Excessive DC Charging Of Tesla Model S, X Leads To Permanently Reduced Charge Rate

9 months ago by Eric Loveday 99

Too many DC fast charges can limit future Supercharging rates

Excessive DC charging takes its toll on your Tesla Model S and X. In fact, it can lead to permanently reduced charging rates.

That’s the latest news coming from a Tesla Motors Club (TMC) forum posting.

Tesla using CHAdeMO adapter for a DC fast charge

Here are the details, truncated for brevity and to focus on factual info, as provided by TMC member Naonak:

“Hi everyone. I just got off the phone with Tesla with some disturbing news.

My car has approximately 30,000 miles on it. I regularly use CHADeMo to charge my car, with the occasional Supercharger charge on road trips. On my last road trip, I noticed that my supercharging rate was significantly reduced, usually staying between 75 kw and 90 kw. At first, I thought it was the station, but each Supercharger on my trip had the same behavior. So I bought my car in for service last week.

After the technicians went over the and presumably consulted with the mothership, it was determined that the car has now entered a permanent degraded mode where it will no longer allow fast charging to “prevent battery degradation.” Read that again… that’s right… if you use Superchargers or any DC Fast Charging, including CHADeMo, your car will eventually enter into a permanently degraded mode that will prevent you from charging your car at reasonably fast speeds.”

Naonak notes that to the best of his knowledge, this is his DC charging breakdown to date:

6,685.603 Energy (kWh)
245 Total Charge Ups

“That does not include Supercharging. You can add probably another 50 – 60 Supercharges to that I would estimate (I can get an exact number at some point, I have records). That number above is 99% CHADeMo charging since March 2016.”

New Tesla Supercharging Stalls In Nep

Naonak later posted the actual technical explanation from the Tesla service center after raising his concerns to upper management. Its reads as follows:

Concern: Customer states: speed of charging at Superchargers is topping out at lower
speeds then previously observed. This has happened at multiple superchargers recently.

Pay Type: Goodwill

Corrections: Supercharger General Diagnosis Conclusion: No Trouble Found
Review vehicle logs and verify charging is topping out a lower rate than observed on
earlier DC charging sessions. According Tesla engineers once vehicle has been DC fast
charged over a specified amount, the battery management system restricts DC charging to
prevent degradation of the battery pack. According Tesla engineers, this vehicle has seen
significant DC fast charging and is now has permanently restricted DC charging speeds.
Important to note, supercharging will always still be available to the vehicle and the battery
pack has not yet experienced significant degradation due to the amount of DC fast
charging performed on the pack up until this point in time. Vehicle is operating as

This seems to now fully confirm what others had speculated in the past.

This is not unique to Tesla though. BMS systems monitor conditions and should respond accordingly. In this case, by limiting charge rate, Tesla is protecting the pack from further damage and degradation. It makes perfect sense to us, though perhaps Tesla should make this more clear to Model S and Model X owners.

Tesla has now issued a statement confirmed the limiting of fast charging (via Electrek)

“The peak charging rate possible in a li-ion cell will slightly decline after a very large number of high-rate charging sessions. This is due to physical and chemical changes inside of the cells.  Our fast-charge control technology is designed to keep the battery safe and to preserve the maximum amount of cell capacity (range capability) in all conditions.  To maintain safety and retain maximum range, we need to slow down the charge rate when the cells are too cold, when the state of charge is nearly full, and also when the conditions of the cell change gradually with age and usage.  This change due to age and usage may increase total Supercharge time by about 5 minutes and less than 1% of our customers experience this.

Tesla is not slowing down charge rates to discourage frequent Supercharging – quite the opposite.  We encourage our customers to use the Supercharger network at their discretion and we committed to doubling the number of worldwide chargers just this year.  We also want to ensure that our customers have the best experience at those Superchargers and preserve as much vehicle range as possible – even after frequent usage.”


Check out the full 43-page (and growing) discussion at the link below.

Source: Tesla Motors Club Forum, Electrek

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99 responses to "Excessive DC Charging Of Tesla Model S, X Leads To Permanently Reduced Charge Rate"

  1. Alan says:

    I can feel a short coming on !

    1. pjwood1 says:

      I feel ignorance pervades, and then gets fed.

      -60’s, 75’s and older 85KWh cars generally top out near ~90KW
      -The cars capable of 115KW+ get it for all of ~15 minutes, as the taper normally lowers wattage as cars charge.
      On this first page TMC thread, is a graph showing how short lived the peak rate is, in the first place:
      Watts = Volts X Amps

      That nobody has elevated this yet, shows the practical effect is limited (most don’t notice). Lots of taxis, etc., are frequent fast-charge users. Tesla should disclose counters, whether launch or DCFC. That much I feel is true, but in both cases the practical effect is quite small.

      1. Michael Will says:

        The title is misleading. The guy intentionally was only DC fast charging instead of charging at L2 for daily use like most people, and documented each use so he has something to talk about. Will be interesting to see teslas response, reminds me of the story when the guy intentionally ran out of electricity and wrote a big article about it.

        But I know why the shorts are anxious and try whatever they can, and its a good thing because it will keep tesla honest and on their toes. And they finance my TSLA shares so I can buy them at a discount and profit when the inevitable short squeeze happens.

        1. MikeG says:

          He was using a Chademo adapter which is limited to 50kW but that rate is less than half the Supercharger rate but more than twice the max L2 charge rate.

        2. sven ¯\_(ツ)_/¯ says:

          Michael Will said:
          “The title is misleading. . . Will be interesting to see teslas [sic] response. . .”

          Put down your Tesla pom-poms and reread the article, because it includes Tesla’s response.

