A Solar Powered Car From Toyota? Maybe Partially Solar Powered

Reports are circulating today that Toyota is secretly working on a completely solar powered car, citing The Nikkei. Here’s the take from the Associated Press.

“According to The Nikkei, Toyota is working on an electric vehicle that will get some of its power from solar cells equipped on the vehicle, and that can be recharged with electricity generated from solar panels on the roofs of homes. The automaker later hopes to develop a model totally powered by solar cells on the vehicle, the newspaper said without citing sources.”

Something may be getting lost in the translation. I can see the first part being true. Toyota could put solar panels on the roof of the car to power some internal electronics. Fisker is doing that with the Karma and General Motors has put solar panels on the roof of some incredibly ugly concept cars, so it’s technically feasible.

The solar panels could even provide some power to a lithium-ion battery pack. A full recharge would take several hours but you could imagine solar panels on the roof of a plug-in a sunny parking lot getting some juice like this. (That brings up the problem of early battery degradation from too many charges but let’s save that for another time.)

I could even see a car that could be partly charged be stationary solar panels (A recharge would take time, but technically it’s a piece of cake.). But to completely power a car with solar panels that it carries around on its own would take one massive solar array to charge in a reasonable (seven hours) amount of time. The Tesla Roadster has a battery that needs to provide 200 kilowatts of power and/or store 50 kilowatts of power, for example. A solar array to feed a battery of that size adequately would be bigger than most of those found on homes.

Concentrators—which could reduce the square footage of solar cells needed would be tough to apply here too. They need a direct angle of sunlight so you’d have to rotate the solar cells on the car roof. Thin film? Low efficiency.

Plus, there are the power requirements for acceleration and freeway speeds. That’s why today’s solar powered cars are golf carts used in retirement communities. They top out at 15 miles per hour or so. It would be a lot easier to charge the car from stationary solar panels built into a garage or a building.

Another suspicious bit: I haven’t been able to find a translation of the Nikkei article yet. So expect updates.

Technically speaking, however, all Toyota vehicles are solar powered. The energy from petroleum comes frmo decayed plant and animal matter, which originally got their energy from the fiery orb in the sky.