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Throttled vs. Non-Throttled Supercharging Comparison

Discussion in 'Model S: Battery & Charging' started by Naonak, Aug 13, 2017 at 8:30 PM.

  1. Naonak

    Naonak Member

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    I have completed my trip. Here is the raw data:

    Pre / Post DCFC Throttle Data

    If anyone wants to collate and/or graph the data, that would be great. I'm not that great with spreadsheets to start with.

    Here are the take aways:

    • Yes, throttling increases your trip time.
    • Yes, it seems ~5 minutes is the increase from an absolute charge standpoint (with a caveat).
    • The amount of time to "continue your trip" has increased dramatically, but not due to throttling. It appears that Tesla has increased the buffer amount by approximately 10% since throttling was implemented, so a throttled car coupled with the new algorithm increases your "time to continue" by 10+ minutes per stop, giving the appearance of a much larger increase in charging time than actually exists. Tesla kind of shot themselves in the foot with this. Or at least the timing of the throttling discovery and the algorithm changes was an unfortunate coincidence.
    Armed with this new knowledge (for me), I feel a lot better about the throttling. Yes, it does increase my trip time, and yes it's annoying and yes I think Tesla really dropped the ball by doing this in stealth mode. My wifes P85 actually has better range than my P90, and hers has 100,000+ miles on it.

    All in all, the 90 packs are inferior to the 85 packs by almost every single measure (with the exception of the max amps I guess?). Usable energy in my 90 pack is actually less than in my wifes P85. My 90 pack has about 76 kWH of usable energy (I measured when the car was new), although that seems to have dropped and I just started a re-calibration to see how much actual usable energy I have now. My wifes 85 pack has closer to 80 kWH of usable energy, no apparent artificial throttling, and presumably a longer life in the presence of DCFC, even on an infrequent basis.

    If I were replacing my pack with a bought and paid for pack today, I'd get an 85 pack instead of a 90, assuming they could do the retrofit. Of course, I'd rather have a 100 pack, but that seems off the table for the immediate future.
     
    • Informative x 12
  2. apacheguy

    apacheguy S Sig #255

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    Tesla may be returning to the older cell chemistry in part because of these issues.
     
    • Like x 1
  3. brianman

    brianman Burrito Founder

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    @Naonak
    Thanks for sharing your data.
     
    • Like x 2
  4. pilotSteve

    pilotSteve Member

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    I *did*replace my 2012 S85 with a late 2016 S90D. I’ve experienced supercharger throttling to a similar degree. Range so far (12k) miles hasn’t decreased but you have me concerned...
     
  5. spottyq

    spottyq Member

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    Thanks for taking the time to collect and share this data.
     
  6. tnt1971

    tnt1971 Member

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    I got one of the last 85s. They called me several times trying to get me to upgrade for $3,000. Glad I did not.
     
  7. Max*

    Max* Autopilot != Autonomous

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    This buffer has been all over the place, I think this change is not due to the throttling but just something Tesla messes with. This time it might have timed it with the throttling. I usually ignore that number, and chose my own safe buffer and drive.


    I've seen it require 7% (red to yellow buffer), either (10% or 15%) and 20% (green to yellow buffer). <-- buffer to arrive at your destination with before it says "enough charge to continue trip".

    It started high, then they lowered it as low as 7%, then brought it back up. I want to say now it's 20%, but I could be remembering wrong.
     
  8. Naonak

    Naonak Member

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    I don't think it was changed due to the throttling. I was just saying it was a poorly timed coincidence.

    Yes, at least for me, it's now at 20% from the previous 10% a year ago. The 10% was optimistic and would never have gotten me to my destination. I always buffered to at least 15% if not 20%.
     

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