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Will hot humid weather effect performance?

Discussion in 'Model S' started by Pulley, Jul 12, 2010.

  1. Pulley

    Pulley New Member

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    I live SC on the coast. In the summer it's not unusual to have a heat index of 100+. Will these high temps effect the Model S's performance? I wonder about the A/C ability to keep the car cool and it's effect on battery life.

    If I am posting this is the wrong forum I apologize.

    Thanks!
     
  2. Cobos

    Cobos S60 owner since 2013

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    Obviously the more your AC unit works the more it eats into the battery. Though at least with a decent heat pump solution it shouldn't be too much. I doubt anyone knows any detail just yet.
    I can't see why performance should change thoug, except you might overheat something requiring you to slow down a bit.

    Cobos
     
  3. Doug_G

    Doug_G Lead Moderator

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    My roadster experienced 100+ heat index last week. The main impact was that the air conditioning became somewhat ineffective. The car kept right on working.
     
  4. stopcrazypp

    stopcrazypp Well-Known Member

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    The thing to keep in mind about A/C is the consumption varies by time. That means the longer you are driving your car with the A/C on, the more energy you waste on it. That is why on trips with a very low average speed (like when you are stuck in heavy traffic), A/C usage can make a huge impact.

    However, that doesn't necessarily mean traveling at highway speeds is the best idea, since at that point aerodynamics will have an even greater effect.
     
  5. vfx

    vfx Well-Known Member

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    It also must be pointed out that an electric car not moving (like in a traffic jam) is not expelling any wasted energy (unlike a gasoline engine that runs constantly).
     
  6. TEG

    TEG TMC Moderator

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    A gasoline car, idling at a stoplight is getting negative MPG.
     
  7. doug

    doug Administrator / Head Moderator

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    Lets not go overboard. The minimum is obviously 0 MPG, unless you're driving backwards, I suppose.
     
  8. ChargeIt!

    ChargeIt! Member

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    #8 ChargeIt!, Jul 13, 2010
    Last edited: Jul 13, 2010
    No ... in "essence" he's correct. Unless you just never go anywhere (with the ICE running), then you REALLY are at ZERO miles (no matter how many gallons or parts thereof you used). But on any average trip, the use of the gasoline, during the time you are stopped, "sets back", or reduces, the miles you are able to get on one gallon, i.e. a temporarily (virtual) "negative miles".

    And if you are driving backwards ... you are still adding to the miles (i.e. "positive") travelled, so that would not really qualify as "negative" ... UNLESS you are only interested in the shortest path achievable ....

    Never mind ... this is getting too hilarious ! :biggrin:
     
    • Funny x 1
  9. edo

    edo Member

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    Could someone with a Roadster post the consumption rate with the AC on full blast (and with it off, if different from the heater discussion)? I have my money on less than a kilowatt.
     
  10. Doug_G

    Doug_G Lead Moderator

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    As I recall, at "idle" the car consumes about 2A, and with the AC going full blast about 6-7A. This is for a Canadian car; I'm not sure what the automatic daytime running lights consume.

    Doug
     
  11. ljbad4life

    ljbad4life Member

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    Do you think that Tesla will have 2-3 condensers built into the Model S (1 hvac condenser for the battery and 1-2 for the cabin (driver and pass)?

    I know in the roadster the a/c is shared between the battery and passenger compartment which during extreme temps (+100F) can seem tepid...
     
  12. Doug_G

    Doug_G Lead Moderator

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    At one the peak of last week's heat wave, my A/C would sometimes produce warm air instead of cold. You know it's bad when opening the windows in a 100F+ humidex feels cooler!

    I suspect Model S owners would be less tolerant of little inconveniences than Roadster owners. But having two systems would probably be too complex and expensive. It might be simpler to just beef up the one cooling system.

    Doug
     
  13. ljbad4life

    ljbad4life Member

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    There is a possibility of having one condenser and two evaporators, which I've seen done in fridges.
     
  14. Model S_HKG

    Model S_HKG Member

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    I hope Tesla would have the a/c worked out for hot humid area, as we in Hong Kong need to have a/c on 11.5 month of year under extreme heat and humidity in traffic condition.
     
  15. doug

    doug Administrator / Head Moderator

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    Heh... I'm sure we're basically on the same page here and this is really just semantics, but having just noticed this post, I guess I'll go ahead and respond. :smile:
    I said the minimum MPG is zero. Meaning MPG, even in an instantaneous measurement, is non-negative, i.e. greater or equal to zero.


    You could choose to look at it that way, but that would be bad math. What's really happening is that you're including a small, yet still nonnegative value in your calculation, thus reducing the overall average. And like I was saying, the minimum value you can include is 0 MPG.


    Yeah, I was half kidding about the driving backwards part (depending how you've set up your coordinates :tongue:). Clearly you should only consider the absolute value of miles traveled, which is part of the reason I find "negative MPG" unnecessarily hyperbolic. (The other part is that something like negative MPGe could be useful when considering regen, but that's not applicable in a standard ICE car.)
     

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