Tesla Model S Surpasses 250,000 Miles – Just 7% Battery Degradation

2 weeks ago by Mark Kane 69

2014 Tesla Model S – More than 400,000 km (250,000 miles) (source: Helsingin Sanomat)

If you ever wondered about how long a Tesla battery can last, here is an interesting example of 2014 Model S from Finland, which has covered more than 400,000 km (250,000 miles).

Tesla Model S

A Finnish taxi driver, Ari Nyyssönen, first received his Model S in December of 2014, and has since driven 250,000+ miles in less than three years.

According to Ari, the rear-wheel drive Tesla was affected by motor replacement, and at one point the 85 kWh battery pack had some problems of its own – once refusing to charge, and indicating only 60 km (37 miles) range, Tesla serviced the battery in the Netherlands and re-installed it back.

Both incidents were covered under warranty – thanks to Tesla’s  8 year or unlimited miles Battery and Drive Unit Limited Warranty.

As for battery capacity loss (always a topic of interest), the range of the Model S now stands at 230 miles, or about 7% less than the 250 miles rated when new.  We think that should be considered a pretty great result.

Ari Nyyssönen now heads for 1 million km (620,000 miles), and is more than happy for Tesla’s  the 8 year/infinite mile warranty.

Also of note:  In the US, Tesloop’s Model S just hit 300,000 miles (482,000 km), but no notes on the current battery capacity of that model are known at the moment – read more on that vehicle at Electrek here.

source: Helsingin Sanomat via Teslarati

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69 responses to "Tesla Model S Surpasses 250,000 Miles – Just 7% Battery Degradation"

  1. an_outsider says:

    Don’t know how is Sparkie’s 2012 Volt battery with almost 400,000 miles by now?

    https://www.voltstats.net/Stats/Details/1579

    1. ziv says:

      The Volt pack is probably the most long-lived pack out there. Though it is a bit hard to tell due to the relatively low percentage of the pack used by the Volt.

  2. fred says:

    Not clear about battery pack repair. Was it replaced?

    1. Mark.ca says:

      “and re-installed it back.”
      What part is not clear to you?

      1. David Nelson says:

        What isn’t clear is what actually was done in the repair.

        1. Mark.ca says:

          In the US example of last year they said it was software that was preventing the battery from charging and displaying the wrong range. In that case they just replaced the battery.

          1. Elooney Muskey says:

            Mark.ca said “..they said it was software that was preventing the battery from charging and displaying the wrong range. In that case they just replaced the battery.”

            Does not make sense. If it was software, use OTA software update to fix it. Why replace the battery if nothing wrong with it? Something smells.

            1. JakeY says:

              Easy: they don’t have the software written for it yet (the Tesloop car was the only example with that many miles on it).

              Rather than have Tesloop use a loaner car or pack, they just replaced the pack. Then they can take their time to write the software and also can analyze the pack themselves.

              1. Mark.ca says:

                That’s the one…

            2. Mark.ca says:

              “Something smells.”
              Not here so it must be you…

        2. Pushmi-Pullyu says:

          “What isn’t clear is what actually was done in the repair.”

          Yes, but no EV maker would replace just some of the li-ion cells in a pack. Li-ion cells have to be carefully balanced, and that means they all have to be the same age.

          Bottom line: If there was a problem with the actual cells in the pack, then Tesla would have replaced the entire pack. Since they didn’t, we can be pretty sure the original cells are still in the car, and that the degradation for 250,000 miles is a true indication of the degradation for that range.

          In theory, li-ion batteries degrade comparatively rapidly as they are cycled for the first few score or first few hundred times, losing a few or several percent of the capacity; but then the degradation flattens out and gets slower over time.

          And in fact, on average this is exactly what we see with the Tesla Model S:

          https://electrek.co/2016/11/01/tesla-battery-degradation/#jp-carousel-30477

          1. Bar says:

            Hey, look at that, you made it more clear.

            I guess it wasn’t clear after all.

  3. ClarksonCote says:

    “Tesla serviced the battery in the Netherlands and re-installed it back.”

    Do we know if they replaced the battery as part of that service?

    1. Mark.ca says:

      How can you re-installed a new pack?

