Tesla engineer writes about maximizing range
Andrew Simpson is a Vehicle Systems Engineer at Tesla Motors and he is charged with squeezing every last mile of range out of the new Roadster. Andrew just put up a post on the Tesla blog where he talks about the challenge of creating the longest range electric vehicle to date. As we all know CEO Martin Eberhard recently announced that the official range estimate of the Roadster had been cut by almost twenty percent as a result of engineering changes made during the development process.
When creating mathematical models for a simulation, it's almost impossible to account for every possible variable and some assumptions have to be made. Once a model is created, it has to be validated against real data to judge its accuracy. Since this is Tesla's first car they had to create all their simulation models from scratch and had no data to validate against until prototypes were ready to be tested. Part of Simpson's job is to use actual vehicle data to improve those models and insure that future estimates are more accurate. To find out more about some of the design decisions the Tesla team made, check out Andrew's post.
[Source: Tesla Motors]
Reader Comments (Page 1 of 1)
art vatsky 4:53PM (5/11/2007)
Sam: Excellent blog! Good data, well presented. I want to see the Tesla succeed so that urban cars become electric cars. Also, I feel that portable battery packs, up to about 20 kg might be needed when longer trips are planned.
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1985 Gripen 5:07PM (5/11/2007)
So much is made of range in EVs. But the truth is that the average commute is under 40 miles a day or something. People are trying to compare apples to oranges when they compare the range of an EV per charge versus the range of an IC vehicle per tank of gasoline. I don't know if we'll EVER reach the range of IC vehicles with EVs and that doesn't bother me in the least.
I would love a practical EV sedan that doesn't look like a golf cart and is as safe as a mass-production car on the market. I don't need a 200+ mile range. It can have a range of 100 miles max for all I care. Those one or two times a year I go on a family vacation and might drive more than a hundred miles in a day I can simply rent an IC car.
Bring me a REAL alternative EV 4-seater with some kind of cargo capacity (hatchback?) and hopefully some decent looks at an affordable price (and no, I don't consider $50K an affordable price)!
I don't care about charging time. I don't care about max range (as long as it's at least 100 miles). Some people just have to see that EV and IC don't compare in some areas. The IC is better in some areas and the EV is better in others.
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Kardax 5:13PM (5/11/2007)
1985 Gripen: Since battery packs age with time and use, starting with a higher number means that it'll last longer before the range gets too short.
In the case a of a Tesla Li-Ion pack, if it starts at 200 and drops to 150 after 5 years... you're still fine if you only need 100. You might be able to get 15 or more years out of the original pack.
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1985 Gripen 7:25PM (5/11/2007)
Kardax: the reason the Tesla Roadster can get that kind of range is because of its very light weight and the fact it only carries 2 people and roughly NO cargo (nobody's going to be using this for trips to the supermarket).
A 4-seater sedan will be much heavier. So you're right, if they can get 200 miles out of the light roadster, I would hope they could get 100 out of a sedan. But Tesla isn't really targeting me with their sedan. I can't afford a $50K car. That's for wealthy families. The follow-up $30K coupe will likely be too small for my needs (wife and two kids).
I'm still looking for my perfect EV out on the horizon and I haven't seen any company propose it yet. Maybe someone can convert a 2005 SAAB 9-5 Aero Sport Wagon to EV for me for less than $30K including the car AND conversion! Naw, I didn't think so either...
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Kardax 11:19PM (5/11/2007)
1985 Gripen: I bet you could get a used WhiteStar for $30k a few years after it comes out ;)
That's my plan, anyway :)
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Jimmy 11:06AM (5/12/2007)
So, during the several years you will wait to buy an affordable used example of a car which hasn't been built from a factory which hasn't been built, what do you drive ? Is it still powered by imported petroleum ?
Biofuels and practical vehicles that run them exist today and are affordable to a typical driver *today*. To quote Al Gore, "we should not wait, we cannot wait, we must not wait".
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Kardax 12:21PM (5/12/2007)
Jimmy: I don't believe burning our food supply should be a primary means of transportation. The way I see it, I need to get into an EV as soon as possible and wasting cash on a new biomobile will only get in the way.
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Jimmy 1:11PM (5/12/2007)
Kardax, I guess we'll just need to respectfully disagree. I think the food vs fuel issue is mostly a red herring and that electric vehicles at this time just represent switching from petroleum fossil fuel to coal and natural gas fossil fuels. I will agree that a modern natural gas power plant charging an EV is clean and efficient.. but natural gas is very limited. Converting the world's electric grid to renewable energy is a far greater challenge (and expense) than replacing petroleum with biofuels.
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Bryan Jungers 11:56AM (7/05/2007)
It should be noted that the Solectria Sunrise drove approximately 250 miles on a single charge, in real-world driving conditions, using NiMH batteries. It was also a 5-passenger sedan (unlike the 2-passenger Roadster and EV1).
If Andrew hopes to break any kind of energy use record, he's going to have to do far better than a 200 mile range.
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