Revelations From a Visible Brake Light

Discussion in 'Cooper SE' started by insightman, Sep 19, 2020.

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  1. GvilleGuy

    GvilleGuy Well-Known Member

    I told my family yesterday after seeing these posts again. Press the brake pedal once you come to a stop. Period. We have four drivers in the house, and, currently, my Mini is the most requested vehicle when someone runs an errand!
     
    wessy, NewGreen, polyphonic and 3 others like this.
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  3. Texas22Step

    Texas22Step Well-Known Member

    Yep. Same for me, even though I have barely learned to "stop" the vehicle using regen. While I will still try to use the regen (single pedal driving), we will all use the brake pedal once stopped to be sure that the brake lights are illuminated for traffic behind us.
     
  4. Since with the ICE cars people normally lift their foot from the throttle before stepping on the brake. I think it would be an easy software fix to program the brake light to illuminate once the throttle paddle senses that the foot is off or it returns to its resting position.

    The test car I drove the other day still roll gently even though the display said "0", so it is normal for me to press on the brake paddle while stopped.
     
  5. insightman

    insightman Well-Known Member Subscriber

    The brake light DOES illuminate when I remove my foot from the throttle pedal. However, after regen braking brings the car to a stop, the brake lights go out (and, as you noted, the car can roll forward if there is a slight downhill--but there is no "creep" like ICE-cars with automatic transmissions have).

    The brake lights goes out even when I remove my foot from the brake pedal while facing uphill and the SE is preventing itself from rolling backwards. Does that mean it's the motor, not the brakes that is preventing the car from rolling backwards?

    Conversely, when you're backing up a hill, the SE won't let you roll forwards after removing your foot from the accelerator pedal.

    I guarantee the operation of the SE's regen braking and brake light is exactly the way BMW/MINI (and their lawyers) intended. So no software patch will be forthcoming.
     
    GvilleGuy and Lainey like this.
  6. Puppethead

    Puppethead Well-Known Member

    My experience would say yes, once the SE comes to a stop from the regenerative braking, the motor is providing friction to keep it from rolling in the wrong direction but the correct direction is "free", meaning the SE can be pushed or will roll on the slightest incline. The friction brakes do not seem engaged unless the brake pedal is depressed (or traction control is doing its thing, which wouldn't happen at rest).

    Since the brake pedal is a "fly-by-wire" control – meaning it's not physically connected to the brake lines, but simply sends signals to the brake system – there could possibly be a software hack. But I don't think hacking the brakes is the first thing I'd mess around with...
     
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  8. insightman

    insightman Well-Known Member Subscriber

    Wait, we know from this thread that when the SE's electric vacuum pump failed on @dmaxwell, "The brake pedal felt hard and the brakes did very little." So the brakes stopped being power brakes, but didn't go away completely. Doesn't that indicate the SE is conventionally "brake-by-fluid," rather than "brake-by-wire?"
     
    GvilleGuy likes this.
  9. Puppethead

    Puppethead Well-Known Member

    Good point, maybe I'm completely wrong? I swear someone told me that but I can't remember from where. Or possibly there's sophisticated two-way sensing? I retract my comment, apologies.
     
    GvilleGuy likes this.
  10. GvilleGuy

    GvilleGuy Well-Known Member

    One of the reasons I love this forum. Possible posting mistakes (of which I have plenty) are respectfully corrected and respectfully received.
     
    wessy, kicksology, Newkirk and 2 others like this.
  11. JOJOtampa

    JOJOtampa New Member

    I know it’s been a year but, I wanted to give this a try and was gonna order the 50, do you still have some?
     
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  13. insightman

    insightman Well-Known Member Subscriber

    Fortunately, the box of 49 LEDs just popped up in my basement. PM me your address and I'll send you a couple.
     
  14. Puppethead

    Puppethead Well-Known Member

    I was wondering just this morning about how often the brake lights are triggered using cruise control, and thought of @insightman's LED mod. Since the regenerative braking happens when the driver eases back on the "go" pedal, does cruise control speed control trigger brake lights at any time?

