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AC Noise - Loud!

Discussion in 'Model S' started by shonline, May 25, 2016.

  1. shonline

    shonline Member

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    I know this has been discussed before, but my 2 month old Model S AC is getting louder. Yes, I know it is getting hotter...!

    I've attached a short version, and a longer one showing how the AC starts and kicks in. In that one, you can also hear the AC unit step up and down responding to the internal temp I think. (gets loud at 30 seconds)

    The SC has heard the audio and after review say it is normal. I have to say my SC is fantastic, very helpful and I will defer to them for now.

    However, this is far louder than it was even a week ago, and can be heard from quite a distance away.

    Anyone else hear this?



     
  2. steve841

    steve841 Active Member

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    Normal ...

    It was worse before they added an acoustic cover.
     
  3. TSLA Pilot

    TSLA Pilot Member

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    We get that on occasion as well (typically when there's a large delta between selected temp and actual (i.e., when it's really, really hot), but we ALSO get a tacky steering wheel vibration that does not suggest "Quality."

    **Tesla: This is NOT appropriate for cars in or near six-figure price points, or even a third of that (Model 3).**


    I assume that Tesla has higher priorities and simply doesn't address this because the condition rarely, if ever, is noted in LA (where Elon lives) or in the SF Bay area . . . out of sight, out of mind?

    We're now in almost our 4th year of MS production and I (and others) really wish Tesla would step up and fix this, to include a better retrofit package for the classic MS's. It's time.

    Thank you Tesla!
     
  4. Gizmotoy

    Gizmotoy Active Member

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    Indeed. I'll never forget the day I'd pulled up to a light with an ICE on either side after the car had sat in the sun all day. I was, by far, the loudest car stopped at the light. A pedestrian was in the crosswalk, did a double-take, and put on the biggest "WTF? face" I'd ever seen. Clearly he wasn't expecting this silent EV to be making such a commotion. I had the "AC Blanket" installed a few weeks later and it got a lot better.

    In any case, sounds pretty normal for the current muffled AC. Still really loud, but not disturbingly so. It's more obvious because there's no engine noise to help mask it, plus the size of the AC compressor is larger than most vehicles because it has to be capable of cooling both the cabin and the battery.

    I wish it were quieter, but I think that's just the way it is. Hopefully a future revision helps.
     
  5. freeewilly

    freeewilly Member

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    I try to avoid the embarrassment of loud AC noise, so I leave my AC off until I reach to major street when there is other cars around. The tire noise will cover most of the AC noise.
     
  6. gaswalla

    gaswalla P4201/85/airsusp/pano/19i

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    If you turn on Range Mode, it won't go to max AC settings and hence saves the noise, embarrassment, and energy used.

    (I did see another thread were max 11 setting may now be active in Range Mode on a very new sw update - need to check into that)
     
  7. jeffro01

    jeffro01 Active Member

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    Electric AC compressors by nature are anything but quiet. What you're hearing is normal.

    Jeff
     
  8. TSLA Pilot

    TSLA Pilot Member

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    Well, it could likely be much quieter. Years ago I read a lengthy article on how GM (or someone else) managed to tame some absurdly loud noises from their electric radiator fans with science. IIRC, one of the major changes was simply changing the spacing between fan blades to make it variable, and adding a lot more sweep to the blades. There is a lot of science in this field:

    https://www.mhi.co.jp/technology/review/pdf/e433/e433023.pdf

    Engineering Acoustics/Noise from cooling fans - Wikibooks, open books for an open world

    Improving an Engine Cooling Fan Using Design for Six Sigma Techniques

    But at this point, Tesla appears to have other priorities so why not let others play in their areas of expertise? My suggestions:

    1. Suppliers are begging to be affiliated with Tesla, especially given the volumes coming with M3. Why not loan Model S's to those suppliers and ask them to do proposals on HVAC/Battery Cooling system noise reduction, both for retrofit and for future MS production?

    2. Analyze the results by parking their project cars (all in black, of course) in the hot sun, and then doing some sound and performance testing, comparing to a control MS, of course. Use those results as a potential "scale tipper" in the bidding process for future Tesla work . . . .

