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Is Battery Cooling activated while driving if AC isn't on?

Discussion in 'Model S: Battery & Charging' started by JasonT, Aug 27, 2017.

  1. JasonT

    JasonT Member

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    Short version: Just wondering if the Tesla's automatic cooling of the batteries works if you're driving but don't use the AC

    Longer version:
    I live in Tucson, AZ, and frequently come up to my Tesla after sitting in the sun all day and hear fans going. I assume this is the active cooling system for the batteries. Being the desert rat that I am, even though the temp is 90+ I usually just open up the roof and drive home without AC. When I get home, as soon as I shut the door of the car I hear the fans kick in again.

    This has gotten me wondering if I'm possibly doing harm to my Tesla (2015 Model S 70) by not using the AC on 'warm' days. Is there possibly a bug in the Tesla battery cooling system that assumes if it's hot enough for the car, that the passenger would have the AC on? Or perhaps I'm just misunderstanding the noises I'm hearing and all is fine?

    Any info on this would be greatly appreciated.
     
  2. Tam

    Tam Active Member

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    Yes.

    When human HVAC is off that does not mean your battery pack does not take advantage of the thermoregulation system for its own comfort.

    Human has our own HVAC. Your battery pack has its own to regulate heating/cooling whether its human suffer or not :)
     
  3. JasonT

    JasonT Member

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    Good. That is what I hoped. I was just concerned from the limited information I had that perhaps that wasn't the case. Thanks for the info!
     
  4. tnt1971

    tnt1971 Member

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    As a related question, does the battery cooling system behave differently when plugged in, even if not charging? In other words, if the battery gets too hot, is the threshold temperature lower when plugged in before it automatically cools because it knows it has unlimited power?
     
  5. Rocky_H

    Rocky_H Active Member

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    Yeah, you're basically correct on all of that. It seems that there is the 'OK' range and the 'Better' range, and if the car has access to wall power, it will do a little more temp management to get it into the 'Better' range.
     
  6. xbox4me62

    xbox4me62 Member

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    I think the battery pack actually shares HVAC from the 'human" HVAC. If it's very hot outside the cooling capacity of the cabin air condition will be decreased due to having to cool the battery pack as well.
     
    • Informative x 1
  7. Hash Browns

    Hash Browns Member

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    This is somewhat old, but Tesla technicians have a tool through which they can view the entire cooling system in Model S/X via the touchscreen. It's pretty awesome.

    As you can see, the car has ability to route coolant from the radiator, refrigerant from the AC system and even waste heat from the chargers, motor and drive inverter to optimize thermal control. You can also see the active louvers for the radiator and AC condensers in the front bumper cover are open in this diagram vs. closed for improved aerodynamics.

    [​IMG]
     
  8. Tam

    Tam Active Member

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    When the weather is so hot, there's a message on the dashboard that I don't remember exact words but it would say something like "Your cabin HVAC is reduced to help to cool down the main battery pack."

    That would make me assume that the cooling/heating plumbing system of both cabin and battery are shared.

    Ingineer from the thread below seems to say that there's a patent to share the plumbing works for heating but the above diagnostic screen does not practice sharing currently:

    Heater on/off Button?

    I am not sure if heating is not shared, how about cooling?
     
  9. brianman

    brianman Burrito Founder

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    @JasonT

    Also keep in mind the Cabin Overheat Protection feature. This might also trigger AC in the cabin, which might confuse your analysis of behavior.

     
  10. tpham07

    tpham07 Member

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    When i supercharge, i hear the HVAC fans roaring loudly like a GE90 engine on a 777. I turn off the a/c in the car and row down my windows and the car doesn't sound like it's screaming anymore, but you can still hear it running to keep the battery cool.
     
  11. tnt1971

    tnt1971 Member

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    I have heard the same thing. I also notice it does it sometimes it turns on just as I am pulling away from the supercharger and my AC is not on. One time, I heard it run when I supercharged and it was less than 10 degrees F outside! You can bet I did not have the AC on when that happened. The first time I heard it I was amazed at how loud it was.
     

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