Revolutionary Better Prius

When I say "make sense", I meant economic sense. If I didn't have to work for a living, I would definitely get the solar option. Assuming that you could get a full charge each day with the solar panel, it would take about 20 years to recover the cost at $3k. But, you know for a fact that you're not going to get good sun every single day for the next 20 years. Also, even if the solar panels were 100% efficient, you can't get 1.0 kwh out of the panels the size of the Prius roof. My estimate is you may get 0.3 kwh out of those panels. I'm being generous with this estimate. So you'll need 10 hours of good sun to get a full charge. Solar makes sense if you're not planning on recovering the cost.

 

Imagining it won't make it possible. The current Prius solar option generates about 30 watts...maximum. Even if you were to more than triple it to 100 watts, at best you'll get 4-5 hours of equivalent full hours on a sunny day considering the angle of the sun, etc. That is 400-500 watt-hours, before the big charging losses you'll have when trying to boost the voltage from~12 volts to 400 (or whatever the battery is). So maybe you'll get 300-400 watt-hours. Enough to about 1.5 to 2 miles.

Mike

 

Only 30 watts? Assuming that I could sell this energy to the electricity company at 14 cents/KWH and we get about 8 hours of sun per day. This would take 244 years to recover the initial cost of $3k.

 

But you can't get 8 hours of sun unless you tilt the car towards the sun. Maybe 4 or 5.
There is (approximately) a double sine curve in effect. First the intensity of the sun coming through the atmosphere varies, low to high (noon) to low with 100% at noon. And if you place the correct tilt towards south at noon, then your panel doesn't get full sun except at noon.

Mike

 

Oh I don't know about that. They are about to test 3D solar cells on the space station. 200% more power than typical solar cells and they claim they can be made cheaper than typical silicon solar cells. Now 150 watts on a Prius Solar Roof does give something to think about. Of course I think the Solar Roof option is closer to 60 watts under ideal situations, but still 120 Watts?

Solar3D - Breakthrough 3-Dimensional Solar Cell Technology

If it works as well as they say, the heck with the space station, let them test it on my roof.

iPad ? HD

 

You should come back down to earth for a few minutes. Space station solar panels get more energy from the sun because they are in space. That's pretty obvious. On earth, a lot of the sun's energy is lost in the atmosphere. The solar panels on the space station are designed to move so that they would face the sun. My guess is that these panels get energy 24/7. On earth, like Mike said, you may only get 5 hours of direct sun light. Besides, I prefer NOT to park my car in the sun because it's bad for the paint. That little energy I'd get from the solar panels isn't worth paying for a new paint job down the road.

 

They get full sun, except for the time they are in the earth's shadow (a.k.a. "night"). The space station is in low earth orbit (205-270 miles above earth's surface).

 

It depends on the orbit, if the orbit passes above the poles then there's no "night"

 

Ha ha yeah they do get a lot of sun and that's actually what I'm far more interested in, their durability and reliability since they see plus and minus temperature swings far greater than they would ever see on earth. That and no UV protection at all in space.


iPad ? HD

 

It still makes the most sense to put solar cells mounted in a fixed place where they get the most sun, their weight doesn't matter, and they aren't likely to be in a crash. I'd like to know the efficiency of boosting 12v DC to ~300v to charge the battery. It has to go from DC to AC, then transform voltage, then DC to AC again.

Mike

 

I think there is a better way to generate electricity from sun light and it already exist. The system uses a whole bunch of gigantic mirrors that focus the sun light to a single point that heat up some sort of industrial oil. The heated oil is then pumped to another system to make steam that turns a turbine to make electricity. I believe this is more efficient than trying to get electricity directly from sun light. If they need more heat, all they have to do is add more mirrors which are much cheaper than solar panels.

 

I think you are confusing issues. Solar thermal plants using liquid sodium are fine...when you have many acres and a crew to maintain such a plant in the desert. But if a person wants to spend several thousand dollars on solar cells they do more good on a house roof than on a car . On a rooftop they can generate more kwh per day and last 20-30 years.

Mike

 

I was trying to say that solar cells aren't efficient no matter where you put it. Certainly, one of the worst place to put it is on top of a car and pay $3k for it. I did a calculation a few months ago, it would take about 10 years to recover the initial cost of solar cells for a house. That's assuming I would get strong sun light 365 days a year.