Regen brake lights....

Discussion in 'Gen III 2010+ Prius Main Forum' started by ChipL, May 14, 2012.

  1. ChipL

    ChipL Active Member

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    After being behind an ICE vehicle that rode their brakes on a downhill run in the hills of VA, wondered how the brake lights work on the Prius. In particular with regen braking.

    I mean, I am braking, but not braking....
     
  2. markabele

    markabele Senior Member

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    I guess I don't really get what you are saying. You are correct that the regen brakes don't slow down the vehicle as much as friction brakes, but they definitely do slow the vehicle down. Because of that the brake lights need to come on.
     
  3. firepa63

    firepa63 Former Prius Owner

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    The brake lights come on only when the brake pedal is depressed.
     
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  4. zebelkhan

    zebelkhan Member in good standing

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    I tested this when I first got my Prius. Brake lights come on after pedal is depressed a fraction of an inch, just like any other car.
     
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  5. ChipL

    ChipL Active Member

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    Just wondering, since we are not always braking in the Prius.... :D

    As much as new laws come about (rear cams in 2013 or 2014) for safety... Something like the pulsing brake lights I have seen on motorcycles makes much more sense than rearview cams IMO...
     
  6. firepa63

    firepa63 Former Prius Owner

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    What do pulsing brake lights have to do with rearview cameras? The rear view camera only activates when the car is in reverse. Pulsing brake lights have nothing to do with seeing what is behind you.
     
  7. vanbran

    vanbran Hmm....

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    I definitely get what ChipL is saying. The brake lights work fine normally, but driving down through the mountains, I ride the regen brakes to stop from gaining speed. You're not really slowing down but the brakes lights are on. If you really do need to stop quickly, there's nothing that tells the people behind you because your lights are already on. Pulsing lights would be great.

    What I don't get is why the brake lights don't come on when cruise control slows you down a steep hill. The cruise control is very aggressive at keeping you at your speed even on a super steep hill (like the Coquihalla Highways here in BC). If I was braking manually I have to depress the pedal quite far and the lights come on, yet if the cruise control does it there's no brake lights. :confused: That seems kinda unsafe.
     
  8. kithmo

    kithmo Couch Potato

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    The UK Prius has pulsating brake lights under heavy braking.
    To the OP, the regen on the Prius, when you take your foot off the gas and are not pressing the brake pedal, is similar to engine braking on a non-hybrid, but not as fierce, unless you have the shifter in "B" mode.
    Any braking with the application of the footbrake, whether just regen or friction, will light up the brake lights.
     
  9. ChipL

    ChipL Active Member

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    I am the OP...:D

    The pulsing brake light would be nice vs the steady brake light with those of us that are just wanting to slow down and save fuel without the need for a full brake...

    Might help in the Prius Rage in the US in the end...
     
  10. samlal

    samlal New Member

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    I agree with the logic of Brake lights not coming on while in cruise control. In cruise control you are not slowing down. You are maintaining your speed , therefore there is no reason for the brake lights to come on.

    Similarly when you slow down by lifting your foot from the accelerator, there is no need for the brake light as the slow down is gradual and not sudden.
     
  11. F8L

    F8L Protecting Habitat & AG Lands

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    This thread makes absolutely no sense. How is regen braking (liftng off the throttle without your foot on the brake) different from simply lifting off the throttle in a non-hybrid? Engine braking and regen braking are essentially the same thing. You are slowing down but not as fast as if you pressed on the brakes.

    If you choose to press on the brakes then the brake lights should come on. Seems pretty simple.

    If you are pressing the brakes then you are not saving fuel. So the idea of riding the brakes to save fuel just doesn't pan out. If you feel you must ride the brakes then you should have lifted off the throttle earlier. :)
     
  12. ChipL

    ChipL Active Member

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    The issue is that they are mandated soon...
     
  13. qbee42

    qbee42 My other car is a boat

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    I was about to post exactly the same thing. Normally I don't quote with a "me too", but this one deserves it.

    The brake lights on the Prius work like any other car. Cruise control on the Prius works like any other car. This thread is a distinction without a difference.

    Tom
     
  14. vanbran

    vanbran Hmm....

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    Sorry, maybe wasn't clear.

    The Prius isn't like any other car I've had. In cruise control in other vehicles I've had, it's never actively slowed you down. If you go up a hill you'll stay at 110 Kph, but down the other side it'll coast down until you manually brake. The Prius is braking to keep you at 110 kph, but it's not lighting up your brake lights.

    It's probably not a huge deal in a lot of places, but here in the Rockies when you're going down a huge hill, you expect someone to keep speeding up until the brake light comes on. It's just odd that your car is braking, but no brake lights come on (even though your speed stays the same).
     
  15. Judgeless

    Judgeless Senior Member

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    I was going to post the same thing. F8L has it dead on. It works like any other car.
     
  16. Judgeless

    Judgeless Senior Member

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    My 4Runner would use the engine to slow down the car going down hill with cruise controll on. I thought all cars worked that way.
     
  17. F8L

    F8L Protecting Habitat & AG Lands

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    I thought so too. I am pretty sure all of my MY 2000+ GM cars and trucks did. On steep roads, however, they often had a hard time keeping speed down so you may overshoot by 5mph or so. My girlfriend's '06 Rav4 will slow down with CC on and going downhill to maintain set speed.

    Vanbran, I think your other car was broken! I'm just giving you a hard time. :p
     
  18. vanbran

    vanbran Hmm....

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    Oh absolutely, it's the same. Reading back I think maybe I misunderstood ChipL. I don't think the brake lights should come on when you just let your foot off the accelerator and the fake drag takes over.

    I do think, however, that the Prius would be one of the best candidates for pulsating brake lights, because we do ride our brakes so much more. There's nothing that tells the traffic behind when we've switched from a long slow using regen-only brake to a hard, perhaps emergency brake. The Prius acts just like any other car, but we tend to drive a bit differently than most drivers. Most generally don't have their brake lights on all the way down a hill (and I was taught specifically not to do that to overheat the brakes in a conventional car, like many others).

    If that's what you meant ChipL then I'm with ya!
     
  19. ChipL

    ChipL Active Member

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    The issue is mandated rear cams in 2013-14, verses other mandates that might make areal difference.

    Lazy folks that don't wait to backup are the issue. In my 30+ years I always have been on the watch for those behind me.... Never needed a cam to tell me...

    But side view marker lights and pulsing stop lights are something thing worth way more money IMO.
     
  20. vanbran

    vanbran Hmm....

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    I can take it. :)

    Well I know 100% that our 2008 Chevy Malibu Hybird still picks up speed going downhill. The Prius is the first car I've been able to keep the cruise on in the big hill highways here because every other car I have to intervene and brake.

    It only became an issue when I was driving on the Coquihala the other night. Its a 110 kph, ~8.5% grade for 25 kms highway. (A bit scary at the best of times). I'm like "why are all these other drivers look like they're about to ram into the back of me everytime we go down a hill again?" That's when I realized looking at the reflection on the barriers that the brake lights weren't coming on, even though the car was doing some big time braking. People just don't expect your car to keep the speed on such steep grades without the brake lights coming on.
     
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