Rolling on Sunshine

A 1973 VW conversion

Inside this Article

First step: The author removes the internal-combustion engine components and the fossil-fuel grime that goes with them.
Using actuators, the PV array tilts up to 40° for optimal exposure. Underneath, a homemade bunk provides sleeping and storage.
The charging port.
An 88-horsepower HEPVS AC51 motor is mated to the stock transmission with an adaptor plate from Canadian Electric Vehicles.
The VW needed more than just a power plant transplant to make it functional: the interior got an upgrade, too.
A reupholstered bench seat folds into a bed and hides the battery box.
Twelve voltmeters on the dash measure each battery’s voltage, an indicator of state of charge. The switches allow real-time control of various fans and certain controller functions.
Twelve Trojan T-1275 flooded lead-acid batteries in a custom enclosure provide energy for propulsion and coach appliances.
Between the batteries and motor compartment hide the two ThunderStruck AC chargers and the main disconnect (center).
In the “motor” compartment: 1. Inverter; 2. DC-DC converter; 3. DC breakers for (L to R) PV array, inverter, DC converter, AC chargers; 4. Curtis controller; 5. Control for AC chargers; 6. 240 VAC input; 7. Throttle control; 8. HPEVS AC51 motor.
A Spyglass meter for the Curtis motor controller displays amps, volts, rpm, and controller and motor temperatures.
EV conversions aren’t usually known for their range, but with on-board PV charging and a little patience, this VW is ready for extended road trips, and luxury camping with electric appliances.
Camping is just a bit cushier with the on-board amenities offered by the PV system.
The Belan kids—Lyric (left) and Brook—enjoy the upper bunk. Mom Kira sewed the tent canvas, while dad Brett designed the pop-up structure.
Time for a recharge—Kira and the kids nap in the upper bunk, while the PV array charges the batteries.
The kids enjoy the view from the rooftop pop-up PV tent. The back sheets on the modules allow ambient light into the tent space.
A Dometic fridge fits between the front seats for easy access to chilled treats.
A custom kitchen includes a sink, potable and graywater storage, and fold-out tables that reveal an induction cooktop.
A JLD404 meter monitors battery performance—displaying volts, amps, and amp-hours.

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.

The Batteries

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.

DC-DC Converter

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.

Regenerative Braking

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.

Web Extras

Find out more about the Belans’ electric VW at

On Facebook and Instagram, find them at Solar Electric VW Bus

Comments (10)

zamboni's picture

The article says Brett consumes 80Ah out of the 150Ah batteries for an 80% DOD. I think i'm not understanding this completely. Wouldn't 80Ah be 53% DOD? Is he de-rating the capacity of the batteries to an effective 100Ah to adjust for the high discharge rate? And if so, is that why 80% DOD is acceptable? I have always read that 50% is the deepest one should take a golf-cart battery. I'm only familiar with lead-acid battery performance in home use, not EVs, so maybe it's different?

Carl Rosenberg's picture

Brett, Your story and conversion it totally inspiring. In multiple ways, your family's personal commitment to 'slowing down', your technical expertise, and attention to detail. Like Allen, I have rode the pacific coast on bicycle and generally had wonderful respect from most drivers. I drive regularly 4000 miles from New Mexico to Alaska at 55 mph, getting significantly better mileage than my speeding neighbors on the road. In this time of limited resources, technology will not save us, we all will serve the planet to slow down and do more with less.
Carl Rosenberg

Kurt Bankord's picture

Wait, isn't 40 mph top speed faster than a gas powered VW van? :-)
But, have to agree that I'd be concerned about the speed differential. Given all the torque of the electric motor, would altering the gearing provide more speed and not use any more juice? Not sure how easy it is to change ratios on a VW. Just a thought if you're not having any issues climbing hills. Very cool build.

Michael Welch's picture
No, wind resistance goes up exponentially with speed--drag increases proportionately with the square of speed. So it's not about the amount of extra energy it takes to spin the electric motor faster, it's about the extra energy it takes to overcome wind resistance.
Kurt Bankord's picture

Good point, although I wasn't saying spin the motor faster, but up the gearing of the drive train.

Michael Welch's picture
Right. Same problem, though. Air drag is the biggest factor in energy use at higher speeds.

This is a very concise, informative and interesting combination of solar PV, storage and usage in an automotive application. Kudos to you for making lower tech tried-and-true components work together.

That said, the mental image of you cruising serenely along at 40 MPH on busy highways with operating speeds of 60 MPH is positively chilling - your rolling roadblock constitutes a clear and present danger to motorists around you.

Your choice to operate in that manner in those conditions endangers you, your family, and everyone around you. Innocent people are hurt or worse when other motorists inevitably fail to account for your imposition of sudden reductions in traffic speed - incidents of following too closely, rapid lane changes, and unsafe overtaking maneuvers are certain to occur.

You are welcome to slow your own pace and enjoy the scenery, but not at the expense of the safety of others. You are in breach of both traffic laws and the unwritten social contract providing for civilized sharing of a common asset - public roads.

Colin McCubbin's picture

Curtis, What a mean spirited put down! If everyone drove slower then a lot less fuel of any type would be consumed for the same distance travelled.

Brett, Great project! Good luck with Phase Two as well! I'm hoping one day retrofit my self converted Pontiac Firefly 'vert conversion from lead acid to lithium iron phosphate batteries, definitely a good choice.

Allan Sindelar's picture

Mr. Kinder,
While I respect your single point - that you disapprove of a slow motor vehicle on a highway - the tone of your comment is painful to me. In your stridency, you sound to me like a judgemental mother shaming a small child.

I have twice ridden that same route on a bicycle with a trailer. It's considered one of the premier bicycle touring routes in the country, yet some sections of the Pacific Coast Highway have no shoulder at all and cars must slow to my human-powered speed while waiting for their chance to pass. Would you also shame me for my joyous human-powered journey, even though I too am 'a rolling roadblock' and constitute 'a clear and present danger to motorists' around me?

If you're willing, I'd prefer to hear you own and offer your opinion as just that, and let go of your implicit message that you're right, the EV family is wrong, and the family should be scolded for moving a a slower pace then most traffic. In my opinion, there's enough room on the roads for all of us.


It was this cringe-worthy phrase in the OP's post that drove me to respond in the manner I did:

"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."

That's a recipe for tragedy - the laws of physics are strictly enforced. Differential speeds kill. Call me strident, mean-spirited, whatever, but it was my intention, and it appears to have succeeded, to call attention to a significant safety concern.

I support EVs and their displacing fossil-fueled vehicles can't come soon enough, but they have to keep up with traffic. Busy public roadways are no place to impose one's own feelings about the pace of modern life. Motorists have a reasonable expectation for safe and efficient movement of traffic.

Though I'm a right-coaster, I've driven the PCH and appreciate its unique place in the US road network. I agree with sharing surface roads (but NOT superhighways) with much slower traffic, be it cyclists, ag equipment, horse drawn wagons, etc, but reasonable precautions must be taken - I wonder if this project vehicle could spare a few Watts to operate flashing amber LED lights whenever it finds itself at a speed below a road's operating speed...

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