# solar panels on a car?



## alterego (Jan 27, 2013)

Why is the hood, roof trunk lid, doors, of a chevy volt not made up of solar panels.

I was down to the fair and seen the lattest 30" x 60" approximate 350 watt solar panels, 

And wondered, why are the electric cars not equipped with solar cells all over them? 

This seemingly would be an easy retro fit as well for a body / fab shop.

I bet with a little size selection, you could get, 

two on the roof,

Two on the hood

one on the trunk

And one on each door.

6 x 350 equals 2100 watts,

If I parked correctly at work I believe you could charge the thing in good weather, these panels as they are 400 a panel would be 2400 cost on an electric car, if they were integrated into the design, probably half of that.

Geez, am I the only person thinking here, come on.


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## Ripon (Dec 22, 2012)

I think there is a market for them to do it by cell not by panel. Incorporate cells into the fit / finish to add power. They could even give consumers instructions on where to park to get the most juice. The area (size of the hood, truck, roof) is not enough to give the car a real charge but every little bit should help.

That said I still have 2 issues with electric cars. One is that we should not subsidize with tax dollars a $40,000 vehicle. People that can afford a $40k car need to pay up. Two is the that it can cost us a lot in terms of electricity and the burdens of the later. MOST people I dare say are not aware of electricity costs. I pay .155 cents per kilowatt hour because I'm in a subsidized power district but others here in CA pay upwards of .33 cents a kilowatt hour. Meanwhile folks in Oklahoma and Texas (I hear they are the least) might be paying under .10 a kilowatt hour. Right now electric car sales are minor, but what happens as they grow and need more juice + our nuclear power plants are aging out which means less juice. This combination is ripe for "supply demand" problems. That can impact us all.

PS these richfolks that can afford a Volt, BMW, or whatever that's pure electric - make them put in a solar system to fuel the bugger.


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## HuntingHawk (Dec 16, 2012)

Debris that normally strikes a vehicle that you think little about would seriously damage the solar panels. Even dirt or sand kicked up by wind will degrade the panels.


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## Chipper (Dec 22, 2012)

The panels need to be point towards the direct sunlight. So if they are on top of the car they would only be working at 100% at noon. Suppose you could open or close the hood and trunk every couple hours.


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## Prepadoodle (May 28, 2013)

The problem is that 1 horsepower equals about 750 watts. (745.699872 w if you wanna be picky) So 2100 watts is only about 2.8 HP.

Since they wouldn't be oriented right, you would expect maybe half this. You also lose power in the wiring and when you convert or regulate the voltage. In the end, you would end up with just over 1 HP on a sunny day, and the panels/cells are kinda heavy. You would have to cart this weight around at night and in rain, and at other times when the sun isn't out. You wouldn't see a net gain from putting panels on a car.

Yeah, thin film and other super light cells exist and would change this a little, but probably not enough to make it worth doing. A better solution might be to roof parking lots with solar panels and let each parking slot plug in to recharge. The excess power could go to the grid.

An idea I have been playing with is to design electric cars that use snap-in modular batteries. These would weigh like 20-25 pounds and each give you about 10 miles. Your trunk would hold maybe 10-20 of these in a rack. Existing gas stations could have solar or wind powered chargers (or charge off-peak to even the loads) and would allow you to swap your discharged batteries with fully charged ones for a fee, much like you would exchange a propane tank. This would give electric vehicles unlimited range, and keep the gas stations in business as we transition from fossil fuels. This would be better than going with a fuel like hydrogen because it wouldn't require us to build a whole new distribution infrastructure.


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## HuntingHawk (Dec 16, 2012)

Chipper said:


> The panels need to be point towards the direct sunlight. So if they are on top of the car they would only be working at 100% at noon. Suppose you could open or close the hood and trunk every couple hours.


Even then it may not be 100% because of the longitude of the sun changing from month to month.


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## pharmer14 (Oct 27, 2012)

alterego said:


> Why is the hood, roof trunk lid, doors, of a chevy volt not made up of solar panels.
> 
> I was down to the fair and seen the lattest 30" x 60" approximate 350 watt solar panels,
> 
> ...


This is done aftermarket... Look up mountain view solar. I used to drive 522 through Berkley Springs WV on my way from my parent's place in PA to my apartment/school in VA and passed one along the side of the road as an advertisement all the time... I've also seen one in downtown Winchester too...

My guess is that it's cost prohibitive for most people. The Volt itself is incredibly expensive. In my opinion it should have been released as a Cadillac instead of a Chevy because of the cost, but that's for a different discussion.


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## pharmer14 (Oct 27, 2012)

Actually MTV Solar's vehicle is a Leaf and not a Volt. But as others have said, I'm not sure it would be effective. My guess is that the "panels" I've seen are just a clever paint scheme and the solar charging stations they build are fixed to the ground.


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## HuntingHawk (Dec 16, 2012)

You miss one important point in your thinking. That is the battery voltage of the car. Seems 96VDC is common. So if you are talking 350 watt panels (assuming 12V panels) you would need 8 in series to get the 96 volts & still only be adding 350 watts maximum.


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## HuntingHawk (Dec 16, 2012)

This maybe alittle off topic, but there is an older couple out where I live that have a 48VDC electric golf cart. They use the cart for checking their mail at the end of the road & such. They have a pair of 240watt 24VDC panels set up for solar charging their cart.


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## Prepadoodle (May 28, 2013)

Watts are a unit of power. P=IE, where P is power in watts, I is current in amps, and E is potential in volts.

A 2100 watts of solar at 15 volts will produce 140 amps because 15 X 140 = 2100. If you fed this into a 96 V system, you would see 21.875 amps, but still have 2100 watts because 21.875 X 96 = 2100. In other words, the power has to remain constant, so if you increase the voltage, you have to decrease the amperage. Power is the ability to do work, and that ability isn't affected by the voltage.

Look at any motor rating. A 1 HP motor will draw twice as much amperage at 120V than it will at 240V, but it's still a 1 HP motor. (a horsepower is another unit of power, and is equal to about 750 watts)

Edited to add:

A 240 watt panel at 24 V will put out 10 amps. 2 of them will put out 480 W, which would be 20 amps at 24 VDC if wired in parallel, or 10 amps at 48 VDC if wired in series. (24 X 20 = 480; 48 X 10 = 480)


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## Montana Rancher (Mar 4, 2013)

My only input is google "stick on solar panels" which would be a super effective addition. Yes it will not power the car but why the hell not do it?

Put a MPPT charge controller on and I would expect a better return on investment than the coat of the panels.


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## pharmer14 (Oct 27, 2012)

Montana Rancher said:


> My only input is google "stick on solar panels" which would be a super effective addition. Yes it will not power the car but why the hell not do it?
> 
> Put a MPPT charge controller on and I would expect a better return on investment than the coat of the panels.


I say mount a windmill on it and kick it into neutral when going downhill...


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## alterego (Jan 27, 2013)

Solar-Powered Cars Hit The Racetrack : NPR


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