      1. MTN Ranger says:

        Were pack electronics and/or cells replaced?

        1. Pushmi-Pullyu says:

          Since the original pack was re-installed, it’s reasonable to conclude that some of the original electronics were replaced, or perhaps just “flashed” and reprogrammed. It’s not reasonable to think Tesla replaced just some of but not all the cells; no manufacturer would do that for a li-ion pack. If Tesla replaced all the cells, then that would involve installing a different pack, not re-installing the same one.

          Since Tesla re-installed the original pack, we can be reasonably sure that the original cells are still in the car.

          The only reason I’m hesitant to say we can be quite sure, is because Tesla may have installed a different used pack (of similar age) in the car, but the owner didn’t understand what was actually done and thinks they put the original one back in.

          1. ModernMarvelFan says:

            “Since Tesla re-installed the original pack, we can be reasonably sure that the original cells are still in the car.”

            There are 16 battery modules per pack in the 85kWh Model S. Each Module has 444 cells.

            The pack can easily be repaired by replacing one of the 16 modules and return the original pack to the car. The part of the modular approach to the battery pack is so it can be serviced quickly.

            It is far likely that a particular module is replaced than individual cells are replaced. Of course, the module itself can be repaired thru individual cell replacement at an offsite facility if it needs to.

            Of course, that is assuming the pack is repaired due to battery cells problem.

            We don’t know what is actually repaired so assuming that battery cells weren’t replaced just because original pack (or a battery pack) is returned to the car is a shaky assumption.

      2. ClarksonCote says:

        “How can you re-installed a new pack?”

        It’s very easy to have the exact process lost in translation. A positive confirmation going beyond that quote in the story would be great.

  4. georgeS says:

    I swear I had a quote from Elon that put the NCA cycle life at 1500 cycles and NMC at 5000 cycles. That puts the life of the Model S battery at 375,000 miles. so these numbers in this article make sense.

    Maybe I should milk more miles out of my Model S.

    This also makes used Tesla’s a good deal. Tons of battery life.

    1. bro1999 says:

      “This also makes used Tesla’s a good deal. Tons of battery life.”

      Just as long as nothing else on the car breaks out of warranty.

      1. Mark.ca says:

        Same with all other luxury brands. My past benz models just milked me of money, 2 in a row that needed new transmissions after 100k miles….never again!

        1. ffbj says:

          Bmw & Mercedes are the top 2 on expensive to repair. Around 18k & 14k respectively over a decade.

  5. premium salmon says:

    Yes, the battery issue should be detailed, above all by Tesla, especially if it did not mean the replacement of the whole 85 kWh battery unit.

    However the replacemnt of the motor – even in a pre-mass production stage – is quite frightening!

    If Tesla confirms it, as the driver was not queted about this in other refences: http://www.carscoops.com/2017/08/finnish-tesla-taxi-driver-has-covered.html

    Also, living on everday use of THE CAR, servicing in the Netherland from Finland is abnormal – again early days? What does Niki say about this?

    Finally the small drop in range is bad news for e-sceptics, however number and speed of charges would be essential to know.

    Is brave Ari safe for 5 more years, even if his Tesla S makes >1 million km?
    Would deserve it 🙂

    1. MikeG says:

      The early motors were somewhat problematic but the updated motors have a much better reliability. My 2014 Model S 85 had a drive unit replacement in 2015.

      https://cleantechnica.com/2016/02/11/dramatic-tesla-model-s-reliability-improvements-elon-notes-audio-recording/

    2. Mark.ca says:

      “however number and speed of charges would be essential to know.”
      We could assume that the number is high since both cars that had this issue were used in a taxi service.

  6. HVACman says:

    Heat is enemy #1 for EV battery pack life. Frequent fast-charging is enemy #2. Tesla has a great active TMS system to keep the cells comfy when it is in operation or plugged in. The article makes no comment about how often, if ever, the owner Super-charged. Note that Tesla – to reduce battery degradation – now derates the available SC rate for their vehicles that have a history of frequent SC’s.

