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The PV EV RV: A Mechanical-Engineering Question for Solar-Electric Vehicles

Left: rigid, glass panel. Right: thin film flexible panel. 

First, here's a quick recap of my solar-electric VW bus conversion.

With the advent of thin, semi-flexible solar panels weighing in at just 6 pounds per 150 watts, the weight limitation of solar panels on vehicles has been lifted. For the weight of a well-fed man, a solar-powered vehicle enthusiast can include a level two charger on board. That’s over 6,000 watts of charging power. On my electric VW bus, that’s a full 100 miles of range in 5 hours of direct solar exposure. (Tracking the sun at all would give the opportunity to grab significantly more miles per day.)

That’s wonderful, but there is a catch: surface area. 5 kilowatts of solar panels would require five 1,000-watt arrays, one on each side of the van, plus the center. Obviously, now with a 15-foot width and some extremely floppy panels, we would have a problem. But what if we fold the panels in? We can then stop, unfold, and charge while we have lunch or enjoy a river swim.

Better yet, with all this unfolded surface area, we have a large shade roof. If I set it up as it is in my mind: a Solar-Electric Transforming Tiny House! It’s an off-grid mobile tiny home with all the electricity you need to heat, cool, light and then drive! In other words, we have a photovoltaic electric-vehicle RV, or "PV EV RV"!

Moving the Solar RV Project Forward

Phase 1

Work has begun on Phase Two of the project. Phase One, however, was a success and would likely be more appropriate for some folks.  The focus of Phase One was cost and the interest of supplying moms and their local transport to and from school, the grocery store, etc.

Currently, my wife is driving Phase One of the solar-electric bus. She sets a timer to have the bus heated when she and the kids get in. She tries to park in the sun when possible. It’s great to see the bus being used in a practical situation. It is a real solution.

The cost for this conversion was around $25,000. I put in many extras and, as a result of it being the “first-time” build, I spent more to get over that hump. If I was to refine the process and lean out on the parts, I could have built this bus for $10,000 to 15,000. Phase One is a financially feasible workhorse!

Phase 2

That said, let’s spend some money. If an individual was not entirely concerned about cost and wanted more the freedom and versatility that getting out beyond the charging stations offer, then immediately one would look at battery pack. The lead-acid pack came in at $2,800. The lithium iron phosphates, which would double storage (range) and reduce the vehicle weight by 500 pounds, comes in at $12,000. Then we have a 100 mile-per-charge RV!

Now there is no need to build a sealed battery box or vent it. A cooling fan would be wise, but other than that, it makes putting the phosphates in much simpler.

Now let’s talk solar. Chinese semi-flexible solar panels come in at about $2 per watt if purchased in bulk.  For 6 kilowatts, that’s also $12,000 — what a coincidence. However, as a result of the Chinese influx of cheap solar panels, tariffs have been imposed on these panels. You could likely get a sizable bill in the mail from the U.S. government after your initial purchase.

Some companies have a 250% tariff on solar panel purchases. It’s worth doing your homework. Using a custom shop like Solbian out of Italy would ensure quality without fear of Tariff. However, I’ve been quoted as much as $800 per 150-watt panel going this route. This would be $32,000 for 6 kilowatts. Granted, they can make these panels custom, and I’m sure with great quality, however $32,000 just for solar panels is a little beyond the financial reach of most of us. (Sponsors?)

Either way, for a $24,000 upgrade, one could drive and live completely on sunshine with an impressive range and an on-board power source. If we lean down the initial cost of the conversion, we are at total of about $35,000, not including labor.

Left: lead acid battery. Right: lithium iron phosphate battery 

Finally

At this point, I’m compelled to face the labor and basic material cost portion of the build. I’m a mechanical engineer working in the alternative energy world now for 20 years. I did all the work myself, from cutting the metal for the top apparatus to wiring up the motor. With this included the cost of the Phase Two vehicle climbs high, likely over $100,000.

Given the circumstances, I would recommend a project like this only to experienced electrical and mechanical engineers for feasibility as well as safety reasons. If you have a friend with this education and experience to guide you, go for it! I will continue to offer guidance so others can enjoy the solar-electric freedom as I have. Education must commence for us all to be more free. In the next blog post, we will be covering motor selection. Check out more specifics on my website: www.solarelectricvwbus.com. Have fun!

Photos by Kira Belan 


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