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Performance model battery degradation question

Discussion in 'Model 3: Battery & Charging' started by diggity, Nov 14, 2019.

  1. diggity

    diggity Member

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    I have a 3 month old model 3 performance with a little under 4K miles on it. I charge about once a week up to 90% and when I go to charge, the car is at around 20%. Battery at 90% charged has 267 miles on it, roughly a 6% degradation. Is this normal?
     
  2. TrooperCA

    TrooperCA Member

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    I think this calculation is based on your wh/mi overall. On your trip log, scroll to the bottom and what is your wh/mi? I think mine is 234wh/mi for a LR AWD. I am showing anywhere from 308-309 for 100%.

    Meaning that if you floor it a lot, dont expect to ever hit 300s.

    The estimated range of 300s is only based on ideal temp and driving conditions. You would have to drive 55mph.
     
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  3. lanbo

    lanbo Member

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    267 / 0.9 = 296.67 miles

    (310 - 296.67) / 310 * 100 = 4.3%
     
  4. jjrandorin

    jjrandorin Another BMW convert

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    • Helpful x 1
  5. diggity

    diggity Member

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    ah I was doing the math wrong I guess: (267*1.1)/310
     
  6. ewoodrick

    ewoodrick Well-Known Member

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    Charge every few months to 100%.
     
  7. diggity

    diggity Member

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    Ok good idea. I will try that. Thanks everyone! I know we have threads that have a lot of info on this, but they seem to be just a hodgepodge to go through.
     
  8. WilliamG

    WilliamG Active Member

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    ....Why? Source?
     
  9. KenC

    KenC Active Member

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    Since you only need to charge once a week to go from 90% to 20%, then your commute is not that far. Perhaps, you should try another charging strategy if the 4.3% loss is bothering you. Why not try 70% and keep it plugged in?
     
  10. diggity

    diggity Member

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    Yeah i might do that. Thanks, Ken! Gonna shake it up a bit lol
     
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  11. Oyinko

    Oyinko Member

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    The rated range displayed by the car doesn't take into consideration driving style.
     
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  12. ewoodrick

    ewoodrick Well-Known Member

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    Number of places, and yes, some interpretation.

    At 90%, the battery really doesn't go into its final stages of calibration and balancing. Only at full charge will the batteries completely balance and that's also the time that evidently the software goes through some recalculation of what the maximum capacity is.

    It's been shown time after time, that charging to 80%, even 90% all the time doesn't allow this to occur. Periodic charging to 100% (not on a Supercharger, and make sure that you leave it plugged in for a few hours) allows all the numbers to reset.

    Of course the much better thing to do is to take a trip and use it. Not only does it give the battery a chance to be worth it's money (driving a car 100 miles a day on a 325 mile battery isn't a great use of money), it helps you get over the obvious range and bettery anxiety that you have.

    What's my max range? I'm really not sure what it has been recently, because I don't worry about it. Every time that I checked, I've had no degradation. That's over 18 months on my Model 3 and 2 years on a 2018 Leaf and 3 years on a 2015 Leaf. (with only 3% degradation).

    I just drive and enjoy my car at 28,000 miles, mostly trips that I barely think about the battery and charging on.
     
  13. WilliamG

    WilliamG Active Member

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    I'd really like to see some actual sources.

    But hey, I've charged a few times to 90% and mostly to 80%, and 6.5 months later and several thousand miles in, I'm still at 310 miles rated range, so I'm going to continue doing what I'm doing!
     
  14. TrooperCA

    TrooperCA Member

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    Just did a check. You are correct. Tesla has a patented way to determine your rated range using voltage and their conversion table.

    So...that leaves me as clueless as anyone else. Which means I can just start driving it like I stole it since I have free supercharging
     
  15. joebruin77

    joebruin77 Member

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    If you want an easy and accurate way of keeping track of your battery's health, I suggest getting and using the Stats For Tesla app. I find the Battery Health graph to be very useful and informative:

    Screenshot 2019-11-15 at 1.24.51 PM.jpg
     
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  16. TrooperCA

    TrooperCA Member

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    Nice looking graph...recently, or almost as soon as I got the latest update, my graph is now trending downwards.

    9/19 LR AWD with almost 5K miles.
    I usually only charge to 80% and have only charged it to 90% maybe twice.
     
  17. ewoodrick

    ewoodrick Well-Known Member

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    You aren't going to see any hard information from Tesla, as their point of view is that the battery doesn't need babysitting and this entire conversation is pretty moot.

    But there have been tweets from Elon inferring as my statements. Some investigations seem to indicate that around 93% or so is actually enough.

    But if you are happy, then be happy. But don't be afraid of charging to 100%. The car, nor battery will self-destruct.
     
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