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A/C drain on battery

Discussion in 'Model S' started by GreenT, Sep 6, 2017.

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  1. GreenT

    GreenT Member

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    I am leaving Florida - you know why - and I have a question about A/C.

    If the freeway becomes stopped, and I just sit there for hours, I realize that the battery can last for days.

    But if I turn on the A/C, how long will it last? 85 battery, 240 when 100%
     
  2. tga

    tga Supporting Member

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    I've seen reports here on TMC that the A/C uses ~1kW. If I turn on climate control with the car plugged in, it draws 4-5A @ 240V. So I'd expect to loose ~1%/hour while stuck in traffic with the A/C on.
     
  3. croman

    croman Active Member

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    It depends. What's the ambient temperature difference? If its 90F and you want the car to go to 65F, it will eat up a lot more energy than 75F ambient and you want 72F.

    Secondly, how "heat soaked" is the vehicle? If you've pre-conditioned the cabin, the HVAC will use a lot less energy to maintain the temp.

    As an example, on the epic 9.5 hour drive back (should've been 2 hours but for massive traffic) from seeing the eclipse in Carbondale, IL, we used ~7kwh of energy for HVAC. The outside temp was 97F and we desired 75F.
     
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  4. tga

    tga Supporting Member

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    How did you determine that 7kWh figure?
     
  5. TIppy

    TIppy Active Member

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    I did a test for a camping in your Tesla thread, and with the car stationary, 90's outside and temp set to 74F, the car was using about 1.35 kw of power combined from the 12 volt and 400 volt battery. The 85 kwh battery has 77 kwh usable, so that would be 57 hours. It's about 4 miles of range for every hour to run the car and a/c.
     
  6. croman

    croman Active Member

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    The system measures average usage for the drivetrain and HVAC per mile. Since we only traveled 10 miles in 4 hours, I was able to do some easy math and assumed the car used 3kwh to move us the 10 miles (it likely used less). That's why I had the ~ sign since I can't be 100% sure. FWIW, my leaf will break out the subsystem usage whereas my far more advanced Tesla just gives me limited data.
     
  7. GreenT

    GreenT Member

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    Car will start out COLD. 1% per hour. Thanks
     
  8. TIppy

    TIppy Active Member

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    That would be 100 hours. It's more like 2% (1.75%) per hour.
     
  9. Nda721

    Nda721 Member

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    Did you make it out greent
     

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