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Horsepower of electric cars?

Discussion in 'Electric Vehicles' started by Cobos, Oct 23, 2007.

  1. Cobos

    Cobos S60 owner since 2013

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    I'm curious about something...
    Looking at the Tesla Roadster and to a smaller extent at the few glimpses we've got of the Whitestar, it seems they will both have good acceleration. In the case of the Roadster as a sports car it is a pretty essential part, especially at that price range. Reading the source material from Tesla it seems that an electric motor is a natural fit for a car with excellent acceleration it's rather due to battery issues the range which is the challenge. So to summarise EV = good to excellent acceleration. Compared to an ICE where good acceleration usually means you need good (read as expensive) transmission and an insane amount of horsepower which means the car gets very thirsty and very complicated.

    Everything seems logical and intelligent up until now right...
    The question now comes with a car like the Th!nk, it is a pure EV and does have a few compromises that goes along with a pure EV. Why doesn't this car even have decent acceleration? Compared to the slowest new small car I could find with a quick search the think has 0-80km/h of 16s while the 1.0L Opel Corsa has 0-100km/h of 18s... So mostly the same level of acceleration but the Think is probably faster into the first 50km/h I suppose. Considering the paragraph above why didn't Think give their car good acceleration? It's pretty universal that good acceleration is universally seen as a good think especially for small cars. So if it is "obvious" for me why isn't it for Think? What am I not seeing here?

    Cobos
     
  2. malcolm

    malcolm Active Member

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    My Two cents: The Think motors are perfectly capable of good acceleration but are electronically limited to a) improve stability and handling, b) reduce current draw to levels which can be handled by whatever battery cooling system is used (is there one?) and c) to help maximise the range.

    Think are into "city cars" - little urban runabouts, even though some of the styling queues they have employed suggest "hot hatch"

    http://www.pivco.no/content.php?id=13
     
  3. Cobos

    Cobos S60 owner since 2013

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    Good points but at least c) should be user controllable as with any ICE vehicle. I can choose to drive economically or not, knowing that if I've got a lead foot my range will hurt. And with a top speed of 100km/h (which is electronically enforced as well) it's quite obvious that the new Think City is intended as a bit more than a pure NEV or pure City car. Similar to a ICE Smart Fourtwo in many ways, you can do highway driving with a Smart, it's just not what it's best at.
    Compare the new Think to this other Norwegian producer making the Buddy, and you see what a true city car looks like :)

    So I figure point a or b is probably right or c might be true as well even though I find that stupid (but somehow Think didn't ask me about their marketing strategy before they launched it :)

    Cobos
     
  4. malcolm

    malcolm Active Member

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    Great Buddy link! Classic Punishment Car looks. It's unfortunate that these sorts of cars are still being developed. Because overall EV numbers are so low these badly styled and proportioned vehicles have a disproportionate impact on the public's perception of EVs.
     
  5. tonybelding

    tonybelding Active Member

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    Malcolm had some good thoughts, but I'll add a couple more. . .

    Most EVs are limited by their dependence on a single (fixed) gear ratio. Therefore it has to compromise between acceleration and top speed. With two forward speeds the Tesla Roadster is unusual in this regard. Compare with the Venturi Fetish. . . It has both a slower 0-60 MPH acceleration and a slower top speed, and I suspect the main reason comes from having only one forward gear.

    With cars like the Th!nk City it gets even worse because they are trying to keep the cost very low, and they will cut corners on anything that isn't deemed essential, and acceleration isn't deemed essential in a city car.

    I might compare with the built-in speakers on your TV set. In the great majority of TVs, the speakers are crap. Putting good speakers in the TV wouldn't be hard and it wouldn't be particularly expensive. It's just that people shop for TVs by looking at the picture, and the sound isn't a priority. The manufacturer can save a couple of bucks on something that won't cost them sales, so they do.
     
  6. TEG

    TEG TMC Moderator

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    Tesla set out to build a performance car from the "get-go", so a lot of design decisions were made to reach that goal.

