Bad news from Tesla: Original range target won't be met!
In a letter sent out to their first batch of 380+ customers a few days ago Tesla Motors has some bad news. They will be coming up a little short on their original 250 mile range target. One surefire thing about developing a new vehicle is that the car you end up with almost never be exactly like the one you initially designed. During the course of testing almost every part usually ends up getting some degree of redesign. Things rarely go exactly as planned. So Tesla is real car company as well.
All that testing that Martin Eberhard talked about in our interview a few weeks back has had the desired effect of shaking out problems before they get into customer hands. The downside is that addressing those problems has added some weight to the roadster, to the tune of several hundred pounds in this case. Unfortunately since batteries make up such a large proportion of the mass of an electric car, this extra weight has negatively impacted the range. In addition, in order to help ensure the durability of the battery pack over the life of the car, they went with a cell formulation with a little less capacity but better long-term endurance.
The bottom line is that once they got the Roadster onto an EPA compliant dynamometer to run the official city cycle, the numbers came up shy. Tesla isn't quoting final figures yet until they finish testing the final validation prototypes, but they still expect them to come in at greater than 200 miles. If they manage that it would still put them well ahead of any previous production electric vehicle. The ABG Garage door is always open if Tesla needs someone to accumulate some real world test miles. It's nice to see a company be so open about their development process and all the details from Tesla are after the jump.
[Source: Tesla Motors]
Media Briefing – April 12, 2007
Darryl Siry
VP Marketing
Tesla Motors
Tesla Motors has achieved some significant milestones recently. The first of our Validation Prototypes (VPs) recently arrived in San Carlos. This car represents a significant step forward toward real production cars as it implements corrections to problems discovered in the Evaluation Prototypes (EPs), hard-tooled components for all body panels, production headlights and taillights, nearly-production interior components (including much more comfortable seats), and many other subtle changes.
We continue to test the Roadster prototypes, and recently performed our first actual driving range tests on an EPA-compliant dynamometer. Based on the results of these tests, we need to revise our initial range estimates downward. We now anticipate that the range of the Roadster will still be greater than 200 miles, but will not meet our original target of 250 miles.
Martin Eberhard, CEO, recently communicated this news to our customers, and we will continue to provide them with updates as we continue development of the Roadster. We think it is appropriate to always communicate to our customers first, and then more broadly to the media and the public.
These are the key factors for the revised expectation:
We made a significant number of design changes to maximize safety and durability of the Roadster, both in its chassis and in its battery pack. These changes added several hundred pounds to the weight to our original design.
We deliberately chose lithium ion cells with a slightly lower capacity because they have better long-term durability and higher tolerance for abuse.
I also think it is important to keep members of the media up to date on our progress to provide you with the context and background necessary for you to do your job. To that end, I am providing some additional context in this briefing.
It is important to note that at greater than 200 miles, the Tesla Roadster will still have the highest range of any production EV in history by a large margin, and we will be working hard to deliver even better range in the coming months.
The original premise of this groundbreaking car was that its range would be high enough that you would not have to worry about charging during a typical day, even if you have a long commute, take the car out for dinner and chores, or even take the scenic route home. Once home, you plug it in - just like you would your cell phone - and by the time you're ready for another day, your Tesla Roadster is fully charged and ready to go. We believe that this premise is still intact with a range above 200 miles.
Our communications strategy is intentionally conservative: we don't want to communicate any further revisions to range unless they are upward revisions. That's why we decided to say that the final EPA-certified range will be greater than 200, rather than try to communicate where we think it will actually land at the end of the day. When the final tests are performed by EPA just prior to start of production, we will communicate final numbers to customers, the press and to the public.
After extensive testing of our EPs, we are confident that we will achieve a final EPA-certified range above 200 miles. Now that we have completed cars and an understanding of the testing methodology, our future range estimates will be based on empirical testing, not simply modeled estimates. This is an important distinction that should be taken into account when comparing Tesla's estimates for range to other companies' claims. Since Tesla has undergone significant testing on our EP cars that have lead us to this revised expectation, I would suggest that these numbers cannot be compared apples to apples with range numbers that are expressed by other companies as aspirational goals or modeled estimates.
In the years that we have been working on the design and development of the Roadster, we have learned an enormous amount about the challenges of electric drivetrain development, including battery system management, power electronics and motor development. We have also learned a great deal about the challenges of developing a high quality electric vehicle for mass production. We expect that other companies in this emerging sector will also experience this steep learning curve when they move from concepts to prototypes or when they attempt to mass produce cars for the marketplace.
The original assumptions and models that lead to the claim of 250 miles were made in good faith based upon the knowledge available to us at the time and our anticipated design specifications for the Roadster (including a lower weight than what we have today.) Our customers who have reserved a car know that they are reserving a car that exists today in prototype form and that is subject to further development and validation. That is one reason that we chose to make the reservation payment fully refundable so that if customers decide to change their mind based upon how the program develops, they can give up their spot and receive a full refund.
As a leader in the field, we expect that we will often be the first to learn from experiences along the way. We plan to continue to be as transparent as we can about our progress (within reason for a company in a competitive marketplace.) That's why we have chosen to communicate this revised expectation as soon as was practical after the conclusion was known to us.