          How exactly is the title misleading? You can read the complete Tesla Service Center diagnostic report for yourself. On Page 3 it says the following:

          “According Tesla engineers once vehicle has been DC fast charged over a specified amount, the battery management system restricts DC charging to prevent degradation of the battery pack. According Tesla engineers, this vehicle has seen significant DC fast charging and is now has permanently restricted DC charging speeds.”


          Diagnostic Report page 3:

  2. bro1999 says:

    Tesla misleading/hiding new updates restricting performance (like the Ludicrous counter) from customers?

    1. William says:

      My golden ticket is starting to tarnish! My Violet Beauregarde is startng to chew through, as I need a Tesla polish and buff, from that factory fresh Freemont shine. Tesla Model 3 where are you? Chomping at the bit and blueberry gum!

    2. Chris O says:

      I’m sure if you insist on destroying your battery by quick charging too often at full force Tesla will adjust your car’s software for you to allow that. After all it is your right to destroy your own stuff!

      I reckon there needs to be some sort of register or something of compromised cars though, to warn buyers of used Tesla’s.

      1. ¯\_(ツ)_/¯ sven says:

        At full force? No. The vast majority of this guy’s fast charging session were on CHAdeMO and Tesla’s CHAdeMO adapter limits the charging rate to 50 KW.

        From the article:
        “245 Total Charge Ups [on CHAdeMO]

        “That does not include Supercharging. You can add probably another 50 – 60 Supercharges to that I would estimate (I can get an exact number at some point, I have records). That number above is 99% CHADeMo charging since March 2016.”

        1. Chris O says:

          According to Tesla:

          “The peak charging rate possible in a li-ion cell will slightly decline after a very large number of high-rate charging sessions. This is due to physical and chemical changes inside of the cells. Our fast-charge control technology is designed to keep the battery safe and to preserve the maximum amount of cell capacity (range capability) in all conditions. To maintain safety and retain maximum range, we need to slow down the charge rate when the cells are too cold, when the state of charge is nearly full, and also when the conditions of the cell change gradually with age and usage. This change due to age and usage may increase total Supercharge time by about 5 minutes and less than 1% of our customers experience this”.

          So no exact number for the total amount of “full force” quick charges that trigger this, because it’s just one factor affecting cell condition. I doubt the 50KW Chademo charges have much effect though.

          1. Waiting says:

            Agree Chris O. I applaud Tesla for wanting to protect owner’s battery packs. Tesla just should have made it perfectly clear the ramifications of excessive DC fast charging.

            Owner should be able to request a software update at the service center to override programming. Then owners can destroy their battery packs and spend big bucks to replace them. Their right to do so.

          2. sven ¯\_(ツ)_/¯ says:

            Since when is 50 kW CHAdeMO DC charging considered a high-rate charging session for a Tesla when a Supercharger can charge at 115 kW? When a Bolt charges at 50 kW Tesla make fun of it for fast charging so slow.

      2. Spider-Dan says:

        No, they won’t, because the battery is still under warranty.

        And Tesla isn’t going to hype the advantage of the SC network and then turn around and say, “By the way, if you use SC too many times, your battery warranty is voided.”

        1. Jake Brake says:

          Tesla doesnt warranty battery degredation, this customet is SOL.

          1. Spider-Dan says:

            You’re right. It looks like this is another case just like Tesla’s “open patents,” where the press release says one thing but the fine print says the opposite.

            From the Model S owner manual (emphasis added):

            Battery Limited Warranty
            The Model S lithium-ion battery (the “Battery”) is an extremely sophisticated powertrain component designed to withstand extreme driving conditions. You can rest easy knowing that Tesla’s state-of-the-art Battery is backed by this Battery Limited Warranty, which covers the repair or replacement of any malfunctioning or defective Battery, subject to the limitations described below. If your Battery requires warranty service, Tesla will repair the unit, or replace it with a factory reconditioned unit that has an energy capacity at least equal to that of the original Battery before the failure occurred. Your vehicle’s Battery is covered under this Battery Limited Warranty for a period of 8 years or for the number of miles/km specified below for your Battery configuration, whichever comes first:
            • 60 kWh – 125,000 miles (200,000 km)
            • 85 kWh – unlimited miles/km
            Despite the breadth of this warranty, damage resulting from intentional abuse (including intentionally ignoring active vehicle warnings), a collision or accident, or the servicing or opening of the Battery by non-Tesla personnel, is not covered under this Battery Limited Warranty. In addition, damage resulting from the following activities are not covered under this Battery Limited Warranty:
            • Exposing the vehicle to ambient temperatures above 140°F (60°C) or below -22°F (-30°C) for more than 24 hours at a time;
            • Physically damaging the Battery, or intentionally attempting, either by physical means, programming, or other methods, to extend (other than as specified in your owner documentation) or reduce the life of the Battery;
            • Exposing the Battery to direct flame; or,
            • Flooding of the Battery.
            The Battery, like all lithium-ion batteries, will experience gradual energy or power loss with time and use. Loss of Battery energy or power over time or due to or resulting from Battery usage, is NOT covered under this Battery Limited Warranty. See your owner documentation for important information on how to maximize the life and capacity of the Battery.

      3. ModernMarvelFan says:

        “I’m sure if you insist on destroying your battery by quick charging too often at full force Tesla will adjust your car’s software for you to allow that. After all it is your right to destroy your own stuff!”

        I clearly remember that Tesla said DCFC doesn’t impact its battery life and in fact, encourage people to use them.

        So, now there is an impact if used “excessively”.

    3. Pushmi-Pullyu says:

      bro1999 posted FUD:

      “Tesla misleading/hiding new updates restricting performance (like the Ludicrous counter) from customers?”

