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A/C issues with heatwave in Texas

Discussion in 'Roadster' started by garry753, Aug 5, 2011.

  1. garry753

    garry753 RoadsterS753 ModelS P1449

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    Hi -

    I am the new owner of Tesla #753, a Roadster Sport 2.0, and it now lives in Austin, Texas. Austin has been hit with a heatwave of several triple digit days now for the past two months, and so the a/c has been challenged.

    Initially it was having faults, and a Tesla Ranger installed a shroud in the front trunk which helped it to not have faults. Before the fix, the a/c was blowing out hot air.

    But now that the a/c is fixed, I am still getting hot air frequently, and I'm wondering if it is related to the high heat, and more specifically I was wondering if anyone else was getting any cool air out of the a/c under these conditions. I know a lot about how the car handles a/c, sharing it between the battery and the occupant, and biasing the battery over the occupant, but yesterday, the temp was showing as 109 - 116 degrees, and as soon as I turned on the a/c and hit the snowflake switch, I was getting no cool air at any setting.

    Has anyone else been experiencing this issue? Any workarounds that you all have found?
     
  2. NigelM

    NigelM Recovering Member

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    First, congratulations on your new ride!

    Some tips and info on these recent threads:

    air-conditioning-and-Texas-heat
    How-much-power-does-the-the-Roadster-s-AC-use

    Do a search and you'll find a lot more.

    The last firmware upgrade my Ranger told me that it included better management of the balance between battery cooling and cabin cooling. It feels like he was right. We have had temperatures above and below 100F recently (not quite up there with your heat) and my 2.5 has been fine so long as:

    1. I park the car in the shade.
    2. I always put the air on "recirculate" inside the cabin and don't draw in hot air from outside.
     
  3. dsm363

    dsm363 Roadster + Sig Model S

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    Congrats as well.

    That's a good tip. I'll try that. It's really hot down here and other than the air conditioning kicking out for a min or two while driving to cool the battery, it seems to come back ok.
     
  4. 7racer

    7racer Member

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    I'm worried about this too...but my roadster isn't scheduled to be finished for another month or so....
     
  5. JohnCappelli

    JohnCappelli New Member

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    Before you turn on the A/C crack the windows a bit to push out the excessively hot air.
    Drive the car a little then crank the air and once you feel the cold air push the recirculate the air button.
    When it's that hot and the humidity is up there most vehicles gas or electric suffer.
    Good luck with the heat.
    All the best with your "electric" car!
     
  6. garry753

    garry753 RoadsterS753 ModelS P1449

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    Thank you for the advice and congratulations. NigelM and JohnCappelli's advice really does work. I've been implementing these suggestions over the past few days, and it has really kept the cabin cool.

    Kindest Regards
     
  7. S-2000 Roadster

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    According to the Tesla Motors blog, they test the car above 100°F - complete with human "guinea pig." Then again, I suppose 109°F to 116°F is significantly more of a challenge!
     
  8. Fabrizio

    Fabrizio Member

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    #8 Fabrizio, Aug 10, 2011
    Last edited: Aug 10, 2011
    Living in Phoenix and using my Roadster for daily commuting I have experienced the A/C blowing warm air at various points in my commute as the electronics heat up. I've noted that up to 100F there is no performance issue with the A/C. Issues start arising once the temps go over 105. My customer representative sent me a list of tips on driving the Roadster in hot weather (attached). In addition to the tips in the attachment, I'd like to add a few of my own from my driving in 115+ temps:

