I recently added a solar panel and a mppt 15 solar controller to my camper. I have some questions regarding the controller that I can't find any info on. What is the load light for? It seem to always be green. Also, on the far right is a symbol I can't make out and 2 empty RJ's for plugs below it that are not being used. What are these for? Lastly, when would I use the reset button? Thanks for any help.