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Why no regen braking system in actual brakes as well as motor regen?

Discussion in 'Model 3' started by Big1matt, May 21, 2016.

  1. Big1matt

    Big1matt Member

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    I have a 15' fusion plug in, and the regen on the car is activated when you slowly begin to press brake pedal. Wouldn't it be better if model 3 used the regen that all the Teslas use, when you let your foot off accelerator pedal, as well as the regen activated through the brake pedal?, for maximum energy return?
     
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  2. Lunarx

    Lunarx Member

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    Agreed.
    I like coast off throttle and blended braking on brake pedal.
    I see no advantage to regen off throttle.
    It could be a user choice for off throttle behavior.
    Either way, more regen could be used and controlled via blended braking.
     
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  3. bhzmark

    bhzmark Active Member

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    I thought that too. See my earlier posts. And then I got a Tesla. Tesla's method is superior.
     
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  4. garsh

    garsh Re Member

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    I have a Leaf with blended brakes. I'm not a fan. It is in no way "better". Braking performance becomes less predictable. If you're braking down a hill and hit a bump that causes the anti-locks to kick on, then the car turns off regen altogether, so now you have to hit the pedal harder. It also becomes harder to know when you're using regen and when you're using friction brakes.

    Tesla made the correct decision. Make heavy regen available off-pedal. People will get used to it and it will become second-nature.
     
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  5. JeffK

    JeffK Active Member

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    Exact same thing happens in my Prius and it's dangerous as hell. If I hit a bump while braking (in perfect weather conditions) the car feels like it accelerates and takes twice as long to stop. I've nearly rear ended people or jumped into intersections because of this. In any other car it would have stopped perfectly fine.
     
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  6. Luke42

    Luke42 Member

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    #6 Luke42, May 22, 2016
    Last edited: May 22, 2016
    We drove a Prius for 12 years and never had any real issues with the braking system.

    We had the first set of brake pads put on it at around 170k miles.

    The most annoying feature of the brakes is that it would take 5-6 stopsigns to get the rust off of the discs the morning after it rains (most cars get the rust off when you out on the brakes backing out of the driveway). It took me a few days to figure out what was happening and add it to my mental model.

    The Prius has coasting regen, too, but it's not really adjustable. If you don't believe me, put it in "N" and see how long it takes to coast to a stop.

    Granted, we drove it like a Prius. It's not built for aggressive driving. Everything about the vehicle reminds you to take it easy.

    I had just assumed that the Model 3 would have blended brakes (in addition to adjustable coasting regen). Because it's worked fine for us for over a decade.
     
  7. proven

    proven Member

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    When we got our Model s two years ago it took us about 1 day to adjust to the regen braking. Now I really feel like one-pedal driving is far superior. I recommend that people give it a chance.
     
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  8. Lunarx

    Lunarx Member

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    Wow, sorry to hear about the bad blended brakes on Leaf and Prius.
    However, Volt (Gen 2) Blended Braking has been a revelation,
    it works perfectly.
    Having the latest gen 911, I know what great brakes feel like and Blended Brakes are excellent when done correctly.

    Tesla only gives 60kW of regen off-throttle.
    Seems like more regen is possible, but its too hard to control more regen single pedal.
    Why not give 100+ kW regen on the brake pedal?
    Seems low-tech for the Tesla brake pedal to be Friction Only.
    Off-throttle regen vs Coasting could be a user choice (like it is in Volt).

    If you ask me, I bet Auto Pilot is so popular on Tesla, because of Single Pedal Throttle Control being tiresome.
     
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  9. Craig9080

    Craig9080 Member

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    Regen braking can either create great brake feel or make a car into a death machine. I think that the more they make it feel like a regular car the better. From what I hear about the budget EV/Hybrids above is that they skimped on the programming of their ABS logic

    Also, I replaced the factory brakes on my wife's regular Ford Focus yesterday at 140k miles...and I definitely could have stretched them for 20k more, almost 1.5 centimeters left of friction materiel.
     
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  10. Az_Rael

    Az_Rael Active Member

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    Blended brakes on the gen 1 Volt are OK. Occasionally when you hit a pothole or traction is poor the regen turns off and the brake pedal drops below your foot. It is unexpected the first time it happens, but now I know to just press harder as soon as it does.

