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Cabin Temperature control...and the air coming out of the vents...

Discussion in 'Model S: User Interface' started by Todd Burch, Jan 22, 2013.

  1. Todd Burch

    Todd Burch Electron Pilot

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    In an ICE, the wasted heat (there's plenty to go around!) is dumped to the cabin for heat. The temperature of the cabin is generally controlled by the mixture--or amount of this waste heat being mixed with ambient air to control the cabin temp. So temperature is essentially controlled by adjusting the mixture of hot air instead of the temperature of the hot air itself.

    Maybe it's just me, but when I have the cabin temp in the Model S set to the low 70Fs, the air doesn't seem to get very warm. It seems to never get the cabin comfortable. But if I crank it to the mid to upper 70Fs, it definitely does and the air feels significantly warmer.

    So is the heat pump actually working harder to generate warmer air at higher temperature settings, or is the car just mixing less ambient air at higher temperatures? In other words, is the heat pump simply on or off?

    I ask because it seems like there's a bug--I drove to work in 30F weather this morning, and with all settings on auto and the cabin temp set to 72F, it never seemed to reach the desired steady state temperature. 74/75? Now we're talking. But 74F would make me uncomfortably hot in a room. Maybe the internal temp sensor just isn't calibrated right.
     
  2. nrcooled

    nrcooled P#8946 VIN 03225

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    I have to keep the cabin temp set to around 81 to be comfortable in the cold that we are getting in VA right now (~24-25 degs F). This was an adjustment for me as I normally kept my ICE cars around 70-72 degs for cabin temp.

    Since the car gets sufficiently warm with cabin temps at 80+ deg F I haven't been too worried.

    Here's something that I found out today, if you turn off the climate control and turn it back on it takes about a minute to get back up to temp. Even having it off for a couple of seconds.
     
  3. Lloyd

    Lloyd Active Member

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    I believe this responds better, but not yet perfect in 4.2. Are you still in 4.1?
     
  4. nrcooled

    nrcooled P#8946 VIN 03225

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    4.1 (1.19.31)
     
  5. William13

    William13 Member

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    My climate control seems to work better than some others. I usually set it between 68 to 74. I keep it comfortable but use the seat heater. It works better than any of my other cars as it heats up with resistance heat very quickly. Cars have very little insulation and wide swings in exterior temps. ICE can overcome this with brute force of enormous heat. The Tesla needs to be more efficient. It does this mostly by minimizing fan speeds while on automatic and using the heat pump when able. Heat pumps cannot be turned off then immediately back on. This damages them, at least it did years ago. I change the target temp slowly, one or two degrees at a time and it works well. My wife has less patience and turns the temp way up or down with resultant swings in air temps.

    The UI for fan speeds really needs fixed. It is very hard to change to a desired speed.

    BTW I am still on 1.15
     
  6. Todd Burch

    Todd Burch Electron Pilot

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    What's hard about it? I haven't noticed a problem (1.19.31).
     
  7. AnOutsider

    AnOutsider S532 # XS27

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    I believe we had another thread on this (escapes me ATM), but I also mentioned having to add about 8 degrees to what I normally set an ICE to. At the same time, HI on the S is 90 degrees, while HI on any of our Audis is 80, so it evens out. I just had to get used to setting at a different scale.
     
  8. nrcooled

    nrcooled P#8946 VIN 03225

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    This was exactly my thinking. If the HI was 84 and I had to keep it at 82 to stay warm I would really feel bad for my Canadian friends. Since HI is 90 deg there is plenty of head room to go hotter if needed. The HI on my ICE (Subaru WRX) was 80 also.
     
  9. capt601

    capt601 Vin02324

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    Turn the fan off of auto mode, and set the fan speed to 3,4, or 5. And it will work perfect at 72 degrees. There is something wrong with the auto mode and the sensors. If you watch the fan speed in auto, it drops down to 1 well before the cabin reaches the proper temperature. Then the fan stays at 1 and allows the cabin to get either too cold or too warm. I believe the sensors are in the wrong spot or the auto mode of the fans are turning the fan down to 1 too early. So far it seems as if 4.2 may have helped the situation but I am not convinced yet as the fan still seems to drop down and stay at 1.
     
  10. Trnsl8r

    Trnsl8r Blue 85kwh since 12/8/12

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    Sounds like I'm the only one using Range Drive mode? In there, you can't go higher than 74, after that it turns to HI. :-/ Makes it tricky if you just want to raise it high enough to turn off AC for the moment, but don't need heat.

    On a related issue, does anyone else hear a vibrating rumble as the climate control starts?
     
  11. AnOutsider

    AnOutsider S532 # XS27

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    Will have to give this a try. Hopeully its a simple software fix
     
  12. Doug_G

    Doug_G Lead Moderator

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    I think you're onto something. I leave my car at 20C (about 68F) and I'm comfortable all the time. But I have the fan set manually. The auto mode doesn't work at all!
     
  13. Todd Burch

    Todd Burch Electron Pilot

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    Interestingly, today I had the climate control on full auto, 70F and it seemed to do just fine. I think warm air is getting diverted from the cabin to the battery pack when the pack is cold, and that may be what I'm seeing.

    Would be nice if the manual covered these things so we know what the heck is going on. Wonder if Tesla's keeping this stuff under wraps for intellectual property reasons?
     
  14. Doug_G

    Doug_G Lead Moderator

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    They probably are trying to keep their designs secret... but I'm pretty sure there's a separate pack heater. Resistive heating elements are cheap.
     
  15. cinergi

    cinergi Active Member

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    It's the fan speed. And it's not a problem for the first ~15 minutes (varies based on how long it takes to get the car to temperature). It's a problem after the car decides to reduce the fan to 2 or 1. Then air doesn't circulate, which means warm air goes to the top where the sensor appears to be, and everything else gets cold. I've measured an 8+ degree (F) difference between what the car thinks the temperature is and the area by my feet.
    I agree changing the fan speed via the UI is difficult to get right. I'm using the steering wheel to do it now (still not awesome, but better).
     
  16. EarlyAdopter

    EarlyAdopter Active Member

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    Hmmm, interesting there's so much variance here. I can leave mine set to everything Auto and 72F on v4.1 and everything is perfect, including several hours driving in 28F. With the seat heaters I can dial it back to 70F and maintain the same level of comfort.

    It could very well be variance in temperature sensors or out of whack calibration. I remember seeing similar issues mentioned in Audi and BMW forums.
     
  17. cinergi

    cinergi Active Member

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    One ask for everyone having issues -- please let ownership know if you haven't already. If only a handful complain, it won't get prioritized/fixed. Especially if it's truly affecting only some cars.
     
  18. Todd Burch

    Todd Burch Electron Pilot

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    I will if I figure out that I'm having a problem! Just not sure now, as yesterday in 28 degF weather (the high) it worked great!
     
  19. capt601

    capt601 Vin02324

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    yes please notify ownership. cinergi was one the one who responded to a post of mine right after taking delivery and mentioned the trick of turning the fan off of auto.
    my wife has mainly been driving the car but so far it seems like 4.2 (not sure how as it doesnt say they didnt anything to the climate) may have helped but i cannot be sure til i get some time in the car for a trip. we also did have our computer changed out last week due to some issues right from delivery , so that may have helped.
     
  20. JoshG

    JoshG Member

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    How much are you using Range Mode? I assume you know that Tesla does not recommend using it very often as it lowers the life of your battery.
    -josh
     

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