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TACC and Braking

Discussion in 'Model S' started by mjtgroup, Aug 6, 2015.

  1. mjtgroup

    mjtgroup Member

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    Question: When one is using the TACC and the car brakes, are you using regenerative braking or the brakes. In other words, are you wearing down the brake pads as if you were manually braking the car? Or is it a combination of both? Think I know the answer but hope I am wrong . . .
     
  2. Max*

    Max* Autopilot != Autonomous

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    Both.

    It'll always try to use the regen first, but often if the car brakes too hard, it'll switch to friction brakes.

    When I see red tail lights, and start letting go of the accelerator to coast to a stop. TACC follows the car, the car brakes, TACC doesn't usually have enough time to only use regen.
     
  3. Cyclone

    Cyclone Active Member

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    I am set up the same. In my car, 90% of my braking is regen. However, when I have a loaner and use TACC, probably only 20-30% of my braking is regen.
     
  4. Max*

    Max* Autopilot != Autonomous

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    You had a loaner recently, it still did that? I felt like the past few updates (not .5.21) made it rely on regen a lot more, or maybe it just felt that way to me.

    I also notice it HEAVILY depends on the driver in front of you. If he's jerky - your car will be jerky; if he coasts smoothly to a stop - your TACC experience will be much smoother.
     
  5. Cyclone

    Cyclone Active Member

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    #5 Cyclone, Aug 6, 2015
    Last edited: Aug 6, 2015
    Yes, it did that in .253. But it was MUCH better than the same loaner under .188.

    I think the road system in Charlotte is just not optimal for TACC. TACC (in .253 at least) HATES merging lanes. In my commutes, I hit 4 Interstates and it makes TACC go nuts as I exchange from one to the next and have lane merges. Then we have surface streets with a 55 MPH speed limit, and TACC hates those with all the roads that turn in and off the main road. So it's cruising at distance 4 at 55 when the person in front needs to slow down for a right turn to a 25 MPH street with no right turn lane.
     
  6. brianman

    brianman Burrito Founder

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    I've never seen TACC use friction brakes and I've got at least a thousand miles under my belt with TACC. This includes a 95mph to ~50mph deceleration test that was only a dozen car lengths or so that I recently did. (My passenger was unhappy with me.)
     
  7. Max*

    Max* Autopilot != Autonomous

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    My TACC only goes to 90mph?
     
  8. brianman

    brianman Burrito Founder

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    1. Set TACC to 70mph.
    2. Accelerate with your foot to 95mph.
    3. Release the accelerator pedal as you approach 50mph traffic (in your direction, not oncoming ;)).
     
  9. Max*

    Max* Autopilot != Autonomous

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    lol, gotchya

    - - - Updated - - -

    What do you set as your following distance? At 2 and 3 that I usually use (3 regular driving, 2 trafficy driving) TACC definitely uses friction brakes in situations where I could easily avoid it.
     
  10. brianman

    brianman Burrito Founder

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    My passengers tend to prefer 4+ and traffic tends to "allow" 4- in my general area. When travelling (road trips), 2 or 3 is somewhat mandated by the rudeness/disregard-for-safety in some areas (i.e. you get cut off).
     
  11. Max*

    Max* Autopilot != Autonomous

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    Hmm... I might try 4 [as you stated] at the risk of constantly being cut off.
     

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