      No just another Tesla bashing post from just another Tesla short-seller.


      1. bro1999 says:

        Tesla secretly implementing the Ludicrous counter and people reporting that was also just TSLA shorts in action too, right? And Tesla was totally innocent?

        Big brother Elon: I do what I think is best for your Tesla! Regardless of what you want.

        Hmm….communism sounds pretty good in theory too!

  3. Peter says:

    More than 80.000 miles mostly on SC and Chademo still no difference in charging speed.
    Maybe the lower temperatures in some northern countries are better for DC charging ?

    1. needa says:

      This goes more along the lines of that user populated degradation page on the Tesla forums. Where it plainly shows that SC charging has the lowest degradation rate.

      I have to wonder if this guy got a dud battery pack, and Tesla had an automated response ready for just such a thing.

      1. Ross says:

        Not sure why it would make a difference, but this guy’s fast charges were almost exclusively Chademo and IIRC he almost never charged using anything other than a fast charger. I believe he only used a SC a handful of times.

        1. Pushmi-Pullyu says:

          The differences are:

          1. Always (or almost always) fast charging instead of standard slow charging

          2. Not using a Tesla designed charging station

          I dunno that #2 causes more stress on the battery pack than using a Supercharger, but certainly it can’t be better for the pack to use a DCFC not designed by Tesla.

    2. zzzzzzzzzz says:

      It is speculated that the reduction applies to around 2015 model year only. It was the year Tesla announced about starting to use extra silicon in anode, that is known for negative impact on longevity. I think taxi drivers in Amsterdam who constantly use DC charging also had power restricted a bit before.

      As is well known, high power chargers are relatively easy part. Making cheap and dense Li-Ion batteries to take all this power and survive for long is more difficult.

      1. georgeS says:

        bingo zzzzzzzzzz,

        There’s another thread on the issue you are talking about.

        There’s data and a spread sheet. I plotted up the data and it definitely looks like the 90’s are being throttled on the low end and the older 85’s are not. I’m seriously hoping this isn’t an issue with the silicon anodes.

        Note that the OP for this article doesn’t say if his car is a 90 or an older 85. It may be 2 separate issues

      2. pjwood1 says:

        The whole universe of Tesla batteries is trending to 5-7% range loss over time. 2015 no different.

  4. Viktor says:

    Tesla have comment on it here

    1. Jay Cole says:

      Thanks Viktor,

      Will add the statement/linkie to the story.

      1. scottf200 says:

        He also posted directly in the TMC thread.

        Here is a key point that is not emphasized. 5 minutes!!! every couple hours. — ho-hum

        “This change due to age and usage may increase total Supercharge time by about 5 minutes and less than 1% of our customers experience this.”

        1. Pushmi-Pullyu says:

          “Here is a key point that is not emphasized. 5 minutes!!! every couple hours. — ho-hum”

          Right, Nix noted that in a previous discussion of this non-issue.

          It’s hardly surprising that someone who abused his battery pack like this would have a slight reduction in charging speed, but it is only a slight reduction.

          Perhaps instead of the car owner trying to blame Tesla for the degradation in the battery pack, he should be thanking them it’s not worse!

  5. Ziv says:

    Not a big issue, but it would have been a non-issue had Tesla warned owners of this potential action a year ago. I would guess that they failed to foresee the amount of people that would use the SC system as a free lunch, and how frequently they would want lunch.
    Tragedy of the commons.

    1. MTN Ranger says:

      I think another key issue is that most of his DC charging was done using CHAdeMO. With 25-50 kW charging it is surprising that Tesla lumps those in with 120 kW superchargers. This is especially troublesome since the CHAdeMO is relatively slow and many assume this would not lead to battery issues with large packs.

      1. Ziv says:

        I am laughing at my lack of reading comprehension, MTN Ranger. I was thinking it was an overuse of SC System and the article clearly quotes the guy saying it was mostly CHAdeMO charging. Thanks for pointing it out. Which makes me wonder what is so bad about slower CHAdeMO charging vs. faster SC charging…
        I am afraid to go back and re-read the article because I probably missed that too! LOL!

      2. zzzzzzzzzz says:

        50 kW is peak power for Tesla adapter. Once battery state of charge gets closer to 70-80%, battery ability to take this power becomes limiting factor and it would be no difference from Tesla supercharger. We don’t know how it was used, maybe he was charging to 90%-100% all the time, who knows.

        1. realistic says:

          “We don’t know how it was used, maybe he was charging to 90%-100% all the time, who knows.”

          No, we don’t, but the fact that this would be a consideration at all isn’t something that you should expect the phalanx of Model 3 hopefuls to simply accept:

          “Be sure you don’t ‘fill up’ your car just any old time. It’s not meant to be ready at full range every morning. If you really have an urgent need to drive some extra distance you can always supercharge… which will become more limted every time you do it, of course. But remember, you’ll never feel a transmission shift.”

          Ditto that same admonition to a one-car family, a rigorous business-use driver, or especially (once the “Tesla Semi” is more than a shadowy PR shot) a freight/delivery owner/operator.

        2. Beng says:

          Yeah, but the restriction that Tesla is imposing is on the initial peak power, the OP’s is down from 115 KW to 90.

          All of his many ChaDeMo sessions never once approached that peak power.

          I do wonder if Tesla hasn’t unnecessarily lumped all DC charging sessions into the same category. Surely a ChaDeMo session that starts at 50 KW wouldn’t have the same impact on the battery as a Supercharger session starting at 115?

          1. ItsNotAboutTheMoney says:

            I was wondering about that.

