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A/C system, S Model

Discussion in 'Technical' started by John Hice, Sep 3, 2015.

  1. John Hice

    John Hice New Member

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    I am interested in knowing some specifics of the A/C system on the Model S. I just purchased a P-90 ludicrous edition. The A/C system works really well and would love to know the type of compressor it is using. I can tell it is a viable speed compressor and is very compact. Is it using AC or DC voltage and what voltage does it operate at?
     
  2. jerry33

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

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    It's a variable speed scroll compressor that operates at the same voltage that the main battery pack does. I'd assume it would be A/C just like the drive motor.
     
  3. apacheguy

    apacheguy Sig 255, VIN 320

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    Wait, really? I can't imagine it's AC. The drive unit has an inverter, but I've seen the compressor and it doesn't seem to have its own inverter.
     
  4. jerry33

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

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    Yes, you're right, it's most likely DC.
     
  5. marcad80

    marcad80 Member

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    If its a scroll compressor it a loud one..... Compared to our Volt it sounds like an ICE.

    I know the Volt uses a scroll compressor, with the noise and vibration on our MS (I can feel it in the steering wheel) I just assumed it was a piston compressor...
     
  6. Saghost

    Saghost Active Member

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    This may be more about the programming than the hardware. GM did some interesting things with the compressor programming - it seems to have a speed related power/noise limiter, it runs at lower speeds/power levels in the parking lot on a heat soaked afternoon than it does after you accelerate - the only time I really hear the compressor is slowing down on the street after the first turn out of work on a hot day.

    I don't know if Tesla did something similar with programming or not.

    It actually wouldn't surprise me if they were the same compressors - the need for a 400 V air conditioning compressor is not that widespread, and it'd make more sense if one lower level supplier was serving all the OEMs to get economies of scale. I'm pretty sure both use the same electric cabin heater modules (our at least models from the same manufacturer line at zero start.)
    Walter
     
  7. John Hice

    John Hice New Member

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    Thanks for the replies! I know its the latest technological scroll type compressor used in most A/C units built today weather it be marine, aviation, auto or home units. It's also variable speed based on demand and temperature settings for the cabin. I have removed the frunk liner and to look at the compressor and its one of the smallest units I have seen in the industry but there is no data tags visable on it giving the BTU rating or operating voltage. Most of the ones I see in the aviation business are 24 volt DC but are belt driven and much larger and heavier. I am working on a A/C system for small vintage aircraft that do not have room for the large units and operate off of 12 volts DC. The compressor has been the holdup and if this unit operates off of 12vdc it could be just what we have been looking for. Something tells me its much higher voltage to keep the amperage draw down.
     
  8. scaesare

    scaesare Active Member

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    You have a 2013 as do I ... there's an update that adds some sound deadeaning to cut down on compressor noise... and in some cases I've heard folks say that some freon lines were re-routed to avoid vibrating steering components... maybe check that out?
     
  9. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    It's definitely not a piston compressor as you can hear the entire variable range of the compressor's operation. It has been described by Tesla as a variable-speed scroll compressor. For space and compactness it doesn't have all of the noise dampening that many other compressors have, not to mention the engine noise to mask it.

    For most EV's, the compressor runs most effectively from the HV battery pack. At roughly 3-4 kW, that would be around 300A or so (+/- 50A) and the cabling would have to be monstrous to deliver that current to the compressor at 12VDC.
     
  10. Saghost

    Saghost Active Member

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    Oh. You didn't say why earlier. AFAIK, all EVs use traction battery voltage for a.c. - it'd be a huge load at twelve volts.
     
  11. marcad80

    marcad80 Member

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    mine is a 2013. This is great to know. When the compressor is at full rpm, it is very noticeable in noise and vibration in the steering wheel. I will put this on my list for the next service visit. Thanks!

    btw mine is 10515, so ours came down the line together. I'm sure I have the same problem
     
  12. scaesare

    scaesare Active Member

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    Sure thing... made a difference on mine. Hope it helps ...
     
  13. gavine

    gavine Petrol Head turned EV Enthusiast

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    One thing the Tesla AC compressor doesn't have is a clutch like ice vehicles do. Those clutches are prone to failure/wear.
     

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