    I would say that putting the regen all on the throttle will have a similar effect when it's turned off. Once you get used to a heavy braking effect on the throttle, you wait longer to take your foot off the gas prior to a stop. If the regen is off because it's too cold, etc, when you raise your foot off the gas, it feels like the car jets forward and you have to mash on the brake at the last second.

    So the real issue is inconsistent regen performance whatever pedal it's mapped to.
     
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  11. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    Having blended brakes adds a lot of unneeded complexity and results in poor brake feel. Tesla's way is far superior. It's just as easy to control the brakes as it is to control the acceleration.
     
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  12. zenmaster

    zenmaster Member

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    If you want to maintain a particular speed down hill i.e. so you don't crash due to too much speed or you are using cruise control, then you want regen on during those times..
     
  13. JeffK

    JeffK Active Member

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    Personally in an emergency situation I can take my foot off the accelerator faster than I can place my foot on the brake.... I appreciate the instant drop in speed when letting off the accellerator.
     
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  14. proven

    proven Member

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    It seems like you have a good deal of experience, just not with a Tesla (yet). The regen on the S/X is really intuitive and easy to control. Just about anyone who has purchased a Tesla has positive things to say about the single-pedal regen. Autopilot is popular because you don't have to steer, it has nothing to do with regen!
     
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  15. Dithermaster

    Dithermaster Member

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    Even gen-1 Volt blended regen worked great; I drove one for 3.5 years. I agree the Prius panicked too easily if you hit a bump during braking. The momentary switch-over from (now zero) regen to friction braking got your attention, that's for sure.
     
  16. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    As far as I know the way you get blended braking to be smooth is to use a larger percentage of friction braking so the transition is hidden.
     
  17. TEG

    TEG TMC Moderator

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    Some driving situations make one-pedal very nice. For instance, if you are driving a slow twisty road and need to slow for corners, it is much more relaxing to be just modulating the accelerator (/decelerator) pedal instead of having to move your foot back and forth between two pedals.


    Something else to keep in mind about this whole discussion... Sometimes regen isn't available. ABS kicking in was one example, but there are others... "pack totally full" (no room to recapture energy), so regen might be off right after a full charge... Also "pack too cold for regen"... Some vehicles will disable regen when the battery pack is really cold. I guess maybe it isn't a good time to put a lot of energy into it then. Hopefully they make the "no regen available" experience not too different from the normal use case. Having it all on the brake pedal means the brakes can feel really different when regen is disabled.
     
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  18. Twiglett

    Twiglett Single pedal driver

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    lots of comments about other systems being "better" without actually trying the Tesla way.
    I have a Leaf that uses blended brakes, it has....
    • Useless pedal feel
    • Road bumps cause braking to completely disappear - crazily unsafe when that happens
    • stupidly sensitive at low speeds
    Having driven Model S, Leaf, and a Volt - the Tesla system is hands down better.
    Brakes are identical to a regular car and regen works like it should.
    Regen should be able to get you down to walking pace without needing to friction brakes or silly extra paddles.
     
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  19. richkae

    richkae VIN587

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    I've owned a Prius for 12 years, and a Tesla for almost 7. I am very familiar with both.

    Tesla's system is superior. The throttle pedal is for controlling your speed. The brake pedal is for when you need to stop.
    It is very easy to coast by controlling the throttle pedal.

    For years when driving the Prius, I wanted the ability to slow the car with only regen. But since it is all in the brake pedal, it is difficult to tell when regen stops and friction kicks in. I'm not an obsessive hypermiler, but I dislike waste, and friction brakes are waste.
     
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  20. saltsman

    saltsman Member

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    I love the Volt blended method and agree with your assessment of single pedal throttle control being tiresome.

    The Volt method works VERY well and I'm convinced that it maximizes regen. The Volt gives you the choice of both. Drive in Low if you want single pedal driving with regen on the accelerator pedal and in D when you want to coast along or when you need your foot on the break pedal just in case typical regen needs to immediately switch to emergency stopping.

    To me, it make more sense that the accelerator is for acceleration and the break pedal is slowing, regardless if that is a combination of slowing by regen, a mix of regen and friction, or full friction. The computer can figure out what is most efficient at that moment.

    When the model S was new, the Prius and Leaf systems were the only comparisons, and they are poorly executed. Now the Volt Gen 2 version is out and it would be a nice upgrade (in my opinion).
     
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