        3. Pushmi-Pullyu says:

          zzzzzzzzzz said:

          “…it would be no difference from Tesla supercharger.”

          Assuming facts not in evidence. We don’t know if Tesla cars’ onboard DC charging systems will work as well with a CHAdeMO adapter as they will with Tesla’s own design, the Superchargers.

          This guy is using DCFC far, far more than the average Tesla car driver does, or anybody driving any other PEV (Plug-in EV) for that matter.

          There’s no mystery here. The guy was abusing his battery pack by using DC fast charging almost exclusively, rather than slow charging at home or at work. No PEV is designed for that.

          Degradation of the pack when abused like that should be expected. Whether or not Tesla added software to its BMS to slow down that degradation is pretty irrelevant to what caused the degradation.

          1. unlucky says:

            Tesla designed the onboard systems. They designed the adapter. If the adapter didn’t work well with their onboard systems they should have said so.

            I don’t see any reason to think using a CHAdeMO charger and the adapter should be more harmful than supercharging. In DC charging the car requests a voltage level and the charger produces it. The car monitors it too. So the voltage should be as the car requested. If it’s not the car should cut off the charge.

            If this system in total doesn’t work as well as supercharging then it would only be due to an error in Tesla’s implementation of one of their two systems involved.

            I don’t see any reason to think this guy’s car is suffering from anything other than the same wear and tear anyone else could expect by discharging and charging the car so often/rapidly. It doesn’t seem excessive or unexpected.

  6. jahav says:

    Interesting. That has some serious implications for Supercharger v3 (the 350+kW). I guess there won’t be a 10 min charging after all, pity.

    On the bright side, 90kW is not that far from 80kW of Bolt EV limit 🙂

    1. bro1999 says:

      The worry for that particular Tesla owner (and others that also have experienced the SC rate neutering) is that the reduced max charging rate is on a sliding scale.

      So perhaps sometime soon, the owner’s Tesla will actually charge slower than a Bolt. 😀

      1. SparkEV says:

        If they cut it all the way to 50 kW, Bolt will charge quicker (more miles per minute) since it’s more efficient. I doubt that will happen.

        By the way, Tesla using Chademo charges slower than Bolt using the same efficiency argument. If this guy was able to live on Chademo, well, he’s got lots of patience! I just hope he didn’t have other people waiting when he could’ve used supercharger instead.

    2. unlucky says:

      Not surprising. It’s only really surprising Tesla bothers to blame it on anything. Pack wear increases the internal impedance (resistance) and that limits charge rates and discharge rates (max acceleration).

      Packs wear out and if you discharge them and charge them more often and faster it’ll happen faster. That’s just life in the big city. Improved battery chemistries will hopefully slow this process in the future.

    3. Pushmi-Pullyu says:

      “I guess there won’t be a 10 min charging after all, pity.”

      Certainly there won’t be with the current generation of plug-in EVs. 10 minute charging will require improvements in the battery packs, and likely improvement in the battery cells themselves to reduce resistance and therefore reduce or eliminate the problem with overheating during fast charging.

  7. Someone out there says:

    I remember Elon stating that supercharging (compared to regular charging) does not affect the battery negatively at all. Apparently that wasn’t true then.

    1. bro1999 says:

      Elon not being up front with customers? Say it ain’t so!

    2. K-lein says:

      If I remember the Tesla statement, it was about the range not being affected any differently when using supercharger than a normal L2 charge.

      But I’ve never seen any statements about the charge speed.

    3. Pushmi-Pullyu says:

      “I remember Elon stating that supercharging (compared to regular charging) does not affect the battery negatively at all. Apparently that wasn’t true then.”

      Hmmm, well, you may be taking Elon’s remarks out of context. Perhaps he meant that to be taken in the context of someone who uses Superchargers for their intended use: Only for occasional long-distance travel.

      I don’t need to be an electrical engineering genius to figure out that always charging secondary (rechargeable) battery cells at a higher current than they are designed for is going to have an adverse effect on battery life!

      Tesla’s cars are designed for the battery pack cooling system to kick in when the battery pack gets overheated during fast charging, and that overheating puts a limit on how fast the battery pack will charge. That’s the primary reason Superchargers taper off the charge when charging a significant percent of the pack’s capacity: to prevent excessive overheating.

      But the cooling system doesn’t prevent the pack from heating up; it only prevents it from getting above a certain temperature. Any electrical engineer can tell you that frequently heating up electronics and letting them cool down shortens their life, even if the heating isn’t extreme.

      It would be naive to think that always DC fast charging, instead of using a slow charger at home or at work, won’t stress the battery pack and cause premature aging. Even if it’s “only” at 50 kW, that’s still a heck of a lot more power than any Level 2 charger!

  8. JeremyK says:

    This makes a lot of sense to me. Tesla/Panasonic don’t have any secret sauce when it comes to battery chemistry (nothing overly significant anyway). It’s not that GM/LG batteries can’t achieve a high charge rate, it’s that GM has done their homework (i.e. validation testing) and know exactly what rate and how many cycles will cause an unacceptable loss of capacity, charge rate, performance, etc. GM, being a more conservative company, simply limits the max charge rate across the board, while Tesla pushes the envelope and allows faster charging, but only for a limited number of times. I actually think Tesla has a good approach here, because it give customers the best possible charge rate, while still protecting the battery long term. I do suspect that this news could affect the uncertainty of knowing a car’s charging history when buying used, however.

    1. realistic says:

      If somebody develops (or Tesla offers) an OBD plug-in device/prtocol that can read the history and make it available in a CarFax-like service, the value impact could be limited to these kinds of cases. Not really the “Tesla Way” for now, but it’s probably needed to accomodate a broader segment of buyers/drivers to preserve residual value.

