Setting Up the Intrepid’s Solar Ground Panels
The video below shows how the Intrepid carries its two 100-watt solar ground panels onboard, and how they are removed and deployed. The usual setup on Four Wheel campers is to carry one panel by using two aluminum rails attached underneath the bed area of the camper, but there isn’t enough of a vertical gap between the camper and the truck’s cab roof to stow two 100-watt panels in this way. Plus, the then-owner of Four Wheel personally interceded on the phone to dissuade me from using that method due to his fear that the combined weight of the panels and the inherent violence of off-roading might cause delamination of the board used in that area. I had wanted to use adhesive tape rather than drill for machine screws through the board from inside the camper, something I’m squeamish about when accuracy is vital. It’s a moot point, though. There isn’t enough physical space available.
So I designed, prepped and had a highly experienced welder assemble an aluminum carrier rack that is bolted to the forward jack mounts of the camper. It’s a twin-track affair which carries both panels in a vertical orientation between the rear of the cab and the front of the main camper wall. It works well, the main drawback being that the jack mounts cannot be used to remove the camper until the rack has been disassembled and removed first. I have had to install spacers at the front wall of the truck bed in order to ease the camper back a fraction of an inch, for proper clearance to the cab. Each truck is unique in this regard, so having to add such spacers is not universal.
In the video, I mention hooking up both these panels in series, which combines their voltage without increasing amperage beyond that of a single panel. This is done since very long runs of wire like this will carry the increased voltage without much power loss, while doubling amperage (as found in parallel wiring) will suffer from increased resistance. That saps power that the controller will never receive, particularly in the very long wire lengths typical of any ground panel setup. At any rate, don’t try this at home. You can’t simply switch from parallel to series hookups on commonly used PCM controllers. They’ll either shut down or be damaged. An MPPT controller must be used, and they are expensive, which is why they aren’t used much for RVs. Their main market is in high voltage residential applications.
The aircraft cable I show with a padlock has two functions. One is to discourage impulse theft in town, of course. The other is to serve as a backup to the bump stops built into the rack. In other words, in very rough going, the cable ensures that the forward panel can’t hop its way out of the storage position and work its way out the driver’s side. So far, this has never surfaced as a tendency in practice. Adhesive-backed UHMWPE tape lining the bottom of the forward rail prevents galling (a type of sliding wear damage) on the panel’s frame or the rack track.
The video is just short of 8 minutes. Enjoy watching me shuffle around and mumble! This is what makes using a real action cam is so vital. 🙂