Braking vs Left Regen Button

Discussion in 'Hyundai Kona Electric' started by JedK, Sep 9, 2019.

  1. JedK

    JedK New Member

    Is there any difference in hitting the brake vs the left regen button?
    If you press and hold the left regen button the car will stop.
    If you hit the brake obviously the car will stop.

    I see when I hit the brake the power flow indicator on the left goes down the same amount as when I put on that left buttons.

    (sorry if I'm using all wrong terms)

    Jed K
  2. nigels

    nigels Active Member

    Both result in regeneration. If you use the left paddle I think the rate of deceleration is fixed (0.25G?), whereas with the brake you can modulate the rate just as if you were using regular friction brakes. I have my car set to auto regeneration, so it does most of the braking I need to stop in normal traffic. I used to use the left pedal to bring the car to a final stop over the last few feet, but I found that its hard to smoothly glide to a stop, and it's not great for passengers (jerky), so now I just use the brake pedal instead. Of course, if you need to brake hard, you'll be using friction brakes.

    Also note that if you use the left paddle, the car will stop and stay stopped. If you use the brakes, you'll get the slow creep behavior of an automatic gearbox after you come to a halt and release the brake pressure.
  3. The foot brake uses a mixture between Regen and friction brake. That mixture rate actually changes with the speed. There is a diagram somewhere here in the forum. I'm sure it always uses at least a tiny amount of friction brakes, though.

    The left paddle uses only Regen, though.

    Sent from my moto x4 using Tapatalk
    nigels likes this.
  4. JedK

    JedK New Member

    The interesting thing is that it seems the left Regen paddle does turn the brake lights on. I was worried about getting rear-ended.
    nigels likes this.
  5. From what I understand, the brake lights only go on with the regen paddle when the regen charge amount is showing two or more bars.
  6. KonaTom

    KonaTom Active Member

    That’s true, but they always go on when using the brake pedal. And that is still very efficient hardly, ever actually using friction brakes
    KiwiME and nigels like this.
  7. That is not true. I had mine come on with less than two bars.

    Sent from my moto x4 using Tapatalk
  8. SkookumPete

    SkookumPete Well-Known Member

    I'd be very surprised if that last statement were true. Why would friction brakes be applied unnecessarily? Please give a pointer to the diagram.
  9. SkookumPete likes this.
  10. SkookumPete

    SkookumPete Well-Known Member

    Thanks. If I understand it correctly, the diagram does show that hydraulic braking kicks in only beyond a certain "driver's demand". It wouldn't make sense to turn energy to heat, and cause wear to the brakes, when slowing gently with the brake pedal.
  11. victor_2019

    victor_2019 Active Member

    if you push the brake pedal, the hydraulic brakes may or may not come on, depending how hard you press on the pedal.

    with the left paddle, there's no mechanical braking at all.
  12. So, how I look at it is that the red line is only an example of drivers demand. The left side of the diagram (I) shows only releasing the accelerator, not pushing the pedal. That's where you get Regen only. The next parts of the diagram show actual brake pedal push.

    Now I'm not sure if the red line is a demand of breaking in relation to the full breaking power (top of the diagram) or if it is only the part that is below the red line which would be drivers demand. Or if it uses the relative mixture of both brakes on relation to drivers demand. The text really doesn't explain what exactly it does.

    However, it may or may not include friction brakes in the process, so if you want to minimize friction brake usage, you need to use the paddle on the left of the steering wheel since you have no idea if friction brakes are included in the brake mix and at what pressure of your foot.

    Sent from my moto x4 using Tapatalk
  13. SkookumPete

    SkookumPete Well-Known Member

    It's a somewhat puzzling diagram to be sure. Section II is the typical case of gradually applying pressure. It’s electric-only until the demand reaches the gray area, which is where friction and electric are blended. Note that if the red line were flatter, it would stay in the electric-only zone. Gradual slowing with the brake pedal will not engage the friction brakes at all.
  14. Until the very end, where it only applies friction brakes.

    Sent from my moto x4 using Tapatalk
  15. Agree with both above
  16. In case it's not clear here's an explanation. The regen envelope is the speed/torque range where regen is possible. It's the combination of the maximum power limit (the curved part) and maximum current limit (the straight horizontal part). The dark grey region is the performance envelope of the hydraulic brakes which clearly encompasses the former.

    And that's correct, the red line is the example annotated at the right, heavy braking outside of what regen can accomplish, then relaxed, finally coming to a stop.
    In normal driving it should be possible to stay entirely inside the regen curve with the exception of the very end, where the motor voltage generated is insufficient to overcome battery voltage. Doing this as transparently as it does makes this an impressive design, IMO.

    The left-paddle-hold will use battery power to force the motor to slow down at those very low speeds and hold position, which certainly must use a small amount of energy. It may be safe to assume that you will get the best economy by only using the brake pedal.
  17. And your brake lights will come on
    KiwiME likes this.
  18. With the latest "high voltage battery update" the brake light behavior changed!
    I made a video here, I think it's kind of entertaining ... :D
    YouTube Link: Brake Lights Stay On
    electriceddy likes this.
  19. If that has indeed been added it is a good thing (for those who choose the paddle stop method). Personally I use the brake pedal itself. Thanks for the video.
    BTW I counted 35 complete Uuuhms so you owe us one on the next video;)
    KiwiME likes this.
  20. Yes, I commented about your video on FB. I'm surprised how soon you noticed such an unexpected change.

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