    The other thing that came to mind recently is I don't see a lot of brake lights activating on Teslas. Do they never slow down, or maybe Teslas don't do regen (doubtful) or just not bother alerting other drivers when slowing?
     
  15. JOJOtampa

    JOJOtampa New Member

    Haha Teslas do slow down and they do have regen braking, their brake lights come on depending how fast they let go of the go pedal. If you let go quickly brake lights come on, they do stay on when you let go completely. If they let go slowly and coasting, it doesn’t come on until a certain point
     
  16. insightman

    insightman Well-Known Member Subscriber

    With my 2021 SE, the brake lights come on when the instrument panel's power/charge needle touches the first regen block. I would be surprised if the 2022 behaves any differently under its adaptive cruise control.
     
  17. Puppethead

    Puppethead Well-Known Member

    Mine's a 2021 without adaptive cruise control and it has to adjust speed for hills, so even it should be doing some slowing down. Or, like I had to this morning, one accelerates past a badly-merging yahoo without disengaging cruise control, and letting the car resume preset speed.
     
  18. GvilleGuy

    GvilleGuy Well-Known Member

    I covered this in my ACC video. On the 2022, as soon as the needle touches the first regen block, brake lights are on with cruise control. But cruise does a better job than I do of keeping the car in the 'ready' zone at speed so that the brake lights are not on.
     
    insightman likes this.
  19. ghost

    ghost Active Member

    I'm bumping this thread bc we're having a conversation about it on the UK forum, and this thread was linked over there.

    Just having bought my OBD2 adapter and bimmercode, I've tried changing the brake force display settings from weak (5 m/s^2) to medium (7). The result was the brake lights still flashed as soon as I let off the accelerator, even at speeds under 25 mph, and using low gen.

    Next time, I'm going to change the setting to heavy (8 m/s^2) to see if that makes any difference.

    Doesn't solve the brake lights activating at full stop issue, but I don't like heavy regen unless I'm going downhill.

    Even in my wife's Tesla, we set it to "roll", after reading about the costly periodic rotor resurfacing from never needing the mechanical brakes (Tesla regen is high by default).
     
  20. Puppethead

    Puppethead Well-Known Member

    I don't think that's as much of a concern in the SE since I believe the traction control uses the friction brakes (because it's the same traction control as the ICE models). Although I'm not entirely sure that's how it works.
     
    ghost likes this.
  21. Carsten Haase

    Carsten Haase Well-Known Member

    One pedal driving will also use the friction brakes instead of regen when the car is close to 100% battery
     
    ghost likes this.
  22. DialCottageInWales

    DialCottageInWales New Member

    Hi folks,I'm just jumping in here with this - don't mean to be rude!
    There are regulations for when brake lights should turn on.

    The regulations for the UK state that if the deceleration is
    • less than or equal to 0.7 m/s/s the signal shall not be generated
    • greater than 0.7 m/s/s and less than or equal to 1.3 m/s/s the signal may be generated
    • greater than 1.3 m/s/s the signal shall be generated

    I've been following a different ev forum for a few years. People there were trying to use changes in speed, and the time it took to make that change as a way of checking their rate of deceleration. I knew that most phones and tablets had good accelerometers in them, so I thought I'd try to find an app that would help. I couldn't find one though, but kept it in the back of my mind til now. I've written an app that should help. You can find it in your appstore from links on http://www.acceleration.wales

    Full functionality for checking brake lights is completely free. I hope it's of some use.
     
    insightman, Puppethead and ghost like this.
  23. ghost

    ghost Active Member

    After a couple of weeks, I realized that if I don't want to flash my brake lights, I'm just going to have to change my driving habits: stay on the accelerator longer and switch to high regen, stopping more abruptly (no more cruising to a gentle stop). This is the opposite of how I learned to drive an ICE vehicle.
     

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