    Speculation, but I think Tesla will be amazed at how much quieter their HVAC and BMS cooling could be, yet with even better and more efficient performance. (For one example of the low-hanging fruit, why are we still dumping the ice cold evaporator water onto the ground when it could be used for misting the condensers or directly cooling the battery? BMW has been using this water for transmission cooling for over a decade now!)
     
  9. freeewilly

    freeewilly Member

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    A lot of people say it's normal, but is it??
    My last BMW has stop/start function, even during extremely hot summer day, the engine shuts off during a stop at intersection, the AC noise was not as loud as MS, it had deep fan sound, not like my Tesla AC noise, it has all kinds of high pitch noise, sound like something is going to fall apart.
     
  10. TSLA Pilot

    TSLA Pilot Member

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    I don't think anything limiting HVAC performance via the "Range" mode is acceptable when it's 100F, 110F or 120F in the shade . . . what needs to be done is for Tesla to fix this problem, once and for all.

    An ICE has to cool both the engine (some 70%+ of the fuel energy is wasted as heat), and cool the cabin. Why is a MS allowed to be noisier than a 7 Series of an S Class? It's not. We just put up with it because we're the Tesla fan club.

    Hate to be harsh, but this is a bit of a product FAIL by Tesla; you'd understand this if you lived in a really hot climate, but I don't think San Diego taxes the HVAC or BMS all that much so you're not seeing or hearing what the OP is talking about.

    Trust me, it's unsat, as is the steering wheel vibration.
     
  11. kort677

    kort677 Active Member

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    AC blanket?? I've not heard of this, please tell me more
     
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  12. kort677

    kort677 Active Member

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    I'm sorry but I don't agree, when my s90d's AC is humming it is LOUD!, I've never owned any car where the noise from the AC unit was so loud.
    My fix is to cycle it off and back on, sometimes that calms things down.
     
  13. kort677

    kort677 Active Member

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    I always thought the engine was cooled with a radiator based system that is separate from the interior climate control system.
     
  14. Cowby

    Cowby Member

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    +1...please elaborate on this AC blanket.
     
  15. Kalud

    Kalud Member

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  16. shonline

    shonline Member

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    Thanks for this everyone. Half of me is relieved that with a 3000 mile trip up next week, I won't be cramming in a visit to my SC. The other half of me is shocked that this can be normal in such a great car.

    Thanks!!
     
  17. kort677

    kort677 Active Member

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    thanks for that, that report is 2 years old I wonder if that fix is still applicable
     
  18. Electric700

    Electric700 Member

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    You can also decrease the fan speed, and that should help. It's very easy if you set the right scroll wheel to the fan speed. You may be able to do it on the left scroll wheel too with the latest software update.
     
  19. Edmond

    Edmond Permanon

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    Cars built post-Sep 2014 have this acoustic cover, as does the front motor.
     
  20. SomeJoe7777

    SomeJoe7777 Marginally-Known Member

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    #20 SomeJoe7777, May 25, 2016
    Last edited: May 25, 2016
    There are two separate noises that come from the AC system:

    1. The compressor. The electric refrigerant compressor is variable-speed, and has a fair amount of vibration. You will notice the vibration when the unit changes speeds in response to the cooling load. Note that the refrigerant compressor may run even if the cabin cooling doesn't demand it, as the refrigerant is also used to cool the battery/motor/charger coolant loops.

    The Tesla compressor is different from other automotive compressors in that almost all ICE refrigerant compressors are variable positive-displacement design that use a variable swash plate and several axially-oriented pistons/cylinders. This design is quiet and can cope with the requirement that an ICE compressor deal with variable shaft speed. The Tesla compressor is a hermetically sealed scroll compressor like a house AC unit. It's far more efficient in terms of amount of refrigerant pumped per watt of power (very desirable in the Tesla), but is inherently noisier.

    2. The radiator fans. The two fans in the front of the car may cycle on to increase refrigerant cooling. These fans are loud, and are the same fans your might hear when supercharging. There is also a passive radiator in front, but it can't cool the refrigerant sufficiently in very hot weather.

    If you are sitting in stop-and-go traffic on a 95F+ day, expect to hear both sources of noise.
     
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