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Covering the Brake

Discussion in 'Model S' started by Todd Burch, Aug 19, 2010.

  1. Todd Burch

    Todd Burch Electron Pilot

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    When I drive my ICE now, I do a lot of covering the brake...particularly on the highway, when someone will pull into my lane directly in front of me, cutting my following distance to near zero. In that situation, I don't want to touch the brakes (being on the highway), but my following distance gets cut short so I cover the brake to be ready to stop at a moment's notice.

    I just realized that doing this in the Roadster is not possible (short of using 2 feet, which is a no-no). Doing it in the Model S probably will not be possible either. Well, it's possible, but (even if a regen "deadband" exists) would cause heavy regen and brake lights to kick in.

    So: the technique of covering the brake rather than braking, which is a way of improving efficiency in an ICE, actually decreases efficiency in the Tesla's regen/braking system (some losses in regen vs. just coasting).

    Just an observation. Any Roadster owners have comments about not being able to efficiently cover the brake anymore?
     
  2. vfx

    vfx Well-Known Member

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    Just that it's part of the reason I dislike the regen taillight coming on. I'm trying to drive defensively and all I'm doing is panicking the people behind me.
     
  3. dsm363

    dsm363 Roadster + Sig Model S

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    Maybe the regen should only set in if the starting speed (speed at which you let off the accelerator) is less than say 40mph?
     
  4. Doug_G

    Doug_G Lead Moderator

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    If someone cuts in front of me in the Roadster, I just ease off the accelerator a bit. The brake lights do NOT come on unless you let off quickly or let off a lot (like half way). The spacing grows between the cars and then I resume my normal speed. It's very easy to control.

    One thing I really like about the regen, if I have to put my foot on the brake really fast, the car is already decelerating BEFORE my foot gets to the brake pedal. That provides just a little extra margin of safety that you don't have with ICE cars.
     
  5. SteveTheTech

    SteveTheTech Member

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    My apologies for bumping an old thread I just found this very interesting, being a typical ICE driver the concept of coasting is something I have come to expect out of the experience I know as driving.

    Acclimating drivers with new technology is a risk that car companies are facing now.

    The concept of coasting is a by product of electronically turning off one of the one way clutches and letting one spin. The classic hydraulically controlled transmission is responsible for a fair amount of parasitic loss and requires more static torque than a direct drive and would adversely effect total range, weight and significantly increase the number of rotating components. In the Tesla uses a direct drive with an inverter attached to the drive wheels. Instead of burning off the kinetic energy to thermal transfer it is captured and reused to charge the batteries. The Volt uses an ICE to regen or recharge itself, from what I have read (which is really not that much), if the electric car could take one good charge and while driving (say on a long trip) it could modestly regen a percentage of the energy used to get it places it would make the "green" impact and significantly improve the perception among the masses.

    Learning to drive a car with an electric motor a center stack like the one pictured in this forum is going to take some time and I do not know about you but I am grinning at the possibility to learn something totally new about cars and the art of driving.

    A question I have for the Roadster owners how long (mileage or time) did it take you to get used to an actual potentiometer as a throttle input instead of a gas pedal.
     
  6. Doug_G

    Doug_G Lead Moderator

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    Oh, a minute or two. It is so beautifully and smoothly engineered that it feels completely natural. I was really liking the car even before I had a chance to floor it!
     
  7. howabout2

    howabout2 Member

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    The same was true for my MINI E. You adapt to it immediately. More importantly, I feel it takes longer to re-adjust to a conventional accelerator in an ICE car. When I test drove the Roadster its accelerator input was just as natural, although obviously a lot more power was available on demand. If the Model S is engineered the same way, I'll be very happy.
     
  8. bolosky

    bolosky Member

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    I had it down by the second stop light. The first one was a bit of a surprise even though the sales guy had warned me.

    Having driven with pretty strong regen on the accelerator for a little more than a year now, it feels like I have better control over the car than with the manual transmission ICE cars I used to drive, and way better than automatics. ICE driving really feels like a lot of the experience is a giant hack to make up for the limitations of the power plant.
     
  9. TEG

    TEG TMC Moderator

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    Once you are hooked on "the better way" it is hard to go back.

    Part of the reason why you see more and more EV drivers saying "I will never buy another gasoline powered car."
    (Not having to visit gasoline stations, worry about smog checks, or oil changes helps too.)
     
