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Would having solar panels on the roof and hood of the Tesla give it even more range?

Would having solar panels on the roof and hood of the Tesla give it even more range?

How much more range? Would it be worth it?

Watt fun | 7 juin 2015

No, and it wouldn't. You might have enough energy to run an automatic hot air extractor fan as other car have installed, or to charge a small battery that powers up small LED lights and gauges. You need about 333 watts per mile, plus charging and converter losses.

bsherry2718 | 7 juin 2015

Well, I wouldn't outright say it's not worth it. Let's do a quick back-of-the-envelope calculation of a best case scenario: let's take a Model S sized solar panel, say 10 square meters. Let's assume 100% efficiency of the panel and assume that you're in a sunny part of the world, you get maybe 6 kwh/sq meter each day. That's 60 kwh per day falling on the panel. Considering that the Model S drains it's 85 kwh pack in a few hours of highway driving, this is most definitely NOT enough to run the car, and that's under impossibly good conditions.

That being said, say you realistically can only capture 5% (I'm pulling this figure out of my ass) of that energy. That's still 3 kwh per day, which would give you about 10 miles each day, without you doing anything. My round trip commute is just over 10 miles, which means I would rarely have to plug in the car for normal daily use. And it's about half of the average commute, which is still pretty substantial.

As solar panels get cheaper and more efficient, this very well could become an economically viable option for reducing your dependence on the grid for daily driving, even if it is useless for powering the car on a road trip.

bsherry2718 | 7 juin 2015

It just occurred to me that by the time solar panels are cheap enough, there may well be enough sustainably powered public charging stations around everywhere you go that this may be a moot point. I guess we'll have to wait and see.

DTsea | 7 juin 2015

You could only get about 2 m2 of panel at 10% efficiency times sine of sun angle.

No no no no its a waste.

bsherry2718 | 7 juin 2015

@DTsea Let's take your numbers. For 2 square meters, that's 12 kwh per day falling on the panel. Let's take the angle of the summer sun in the middle of the US, say Denver: about 70 degrees. That yields over 1 kwh per day. About 3-4 miles. It's my estimation that most people could go two weeks without charging their Model S, in that time period, you would get an extra 50 miles or so.
I'm not saying this would be a big step up in Model S technology, but hell, Tesla tries to squeeze every last drop of energy out of their batteries (just think about the cameras instead of side mirrors), and given that solar panels will become dirt cheap and far more efficient over the next couple decades, I'm still not convinced it's an idea we should discard just yet.

DTsea | 7 juin 2015

3 to 4 miles per day.

11 cents worth of electricity. In the summer.

That would be about $180 worth per year.

For a $5000 option.

Silly.

Brian H | 8 juin 2015

Groan. A hamster wheel in the frunk would work better.

jordanrichard | 9 juin 2015

Are we forgetting one tiny detail, there isn't a flat panel on the Model S. From my admittedly limited knowledge of solar panels, though there are flexible panels, they are not as efficient as the solid ones. You also then have to consider the additional weight.

One other detail, look at the incredible job Tesla did in building the Models S, we can all agree Tesla knows what it is doing. If simply putting some panels on the car would improve things, don't you think they would have done it?

It's like people believing that putting a K&N air filter in the ICE car is going to increase horsepower and fuel economy. Car companies spend millions of dollars developing and refining their engines to improve mpg. If it was a simply as dropping in an oil soaked air filter, wouldn't they have done that?

Bubba2000 | 10 juin 2015

Tesla could cover the Model S with multi-junction solar cells and may be get a max efficiency of 30-40% at best. However, the cost of the cells, wiring, power control would be way to hi. Better off installing the solar panel in the roof and charging the car battery.

I am wondering if Tesla can reduce the weight of the MS using composites, improved metallurgy, structural design refinements? How about aerodynamics, especially underneath the car, wheels + covers, nose cone, etc? Hide windshield wipers?

Any materials, aircraft experts in the boards?

Timo | 10 juin 2015

MS already has pretty close best CD of all mass-produced cars. Not much what you can do to make it even better without sacrificing function.

Material techs advance currently really fast, so there you can get better. Good thing is that SpaceX benefits even more from best materials possible, and from there new inventions get to Model S as soon as they get affordable to make. Key thing there is the cost of using these "better materials" when mass-produced. You need to be able not just make them cheap, you need to be able to make them cheap and fast.

wildcatzoo | 10 juin 2015

Bubba2000 the Tesla is already the most aerodynamic vehicle on the road.

Using more carbon fiber would be lighter but that is about the only thing right now that would be helpful. Tesla used a lot of that in the Roadster, but it is far more cost effective to use the aluminum that the Model S has.

As for the Bsherry comment on the side mirrors and squeezing miles, at high speeds those create huge amounts of drag - so much so that many auto makers have sought the same solution.

Tesla actually gets a better MPG rating for highway driving than for city use. That is due to the design.

Adding a small solar panel to maintain the 12 volt battery charge would likely be worth the weight and cost, but for most users it won't matter at all.

DTsea | 11 juin 2015

Bubba, the weight of the body in white is probably under 1000 lb so aluminum to carbon weight savings will be modest as percent of gross vehicle weight.

Bottom of car is already flat so not much gain available there.

