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Has anyone tested the decline of power on the P3 with the decline in total battery?

Discussion in 'Model 3' started by AndrewAllen, Nov 2, 2019.

  1. AndrewAllen

    AndrewAllen Member

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    I perceive to notice a small decline in power starting around 80% of battery left. At 50% it’s more noticeable. Has anyone tested this and if so can you point me to the source? Just curious. Thx.
     
  2. Xevex

    Xevex Member

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    I wondered about same thing and without seeing the percentage, I couldn't notice the difference. Probably same in your case too.
     
  3. Electric Dream

    Electric Dream Pilots the Millennium Milkfloat

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    • Informative x 2
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  4. KenC

    KenC Active Member

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    Not sure I understand you, but I always thought the power output was lower the lower the state of charge, that's why they charge as much as possible when they go tracking.
     
  5. Watts_Up

    Watts_Up Active Member

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    I'm not too much into drag racing but when watching some of them on Youtube, having a top SOC was always mentionned as a must.
    Which make sense for a given max current, more voltage would give more power.

    However, unless you are in a energy saving turtle mode, I wonder if it's something really noticeable?
     
  6. Adrien

    Adrien Member

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    I would be noticeable. Like you said Volts*Amps= Watts. Current is going to be hard limited at the top end. Voltage is basically the SOC. 4.15V at he top end quickly scaling back to 3.8V or so around 80% and then down from there fairly linearly. An S curve. Do the math and you're down 10% just at 80% and in the lower voltage levels down 25 even 30%. So yeah, to the OP, it should be noticeable.
     
  7. skrtskrt

    skrtskrt Member

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    The less battery you have the less power you will have, why is this a surprise?
     
  8. ElectricOrgan

    ElectricOrgan Banned

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    Capacity and power are two different things. I can fill a 5 gallon bucket from a 1 gal/min tap or fill it from a 5 gal/min tap. Power in batteries is measured in watts, capacity in Ah or Wh which are related by the battery voltage.
     
  9. ElectricOrgan

    ElectricOrgan Banned

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    It is to a small extent, but at the track a small difference matters. The wattage of the battery is the current times the voltage. The current available changes only a bit over most of the charge range, but the voltage changes more. When peak charged the voltage is perhaps 5% higher. The combined effect is noticeable when timing a run.
     
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  10. AndrewAllen

    AndrewAllen Member

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    Not a surprise. Just wondering if anyone has done the math to empty.
     
  11. tna9001

    tna9001 Member

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    I’ve just started logging data to answer this question. The first is at 11% SOC the second at 20% SOC. I’ve been too busy the last couple of weeks to get more runs but I’ll post them when I do. Guess I should mention my car is a P3. 2B004366-E95A-41ED-9194-EC394C7DF355.png 7F71BC8C-2BD8-4C96-A777-6085CAD4D3F5.png
     
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  12. skrtskrt

    skrtskrt Member

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    Gotcha. Somebody has already done the math with screenshots in the forum. It was posted awhile back
     
  13. AndrewAllen

    AndrewAllen Member

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    Can you link it for me? I couldn’t find it. Thx.
     
  14. StealthP3D

    StealthP3D Well-Known Member

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    I have a P3 and there is a barely discernible decline in acceleration at progressively lower charge levels. But it's really subtle because even at 20 % state of charge, the car is ungodly fast and will still take just about any combustion car off the line. By the time it gets down to 10% it's definitely noticeable (although it's still faster than most V-8's).
     
  15. ZOMGVTEK

    ZOMGVTEK Member

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    I’d like to see a dyno for an AWD and P3D over various SOC’s. My AWD sure feels slower as it drops below ~85%. By 60% it starts to feel slow. The top end starts to get especially weak below 60 or so, it’s super noticeable if you ask me.
     
  16. Electric Dream

    Electric Dream Pilots the Millennium Milkfloat

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    There's some good information and test results in this thread: P3D+ Acceleration

    My experience on track suggess the P3D+ in track mode performs in a very similar way from 90% all the way to 10% at least. Looking at data I logged last time I tracked it, there was very little difference in top speeds at the end of the fastest straight (2-3mph tops) between 80% and 10%.
     
  17. destructure00

    destructure00 Active Member

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    I've noticed significant drop in acceleration at the track below 30%. Below I think about 15% it really falls on its face.
     
  18. Electric Dream

    Electric Dream Pilots the Millennium Milkfloat

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    Have you measured it with a data logger or are you going by feel?
    What was the ambient temperature at the time?

    I ran mine down to 10% a couple of weeks ago (chasing a F488 around) and the only way I knew I was so low was when I glanced at the display. The data I've got bears me out too.

    There must be another difference between your experience and mine rather than just SOC alone.
     
  19. destructure00

    destructure00 Active Member

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    Feel...number of people I pass and the ease at which I pass them. 2 track days with same results. Ambient temp probably around 90. I don't have any data to back it up but I'm 100% confident power is down quite a bit below 20%....30 may be too high. Below 10% the car is a complete dog.
     
  20. skrtskrt

    skrtskrt Member

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