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Article on Supercharging effect on Model S battery capacity

Discussion in 'Model S: Battery & Charging' started by Father Bill, Jul 28, 2015.

  1. Father Bill

    Father Bill Member

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    Just saw an article over on Green Car Reports that gives some anecdotal analysis on the effect of Supercharging on the MS battery. I have not had his experience but I will be watching my numbers in the coming months. One of the primary reasons I bought my CPO MS 85 was for the range. The author of the article claimed a 9% reduction in battery capacity over 35,000 Miles. I can only hope that his experience is atypical.

    Peace,

    Father Bill
     
  2. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    A few observations:

    I have 58,500 miles on my car, and 39,500 of those are on the replacement battery pack I received after my contactors failed last year in February. The newly-refurbished battery pack charged to 268 miles the day I received it on a range charge - and just yesterday, it charged to 267.

    I range charge at will... I supercharge at will... I took a 2 week, 15-supercharger trip to Florida and back loaded down with my wife and kids. No issues with range whatsoever as a result of supercharging. I don't do it locally (we aren't that lucky), but I'm not a rare, rare supercharger visitor. Unless you supercharge each and every day on a 100-mile commute, I don't believe supercharging has the impact that the author suggests it does. (The author has occasionally posted on TMC, perhaps he'll chime in.)

    Relying upon the Tesla's "since last charge" display is problematic, for a number of reasons:

    • First, it just isn't accurate and only counts certain aspects of the drivetrain and climate control. It doesn't count energy consumed when at 0 mph, or when in P or N. it doesn't count energy consumed during pre-conditioning, when the car is off. Some of the electronics load is not considered. You cannot rely upon it under any circumstances.
    • Second, I've noticed that the "since last charge" is occasionally very, very buggy. The other day, it was "stuck" on 103.3 mi for over 15 minutes, then jumped by 12 miles over the next 60 seconds. During this time, I was driving with cruise control at 75 mph. The car drove far more than 12 miles during that time.

    Bottom line: don't rely upon "since last charge". An analysis of this needs to be done with better instrumentation than what Tesla shows us (and I'm willing to bet they've done it).
     
  3. jbcarioca

    jbcarioca Active Member

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    A quick look at the article makes it clear they're discussing Nissan Leaf. Whether the data is accurate I have no idea. However, the leaf has minimal thermal control, as is well-documented in Arizona comments on leaf performance. The CHAdeMO fast charging as applied to the leaf could potentially have some negative effect, but frankly I doubt it. My Leaf driving friends do not report serious degradation, nor is that evident in Leaf battery survey data:
    EV Batteries Last More Than Youd Expect, Survey Finds - The Green Optimistic
    Plug In America
    The Plug In America data is the best general data I know of.
    What it shows is that Tesla batteries perform well. The Supercharging pretty obviously has no negative effect. As for range charging, there is no solid enough data to judge. I'd follow Tesla's advice and use it when you need it then don't worry. FWIW I charge to 70% for daily local use, and to 90% for most trips, 100% for long legs. There is no evidence that Tesla batteries cannot handle higher regular charging, but it cannot harm them to be babied, so that is what I do.

    Regardless of who makes a judgement based on a single trip, we all probably know enough statistics to know that a single observation means nothing much. There are too many uncontrolled variables, among other things.
     
  4. AmpedRealtor

    AmpedRealtor Active Member

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    David Noland, the author of that piece, is almost entirely negative on Tesla. He published an alarmist article a couple of years ago about how Model S has a major flaw because he keeps hitting the brake and go pedal at the same time with his big, construction shoe-clad Fred Flintstone feet. I recall that many of his articles are negative. This article is complete speculation, and refers to studies done on the Leaf for goodness sakes!

    I find his musings to be moronic.
     
  5. Johann Koeber

    Johann Koeber Member

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    Just another data point:

    My Model S (and Battery) have 98,000 km (over 61,000 miles).

    A full charge (100 %) gets me to 373 km. When it was new it was 400, so I lost 27/400 = 6.75 %.

    Because I drive a lot I need to use Superchargers all the time. No problem for me whatsoever. Should the range decrease to less than 350 km, I would consider upgrading the pack. But I do not anticipate the need for another 2-3 years, as the degradation has been flat for the last months.
     
  6. Zythryn

    Zythryn MS 70D, MX 90D

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    I don't know that David's ire is only reserved for Tesla.
    He is very negative, about pretty much anything.
    He also jumps to conclusions based on poor methodology.

    Anything of his should be taken with a few blocks of salt.
     
  7. Lex

    Lex Member

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    I think we're right to see this as more of a blog post than a news article, and as such I think it's fine -- I found a fellow Model S owner who is anxious about the life of the battery and interested in knowing more about his car.

    After I did my own assessment of the owner survey data, I figured capacity fade seemed better than other devices power by lithium ion and I made up my mind that it was not a "big deal" to me. And in 10 years, there will certainly be better battery tech.

    What I do find interesting is some owners' obsession with the numbers -- while I'm fascinated by my energy consumption (made it home from a road trip with 1% yesterday, the things I do for fun these days) for me it's about getting from A to B (B to A in this case ; ). I don't much care about getting good "mileage" otherwise in such an overall highly efficient vehicle, and I don't care to micro-monitor my battery or alter how I need charge it to get from A to B.

    In fact, I am starting to use the battery % display more than the "rated range".

    Based on the owner survey data, this is the experience I am anticipating -- a 6% drop in the first 50,000 to 100,000 km (for whatever reason -- new car smell-infused launches for family and friends, SC-powered road trips... or just the nature of the tech) and then approx. 1% drop each 50,000 km after (a.k.a. the "hockey stick" curve). For me that would mean less than a 10% drop in overall battery range in the first 10 years and that seemed really impressive for a lithium ion battery.
     