      1. zzzzzzzzzz says:


        You can do it in Leaf and have all the information up to individual battery parts I think. However Tesla doesn’t have usable OBD, only compliance one. That is it the root of the problem – company culture. Everything is proprietary, hidden and controlled from mothership, and a gang of true believers is ready to squash you if you complain too loudly.

        1. Pushmi-Pullyu says:

          There certainly are anti-Tesla FUDsters — like you, zzzzzzzzzzz — hanging around like vultures, always ready to take a non-issue — like this one — and try to turn it into a smear campaign against Tesla.

          Again, the “issue” or rather non-issue here is someone abusing his BEV by always using DC fast charging, instead of normal slow charging.

          Any BEV made by any company would have the same problem with abusing the battery pack causing premature degradation. It’s simply counter-factual to claim this is somehow a “Tesla problem”.

    2. 2EVsCO says:

      Volt batteries charge at 3+C on Regen and similarly when using the genset although for 10s only max on Regen. still impressive over hundreds of thousands of miles on a 16 to 18 kWh pack. People mistake GMs conservative designs as hamstringing, but really it is about long term happy customers and attempting to retain the cars value and usefulness in the long run.

      I told my buddy with a 2013 85kWh (80 actual new…) MS about this issue and he seemed to not care, but I’m guessing in a few years on a long road trip he won’t be too pleased that he spent potentially an extra hour or so charging. Once you have something like super fast charging you don’t want to give it up even if it is only 10% different. And I agree this could negatively affect used Tesla values due to uncertainty across previous users. I would also like to know max/min temps batteries have reached as well and how many times it was charged to 100% for this same reason. Some people know how to treat batteries and some don’t.

      1. SparkEV says:

        SparkEV charges at 2.6C for 20 minutes. GM was not so conservative with SparkEV.

        From what I read, Tesla’s peak power is reduced, but that may have little effect on average power, because 120kW peak power is held only for few minutes. Heck, even 90kW isn’t held long before taper begins. As such, it may add a minute or two to supercharging, which isn’t a big deal.

        Bigger question is how deep will the cuts be made. Can they cut it all the way to 50 kW? Then using Supercharging will be no different than using Chademo.

  9. realistic says:

    For the moment, not really a giant issue. Few candidate Tesla buyers in the near-term will subject their cars to this charging duty cycle.

    However, as more owners reflect the broader spectrum of auto use — everything from daily business driving >150km per work day to adjoined housing, strret-parking city dwellers with no access to “normal” overnight charge — it becomes real. In other words, it’s a notcieable issue in the projected/presumed world of the Model 3.

    In the Muskian Vision World of 24-hr available Autonomous EVs running 1,5Mkm without maintenance and OTR trucks running >500,000km/yr, it’s a real problem.

    I know, I know: the issue will all be fixed by then. For the Elon told me so. Yet the issue wasn’t even supposed to exist at all, according to the same guy… er, Prophet.

    1. Pushmi-Pullyu says:

      I find your user name, “realistic”, to be rather ironic when asserting that Tesla should somehow be able to change one of the basic properties of rechargeable batteries!

      Just like anything else, if you abuse a BEV’s battery pack like this guy has, it’s going to wear out faster. Tesla doesn’t have any magic batteries which are immune to entropy or the laws of physics!

      Gasmobile, PHEV, or BEV, your car will last longer if you care for it properly, and will wear out faster if you abuse it.

  10. Warren says:

    I have been fascinated by all the talk of soon charging li-ion batteries in minutes, like pumping gas. The commenters seem to assume it is only a lack of huge DC chargers that is holding us back.

    Once more than a handful of acolytes are driving long range EVs every day, people will have a more realistic view of current battery technology.

    Goodenough, or someone else, may have the ICE-killing battery, in their lab, but that battery is not available today.

    1. realistic says:

      Well-stated, Warren. As someone with significant professional experience in the evolution of power electronics technologies, more than a decade of electric propulsion hobbies, and a daily EV driver for more than three years, I am the last guy to unreasonably challenge the promise of electrification. But I also see the many challenges, from infrastructure to thermal management, that stand in front of us before the battery barriers are addressed.

    2. pjwood1 says:

      I am amused at how creative the internal combustion die-hards are, at ignoring inconvenient service and weekly gas station detours. Because someone has to spend an extra 10 minutes at a mall supercharger during the 2 or 10 times they actually go more than ~250 miles, somehow it is all rationalized as being worth it. Let’s spend 3 times as much, per mile on fuel. Their aim isn’t comparison to inferior reality, but instead to a future that doesn’t exist so people will hang on to what amounts to a mechanical watch.

      Batteries will not fill as fast as gas tanks any time soon. But people are connected, everywhere, and when that two state trip becomes necessary it’s not too hard to find a use for that extra time. It’s an argument likely to exist for a long time, but take steps back and it really isn’t compelling. You start full, and leave <30 minutes to SC if you're going 400 miles. That's already somewhat "outside the realm".

      1. Warren says:

        So. I have five and a half years, and 28K+ miles on my first electric assist bicycle. I have lost about 15% capacity so far. I guess I won’t be losing anymore, by you logic.

        1. pjwood1 says:

          Yes. When a battery is this big, its easy not to cycle it as much and end up with the longevity Teslas are seeing. A charge from, say, 150-200 miles can be done thousands of times.

          What DOD charge window are you putting your bike battery through?

    3. Pushmi-Pullyu says:

      Warren said:

      “I have been fascinated by all the talk of soon charging li-ion batteries in minutes, like pumping gas. The commenters seem to assume it is only a lack of huge DC chargers that is holding us back.”

