Eli5: Amid of soaring gasoline and electricity prices, why aren’t we seeing solar powered cars making to the mainstream?


Eli5: Amid of soaring gasoline and electricity prices, why aren’t we seeing solar powered cars making to the mainstream?

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When it gets dark it wouldnt produce any energy.
So we would stil stick to using big batteries with charging port to solve the problem of nighttime driving.
It would be unnecessary to have build a pure solar car.

solar powered cars also don’t have enough surface area to have enough solar panels to run a car a consumer would want.

at the equator at high noon on an equinox (peak solar power as the sun is directly overhead), there’s around 1000w of solar energy per square meter.

1000w is a bit under 1hp (horsepower).

now consider that extremely efficient (and therefore extremely expensive) solar panels are roughly 30% efficient, you are pulling *tops* 300w (a bit under ⅓hp) per square meter.

if the vehicle in question is pretty big, say 3x4m, this gives us 12m^2, multiply by 300w and we get 3600w in absolutely perfect/ideal conditions, a fair bit less in most normal conditions. this is roughly 3.6hp… less power than a decent lawnmower.

A solar panel on the roof of a Tesla would only produce a few watt-hours of electricity. A square meter of Earth can get perhaps 164 watts of solar radiation, only a fraction of this can be converted to electricity by a solar panel. Even if the reception and conversion of solar energy were 100% efficient, the solar panel would only collect 164 watt-hours of electricity each hour. Put another way, it would only produce 0.164 kWh (kilowatt-hours) per hour. This also assumes optimum conditions—a lower latitude, no clouds.

The battery pack in a Tesla ranges from about 50 kWh (220 miles of range) to 82 kWh (353 miles of range).

Assuming, again, the process was 100% efficient, it would take a square meter of solar panel on the roof of a Tesla 305 to 500 hours of charging to recharge the batteries.

And that is why we don’t have solar-powered cars.

Solar energy is great, but only because it scales well, which isn’t a luxury you get to utilize when it comes to engineering personal vehicles. A single solar panel doesn’t provide a ton of energy, but you can stick thousands of them in a desert somewhere or on top of roofs and boom you can get a decent amount of power output. Sadly we cant stick a thousand solar panels on a car so you are stuck trying to optimize the panels you can stick on or by cutting weight to the car in an effort to make them more efficient. This is why 100% solar cars, which do exist but largely as a college science project, are very small with basically no comfort options. No AC, upholsters seats, Radio, room for a second person, trunks, etc. Despite all this aggressive weight cutting they still have relatively low top speeds. Solar panels just dont have the energy density to be useful on a car.

There’s an issue of weight and aerodynamic shapes not playing well with the cheap flat solar panels currently available.

Solar charging is just reaching the “exotic” car market, because optimizing for weight, aerodynamics and efficiency is expensive, especially without high volume production. The thin lightweight solar cells they use are also quite expensive per watt compared to rooftop solar.

Lightyear zero was just announced – carbon fiber body, solar panels that produce “up to” ~40 miles per day with good sunlight. (Much less if it’s cloudy). Cool $260k list price. Weighs half what a Tesla does and uses relatively low power motors (probably closer to the wheel motors used on some electric mopeds). 4 motors, 0-60 in a stately 10 seconds (about on par with a modern econobox sedan/hatchback)

If they are using the type of thin flexible solar cells I think they are, the 5m^2 of cells is probably on the order of $80k just in solar cells alone.


Technology might some day become more affordable. There are a couple other cars out there that are slightly cheaper and make different compromises to get at least some at least minimal (3 to 45 miles per day) solar charging range (Aptera Sol, Mercedes EQXX, Sono Sion, and options on Hyundai Ioniq and Fisker Ocean)