We have both a portable and roof mounted solar panels, rigs that come with an exterior port are just leads that are directly wired to the battery bank. At least from what I've seen and from the Renogy portable solar suitcase we own, a charge controller is already included and you would just plug into the port. We don't have a port on our rig but I have added a set of wires that I plug our solar suitcase into without having to remove battery covers. Due to parking in shade and the ability to easily adjust solar suitcase as the sun moves, in many instances it outperforms our roof-mounted solar panels although there are about half the wattage.