  8. ViperDoc

    ViperDoc Roadster 1305

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    I have a Roadster and Signature S. I know that we a Roadster, we are advised that Range charging will decrease battery life. There are also a number of threads discussing Roadster charging that charging at higher amperages will shorten battery life—I believe this is due to the higher heat the battery endures. I suspect the same is true of the Model S, even though its battery technology is somewhat different. So it would not surprise me in the least if direct DC high speed charging ages the battery faster. For myself, I keep our Model S at 50-70% unless I need the range, and I have stopped the amperage down to 30 amps or so and only increase it if I need a faster charge for a reason.

    I don't have stats on my Model S, but my Roadster is my daily driver with about 45K after 4 years, and I have lost < 4% in battery capacity by treating the battery well (eg, only charge low and slow and keep out of performance mode).

    DJ
     
  9. AnOutsider

    AnOutsider S532 # XS27

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    That may be true, but

    Model S Brake Accelerator Pedal Positions

    also:

    It's not a huge issue, but it's not like he made it up either.
     
  10. mknox

    mknox Well-Known Member

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    At about 53,000 miles, I am down about 10%. I rarely Supercharge.

    - - - Updated - - -

    I switched to % a couple of months ago, but it was mainly because seeing my Rated and Ideal numbers gradually getting lower was making me sad.
     
  11. glhs272

    glhs272 Unnamed plug faced villian

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    I found this article and it's methodology complete BS. In my case on my 60 I have about 1% or so degradation at 51K miles. My last range charge:
    IMG_2006.JPG
     
  12. JohnQ

    JohnQ Active Member

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    Regardless of your issues with methodology you can't argue with anecdotal evidence of battery degradation. Some may say "the algorithm has changed," others may say "do a bunch of range charges and depletions," but the reality is that at 35k miles and 2.5 years my 85 kWh battery registers 246 on a full charge. You can do the math on the difference.

    And, yes, I've done a full charge, depleted to 5 miles and followed that up with another full charge. I may not know what the current capacity is on my battery right now, but I know what the car is telling me.
     
  13. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    Oh thank you, saves reading. He's likes to make life hard for himself and then whine about it.
     
  14. Zythryn

    Zythryn MS 70D, MX 90D

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    I certainly wouldn't argue that you are not experiencing that.
    What I can argue is that your experience is typical.

    There are numerous reports and data showing that much range loss is very unusual.
    What has the service center said?
     
  15. golfski

    golfski Member

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    I wish I was as lucky as you. I am about 26,000 miles into my 60 and have charged to 90% regularly, super charged maybe 15-20 times, CHadeMo another 10-15 times and my max charge is 187 :(. I was rolling steady at 178/179 mi @ 90% but have lost a few miles a number of times. I am down to 169/170 @ 90%. I have had two events that have lost 3-5 miles for seemingly no reason and overnight. Both times was running the car lower to about 15-20%.
     
  16. Dwdnjck

    Dwdnjck Member

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    If David Nolan thinks that he is degrading his battery by using super chargers for local use, that's fine with me.
     
  17. Matteo

    Matteo Member

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    #17 Matteo, Jul 28, 2015
    Last edited: Jul 28, 2015
    I think we can do better than anecdotal evidence from just one owner. In Merijn's Battery Survey we have data from 110 Model S owners. The data is not entirely consistent but it largely shows that supercharging is good for the battery. According to the data, people who never supercharge have about half a percent less battery capacity than others at the same mileage. People who supercharge weekly have half a percent more capacity than others with the same mileage.

    pRmZfjr.gif

    It also shows that if you supercharge daily, you will have 0.88% more capacity but I wouldn't take that seriously just yet because only one person so far said they supercharge daily. The number people in each group is shown here:

    Frequency of supercharging
    A) daily 1
    B) twice a week 7
    C) weekly 15
    D) twice a month 26
    E) monthly 30
    F) a few times a year 14
    G) once or twice a year 5
    H) never 12
    Total 110 users
    This list shows numbers of unique entries. Only the last entry from each person counts to increase accuracy. To see this data go to the stats page on the battery survey.
     
  18. JohnQ

    JohnQ Active Member

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    I must have been in a bad mood when I posted last night. The tone was pretty angry, wasn't it? Anyway, I haven't opened a case because I'm not that stressed about it right now. I know mknox and others have experienced similar declines as well.

    I'll be taking a 2,000 mile trip in October and I'll see if there's any change; I can also do a full battery drain (or at least to near zero) on a single drive without stopping and see how much energy is used. That will give me a good sense of the actual capacity. Might contact the service center after that.

    On the other hand, no drive replacements or contractor failures so far :biggrin:
     
  19. hpham007

    hpham007 Banned

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    I think you're missing the point of the article. His point was that you can't tell if you have degradation from what is showing on your screen. The miles shown for him was different from what he was able to extract from his battery.
     
  20. jbcarioca

    jbcarioca Active Member

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    OK, and that means he published without doing the minimal research needed to know that:
    1. periodic recalibration (i.e. going from range charge to low SOC) is needed to maintain high reliability of screen estimations.
    2. these are estimations. we all know that, and we also know that the algorithms that produce the estimate change from time to time.
    Despite those points we are all very interested in the subject. Thus, we often report actual driving experience in these threads. The one thing we all should know by now is that EV battery life, for most manufacturers, is exceeding the most optimistic estimates of five years ago. tesla even more so.

    No amount of false and/or distorted reporting will change the facts, although it might change opinions of ill-informed people who probably would not buy an EV anyway in the near future. Such views will eventually disappear as did the Seldon patent.
     

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