    1. I don't have an issue driving to work in the morning - the batteries have been cooled by the overnight charging so the A/C works well for the most part.
    2. I do play with the vents - I start by pointing the far left vent to blow air off the windshield and over my head, the center left vent is closed, the center right is open and the far right is pointed toward me. This keeps me cool without making my hands frozen.
    3. When I start to feel the temp rise, I close the far right and center right vents, open the left center vent (so it blows directly on my right hand) and redirect the far left vent so it blows on my left hand. This helps cool me down.
    4. Once the air starts getting real cold again, I adjust the vents as described in #2.
    5. My car is parked in a covered garage while I am at work, but the air temp is still 105-115, and I have no place to charge at 220v while it is parked at work (this would cool the electronics). This means everything is very warm to start with - alomost at the same level as when I ended my commute to work.
    6. When I start home, I monitor the motor, PEM and battery temps. Because I drive the HOV lanes, I can cruise at 65 mph+. This heats up the electronics, especially the PEM. Hard acceleration heats up the PEM more so than the motor or the battery. When the PEM goes to the last blue bar or the first yellow bar, that's when the A/C gets warm.
    7. I play with the vents (as in #2) and try to slow down or not accelerate very quickly.
    8. If the PEM goes to yellow, you will get a power limited light on the dash and your acceleration will be greatly reduced.
    9. I am going to have ceramic window film installed. This reflects heat from the sun and does not appreciably reduce visible light transmission - in fact it has been used on windshields with no problems. This will help with the heat from the sun beating on me while driving home, which should help with cabin temps as well.
    10. Park in the shade if at all possible. The sun will raise the temps of the electronics, but if you have to park in the sun, start the Roadster up, turn on the A/C and let it cool the electronics for 10-15 minutes before driving.
     

    Attached Files:

  9. doug

    doug Administrator / Head Moderator

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    That's interesting. I didn't think the A/C interacted with the PEM, just the cabin and the battery.
     
  10. zack

    zack Member

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    When my PEM goes to the last blue bar or the first yellow bar, I get power reduction. I had that happen last week in an embarrassing way as I attempted to entertain a few of my girlfriend's nieces and nephews with my "amusement park on wheels."
     
  11. S-2000 Roadster

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    Don't you have the Solar Guard Windshield on your Roadster? How does the ceramic window film compare to Solar Guard?

    As for the tips document, the last three "Care, maintenance, and efficiency" items had me laughing. Does a fresh coat of wax make your Roadster slip through the air faster and more efficiently? Tesla sales told us that we wouldn't have any of those pesky fluids to check like in an ICE vehicle, so what's with the battery coolant top-off? Just kidding.
     
  12. GSP

    GSP Member

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    Very interesting. Sounds like the PEM is turning off accessory loads to reduce its internal heat generation before it reduces propulsion power.

    GSP
     
  13. doug

    doug Administrator / Head Moderator

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    But does that make sense? One is much bigger than the other.
     
  14. rabar10

    rabar10 FFE until Model 3

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    Note he says that the A/C has redirected to battery when the PEM is EITHER on the last blue bar OR the first yellow bar.

    I don't think these two (PEM temp, cabin A/C off) are directly correlated. Rather, the battery warms up due to driving and the A/C gets redirected to cool the battery. The PEM is warming up at the same time though.
     
  15. dsm363

    dsm363 Roadster + Sig Model S

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    Thanks for that PDF and the tips. I don't think I'd seen that before.
     
  16. strider

    strider Active Member

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    I have the Solar Guard Windshield but I went ahead and tinted the other 3 windows. Helps keep the cabin cooler and reduces the blast from headlights behind me when driving at night.
     
  17. Ladman23

    Ladman23 Member

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    I love my 2010 Roadster #1060 2.5. What I REALLY do not like is when my 50 mile comute includes the A/C going out 4 times and starts to blow hot humid air. I hit the blue A/C light, push it again, then wait about 45 seconds before cold air comes out again. UGH! My windsheild also gets fogged up making it dificult on the bottom to see clearly. In Fresno the temp is at 100 degrees quite often, that is even more of a reason why A/C is so important. I think I should have the service shop look at it again, that doesn't seem normal does it?
     
  18. NigelM

    NigelM Recovering Member

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    Which %age of light transmission did you use? Pics?
     
  19. Fabrizio

    Fabrizio Member

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    The Solar Guard is only on the windshield - the sun coming through the other windows really heats up the cabin.
    Actually, wax does help with efficiency as it does help reduce drag (at high enough speeds).
    There are three fluids to check on periodically - coolant for the battery (it circulates even when turned off), brake fluid, and windshield washer fluid.
     
  20. S-2000 Roadster

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    ... and gear oil for the single-speed transmission, although that's probably good for almost 100,000 miles.
     

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