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Power limited at 50% SOC, only when flooring it?

Discussion in 'Model S: Driving Dynamics' started by Stoneymonster, Feb 12, 2014.

  1. Stoneymonster

    Stoneymonster Active Member

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    I was doing some driving yesterday, and had some (ahem) opportunities to zoom a bit. I noticed that each
    time I floored it, once the power got near 300kw, a little yellow line appeared near 300kw (like the your battery
    is too low limit, but not there all the time). Interstingly, the power exceeded that line every time.

    Anyone know what this is/means?

    I wouldn't have expected a power limit at 50% SOC, and it's weird that the actual draw exceeds it.
     
  2. Lloyd

    Lloyd Active Member

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    #2 Lloyd, Feb 12, 2014
    Last edited: Feb 12, 2014
    I have seen this in my earlier model. I believe it is a heat issue. Not sure if it is in the motor, inverter or battery. My newer model seems to have cured this.
     
  3. mnx

    mnx 2013 P85

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    I believe the yellow line will come up at any SOC when approaching ~100mph as well...
     
  4. Stoneymonster

    Stoneymonster Active Member

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    I can neither confirm nor deny that that is possible.
     
  5. apacheguy

    apacheguy Sig 255, VIN 320

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    Great, sounds like this is going to be another "A" pack disadvantage. Can a Sig with a pack swap verify this for us?
     
  6. joer00

    joer00 Member

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    It's not A/B battery. I do have the newer battery and get the same yellow line. I suspect it has nothing to do with 100 mph, just that one usually floors until reaching 100 mph. I will test if I accelerate slowly if I get the line too.

    It's indeed frustrating how fast the yellow line appears on all kind of acceleration especially when the SOC is lower.
     
  7. Stoneymonster

    Stoneymonster Active Member

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    FWIW, I have a B pack.
     
  8. brianman

    brianman Burrito Founder

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    I've seen the described behavior well below 100mph. I don't know what triggers it during street driving, but it's rare for me off-track.

    - - - Updated - - -

    This was reported almost a year ago by some autocross drivers. ;)
     
  9. darthvdr

    darthvdr Member

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    Whoa. This thread makes me feel like I'm driving like an old geezer.
     
  10. mnx

    mnx 2013 P85

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    Don't get too excited guys, I have a B pack as well. :)
     
  11. AmpedRealtor

    AmpedRealtor Active Member

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    Has your car received the proactive replacement of your coolant pumps?
     
  12. Stoneymonster

    Stoneymonster Active Member

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    No, and it just had its annual service a month ago.
     
  13. strider

    strider Active Member

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    It's not the battery getting hot though Li-Ion cells do generate more heat when discharging at lower SOC so the car will limit power at low SOC. There is a LOT of thermal mass there - a few, even several, punches of the accelerator will not change the battery temp materially. In the Roadster this is typically caused by the PEM (inverter) heating up. Model S should be less susceptible due to having a liquid cooled PEM but that's still my vote.
     
  14. jweinstein

    jweinstein Member

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    I just thought I would refresh this post to see if anyone else is seeing a power limit (dashed line) at 50%+ states of charge when "punching it".
     
  15. Alysashley79

    Alysashley79 Member

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    I am! In fact this is new to me. I have a P85 with primacy tires on and not sure which battery but not an A pack. Delivery was in nov 13. I just had my drive unit replaced about three weeks ago and up until the drive unit was replaced I never had this issue at all..I could each top speed and cruise at top speed for awhile and then see the. Limiter line come on...since getting the new drive unit I cannot and have not been able to reach top speed the closest I've gotten is 127 and immediately had the line and it began bringing me down in speed which it would then not let me exceed 90mph after that. I called my SC about this because it seems really odd that this is happening and it never acted this way before...not even close....they keep telling me this is normal and that these cars are not meant to "perform" this way....but I have the performance model...and it DID use to do it so why now? For those of you that have driven your cars on the track what should I truly expect out of my P? Before I'm limited to how fast I can drive? I should also state my SOC was at 90%.
     
  16. pete8314

    pete8314 Vendor

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    I am too (S85 with, I assume, an A pack). I only noticed it over the past few weeks, but that doesn't mean it wasn't always that way, in theory if you're punching it, you should be look at the road, so maybe I just missed it. But now, as soon as a floor it, the dotted line will appear as soon as it touches 300kw, that's on any SOC, and accelerating from a low speed, so I guess by the time the line appears, I'm maybe doing 50mph. The problem is I do not have an easy way of testing what happens if I keep my foot hard down, generally by the time the dotted line appears, I'm starting to lift off anyway. I ideally need a red light on a clear freeway, not many of those around these parts though. I'll carry on experimenting though...
     
  17. AmpedRealtor

    AmpedRealtor Active Member

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    Maybe it's Tesla's way of fixing the balloon squeal at maximum throttle?
     
  18. mknox

    mknox Well-Known Member

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    I have an A pack and have seen this as well. The last time I was at around 40% SOC and saw the limit line at around 80 MPH under heavy acceleration (don't ask :wink:) One other time, I was driving around town, pleasant 75 F day at around 40 MPH under "normal" acceleration and the line popped up as well. That was more puzzling to me, but it only happened once and never again under those conditions.
     
  19. ElSupreme

    ElSupreme Model S 03182

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    Remember that the Model S only produces peak power between ~45 and 70 mph. And even in that range there is a slight drop off from peak. Outside of those speed ranges power drops off more significantly. So the dotted line may indicate this slight (300kW is a LOT) drop in power at the speeds where motor power is not able to achieve peak.

    I can't seem to find the torque curve images that exist on these forums.

    I'm not sure it is really indicating a 'loss' of available power. More a display of less available power at certain speeds.
     
  20. WarpedOne

    WarpedOne Supreme Premier

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    Talking about this?
    At 100mph there is ~150/~220/~225 kW available.
    attachment.php?attachmentid=47712&d=1398288415.png
     

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