      That certainly doesn’t apply to everyone. I have repeatedly pointed out that we need improvements in the battery cells themselves to allow faster charging without overheating.

      Such cells have been shown in laboratory demos, for example by coating the electrodes with carbon nanotubes or graphene, to greatly increase the surface area and thus greatly reduce resistance.

      But so far, nobody has managed to put those into mass production.

      EV manufacturers are also going to have to beef up the wiring inside the cars, as well as the wiring and electronics of the fast chargers, before we get cars which can ultra-fast charge. Supplying that much power from the grid is an issue, too. In many places, the electrical grid will have to be beefed up to handle that much power.

      I also don’t think it’s realistic to suggest it will ever be commonplace to fully charge EVs in two minutes or less. The cost/benefit tradeoff just isn’t going to support that. A 10 minute charge seems like a reasonable goal, altho perhaps not a near-term (less than 5 years) one.

      Tesla has said it wants to get charging times down to 5-10 minutes; 5 minutes may be possible. But to try to pare another minute or three off a 5 minute charge time appears to me to be far too expensive to justify saving so little time. There will be increasing cost to shave minutes off; the cost to go from 10 to 9 minutes will be far less than to go from 5 to 4 minutes, due to exponentially increasing power requirements.

  11. William says:

    Cry me a river Tesla Chademo users! My 4 year old Nissan Leaf with 12 bars remaining (barely), was charging on Chademo below 30kw this morning, after only 12 minutes and 50% SOC. Any 60kw charge rate, would be a dream come true, for US Leaf Lovers!

    1. Stephen Hodges says:

      Restricting charging to prevent battery degradation…. lucky my Leaf allows me to charge at all!. I don’t think you could find the effect against the background degradation with mine… 32000 miles and 7 bars remaining, and never ever fast charged. Poor poor Tesla users, its such a hard life!

    2. SparkEV says:

      50% SoC and 30kW seems something major wrong. I have never seen any Leaf so low, though I have seen about 36kW at 50%.

      If Leaf can charge quicker, especially those with no charge to charge, it’d be dream come true for the rest of us who use DCFC, because Leaf (and free chargers) would get off the DCFC quicker. Sadly, we, as in everyone who have to wait for Leaf, have to suffer through Leaf’s slow charging.

  12. bjrosen says:

    I’m amazed at how well battery management in cars works. We all have an example in our pockets of an unmanaged lithium ion battery, cell phone batteries are significantly degraded after a single year but cars with good battery management are good for 8 or 10 years. In order to achieve that longevity there are significant compromises that have to be made, only 80-90% of the battery’s capacity can be used, the temperature of the battery has to be strictly controlled, and the charge and discharge rates have to be limited. It’s a fact of life with lithium ion batteries, they aren’t nearly good enough and one hopes that there will be a better battery or supercap in the future that has fewer limitations. But even with it’s limitations car manufacturers have found a way to get them to last for a near normal car life. Tesla might be criticized for not communicating about the compromises that they’ve made, but they are to be commended for finding a way to stretch the life of the battery packs to a reasonable time.

    1. Warren says:

      We are six and a half years into the li-ion powered EV age. The beauty of 200 mile range EVs is that at ten years you will still have as much usable range as the vast majority of EVs sold until now had when new.

      1. pjwood1 says:

        It’s so awesome, Warren, you’ll have a lot more than the proverbial 100 mile EVs. Capacity has been flat-lining at 100k mile Teslas. That’s 85KWh Model S’s retaining over 200 miles of range, after what for many will be ten year worth of driving. How about that? If these cars get anywhere near the low range of the rest of the crop, warranties will lead to new batteries, anyway (10 years in CARB states).

        This compares really well to new BMW’s, that deliver, what, ~120? It’s so good to sell all makers increase their EV range.

        1. pjwood1 says:

          ..Capacity has been flat-lining at 10-20% loss, on 100k mile Teslas.

          1. Warren says:

            The first Model S’s are not yet halfway to ten years but Tesla has ended entropy. Damn! They are good. 🙂

            1. David Cary says:

              As you know, people just look at mileage when time is a big factor.

              That being said, Tesla is doing pretty well even looking at time. Do we have any updates since we are 5 years in now?

              I think every EV battery flattens the degradation curve but I’m not sure about that.

              As someone who has used Chademo at the high end of charge percentage, it doesn’t seem to taper as well as supercharging. I find Chademo very useful for 90-100% – scary useful. I’ve only done it twice – but I was shocked how fast it was.

  13. ffbj says:

    This probably explains some of the outliers in the recent chart which battery degradation. I wondered why there was a relatively large divergence, especially in the early part of the chart.

    So this could be part of the answer in that the best performance, least degradation, was achieved by those who never used DCFC, against those, that used it almost exclusively.

    You could run an experiment and find out the difference, probably something like 5%-8%, perhaps 10% in best case vs worst case, but that is not likely to happen.

    1. Pushmi-Pullyu says:

      It puzzles me that anyone should be surprised at this. The rapid aging effect on Leaf batteries if you frequently subject them to DCFC, is well known. Of course Tesla’s battery packs have active cooling and the Leaf does not, but that only mitigates the aging of repeatedly fast-charging, it doesn’t entirely eliminate it.

      I’m no electrical engineer, but this is pretty basic engineering fundamentals. If you repeatedly stress a mechanical or electronic system, then it will wear out faster.

      1. Nick says:

        This summarizes the study comparing a leaf which is exclusively charged via DCQC vs one which is exclusively charged via L2 and driven on very similar drive cycles in the same climate.

