How close are we to a solar powered car?

[sensij]

OK, how about this. The road down from my cabin goes from 5500 ft to 1000 feet in 10 miles. Could the alternator charge the battery enough to get back up the hill?

The convention is to use comic sans font when posting in jest.

[Sunking]

My chevy spark ev is around 250 w / mi if i stay off the highwsy, but that doesn't change your main point.

Yes there are exceptions, but if you look at all of them as a whole, 300 to 400 is a good estimate. Heck my 780 pound golf cart with my butt parked in it only gets roughly 130 to 150 wh/mile.

The main point is no matter what efficiency panels go up to, you still hit the brick wall of not having enough space to place enough panels. Even if you can over come that, weight and drag now bite your ass.

Here are the Numbers on my cart

Gross weight, me in it with cargo 1050 pounds.
Cd or coefficient of drag = .5
Frontal Square area = 16/ft2
Speed = 30 mph

Takes 1.47 hp to overcome air drag, 1.09 to overcome weight and rolling resistance on flat paved surface for a total of 2.56 hp

To go 60 mph it takes 11.8 hp to overcome air drag, and 2.18 Hp to overcome Rolling Resistance and Weight for a total of 14 Hp

So which is more efficient?

[DerGiLLster]

So what would a small solar panel on the roof of a car do at best? About a mile every couple hours?

[lkruper]

So what would a small solar panel on the roof of a car do at best? About a mile every couple hours?

Between 10AM and 2PM.

[bcroe]

Between 10AM and 2PM.

And on level ground.

[sensij]

Yes there are exceptions, but if you look at all of them as a whole, 300 to 400 is a good estimate. Heck my 780 pound golf cart with my butt parked in it only gets roughly 130 to 150 wh/mile.

The main point is no matter what efficiency panels go up to, you still hit the brick wall of not having enough space to place enough panels. Even if you can over come that, weight and drag now bite your ass.

Here are the Numbers on my cart

Gross weight, me in it with cargo 1050 pounds.
Cd or coefficient of drag = .5
Frontal Square area = 16/ft2
Speed = 30 mph

Takes 1.47 hp to overcome air drag, 1.09 to overcome weight and rolling resistance on flat paved surface for a total of 2.56 hp

I had an efficient day yesterday, 57.4 odometer mi needed 4 hours @ 3.3 kW to recharge last night. Drive was round-trip (symmetrical), not especially flat. (4 * 3300) / 57.4 = 230 Wh/mi. 31 mi of that was on the highway with cruise at 65 mph (sort of safe to do in the HOV lane). The day before, I had hit it for 12 min with a DC Fast Charge (50 kW)... it seems like if I do that every couple weeks, the battery gets more efficient for a few days, but it might just be a software thing that is tricking me. I haven't watched it close enough yet.

Published Cd = 0.326, Gross Weight = ~3230 lbs as driven. 19 kWh battery is routinely good for 85-90 mi, with 3500 mi on it so far.

[J.P.M.]

I had an efficient day yesterday, 57.4 odometer mi needed 4 hours @ 3.3 kW to recharge last night. Drive was round-trip (symmetrical), not especially flat. (4 * 3300) / 57.4 = 230 Wh/mi. 31 mi of that was on the highway with cruise at 65 mph (sort of safe to do in the HOV lane). The day before, I had hit it for 12 min with a DC Fast Charge (50 kW)... it seems like if I do that every couple weeks, the battery gets more efficient for a few days, but it might just be a software thing that is tricking me. I haven't watched it close enough yet.

Published Cd = 0.326, Gross Weight = ~3230 lbs as driven. 19 kWh battery is routinely good for 85-90 mi, with 3500 mi on it so far.

Practical, real world info. Was the A/C on for the trip ?

[sensij]

Practical, real world info. Was the A/C on for the trip ?

Something like 5-10 min of real A/C initially on the return home, to cool it down after being in the sun all day. Mostly just the fan on low, for circulation, but not actual conditioning. The window was open (with no fan) on some of the non-highway stretches. When A/C is on for the entire ride, the computer indicates 10% of the energy consumed goes toward climate control.

If I make that same drive as I drove my previous car (approaching 80 mph on the highway), the range drops into the 70's. Rain really hurts the range too, even at lower speeds.

[UkiwiS]

So, if one drives less than 2920 miles per year and less than 8 miles round trip per day, a solar powered car is feasible?

My numbers were extrapolated based on my very limited real life experience with my car and with my PV system which was powered on 2 weeks ago.

The numbers for generation were based on a good day.

On a bad day such as 7/18, my 18 panel system produced 9.273 kWh or about 0.5 kWh per panel.

The hypothetical car with 1 panel on the roof would have been able to travel 2 miles.

I'll let you can come to your own conclusions re feasibility.

[J.P.M.]

Something like 5-10 min of real A/C initially on the return home, to cool it down after being in the sun all day. Mostly just the fan on low, for circulation, but not actual conditioning. The window was open (with no fan) on some of the non-highway stretches. When A/C is on for the entire ride, the computer indicates 10% of the energy consumed goes toward climate control.

If I make that same drive as I drove my previous car (approaching 80 mph on the highway), the range drops into the 70's. Rain really hurts the range too, even at lower speeds.

Interesting. Thank you.

[SunEagle]

So what would a small solar panel on the roof of a car do at best? About a mile every couple hours?

There was a car made by Fisker Karma that had a solar panel roof. The panel did not help much in charging the battery but could help boost power to the AC system when the car was sitting in direct sunlight.

As for new technology there is a "race" going down in Texas with a number of solar cars running a specific distance.

Solar Car Race.

[Sunking]

So what would a small solar panel on the roof of a car do at best? About a mile every couple hours?

You would not go anywhere. Just sit there and bake in the Sun because a panel does not have enough Specific Energy Density to even make the car budge. A single 200 watt solar panel at full power at noon is less than 1/4 hp, about as much energy as you can generate pushing the damn thing. You need several thousands of watts or several horse power to accelerate and get rolling.

[Mike90250]

Or telecommute! The other think I was thinking about is that it is not necessary to have all the panels on the car for it to be solar powered. It can be parked in a car port with solar panels on the roof when it is not being driven.

Exactly, people on the night shift have it made! Charge all day in a carport, drive half the night.

[lkruper]

Exactly, people on the night shift have it made! Charge all day in a carport, drive half the night.

I have never looked into EVs. Can they be charged directly from a CC?

[sensij]

I have never looked into EVs. Can they be charged directly from a CC?

Not really. There are high power direct dc chargers, but you need commercial equipment and proprietary protocols to make that work. The charge port accepts AC... the actual charge circuitry is in the car itself, not at the station. You could charge a car with a standard 120 V or 240 V inverter hooked up to (really big) batteries, though. At 240 V, most cars today want 6.6 kW, some (like mine) will only take 3.3 kW. A few are up at 10 kW.