  10. SteveTheTech

    SteveTheTech Member

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    That is exactly how I feel and I haven't had an opportunity to drive on yet.
     
  11. eledille

    eledille TMS 85 owner :)

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    #11 eledille, Sep 27, 2010
    Last edited: Sep 27, 2010
    Warning: Don't try an electric car until you have the option of actually buying one. Any EV that is not a quadricycle in disguise is likely to hook you in just a few hours.

    We bought our Think three years ago primarily because they're allowed to use the bus lanes. We chose a Think because it was the quickest "real car" EV available here at the time with its 27 kW AC motor. I didn't have the slightest idea it would completely change my perspective on cars.

    I've always been interested in cars, and while the Think doesn't seem like a very desirable car, that's only until you drive one. It has completely converted both me and my wife to EV nuts. I haven't been dreaming about any ICE car since. If somebody told me I'd just won a Bugatti Veyron, I'd be overjoyed - I would have sold it the moment I got it and reserved a Model S and bought two Roadsters and a MiEV instead :)
     
  12. Kevin Harney

    Kevin Harney Active Member

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    And probably have 1.5 million or so left over :)
     
  13. Jaff

    Jaff Active Member

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    This is good advice! :biggrin::biggrin::wink:


     
  14. eledille

    eledille TMS 85 owner :)

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    True. Hmm. I could have had charging stations installed everywhere I usually park - now there's just one imaginary million left :)
     
  15. vfx

    vfx Well-Known Member

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    While it's blasphemous to mention the G word here, no one has a problem getting in an electric Golf Cart and "figuring it out" Those things and their Taylor industrial cart brothers are no-brainers. They don't really have regen but thet do down slow down a lot and you only need to lift your foot to apply the brake for complete or fast stops same as a full sized EV.

    It's also fun to watch Tesla drive videos as first timers learn not to brake. It's part of the machine that creates the EV grin.
     
  16. SteveTheTech

    SteveTheTech Member

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    I don't know the Veyron is the supermodel of automobiles currently, I'd have to spend some time with it... car guy rules.

    It would still have to let it go, although I might have an SLR as a daily driver.

    [​IMG] Cheers to the future

    I think the heavy reverse parasitic load from the regenerative braking will have to be modified for full size vehicles as we have seen what can happen when software logic does not meet what the public expects of driving. Stacking floor mats is another one that drives me nuts. Once the technology is perfected to build and power EVs full size vehicles will be soon to follow. It is always interesting to look back in decades as the technology has progressed to see the difference, I'm betting the next 9 will be some of the most interesting and progressive.
     
  17. PopSmith

    PopSmith Saving for a Model 3

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    I agree with your "warning" but a few hours isn't need. It only took me 30 seconds into my test-drive of the Roadster when I came upon the first chance to dip into the Roadster's torque pedal to want an EV.

    Before my Roadster test drive the "sportiest" car I'd driven was a 2008 S4, which belongs to my cousin. It's acceleration is good for an ICE car but it's nothing compared to the Roadster.

    Sorry for going a bit OT but I'd drive the Veyron through the first tank or two of gas; even if I was allowed to sell it right away, just to say I owned one. I'd then sell it to buy a Roadster Sport, a Model S (or 2) and most of the remainder into my company.
     
  18. eledille

    eledille TMS 85 owner :)

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    I admit that I too would have tested it for a couple of hours - right after having advertised it for sale :)
     
  19. SteveTheTech

    SteveTheTech Member

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    Ha I agree,

    First rule of sales is know thy product right?
     
  20. howabout2

    howabout2 Member

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    It's funny to see the several recent posts in this thread having just earlier today explained to someone that I would never want to own an ICE car again. One of the most reassuring things I take away from this is based on Elidille's story of his first EV. That is, that so far, the input mechanics involved in driving most EVs is very similar. Sure, the available power of the motor and the car's weight distribution play a big part, but the way that EVs process and react to driver input has--so far at least--appeared to be more or less consistent.

    Although this doesn't fully put to rest some fears I have about the Model S ("Will the government require artificial noise?" "Will they reduce the aggressiveness of regenerative breaking?" "Will they add forward coasting to simulate an automatic?" "Will I need to hold the brake pedal down at stop lights?" etc.), it gives me some confidence that these things are more likely to stay as they are in current EVs than change just for the sake of changing.
     

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