        Exclusively quick charging has little effect on battery degradation.



  14. jheartney says:

    Going forward, it ought to be a given that EV owners should do most of their charging at Level 2 rather that fast charging, at least until we have battery chemistries that can handle it. This probably would have been evident earlier, absent Elon’s overpromising.

    1. Pushmi-Pullyu says:

      Yeah, I don’t find the exact quote from Elon, but I do vaguely seem to recall being very surprised — or even shocked — that he would claim that Supercharging your Model S won’t reduce battery life. I realize he was trying to promote his company’s product, as well as the Supercharger system itself, but he shouldn’t have made that an unqualified statement. He should have said “Occasionally charging your Tesla car at Superchargers is going to have negligible effect on battery life.” From data I’ve seen, that appears to be a true statement.

      Tesla never planned for people to use Superchargers for most of their charging, nor for the 99% of charging to be at DC fast chargers that the guy described in this article did. Tesla always planned for most charging to be slow charging at home or at work.

  15. Chris O says:

    Bad Tesla! Of course everybody knows that quick charging too often will shorten battery life but people have the right to destroy their own stuff! What were they thinking protecting their customers against themselves like that!

    Oh well, I’m sure all Tesla owners who insist on it are just a software update away from happily destroying their batteries.

    1. (⌐■_■) Trollnonymous says:


      Damn, you beat me to it!

      Wasn’t there always a warning that fast charging all the time was bad bad for the Tesla battery packs?
      Charge rate limitations are at the cell level, not sure why anyone thinks it wouldn’t apply at the pack level……lol

      “That number above is 99% CHADeMo charging since March 2016”

      I wonder what would happen to a Bolt if they charged at 99% of the time at 50-80KW?

      Just goes to show you that you can’t idiot proof anything.

      1. ffbj says:

        Well this dude hasn’t seen much degradation, after 62k miles, charging to 100%, and almost daily use of the SC.

        1. BenG says:

          The DC charge counter and restriction apparently aren’t implemented on earlier Model Ss like his 2012 60 kwh model.

          It has been confirmed on the 2015 90 kwh model, which coincided with a chemistry change in Tesla batteries which gave better energy density, but which may need more babying to extend lifespan.

          1. BenG says:

            Er, his is a 2013, not 2012.

          2. ffbj says:

            Yeah I noticed that too, from the article, I just thought people might enjoy this guys experience, which is more about degradation, than charging rates anyway.
            Thanks for the comment.

        2. Pushmi-Pullyu says:

          “Well this dude hasn’t seen much degradation, after 62k miles, charging to 100%, and almost daily use of the SC.”

          How much degradation is “not much”, does he say?

          Maybe he has more realistic expectations than TMC member Naonak, the guy who this article is about, who seems to find it shocking that his abuse of the battery pack resulted in pack degradation and reduced charging speed.

  16. przemo_li says:

    I think this title may be misleading.

    50-60 Supercharges would NOT do that. We would see that same drop in performance for 80% of the cars on the road by now…
    I think it’s how Tesla car treat CHAdeMO.

    Did car owner used Tesla (company) own CHAdeMO adapter? Did Tesla (car) treat those sessions as Supercharger sessions?

  17. Bill Howland says:

    I wonder what future model 3 buyers (50-55 kwh being bandied about, lately) will think, now that their basically 1/2 sized batteries may ALSO be throttled due to excessive supercharger use. If they are limited to 60 kw at the start (5/8 of 115 kw peak of 100 kw batteries), what will the final throttling be? 45 kw? 40 Kw?

    Probably something to think about…..

    Now, what do other large battery cars do in this instance? Is there something to be going on in the BOLT ev that we don’t realize as of yet?

    1. MTN Ranger says:

      Yet many Tesla fans on Facebook believe the Model 3 will be able to charge at 350 kW. I think they will be disappointed when we find out what the actual rate will be.

      1. ffbj says:

        Wow! Well I guess believe what they want, on whatever side of a question that they want to believe in. I think you definitely correct in your view on that particular question.

  18. flmark says:

    I tried to remain neutral and thoughtful as I read through LOTS and LOTS of the linked material. Many react strongly to original posts and accuse OP of trolling.

    Then I finally got to something OP wrote about himself as he discussed his need to fast charge:
    ‘I drive approx 220 miles at around 80 mph in average every day’
    Um…driving at these speeds on a constant basis is like permanently driving uphill or with a small trailer behind you. If you abuse your machines, you should expect them to wear out faster.

    People who think nothing of the mechanical punishment enacted due to power of the cube of speed on their devices…ought to get on a bicycle every once in awhile. Speed doesn’t just kill; it is also very tiring.

    I used to drive faster…until I got my first hybrid which showed instantaneous gas mileage. Wow, does that mpg go down over 70 mph! And likewise, other material costs should be expected for those with a need for speed. As for myself, reading the above quote was enlightening; I do not expect to be effected with my use of my Model X and the lengthy (SC) trips that I take for my hobbies and my seasonal home arrangement.

    1. sven ¯\_(ツ)_/¯ says:

      I don’t know if I’d consider the steady extra draw on the battery from constantly driving 80 mph to be abuse of the battery. I would think the battery is under greater strain in stop and go traffic due to the constant cycling between brake regen and acceleration. IIRC, max brake regen is about 60 kW on a Tesla, which is greater than the max 50 kW charge rate of the Tesla CHAdeMO adapter cable that the OP used for vast majority of his DC charging. I know that brake regen doesn’t last long like a DC charging session, but sudden bursts of 60 kW max regen has to put some stress on the battery if Tesla considers frequent 50 kW CHAdeMO charging stressful.

