New EPA sticker are announced for feedabck

[raymond]

By 2020, the same EV will use much fewer kw-h to move it, so it should get a better grade.

Will it? The efficiency of charging, battery storage, DC/AC conversion and the motor leave some room for improvement, but when these components at 90+% efficiency, that room for improvement is pretty tiny.
Unless you're going for an Aptera or E-bike and don't expect EV efficiency to change that much. Ever.

Any thoughts on this?

 

[kgb]

I find it hard to believe - but it would be nice if true - that 90% of the power that comes out of the socket, through the battery, gets applied as motion at the wheels.

 

[raymond]

I find it hard to believe - but it would be nice if true - that 90% of the power that comes out of the socket, through the battery, gets applied as motion at the wheels.

Unfortunately it's a little worse than that. Charging is e.g. 90% efficient, and so are the batteries, the DC/AC converter and the motor. All in all these could add up to 0.9*0.9*0.9*0.9 ~= 65% efficiency. (The 90%'s are guesswork on my part.) Improvements will be made, but - and maybe that's my fault - I find it hard to imagine a motor producing 15kW without producing any heat.

But an efficiency gain from 65% up to 80%(?) may be possible, and that would be a Good Thing!

 

[kgb]

But an efficiency gain from 65% up to 80%(?) may be possible, and that would be a Good Thing!

I rest my case.

 

[edo]

There can be room for improvement even if 100% of the energy went to the wheels.

There would still be air friction and regeneration losses (of course, if you have 100% efficient generation of kenetic energy, the absorption should be pretty close.).

 

[mt2]

For me, the bottom line is that vehicles will continue to be different to attract buyers. The aerodynamics, weight, rolling resistance and performance all play a part. I stick to my point from earlier that the bands will narrow to where the grading system will have to be recalculated eventually. But if updated properly, I don't think it will become irrelevant.

 

[vfx]

Isn't this the point?!

http://www.mnn.com/transportation/cars/stories/no-letter-grades-on-new-cars-house-lawmakers-say

 

[DrComputer]

What? A Tesla (or other efficient electric car) might get an A+ while a Surbaban might get a D. We can't let that happen. We can't let consumers know what they are actually getting. That might lead people to actually use their brain to make intelligent choices. Never, I say never!

 

[TEG]

Extreme window sticker: Tesla Roadster rated 111 MPGe

Extreme window sticker: Tesla Roadster rated 119 MPGe

 

[vfx]

I know it says "yet" but it's sweet that the Roadster is the highest mileage car in the world.

Probably have to say mass produced or sumtin'

 

[doug]

They nixed the letter grades.

 

[mt2]

I don't like the way Consumer Reports clarified that zero emissions does not consider how the power is generated. Sure, they pointed out that how clean the electricity is generated depends on where you live. But if you are going to invoke the long-tailpipe discussion, you should frame it as well-to-wheel and point out that gasoline production has emissions also.

I understand where Consumer Reports is coming from. They felt compelled to point out that a perfect 10 for emissions doesn't mean there aren't downstream emissions. But it is certainly out of context of the article to get into the whole 'electricity is better than gas' argument. So at least refer to Tesla Motor's well-to-wheel research and play it down as something they haven't independently verified.

I would have commented, but I let my Consumer Reports on-line subscription lapse.

 

[vfx]

Good point Mark. Also it does not mention that a homeowner can generate their own power.

 

[Slackjaw]

"Extreme Window Sticker" for EPA 119 MPGe rating

This actually has some useful info on it and might save a few minutes of Tesla Time if people can read it for themselves...

Extreme window sticker: Tesla Roadster rated 119 MPGe

Text of article:

At an event in Palo Alto this afternoon, the Environmental Protection Agency (EPA) released its highest mileage window sticker yet - for the Tesla Roadster.

The sticker for the Roadster 2.5 shows 119 miles per gallon equivalent: 112 MPGe on the highway and 124 MPGe in the city. In addition, it shows the Tesla Roadster will go 245 miles on an eight-hour charge. The EPA’s 245-mile figure is what Tesla uses for its own range claims. (We haven’t tested the $120,000 sports car, so can’t vouch for either the range or energy usage figures.)

I love the way the sticker says "The best vehicle rates 99 MPGe" right next to the 119 MPGe. So it means the Roadster is "Better than the best".

P.S. If anyone can find a high quality PDF of that sticker please post a link. I can't find it but would love to have a few to hand out!

[Edit: P.P.S... Sorry, only just saw the original thread by vfx on this. ... Admins can delete this new thread if desired]

 

[vfx]

The Roadster gives 120 percent!

 

[eeenmachine]

I'm going to print this out to display on my roadster at an electric car show in Encinitas, CA tonight. Anyone been able to find a higher resolution image?

 

[tdelta1000]

That report puts Tesla Motors on top with the Roadster 119 MPGe rating and it validates the claims of going 245 miles on a single charge.

 

[strider]

Hmm. Also, on PG&E's EV rate, I'm only paying $0.056/kWh when charging at night so my savings would double! And it looks like the benchmark gas price is $3.70/gallon so in Cali there's more savings there as gas costs more than that here.

 

[AndrewBissell]

Isn't it amazing that the most energy efficient car on the market is also one of the best performing. Really rams home the fundamental advantages of electric drive.

 

[TEG]

Isn't it amazing that the most energy efficient car on the market is also one of the best performing. Really rams home the fundamental advantages of electric drive.

Hmm. Also, on PG&E's EV rate, I'm only paying $0.056/kWh when charging at night so my savings would double! And it looks like the benchmark gas price is $3.70/gallon so in Cali there's more savings there as gas costs more than that here.

Win! Win!