On-the-Road Solar

While the last streaks of daylight slipped behind the rolling hillsides of Virginia’s Blue Ridge, I snapped a few rolls’ worth of digital pictures, trying to savor the “magic light” that photographers cherish. It was a moment like this—perched on the Blue Ridge Parkway, nary a soul in sight—that brought my journey full circle. Here I was, far from home, capturing in pixels the same light that charged the PV-powered digital photography studio that traveled with me in my 32-foot RV.

For as long as I can remember, I’ve wanted to pursue photography more seriously, but whether it was a job, money, or family, I always found one reason or another not to go for it. Life, however, has a funny way of forcing experiences on us—for better or for worse. One day, little more than a year ago, I woke up to discover that I was 47 years old, finalizing a divorce, leaving my job in PV sales, and selling my off-grid, solar-powered home. Though I had no real plan, I also had no more excuses. All I knew was that I wanted to find a way to see the country while working as a photographer and remaining true to my off-grid sensibilities. But how? My off-grid, mobile solution: Hit the road in a 1989 RV retrofitted with a PV system to power a digital photography studio.

Having worked in PV sales for more than 15 years, I understood the technology and the general mechanics of a system. But since I spent more time in the office than out in the field, the installation process was still fairly intimidating. As luck would have it, I met another semi-professional photographer, Ken Dilello, who shared my passion for solar energy and my vision for life on the road. He had six Siemens 100-watt PV modules, and I had the RV. His strengths in carpentry and fabrication complemented my weaknesses, and vice-versa, so we decided to join forces. From North Carolina, we headed for Florida, where Ken had connections with owners of a metal shop who agreed to let us camp out while we worked on the vehicle.

 Our plan was to remove the dining area table and cabinets in the RV and transform the space into a work area for my digital photography studio. We sized the 600 W system to provide enough electricity for both our professional and domestic loads—a desktop computer and a printer, two laptops, various battery chargers, a flat-screen TV with a stereo system, a microwave, and other small household appliances.

Metal Fabrication & Mounting

The first, and most time-consuming, part of the process was making room for additional battery capacity and fabricating a roof rack for the PV array. The RV came equipped with only two, 90 amp-hour, 12-volt batteries for its DC loads—not nearly enough storage for the potential energy generation of the six-module array. The existing batteries were located in the front engine compartment, where there was no room for additional batteries. To accommodate 10 new 12 V batteries, Ken, a tile and stone setter by trade, devised a plan for a battery cage that attached to the undercarriage and dropped down, when unbolted, to allow easier access to the batteries. 

Over the course of a few weeks, Ken fabricated the 2.5- by 3-foot battery box from a mix of expanded and extruded steel, and then welded the lid of the box in place. Essentially, the bottom of the box is bolted into the lid, which is welded to the RV’s chassis. He also cut and welded the pieces for the roof rack, which provided not only a sturdy, aerodynamic support system for the modules but also a means for reducing the number of holes that we’d need to put in the roof. Ken’s design also accommodated the TV antenna and left room for an observation platform at the front of the roof. 

While Ken secured the roof rack, I worked on the ground, wiring the PV arrays and attaching them to the aluminum rails that Ken had fabricated. I ran wiring through conduit throughout the system, making for neat and tidy connections that can withstand the elements. Next, we raised the arrays onto the roof and mounted their aluminum frames to the roof rack. Though I had dreaded the logistics of raising the modules onto the roof, we moved them in less than 30 minutes—thanks to the shop’s forklift and Ken’s experience with running one.

Wiring the Controller 

The output cabling of each PV module was routed through a combiner box installed on the roof. For a weather-tight seal, we included a double-sided elastomeric membrane on the roof beneath the combiner box. Six-gauge wire was run in EMT conduit from the combiner box to a Trace C-60 charge controller, which we mounted alongside an OutBack inverter in a storage compartment under the interior floor (known as the “basement compartment” among RVers). At some point, we’ll upgrade the controller to a maximum power point tracking unit to optimize the output of our PV array. 

Using a hole that we drilled for the array cables, we ran the AC conductors up from the inverter to the house mains, located in the cabin beneath my desk. To cut down on costs, Ken had rummaged for cable at the junkyard and came back with a few choice pieces from an old BMW—a pretty good find considering that the same cables would have cost us more than $150 in the store. The cable that runs from the charge controller to the batteries is a #4 wire that he salvaged. Though probably overkill for our power generation, this size helps minimize losses in our small system.

Wiring Up the Battery Bank

When it came to choosing a battery, we entertained a few ideas, namely T-105s and similar deep-cycle and marine batteries. In the end, we went with 10, 125 AH, 12 V deep-cycle batteries from a big box store. In retrospect, one drawback related to our decision was that we ended up with 10 batteries in parallel. Large numbers of batteries (or series strings of batteries) wired in parallel are subject to unequal charge/discharge rates and premature failure.  Most system designers recommend limiting the number of batteries wired in parallel to three. A better approach would have been to install higher-capacity 6 V or even 2 V batteries to minimize the number of  battery strings in parallel.

We used copper lugs and a large crimper to make the interconnects for the batteries. Instead of ordering pre-made battery connectors that never quite fit right, we fashioned our own connectors out of 2/0 cable—some of which I bought at the local hardware store ($15 per foot) and the rest Ken found at the junkyard. To prevent corrosion, we sealed each crimped lug with heat-shrink tubing. Once we wired up the bank, we had 1,250 AH of storage at 12 VDC nominal at our disposal.

We built two inverter cables the same as the battery cables—with lugs, crimped and sealed with heat-shrink tubing. We also added a 200-amp fuse for overcurrent protection and to serve as our DC disconnect in line on the inverter-to-battery connection. Although a disconnect switch would have been better, this was what fit into our budget.

Rewiring the Rig

Finally, we were ready to rewire the main house lights (DC loads) from the original battery bank in the front of the coach to the newly installed bank. Almost all of our major loads now run off the new battery bank—except for some cargo bay lights that still run off the original battery bank, which only charges when the engine is running. 

On the inside, we reconfigured half of the house system. Ken customized a store-bought standard circuit panel to fit our space by cutting it down with a band saw and welding it back into shape. Fortunately, the RV came equipped with a transfer-switch that allows us to switch power input from the onboard gas generator to the grid when we hook up somewhere. This is a particularly important feature because if we’re ever running low on solar energy, we can either plug into the grid or turn on the gas-powered generator. I’d rather eat a bug than turn on the gas generator, but on occasion, it’s a necessary evil.

We ended up hooking up the inverter at dusk, by flashlight—admittedly not the best light for working with power cables. We carefully attached each cable to the opposite ends of the battery bank. When we went inside, we switched on the main circuit breaker to the inverter. The inverter was on, and we had solar electricity.

Focused on Horizon

For the final touches, we installed a desk in the RV’s dining area, which is a perfect space for my growing portrait business. All told, it took about four to five weeks to install the system and finish the remodel. We’re still tweaking the rig here and there, upgrading to LEDs and energy-efficient appliances. Our small system, which produces about 1.5 KWH per day, doesn’t leave us with much excess energy, but we’re just fine with that. We make every watt count. Besides, it’s a trade-off for the freedom that we now have to roam the country and pursue our passion.

Access

Lynne Allen operates an art and portrait photography business out of her solar-powered RV. Her specialty is human-form images in nature and nudes. She and her partner Ken Dilello spend most of their time in the Carolinas and Maine.

Major System Components:

OutBack Power Systems • www.outbackpower.com • Inverter

SolarWorld • www.solarworld-usa.com • PVs 

Xantrex • www.xantrex.com • Charge controller