Mike83 | 11 juin 2015

All you have to do is outfit a blimp with PVs connected to the car and have one of those dog leashes that pulls out when you accelerate and retracts when synchronous velocity is reached . There problem solved. ;-D

Brian H | 12 juin 2015

Bubba;
Have you seen a MS? The wipers are hidden except when wiping.

Red Sage ca us | 13 juin 2015

DTSea: According to the MegaFactories documentary for the Fremont facility, the aluminum body and frame for Tesla Model S weighs ~400 lbs.

Captain_Zap | 14 juin 2015

As for the solar panels on a car, that was one of Fisker's follies.

@Red Sage

I had that number verified by another source at Tesla.

DTsea | 14 juin 2015

Thanks red sage.

Then a carbon body would indeed be a very ineffective way to improve range.

Red Sage ca us | 15 juin 2015

Yes. It is also why I sincerely hope the Model ≡ is of wholly aluminum construction for chassis and body. Tesla Motors already gets their aluminum sheet metal from Alcoa. It turns out that Ford Motor Co also has the same supplier for the F-Series pickup trucks, which switched to aluminum bodies. I would think that Alcoa would rather maintain their relationship with Tesla by being the supplier for Generation III vehicles as well as the high end Generation II rides. The publicity afforded Alcoa for supporting the best selling pickup truck and the best selling EVs would be a definite plus, and a victory over the steel industry.

DTsea | 15 juin 2015

Alcoa is a pure profit driven company. They dont care about publicity and supporting this or that. They do care about getting patens and charging as much as they can get.

Red Sage ca us | 15 juin 2015

Just speaking as someone who's entire Paternal Family Tree hails from Alcoa TN is all...

ALCOA CAN'T WAIT!!!

DTsea | 16 juin 2015

What does that mean red?

Brian H | 16 juin 2015

I hope Tesla installs their own micromills (new Alcoa invention).

MitchP85D | 16 juin 2015

I don't know if Yahoo is reputable enough, but I read an article from there that Tesla will use steel for the Model E to keep costs down. Considering the source, take it as a grain of salt.

Red Sage ca us | 16 juin 2015

A lot of people presume that Model ≡ would be constructed with a steel frame and body panels. In an interview, the Tesla Motors executive in charge of production only said it would be made of 'appropriate materials'. Elon has been loosely quoted that steel construction is not out of the question.

So, yeah... This is very much wishful thinking on my part. I believe the Model ≡ should be... Special. That will always guide my expectations for Tesla Motors.

It is enormously tough to hit all markers at once. But I hold out hope that it may happen. It is very much a matter of magnitude. Critics, Naysayers, and Realists alike are unhappy with my expressions of faith. That's fine, because I am equally peeved by the League of Lowered Expectations.

I think that too many simply don't realize that Tesla will never release a wimpmobile. They expect so little of the Model ≡, that they don't realize that is a direct result of what traditional automobile manufacturers have been conditioning them to believe about EVs for decades. So, with an eye on their minimalist expectations, I purposely aim higher - much higher.

Bikezion | 17 juin 2015

More range? Very little. Worth it? Not at all. Put the solar panels on the roof of your house.

Steel is 3 times the strength, and 3 times the weight of aluminum. If Tesla can use 1/3 the material, it should be the same strength and same weight. (they do have to use slightly more than 1/3 the material).
A high end chromoly steel bike frame, and a high end aluminum bike frame, are very similar in strength, and weight. A carbon frame is slightly lighter, but only lasts a few years.
Steel (for cars) is about 1/5 the cost of aluminum.
It'll be interesting to see what the do.

03Insight | 18 juillet 2015

Do Tesla vehicles charge when coasting? This is "regenerative breaking"?

ian t.wa.us | 18 juillet 2015

Yes.

Except it's called regenerative "braking" for a reason. That being the fact that it is actually slowing you down. Which, of course, some don't consider to be true coasting.

Larry@SoCal | 19 juillet 2015

Ian, you are correct of course.
However on long downgrades - Grapevine Pass in CA - you can generate power, yet maintain a constant speed.
~Larry

Maxxer | 21 juillet 2015

@Bikezion

You got it all weong. Aluminium frames lose stiffness over time while carbon frames do not.

As long as you have monocoque frames without floppy junctions you won't have loss of stiffness on a high quality carbon to resin ratio frame.

jgk76 | 21 juillet 2015

We've had convertible roof cars for how long now?

A parked Tesla should take a spot away from other cars so it can deploy its solar array, larger than the car itself. And when cars are getting too close, some are folded/retracted.

And let's not leave it there. A wind tubine can take many shapes, and of course also compactly folding ones. On a windy night, get some green energy that way. Just using the outlet doesn't make the car green as can be.

DTsea | 23 juillet 2015

Evolution. Where do you get the idea that aluminum structure loses stiffness over time?

Remnant | 26 juillet 2015

@ Bikezion (June 17, 2015)

<< Steel is 3 times the strength, and 3 times the weight of aluminum. If Tesla can use 1/3 the material, it should be the same strength and same weight. >>

The UltraLight Steel Auto Body (ULSAB) is a lighter, stronger automotive body structure that offers greater fuel economy and costs no more to build than current vehicle body structures.

Check: http://www.bluescopesteel.com.au/go/news/ultra-light-steel-auto-body-uls...