Reader Comments (Page 1 of 1)
Phil L. 10:56AM (4/18/2007)
It isn't the first time an EV has overpromised on battery capacity; it won't be the last. Still, a realistic 200 mile range rocks.
I wonder what problems were addressed? No hints given in the press release. Adding "several hundred pounds" to a car that only weighs 2500 pounds (according to Wikipedia) implies significant changes had to be made.
While the Tesla is only marginally interesting(sadly, the market for 2-seat sports cars with prices tags in the 6-figure range doesn't include me), they are paving the way for other designs.
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Tony Belding 2:17PM (4/18/2007)
According to what I have gotten from Tesla, there was no single big change that added a lot of weight to the car. Instead it was a long laundry list of about 30 little changes, each of which added a bit of mass. The redesigned transmission was probably the biggest, but there is also a beefier coolant pump, stronger motor mounting brackets, improved motor housing, stronger doors, improvements to the ESS, and even things like better stereo speakers and door latches. As the weight crept upward then they had to go back and beef up the suspension and brakes to compensate. By the time they were done it adds up to "a couple hundred pounds".
It's obviously disappointing. I have heard comments from a few people on the waiting list, but I haven't yet heard from anybody who considered the reduction in range to be a deal breaker.
Incidentally, it looks like raw acceleration performance may not be negatively impacted. Tesla expect that improvements to the power train should compensate for the additional mass.
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Don 2:38PM (4/18/2007)
So that means if these figures are EPA approved...it'll actually get LESS miles per charge than what Tesla's claiming.
Groovy.
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Joseph 7:42PM (4/18/2007)
NO!!!! Tesla needs to try as hard as possible to reach their original 250 miles with whenthe car was lower weight!!! This will be a HUGE factor in determining the trust factor with the public!!!
And where on earth does it say that the transmission on the Tesla was changed?
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Tony Belding 4:29PM (4/18/2007)
There's an interesting point. . . It's going to be a 2008 year model car, so won't they have to use the new revised EPA testing cycles? Those should give more realistic results.
Details here: http://www.ucsusa.org/clean_vehicles/fuel_economy/fixing-the-epas-fuel-economy-tests.html
As always, your mileage may vary. :)
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Jimmy 5:13PM (4/18/2007)
So the range is between 200 and 250 miles on the EPA city cycle. Any info on the highway range ? Can one get on the highway and drive 75-80 mph for 200 miles ?
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Noah 5:16PM (4/18/2007)
The car is still the coolest thing this side of Bladerunner. As long as it's over 200 miles its still an effective commuter car for most people. At 150 miles I'd change my mind, but I would still buy one if I could afford it.
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Tony Belding 5:53PM (4/18/2007)
Sometime earlier Tesla said their 250 mile range was on the EPA highway cycle and it should do "slightly better" in city driving. I would tend to assume they are still using highway driving as their benchmark.
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M@ 6:23PM (4/18/2007)
Seriously folks, sit down and chart how far you drive in a day during a work-week.
The average United States driver travels 29 miles per day and is driving a total of 55 minutes per day. (This is an average vehicle speed of 32 mph.) -- US Department of Transportation, Bureau of Transportation Statistics
As you drop percentages, it's like 80% drive 20 miles or less. A day.
Over 200 miles per charge is more than enough for your average American, but please note that these are CITY miles, and if you're communting on the open (yeah, right) freeway at 75-80 mph you can bet the miles per charge is gonna plummet.
The real questions to ask (in addition to how far can you go at highway speeds) are how long does a full recharge take (when you're NOT using the high voltage home recharging system -- ie, you're stranded out and about), how long do the battery packs last, and how much do they cost to replace -- lithium-ion ain't cheap, and it starts losing permanent capacity the moment it's manufactured, no matter how much (or little) you use it. Wikipedia quotes a rate of 5% per month/20% per year at optimum usage temperatures, but also states leaving your laptop in your car will seriously shorten it's Li-Ion battery life.
Tesla looks cool, but I like Twike for a real-world practical CITY vehicle (also on Wikipedia). 400-600mpg vs. 135mpg. A car that's designed for a top end of 135mph and 200 miles (but not at 60mph) and how long does it take to get a recharge from a standard 110V (ie, when stranded and out of electrons, do I need to take a long lunch or go see a long movie, or BOTH before I can milk it home?). When we only go 30 miles or less at an average of 32mph... the Tesla does not make a good daily driver/commuting car for the majority of Americans. And as far as long distance travel, a bio-desiel/SVO/electric plug-in hybrid is my car of the (near) future.
Damn sexy, but like my wife's roommate in college, you couldn't live with her on a daily basis.
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Tony Belding 9:29PM (4/18/2007)
The change in transmission was reported previously. The original transmission was sourced from Xtrac, but it proved unreliable. The switch to another transmission from a different supplier was the major reason why Tesla's production scheduled slipped several months. (I'm unsure whether they still expect to deliver any cars to customers before the end of this year. If they do, it won't be many.)
The new transmission is a more sophisticated design which should shift faster as well as being much more robust and reliable. Unfortunately, it also adds some weight. Tesla have specified a heavy-duty design because they can't afford another failure, they have to get this one right on the first try.
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Jimmy 12:08AM (4/19/2007)
#7, Tony says "I would tend to assume they are still using highway driving as their benchmark" but Sam wrote in the original post "EPA compliant dynamometer to run the official city cycle, the numbers came up shy"
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