I’ve spent much of my life building cars. One of my earliest memories is sanding the wooden spokes on a 1926 Ford Model T. My teenage years found me hot-rodding early Camaros, Chevelles, and a 1932 Chevrolet. I have always enjoyed building motors. I went to engineering school, and worked for Ford Motor Co. as well as Jaguar Land Rover in England, but never found creative outlets for my motor-building passion.
Then I found electric motors, with their “clean” design and alternative fuel possibilities. This interest combined well with my enthusiasm for renewable energy—for the last 15 years, I’ve been passionate about off-grid power. I’ve designed and installed about 30 off-grid PV systems. I’ve also retrofitted some golf carts with PV modules. So by the time I was ready to build my electric vehicle (EV), I had it all planned—not only would I convert a gas-engine vehicle to electric, but I would add a PV system to supply the energy for traveling and off-grid camping.
Life in the Slow Lane
I chose the Volkswagen Transporter for its large roof surface, which could accommodate several PV modules on a tiltable rack. I spent many hours in the design phase to figure out how best to make a watertight installation. My wife Kira pieced together canvas to make a large tented area underneath the array—there’s enough headroom to stand up. She also made a door with a screen and removable window for a rear exit.
The array consists of four 305-watt LG Solar modules, for 1,220 watts. One edge of the array is hinged in the front of the van, and actuators (one on each side) tilt the array up to 40°, creating a large space above the van. Being able to move the van allows positioning the array to receive great solar exposure. When we stop driving for the evening, we can orient the array to capture the evening sun. Facing the array east in the morning ensures that the array gets the best exposure at that time.
Four Drok DC/DC converters boost each module’s voltage from 40 Voc to 50 Voc for better power transfer from the modules to the batteries. These converters are wired in series for about 200 Voc. The array generates 8 A total (at 150 V) into the battery. I can adjust the converter output voltage and manually power point track the modules.
Our family has lived with a 1,200 W PV system for years, and we know how to use electrons wisely. Camping loads, such as our small Dometic fridge, a clamp-style work light with a 7 W compact fluorescent bulb, and a 1,200 W cooking element, also consume energy from the array. Other loads include a water pump under the sink and a swamp cooler. However, our daily camping load (about 800 watt-hours) isn’t much compared to what the van uses for propulsion.
Twelve Trojan T-1275 lead-acid batteries provide 150 Ah at a 20-hour rate. Since I load the batteries at a minimum of 50 A (at a discharging rate of C/3; up to C/2), I use about 80 Ah out of the batteries for an approximate 80% DOD, or 11,520 Wh (80 Ah times 144 V). The slower I discharge the batteries, though, the farther they take me. Finally, a good reason to slow down! Twelve Murata Power Solutions digital volt meters, one for each battery, alert me to any performance issues.
These batteries were selected for affordability. For three times the price, I could have installed some lithium iron phosphate batteries, but I’m trying to make a point about the economics of having a converted electric vehicle. I’ve spent a lot of time working with lead-acid batteries, and know how to maximize their life and performance.
The battery gasses are fan-driven from the battery box out past the motor. The battery posts are covered with rubber boots for each post. The solid copper wires give a good connection and rigidly solidify the pack, which is good for bumpy roads. The battery box is secured to the floor to survive full inversion of the vehicle. There is a liner at the bottom of the box to contain spills.
A MeanWell 12 V, 53 A DC-to-DC buck converter keeps the 12 V accessories operating in efficient isolation from the main pack.
I’m using an AC motor and 500 A, 144 V controller from Hi Performance Electric Vehicle Systems. At first I ordered the AC76, a larger motor with a lot of torque, but it had a misplaced winding and burned a black streak down one of the phase wires, making my maiden voyage disappointing. I swapped it for a smaller AC51 motor, which lightened the load by about 100 pounds, and it has more power than I need. I almost exclusively use the economy mode on the Curtis 1239-8501 AC motor controller. It keeps energy consumption to a minimum.
I will be boxing in the entire rear engine bay so none of the components back there will need individual weatherproofing. Just the motor will be exposed.