    Removing fast-charge issues, sub-arctic Finland would be the sweet spot for long-lived batteries. I bet even a Nissan Leaf could hold almost all its bars for 200K miles there. I wonder what the degradation rate is for MS/MX batteries in hot climates like Phoenix, especially with frequent SC’s and summer driving?

  7. ModernMarvelFan says:

    “Tesla serviced the battery in the Netherlands and re-installed it back.”

    Unless we know exactly what they did with the pack, it would be misinformation to assume that the degradation reflects the “original” pack.

    They could have fixed the defective cells, modules of cells or replaced the entire pack…

    With all that said, we are confident that EVs (except for LEAF) should handle at least 150K miles to 200K miles without major repairs.

    1. Mark.ca says:

      “it”

      1. ModernMarvelFan says:

        “it” implies a battery pack, which has NO Information on how many of those 8,000+ cells are replaced or if they are replaced.

        The Tesla Model S has to have the battery pack installed to work…

        The lacking of detail of what Tesla did to “IT” is the question here.

      2. Bar says:

        Yes, yes, Mark, you are really helping everyone understand the article better.

        1. Mark.ca says:

          Happy to help…Stay tune, next week i will post the dex definition of “it”!

    2. Pushmi-Pullyu says:

      ModernMarvelFan said:

      “They could have fixed the defective cells, modules of cells or replaced the entire pack…”

      Nobody “fixes” defective cells. You replace them.

      Nobody but an obsessively dedicated (or sadly clueless) DIYer tries to replace individual cells or modules in a li-ion battery pack, since the cells have to be very carefully balanced. That would be too much time and trouble for a manufacturer like Tesla, and would almost certainly result in a battery pack with reduced life.

      And if Tesla re-installed the original pack, as the article claims, then they didn’t replace the pack.

      From what the article says, it’s far more reasonable to conclude there was a problem with the battery pack’s electronics. That was fixed, and the same pack was put back in the car. We can’t be absolutely certain that’s what happened, but it’s by far the most likely scenario.

      1. ModernMarvelFan says:

        “Fixed” implies the cell or modules of cells were replaced. That is how battery packs are repaired.

        You can easily replace a bunch of cells or modules in the same pack and return the same “battery pack” back to the car.

        1. Mark.ca says:

          If i’m not mistaking, you would have to balance the new module with the existing ones and that would be impossible with new cells.

          1. ModernMarvelFan says:

            You are mistaken…

            1. Mark.ca says:

              You’re right…the modules are connected in series.

      2. ModernMarvelFan says:

        “DIYer tries to replace individual cells or modules in a li-ion battery pack, since the cells have to be very carefully balanced. ”

        Why is replacing 1 of the 16 modules not something Tesla would do?

        The pack is designed to be modular. Each module is balanced within and have SW to calibrate and balance them each time as it charges and discharge.

        Each battery module (1 out of 16) has self terminated control as well as its own cooling loops. Each Module is configured into 74 in parallel and 6 in series configuration. So, it is highly likely that Tesla would replace one of the 16 modules rather than individual cells if battery pack needs service.

        Also, each and every cell is individually fused to prevent failure. All of them are basically suggesting it is far easier to swap out 1 out of those 16 modules than doing individual cell diagnostics. If they do, they can do the cell repair at another site with defective module.

        The entire design is purely modular and efficient from an engineering point of view.

    3. pjwood1 says:

      I’m NOT confident the 2014 Model S was originally rated for “250” miles. I believe 265 was its rated range, making range loss closer to 13%.

  8. fotomoto says:

    “As for battery capacity loss (always a topic of interest), the range of the Model S now stands at 230 miles, or about 7% less than the 250 miles rated when new.”

    The ESTIMATED range doesn’t tell the full story. How many kwh’s does it now use from full to empty? Does the BMS allow more of the original, unused portion of the pack to be accessed as it ages?

    1. MikeG says:

      Also 230/250 = 92% or 8% loss. My 2013 Model S 85 has about 64k miles and charges to 247 out of 265 EPA rated miles or 6.8% capacity loss with the original battery pack and 1/4 the miles.

      1. MikeG says:

        Oops, 2014 not 2013 model S.

    2. Pushmi-Pullyu says:

      “Does the BMS allow more of the original, unused portion of the pack to be accessed as it ages?”

