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P85D: loud motor humming sound at highway speeds and over 15kW power (or regen)

Discussion in 'Model S: Driving Dynamics' started by MarcG, Jan 26, 2015.

  1. MarcG

    MarcG Active Member

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    #1 MarcG, Jan 26, 2015
    Last edited by a moderator: Mar 13, 2016
    Hi guys,

    I've had my P85D for a month and a half now and after 3,500 miles I'm still loving it!

    However I did start noticing a loud humming sound from the motor(s) at highway speeds, when the power hits 15 kW or above, or when the regen is high (also around 15 kW and above).

    I've tried to capture this in a video, and although the road noise is the main sound you hear, there's also a noticeable hum when power or regen hits and exceeds 15 kW:



    Has anyone else noticed this on your P85D?

    Thanks,
    -Marc
     
  2. wk057

    wk057 Senior Tinkerer

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    I can't here anything except road noise in your video. :(

    However, I've noticed that the motor noise is slightly louder on the P85D vs the P85, but it's not loud by any definition.

    Regen is louder than acceleration for sure in my P85D.

    Seems normal on mine though, I wouldn't expect it to be any quieter.
     
  3. benjiejr

    benjiejr Technogeekextraordinaire

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    Hello Marc,

    I think hear the sound on your video and my P85D does not make that sound. I think it's worth having the service center look at it. Good luck! I am curious to know what they say.

    Regards, Ben
     
  4. sundoc

    sundoc Member

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    Yeah I hear the hum you're mentioning... Haven't noticed in mine. I'll listen more careful today though.
     
  5. mknox

    mknox Well-Known Member

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    Had the same with my S85. Hum whenever power or re-gen was applied, but went away when power was at zero. They replaced my drive unit. I suspect it was noise coming from the inverter, but they replaced the whole thing as an assembly.
     
  6. AMPUP

    AMPUP Member

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    Humming from a drive unit was 'somewhat' more common on models in 2013 and early 2014, Tesla replaced many of these units for customer satisfaction. However, now they tend to not replace them until its really loud (they measure the sound to a threshold). Mine has been annoying for sometime and every time it goes in its not meeting the threshold for replacement. The notes from the tech are even to the point of something like 'Imminent failure of the drive unit is not expected'. I'll be complaining yet again on my next appt:biggrin: .
     
  7. MarcG

    MarcG Active Member

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    Wow, looks like Tesla's engineers are actively monitoring this forum!

    I just got an unsolicited call from the service center (I haven't called them about this issue yet) stating that they'd like to schedule a time to check the humming sound.

    They apparently got word from their engineers that I was having the issue, so they wanted to take proactive action - kudos Tesla!
     
  8. wk057

    wk057 Senior Tinkerer

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    Yeah, I've had this happen to me twice with Tesla calling me about things I've posted here. They definitely monitor the forums. It's probably a good thing, too. Go Tesla! :)
     
  9. MarcG

    MarcG Active Member

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    #9 MarcG, Feb 4, 2015
    Last edited by a moderator: Mar 13, 2016
    Ok quick update to this thread: I just upgraded to firmware 6.1 v2.2.139, and the hum I was getting at speed and over 15 kW of power is no longer there when RANGE MODE is set to ON.

    For background, v2.2.139 has a new feature when RANGE MODE is ON that, besides reducing climate control power as it always did, now "will also distribute torque between the motors to improve range".

    Well, I took another video with RANGE MODE both ON and OFF, and it definitely sounds like the hum is gone when torque sleep is active:

     
  10. Andyw2100

    Andyw2100 Well-Known Member

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    Another interesting discovery.

    Not sure what to make of that, since it was the rear motor that was to be idled during torque sleep, and presumably you'd be hearing the hum from something in the front. Perhaps the engineers can fill you in. Did anything ever come of their having contacted you, or was something scheduled that you may now cancel?
     
  11. dhanson865

    dhanson865 Active Member

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    Are there two inverters or just one? If only one inverter idling an engine could lower the load for the inverter and reduce/eliminate the hum from a part of the car where the engine isn't.
     
  12. wk057

    wk057 Senior Tinkerer

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    There are two inverters.
     
  13. MarcG

    MarcG Active Member

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    I'm scheduled to bring the beast in next week and will keep the appointment since the hum is still occurring when RANGE MODE is OFF (it didn't use to hum at all), so better safe than sorry in case anything is wrong with the motor(s) or inverter(s).
     
  14. AmpedRealtor

    AmpedRealtor Active Member

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    I've had a few drive unit replacements on my P85 due to noise above 70 MPH. This noise was due to a bearing issue that can now be serviced locally. The drive unit in the rear of the P85D is the same as in the P85. The S85 also shares the same motor, but is coupled with a lower power inverter as part of its drive unit. In fact, I received my fourth drive unit yesterday (third replacement) and I hope the issues are finally resolved. My last replacement was in early 2014, and they had still not solved the issue at that time.
     
  15. MarcG

    MarcG Active Member

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    Interesting, thanks for the heads-up. Let me know how this latest replacement turns out.

    Well I just got a call from the service center, and turns out my rear drive unit also needs to be replaced. Should be done by tomorrow (that's fast!)
     
  16. AmpedRealtor

    AmpedRealtor Active Member

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    I predict you will have an excellent service experience! :)

    One week on the new DU and so far so good. Ask me again in six months. lol
     
  17. PlanB

    PlanB Banned

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    HA!
     
  18. MarcG

    MarcG Active Member

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    Quick update: just got my P85D after the DU was replaced. It was a remanufactured unit, but the hum is gone! (for now, let's see again in 6 months :wink:)
     
  19. AmpedRealtor

    AmpedRealtor Active Member

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    I am troubled. Yesterday JB Straubel said during Tesla's Q4 call that the issues with the drive units has been resolved and has been implemented in production. These humming issues have been ongoing since 2012. If what JB said is true, and I have no reason to doubt him, why are P85Ds experiencing an issue that was supposed to have already been resolved in production?
     
  20. Andyw2100

    Andyw2100 Well-Known Member

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    And Elon Musk said something about the issue being overblown on the forums.
     

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