    Most EVs to date don't use Li-Ion batteries, so they have a weight penalty that hurts performance.

    Most EVs don't use exotic carbon fiber and bonded aluminum technology to keep the weight of the frame & body down to the bare minimum.

    Also, you may have noticed from reading the Tesla blogs that the performance of the roadster is such that they had to re-engineer things like motor braces, and transmission to get reliability at their performance level.

    Another thing Tesla did with the Roadster is a somewhat "cost is no object" approach.

    If you look around, there are a lot of home built electric drag cars that offer tremendous performance, but they tend to require a lot of maintenance. Most use DC motors and sometimes burn out motor components. They also frequently run into battery issues. If Tesla manages to engineer in "life of the car" reliability and still have this level of electric performance they will have set a new standard.

    Tesla used a methodical, wise approach... They sought out the best technology (drive-line ideas from ACP, chassis ideas from Lotus, etc.), and tried to make incremental improvements on everything they saw. For any area (such as the battery pack) where nothing existing suited their needs, they went and designed it from scratch.

    Don't forget about Wrightspeed X1, Ellica, Venturi Fetish, TZero, Tango, etc.
    Tesla isn't the only company to engineer a high performance electric car.
     
  7. Cobos

    Cobos S60 owner since 2013

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    I can understand the fact that at a certain level of RPM's you hit the redline and that limits your maximum speed. But the fact is that the Think is not really cheap. The basic model costs $36 900 + a monthly battery lease of $220. In Norway with our good incentives for EVs the basic model VW Golf (a good and very popular compact) starts at $39 700. So in other words Think can't really compete aggressively on price, and since range, seats and quality/comfort feel of the interior is far below the Golf why doesn't Think create a speed monster with their electric drivetrain.
    Looking at the Buddy linked above those start at $25 500 including Pb-batteries, and at that price point I can understand the choices since it's clearly a nr 2 car.

    So if you knowledgable guys should speculate the Think can't go faster because they need a transmission then, any other reason but heat that they have capped the speed at 62mph?

    I suppose the reason I'm so hung up on this is that I had intended to buy the Think but I can't just understand the product... It's simply too crap to be this expensive to quote Martin.

    Cobos
     
  8. Cobos

    Cobos S60 owner since 2013

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    The site is very slow today so instead of an edit:
    So if you knowledgable guys should speculate the Think can't go faster because they need a transmission then, any other reason but heat for the truly lethargic acceleration of 18s up to the capped speed of 62mph?


    Cobos
     
  9. TEG

    TEG TMC Moderator

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    You can use a more powerful motor, but then you need a more powerful motor controller... Then you need batteries that can output more current. Then you need stronger half-shafts, then you need stronger brakes... Unless the car is engineered as a performance car, it is hard to suggest just one thing that is the reason.
     
  10. Kardax

    Kardax Member

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    Let's not forget the obvious: Tesla's motor. They're using a watermelon-sized 185-kilowatt monster of their own design, manufactured in facilities they own by their own employees.

    If Tesla can manufacture that motor cheaply enough and in enough quantity for WhiteStar and other future models, they'll be the performance leaders in every category they enter.
     
  11. Cobos

    Cobos S60 owner since 2013

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    Kardax: I was under the impression that similar performance from an off-the-shelf engine could be had for anyone, if anything it was the controller which was the real genius? It seems I was completely wrong?

    Cobos
     
  12. TEG

    TEG TMC Moderator

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    Personally I think the balance of the whole package is the real win.
    Like I said, they made incremental improvements on all the technologies they touched and they mated them into a package where all the components are working near their design limits to provide the best performance and range without any one component being "over engineered".

    The Wrightspeed X1 does better 0-60 using off the shelf ACP components, but sacrifices range and creature comforts.

    The PM Flightlink hub motors claim to be more powerful, and may well give the Tesla products some competition eventually.
     

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