      1. Pushmi-Pullyu says:

        sven said:

        “I don’t know if I’d consider the steady extra draw on the battery from constantly driving 80 mph to be abuse of the battery.”

        I don’t know that I would characterize it as “abuse” either. But whether or not it’s “abuse”, it’s certainly heavy use. If you subject your car to heavy use, whether it’s a gasmobile, a PHEV, or a BEV, it’s going to wear out faster. That’s just common sense.

        And whether or not you consider it “abuse” to nearly always charge your BEV at a DC fast charger, instead of slow charging the car as it was designed for, it’s certainly is heavy use, and it’s going to wear out the battery pack faster.

        Those who think otherwise need to try exercising some common sense. Tesla’s EV engineering is superior in many or most ways, but Tesla cannot repeal or ignore entropy!

        1. sven says:

          Pu-Pu said:
          “. . .[constantly driving 80 mph is] certainly heavy abuse.”

          Certainly heavy abuse? How much additional electric draw is put on the battery by drving 80 mph as opposed to 70 mph or 65 mph? How do you know that the battery is not designed to handle as normal use a Tesla driving at those speeds on a highway for long periods of time, like on a family vacation road trip.

          Is it also certainly heavy abuse to drive 7 people in a Model X as opposed only carrying no passengers and only the driver? If the 6 extra weighed an average of 175 pounds, that’s an whopping extra 1,050 pounds to lug around. Isn’t the Tesla battery designed to handle the electric draw of driving around with every seat in use as “normal use” and not “heavy abuse,” much like a Class 6 tractor is designed to haul around 80,000 lbs as “normal use” and not “heavy abuse.”

          Pu-pu said:
          “. . . instead of slow charging the car as it was designed for, it’s certainly is heavy use, and it’s going to wear out the battery pack faster.”

          Define the “slow charging” that the car was designed for. Is it charging from a 120v socket? Would it wear out the batter pack faster to charge from a 240v outlet? A Tesla wall charger charges at 10 kW. Is charging on a Tesla High Power Wall Charger (HPWC) at 20 kW heavy use that’s going to wear out the battery pack faster? Many/most houses in Europe have 32A 230V 3 phase electricity that will charge a Tesla at 22 kW. Does charging at 22 kW in Europe wear out the Tesla’s battery pack faster than charging at 6.6 kW on a 240V outlet in the US?

          Are you sure that the Tesla battery pack wasn’t designed to handle the 50 kW max rate of a Tesla CHAdeMO adapter? CHAdeMO’s 50 kW max rate is lower than the 60 kW max rate from brake regen. Does braking hard wear out the battery pack faster? Should Tesla owners shut off brake regen or lower the setting for brake regen to the lowest possible level to avoid “wearing out the battery pack”? Or did Tesla design the battery pack to easily handle accepting up to 60 kW of charge so that max brake regen would not shorten battery life, which would mean charging on CHAdeMO at 50kW is no sweat for the battery pack?

  19. Volt says:

    Have never used a DC charger so dont care

  20. Jake Brake says:

    I believe GM took the conservative way out on this issue with the Bolt. It can only do 50kW but it can likely do it 100% of the time and make it to 60-70% capacity at 100k miles and be under warranty.

  21. Pushmi-Pullyu says:

    So, if I understand the facts given above correctly, this Model S owner has charged his car 245 times in 30,000 miles (which comes to an entirely believable 122.4 miles per charge), and he says “99% CHADeMo charging since March 2016.”

    In other words, he’s abusing his car by charging almost 100% using non-Tesla DC fast chargers, instead of charging at home or at work. Is this guy using his Model S for a taxi, or what’s going on here?

    At any rate, I don’t see the issue here. If you abuse your battery pack by frequently DC fast charging it far more than it’s designed to do — as this driver is doing — then it’s going to degrade the pack, which means that reduces the amount of power the pack can accept while charging.

    If Tesla has been pro-active in designing their battery packs’ BMS to detect when this starts happening and preemptively reduce charging power to slow down the degradation, then that’s a good thing! I don’t see that there is sufficient evidence here that Tesla has done that, but whether or not they did, the reduction in charging speed at a DC fast charger is a direct consequence of the driver using fast charging far more than any EV is designed for.

    Only someone who doesn’t understand the realities of battery pack degradation, or a Tesla basher (or anti-Tesla troll) would try to characterize this as “Tesla has done a bad thing”.

    Or, to summarize: This twit is complaining because his abuse of his Tesla Model S battery pack has lead to slower charging when DC fast charging, and he’s trying to blame that on Tesla instead of admitting his abuse of the car has caused the degradation.

    Nothing to see here. Move along, move along!

    1. Warren says:

      Many of Elon’s followers are religious zealots, with totally magical belief in their messiah. When he and his products turn out to be merely mortal, they will turn on him with a vengeance. Luck the person who has the stone concession.

    2. ¯\_(ツ)_/¯ sven says:

      “he’s abusing his car by charging almost 100% using non-Tesla DC fast chargers”

      Elon specifically said that fast charging wouldn’t hurt the Tesla’s batteries.

    3. hrm says:

      if even 50kw chademo counts as abuse, how are non-homeowners supposed to go electric? where are they supposed to find a level 2 charger that they can plant their car at for the 1-3 hours daily necessary to recover a workday’s worth of mileage?

    4. unlucky says:

      There’s no reason to think that charging his car with a Tesla-provided adapter should be considered abuse. If it were, then Tesla would have said so, right? They did sell him the adapter and the car. They can communicate what is abuse to him.

      It does seem like heavy use to do as much charging as he did. And we expect things to wear out more quickly in heavy use, don’t we?