The inverter is a 2 kW EV Enterprises Blue Flash, which inverts 144 VDC to 120 VAC quite efficiently without any magnetic component. We can cook, cool, and run my electric chain saw, which is great for prepping firewood for campfires.
Charging from the Grid
I have two ThunderStruck 2,500 W chargers. At 20 A each, a full battery recharge takes two hours and 20 minutes. Programming the chargers is a snap; I can create charging profiles for 110 VAC as well as 220 VAC at any current draw I choose.
I use a small vacuum pump for the brake booster, which runs when 12 V key ignition is on. The brakes work nicely. The regenerative brake adds stopping control for the heavy VW. Regeneration engages the moment I take my foot off the accelerator. I recently took the fully charged van up a mountain, climbing a steep hill for 18 miles. I recharged with PV at the top of the mountain, then traveled another 20 or so miles on the plateau. By the time I made it back down the mountain, the van’s batteries had a full charge from a half hour of regenerative braking—I was able to put 20 miles of range back into the pack on the downgrade.
After resolving some brake issues, the van went from a 35-mile range to a 50-mile range. The pistons on the brake calipers were stuck and dragging on both front brake rotors. I was happy to get the added range. If the vehicle is driven casually (30 to 35 mph), a 75-mile range is possible. This is a camper and I’m in no hurry. I’m definitely the minority.
Locally, there is no need for plugging in. This means it is a “zero-fossil-fuel” vehicle, since it charges the batteries with free solar energy. The van usually sits for 5 hours in the sun every clear day, with the PV system providing 40 Ah—25 miles—to the batteries. It’s a joy to have your fuel tank refilling on its own! A car like this, for the proverbial soccer mom, provides a way to get the kids to and from activities, and her to and from errands, with no impact on the budget or the Arctic ice caps.
With that said, how does it do on longer trips? We decided the next test was to see how the van performed on the open road.
I built this vehicle with the dream of taking my family to the Pacific coast for camping trips, and that was our first test (see “Solar-Powered Road Trip” sidebar). The van performed beyond my expectations, getting consistent 40-plus mile runs (and sometimes even 50 miles on a full charge). Unfortunately, the coast was cloudy most of the time, so it was necessary to find charging stations for recharging the batteries. After a couple of hours of charging and the batteries full, we’d hit the road again.
We drove about 100 miles per day, traveling slowly, and averaging about 40 mph—which was scary at times, with traffic screaming by. It felt like we were trying to slow down the whole human race and its frantic affinity for speed. But I soon got familiar with the necessary style of driving the van and found a cadence for yielding to faster traffic while maintaining an efficient 40 mph or so. Heading up long, steep grades was rough, requiring lots of energy from the batteries and going slowly. Fortunately, we weren’t alone—big trucks and RVs kept us company.
It wasn’t until the last leg of our journey—camping beside the Smith River—that the PV array generated 55 Ah of charge from the sun in one day, as shown on the JLD 404 meter. I designed the system to provide a full charge to the batteries on a full day of summer sun. However, my Drok controllers were limiting the energy transferred from the array to the batteries. The meter showed only 6 to 7 amps of output. In the cool redwood forest climate, the meter had shown 8 amps, revealing to me that the modules were losing performance as ambient temperature climbed.
The ability to power electric appliances is terrific—I can run my electric chain saw to cut firewood or cook on the induction cooktop. An hour of cooking is equivalent to one-eighth of the van’s daily range. The refrigerator runs at 36 watts, for 15% of the day, consuming about 150 Wh daily. Nothing else is a significant load.
It took me two years of patience and steady focus to build this safe, functional vehicle, and the payoff has been rich. We had only two malfunctions the whole trip—one battery meter stopped working and a brake clip from the brake pad area broke. Other than that, things went smoothly.
There was something really special about pushing through the anxiety of going 40 mph when everyone else was going 60. Settling into that stillness was something we’ll take with us forever, and slowing down gave me a perspective of my family I never would have had speeding along and missing the view.
Find out more about the Belans’ electric VW at solarelectricvwbus.com
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