Stealth Solar

By Vern Modeland   –   December, 2010

My goal in converting my 1994 GMC 2500 Vandura Tiara conversion van into a van for RV living was to keep it low profile and stealthy, while also self-sustaining. My hobby of amateur radio sort of ran counter intuitive to stealth, but people don’t seem to notice the “big stick” when it is folded nor the four other black antennas that decorate the waist level and top of the van. It’s sort of surprising how people look past that sort of thing. But, would they look past a solar installation? I decided they might if it was tucked inside of the existing luggage carrier on the roof. That meant the panels would have to fit inside a 4 foot by 4 foot space. And most of the higher power ones I found wouldn’t. So, I went searching at local dealers and on the Internet.

Here in the Ozarks, local dealers turned out to be ready to do big installations, on houses or boat docks, and turned down my request for help with a mobile need. So, the Internet became more important. But more productive, too, if I was willing to do the work myself. Fortunately, it really isn’t that hard, even if the bones and joints are older than ’77.

I narrowed my quest for quality and most power in a small space to Canadian maker Carmanah’s GP-RV-95 monolithic crystal panels. www.gpelectric.com. The panels are about 21 by 41 by 1.25 inches in size and weigh about 16 pounds. Output is a maximum of 95 watts each. That meant I could get 190 watts inside my 4 by 4 foot available space and they would ride low enough to not stick up higher than the luggage rack rails.

More reading and corporate contact showed the GoPower GPR-25 regulator, a GP-1000 DC to AC modified sine wave power inverter and a FBL-110 fuse and mount would fill the need, especially to power my Engel refrigerator full time, a computer part time and the radios intermittently too. The work then began. First was to see where all that plus a big battery would fit on and inside the van. And this is not a bare-bones van, but one with interior already finished out. Measure twice and cut very carefully, if at all, is most important.

The problems included; first, mounting the solar panels. Four stainless steel “L” brackets come with each panel. Then I needed some weatherproof way of routing the wiring inside. With a conversion van, there is almost always some sort of trim inside running the length of the center of the ceiling. Unscrewing mine gave access to where two of the mounting brackets would be placed and an amount of space inviting some sort of weather head to bring in the four cables from the panels.

GoPower! has a wiring harness with weather resistant connectors to join the panels in parallel. But I wanted any connectors to be inside, if possible, to combat corrosion. And, there also were two more brackets on each panel that would have to be blind — that is, fastened from the outside only. This meant expanding nuts that would slip through a hole then swell as tightened to hold the connection firm. A local company, I found, made them for the big box and hardware stores.

It all came together. I coated the bracket bases and bolt hole liberally with 3M’s best automotive sealant, then turned my attention to the weather-proof entry point at center roof top where the wires could be pushed in to connect inside. My solution for a cover was a 120 volt weather head used in home wiring. It had a movable lid and a center hole about an inch in diameter. And four mounting screws. I cut the holes in the van roof, spread on the sealant and screwed it into the roof centered side-to-side and about half-way the length of the panels, making sure the wires were not stressed but most of the excess would be inside the van.

After dropping the walnut trim held in by long brass screws, I routed the panel wires to the connections of the extension wiring (all necessary solar system hardware and extra wiring is supplied in the panel kits, incidentally). I routed the wires forward to where there is a cross trim piece in my van, unscrewed it and routed them to the driver’s side where I could remove more trim and go down the inside of the post between driver’s door and first side window. When all was in place and enough wire remained for connections, I put wire ties on my work and replaced the headliner oak trim.

Then came the interesting part. That was getting a Group 27 deep cycle battery behind the driver’s seat in about the only place still empty in my do-it-yourself RV project. There turned out to be just enough “place.” An outboard type battery container held the battery, leaving me a small adjoining  space on the side of a Sauder cabinet to mount hardware and the solar charge regulator. The regulator had to be mounted with an “L” bracket and wing nut for temporary removal when it was time to check battery water levels. That’s how little room there was. I vented the battery case with half-inch flexible vinyl tubing. The tube runs from a press-on fixture in the top of the battery case up (lighter-than-air hydrogen rises) and out the side of the van through screw-on hardware there. All fixtures and hose were found at my local farm and feed store. All wiring connects at the battery posts. I chose Walmart as a battery source since they are so “everywhere,” and easy to deal with for warranty and such. A Group 27 is adequate for now but a Group 29 may be squeezed in in the future, to better handle temporary loads. The Group 27 battery’s main load is 24/7 for my Engel 40-quart refrigerator.  I have yet to experience enough cloudy days that the battery charge and output level are in question.

After I’d made my installation and watched when parked or around others to see if any one really noticed the solar panels, I turned to the power inverter. My one-and-only pure sine wave need would be for the Hughes.net’s modem. I have a Hughes tripod Internet system that sometimes goes along on longer trips. The only 120 volt part, I thought, would be the modem. But, it turned out a friend of mine who is Alaska’s biggest Hughes system dealer knew of DC to DC power units for the modem. That left me with only one more 120 volt piece of equipment, other than a single reading light fixture (which has a 14-watt low-energy bulb). That is my 750 watt microwave oven. And it can be run off of a Group 27 battery as long as you don’t want to cook a full Sunday dinner in it. My microwaving is limited to 90-second omelets and Hormel Completes and other 90-second entrees. That made a modified sine wave inverter and 1000 watt inverter power enough. Modified sine wave is sufficient for a laptop computer too as the laptop really works off of its own battery and all you need the 120 for is charging.

I’ve managed to fit it all in and still leave space for me in my converted conversion van. The solar has been the talk of the campfire cocktail hour from Canada to south Texas. And it draws no attention to date when stopping, even overnight, in commercial parking lots.