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Regenerative Braking Behavior Poll

Discussion in 'Model S' started by Quick2Judge, Mar 29, 2018.

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Would You Like Regenerative Braking Bring the Vehicle to a Complete Stop?

  1. Yes

    80.3%
  2. No

    19.7%
  1. Quick2Judge

    Quick2Judge Member

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    Would you prefer it provides resistance / regeneration until the car comes to a complete stop instead of allowing the car to coast?
     
  2. Bebop

    Bebop Active Member

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    That would be awesome!

    But I don't think it technically is possible. Like regen literally can't get to a complete stop. just to 1-2mph. Someone correct me if I'm wrong. That is what I heard.

    I would imagine there would be a "Regen+" button in the settings. So the car regen up until it actually can and then at that moment a switchover happens and the actual brakes automatically start applying without you putting your foot on the brakes themselves.

    So the car detects "okay we have reached our regen limit" (aka we are at 1-2mph) and then starts to automatically apply the brakes to bring the car to a complete stop.
     
    • Informative x 1
    • Like x 1
  3. juju

    juju Member

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    I dream of a world where I never have to use my brake pedal.
     
    • Like x 3
  4. Jeff N

    Jeff N Active Member

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    • Like x 1
  5. cgrubbe

    cgrubbe Member

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    This is the one major feature I miss from my i3. The complete drop off in regen on the Tesla when you get down to 10mph is just annoying. It’s only software, add an aggressive regen option so those of us that would like to one pedal drive can.
     
    • Like x 1
  6. Brian Anderson

    Joined:
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    Minneapolis
    Love the regen / one pedal driving in the Bolt. Hoping my Model 3 coming in a couple weeks won't be too far behind, but expectations are not high given reviews I've read. The PMSRM motor in Model 3 is capable of greater regen at lower speeds than the AC induction motors in S & X, but may be somewhat less capable in that regard than the typical PM motors in Bolt, Leaf, etc. Anyone have a good source on that?
     
  7. Brian Anderson

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    It is a bit more than SW as the AC induction motor in S & X is inherently less capable of providing regen at low speeds than a PM motor. Electronic brake application could simulate it, but that wouldn't be regen.
     
  8. cgrubbe

    cgrubbe Member

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    The Magic of Tesla Roadster Regenerative Braking

    From the blog:

    I should also note that the motor and controller can deliver the torque command at any operating speed, including 0 mph. This means that we can regen the car to a complete stop. But as a practical matter, the kinetic energy of a slowly moving car is low enough that very little energy is put back into the battery as the car comes to a stop. In fact, the last little bit of slowing the vehicle down generates such a small amount of energy that it does not even cover the fixed losses in the inverter and motor.

    Software...
     
    • Informative x 1
    • Like x 1
  9. dgpcolorado

    dgpcolorado high altitude member

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    No need for brakes: another way to do it would be to gradually apply a reverse field to the motor to bring the car to a full stop. I assumed that was how other manufacturers did it but never bothered to look into it.

    I'm content with the current system because it follows the KISS principle. One advantage of using the brakes to bring the car to a complete stop at stop signs and lights is that they aren't rusted or stuck when they are needed.
     
    • Like x 2
  10. whitex

    whitex Well-Known Member

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    Me too, but regen would not be necessary in my version, except at final destination. :)
     
    • Like x 1
  11. appleguru

    appleguru Member

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    It’s good to periodically excercise the brakes so when you do need them they’re not corroded/seized. Not having full regen helps with this!
     
    • Like x 1
  12. BinaryField

    BinaryField Member

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    On the topic, am I the only one who worries about using regenerative braking to its (current) full length? The deceleration profile seems much different than most of the regular cars around me, which would mean that people would have to ride on their brakes if they followed me to a stop. I would think that it annoys other drivers and increases the risk of a rear-end collision if I don't try to imitate stopping like everyone else. Any thoughts?
     
  13. croman

    croman Active Member

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    My thoughts are that they all need to buy EVs. Problem solved.
     
    • Funny x 4
    • Informative x 1
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  14. Quick2Judge

    Quick2Judge Member

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    I enjoy using one pedal driving and trying to mimic the braking behavior of the other cars. I really have to "ride" accelerator gently down to ease the deceleration.
     
    • Like x 2
  15. GatorGuy

    GatorGuy Member

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    Are you saying regen takes too long to stop the car?

    I don't find that to be the case at all. I actually worry about being rear-ended because I find it similar to braking hard.
     
  16. Quick2Judge

    Quick2Judge Member

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    Can somebody share the benefits of having the car coast instead of coming to a complete stop?
     
  17. ggr

    ggr Expert in Dunning-Kruger Effect!

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    The benefit is an interesting question. It's about Tesla's approach to technology, and the use of AC induction motors. With permanent magnet motors, you can suck current all the way down to zero, but with AC induction, you need current to generate the magnetic field in the rotor, and so you get the "zeno's paradox" of braking: as the speed decreases, so does the maximum possible braking force. Now, Tesla could easily bring the car to zero speed using software, but it would require actually putting current into the motor in reverse. It wouldn't actually be regenerative braking any more. Just like having the regeneration applied by the brake pedal, I think the purist design philosophy in Tesla rebels against this.

    Note that this way you could brake to a complete stop even on a downhill, but it would consume current to do it. Bolts roll downhill and continue to regenerate, if the hill is steep enough. Anyway, I agree with Tesla, and it's safer to hold the brake when stopped, in case you get rear-ended.
     
    • Informative x 1
  18. Farzinfar

    Farzinfar Member

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    Hi everybody

    I am not sure if this is relevant to this thread but since the latest upgrade 10.4, my regenerative brakes are less responsive than before in lower speed. There is a relatively steep slope near my home which I have to use everyday to get to the main road. Before the latest update, when I was going downhill, without touching any of mythe 2 pedals, the car could build up speed up to 35 miles an hour using almost full regenerative brake and I could see the green indicator on the dashboard going close to -50. Since the latest software update, the car builds up speed very quickly and if I manually do not apply the brake, it can just build up speed to over 80 miles before getting to the bottom.

    In highway and with high speed the regenerative brakes works fine and similar effect of before update but in speed lower than 40 miles an hour it is not as responsive as before. I used to control my car almost with one pedal only and I had to apply the brake very lightly and at speed below 5 or 7 miles before coming to standstill but now I have to use the brakes to slow down the car. I checked my setting to see if the setting was changed to low or standard and it was in standard setting.

    Has anyone had such experience after the latest software update?

    Is it possible that Tesla realised the high effectiveness of regenerative brakes means less tear and wear of brake pads and less need to change them so they changed the setting forcing us to use more brakes?

    There are other changes to the car behaviour especially AP since the latest update but I will post my experience in other threads about them.

    Thanks for sharing with me yout thoughts.

    Kind regards
     
  19. RAW84

    RAW84 Member

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    I HIGHLY doubt this is the case.

    To be sure, is your dash screen showing regen is limited?
     
    • Like x 1
  20. RogerHScott

    RogerHScott Active Member

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    How would this work when regen is limited, or even non-existent, due to full charge, cold, etc.?
     
    • Like x 1

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