new circuit breaker. I'll be posting some pictures on my site www.rvyourway.com
with in a few weeks once the weather warms up here. For the solar I went with a Renogy 100w suitcase style with the Voyager controller. I removed the controller from the panels and installed it in the basement. I rewired the factory side solar connection to the controller.