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Autopilot and Towing

Discussion in 'Model X' started by ohmman, Oct 22, 2015.

  1. ohmman

    ohmman Maximum Plaid Member

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    I've been thinking about towing a trailer with the Model X, and it occurred to me that AutoPilot may be disabled while towing, or at a minimum not recommended. Specifically, I'm thinking of some of the reports of occasional "jerky" movement, which would be unwelcome when hauling any trailer. I recognize it's going to get better over time, so probably not a permanent thing. However, my guess is that if you're hauling a trailer, you're probably going to be unable to use lane assist.

    Thoughts?
     
  2. Cosmacelf

    Cosmacelf Active Member

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    If you've travelled the freeway route several times before on AP and it has worked without corrections, then it should work fine towing. But you're right, I wouldn't trust it at this level of beta right now on a new route. As the fleet trains the system better, maybe this won't be an issue in a year...
     
  3. SabrToothSqrl

    SabrToothSqrl Active Member

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    My question is... why so few Model X videos w/auto pilot?! Or X videos at all? I've seen the S... I own the S... I need the D. I mean X.

    perhaps it would not be best to try auto pilot beta while towing, but in a few years it could be argued that it would be safer than a human driver.
     
  4. pmadflyer

    pmadflyer Member

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    the blocked ultrasonic sensors may be enough to disable it. Though maybe on an unrelated note, that's how it selects one of the three spoiler positions.
     
  5. MrBoylan

    MrBoylan Member

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    There are over 80,000 Model S cars in the wild. There are 6 Model X cars in the wild. Math.
     
    • Funny x 1
  6. SabrToothSqrl

    SabrToothSqrl Active Member

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    I would think those six people would be making some videos! and is it still only 6?
     
  7. shokunin

    shokunin P85 & S40

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    Those 6 are probably not the type to be posting videos, even if one of them co-founded the company that owns youtube.
     
  8. MrBoylan

    MrBoylan Member

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    At least 33% of them have. :)

    Bubba Murarka on Twitter:
    Mark Templeton on Twitter:

    Steve Jurvetson (first video) also posts pictures on Twitter of his X from time to time. Mark Templeton (second video) has also posted a couple of pics.
     
  9. BerTX

    BerTX Member

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    I suspect Tesla has done fairly limited testing of the towing system. I suspect Tesla has done fairly limited testing of the AP. I STRONGLY suspect they have done little or no testing of both together.

    To me, that spells a strong warning from Tesla not to use the AP system while towing. But people will use it anyway -- hopefully under optimum conditions at first until we get more data.

    I wondered about the TACC and towing. The Ford F-150 has adaptive cruise control, and they do NOT warn against using it while towing (except when using aftermarket trailer brake controllers) and simply say it may not work well in hilly terrain or when towing heavy loads because the cruise control disengages if speed drops 10+mph below the setting.
     
  10. ohmman

    ohmman Maximum Plaid Member

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    This bring up another issue. As we know, the MX will use regenerative braking when slowing. The trailer brakes would need to be connected to the brake light accelerometer if we want those to also be depressed during regen; but to what degree will they be depressed? Or will they only become activated with physical braking?

    Someone with more trailering knowledge should chime in here - if the car slows and a heavy trailer is pushing, does that cause any issues other than the obvious reaction time adjustments? Is there any different stress put on the actual hitch? I'm guessing no more than rapidly accelerating with the trailer, but who knows.
     
  11. Cosmacelf

    Cosmacelf Active Member

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    I think that's the whole point of the tow package. The tow package includes a brake controller. Often trucks and SUVs will have a tow package wiring harness, but they leave it to you to buy a brake controller. Although it isn't spelled out (does Tesla spell out anything important?), I believe the Model X tow package comes with an integrated brake controller which would presumably brake when regenning in an appropriate manner.
     
  12. mtebbe

    mtebbe Member

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    Why make a video??

    Honestly, I'm too busy to make a video and post it to YouTube.

    ...mark
     
  13. santana338

    santana338 Member

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    This is the first I have heard of an integrated brake controller in the X. Are you speculating or did you get that info from a reliable source? What source?
     
  14. goneskiian

    goneskiian Active Member

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    Probably assuming there is one since the Tow Package language implied there was one.

    TlePl8Z.jpg

    Edit: Or maybe it didn't. I guess the braking language could mean it simply adjusts the braking of the vehicle itself and not the trailer.
     
  15. Cosmacelf

    Cosmacelf Active Member

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    I got a call back from Tesla (on a Sunday no less) answering my question about the Model X tow package. Unless there is some confusion (I did ask the person some clarifying questions which she will get back to me tomorrow), the Model X just comes with a 4 pin wiring harness that you can then attach to your own third party brake controller to, just like as with other SUVs and trucks. Some people here have asked about regen braking, but presumably regen braking would also trigger the brake controller, just as it triggers the brake lights now.

    - - - Updated - - -

    Separate question for those that tow more often than I have. I'm looking to tow about 1,000 pounds. I'm thinking that I don't need a trailer than has brakes. I will be towing down a mountain though. What do you guys think?
     
  16. ohmman

    ohmman Maximum Plaid Member

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    To pile on to your question for people who know more than I do about towing - when you feather the brakes on your towing vehicle, I'm assuming the brakes on the trailer closely match how hard you're depressing the brake. If so, then it seems like the regen connection would be more complicated than just an on/off when the brake lights are on. Surely I am missing something, though.
     
  17. Cosmacelf

    Cosmacelf Active Member

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    Brake controllers usually come with a dial or other way to set braking strength. It has to be this way since the weight of the trailer varies. If you are towing something light, you set it to not give as much braking power to the trailer brakes. But if you towing something heavy, you have to tell it to give more braking strength for any given input. I have found that it takes some trial and error fiddling when you first start towing something to get the right setting (you can feel the trailer brakes dragging the vehicle back if you set it too strong).

    I don't know if the brake controller gets a variable braking signal rather than just on/off. I would assume it gets a variable signal.
     
  18. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    In the U.S. 4-pin trailer connectors are for lights only (ground, running, left, right). The 7-pin connector includes +12 Volt power and a proportional, electric brake signal. See Wikipedia: Trailer connectors in North America

    I would have hoped that Tesla included a 7-pin trailer connector with proportional trailer brake controls in their tow package...
     
  19. dhanson865

    dhanson865 Active Member

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    The reality is that trailer brakes aren't strong enough to stop the trailer on their own. They are just there so that the trailer doesn't act in an undesirable manner such as passing the car towing it on the left, right, or over top. :)

    So long as you have sufficient braking on the tow vehicle the trailer just needs stability. It doesn't have to exactly match the braking power of the tow vehicle.
     
  20. ohmman

    ohmman Maximum Plaid Member

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    Thanks for all the responses. The things I learn around here..
     

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