      No. GM has pretty clearly engineered the Volt packs to keep a lot of reserve to hide the capacity loss over time, but Tesla allows the car to use the entire usable capacity from the start. That’s why Tesla cars do show some degradation in range as the years pass.

      Of course, Tesla just like all EV makers does reserve some of the pack to prevent charging to 100% of the manufacturer’s nameplate capacity, or discharging to 0%; both to prevent premature battery aging.

      In other words, usable capacity is never full capacity in a mass-produced EV. What is less clear is exactly what number the various EV manufacturers are giving as the battery capacity. Are they giving us the full capacity, or the usable capacity, or something in between? I don’t think GM is giving us the full capacity of the Volt’s battery pack; I think they give us a number that is less.

      And as has been heavily discussed on the Tesla Motors Club forum, Tesla rounds off the actual capacity of their battery packs to the nearest 5 kWh. Some of their battery packs have slightly more, and others slightly less, than the kWh Tesla indicates.

      1. ModernMarvelFan says:

        “but Tesla allows the car to use the entire usable capacity from the start.”

        How do we know? Just because it doesn’t match what the designation is (60, 77, 85 or 90), it doesn’t mean there isn’t any “buffer” left in the cells. It could be that it is very small compared with what GM does with the Volt, but that doesn’t mean there isn’t any buffer.

        Also, has any one who claims “small degradation” compared its “fully discharged” kWh against its brand new “fully discharged kWh”? I haven’t seen any evidence to suggest that. Most of them are based on Guess-O-Meter so far which we all know are defective sometimes…

        1. pjwood1 says:

          We know because the same people with the “electrical chops” to buy a Tesla, have aimed those chops at figuring them out, like WK057.

          The Volt has a rediculously low DOD window, of 65% (first version). Tesla, using the range-charge window, allows all but about 4-5KWh, or ~92%. In order not to brick the car, the Model S shuts down before KWh are fully shot.

          Since Volt1, others and GM have become more confident in using more of the battery capacity (including Volt 2, at near 75% DOD on 18.4KWh, I think). The more of a full charge and discharge window you use, the closer you get to a unit of “1 cycle life” from the battery. Batteries are rated in cycles, which I believe is close to repeated 100% charge/discharge. The further you get from these full fill/empty lab cycles, the more non-linearly your battery’s cycle-life goes up. -how I understand it/not an engineer.

          1. pjwood1 says:

            ..should say, “the less of your batteries life gets used”

  9. speculawyer says:

    These stories are great to have around. You still get the trolls posting “If you buy an electric car, you’ll need to replace the battery in 3 to 5 years! hur hur hur”.

    1. Joshua Burstyn says:

      No kidding. Even pseudo respectable journalists in a variety of newspapers seem to take delight in speculating how long these packs will last.

  10. I3 says:

    The purpose of Lion battery was a light-weight, overnight charging, high-density
    battery for electronics

    The purpose of Sodium Glass battery was an even lighter, denser, quick-charging
    non-flammable, very cheap, solid-state battery for EVs, but no body seems to even bother about producing them yet

    1. Some Guy says:

      Contrary to common believe, any rechargable battery technology with sodium (except maybe for molten sodium sulfur systems) is nowhere near mass production application. Also, the energy density is inferior to Lithium ion technology. Average cell voltage is lower, so one needs more cells. In $/kWh, the most important figure, advanced Li-ion will always beat sodium systems on pack level. That’s why there are no serious sodium offerings. Some say, “but sodium is so cheap and lithium so expensive”. True, but Li is in fact responsible for less than 5% of the material cost of a lithium ion battery, meaning if lithium price doubles, it has a marginal effect on $/kWh on pack level.

    2. Pushmi-Pullyu says:

      I presume you’re talking about molten salt batteries?

      I don’t know that much about them (other than the fact they require high operating temperatures), but it’s safe to say that if they were economically competitive, then they would be used in mass produced EVs.

      The only EV I recall reading about using that type of battery was the SolarTaxi, a prototype vehicle, and at that time the molten salt battery was very expensive. I’m guessing it still is. I don’t know that molten salt batteries have ever been mass produced.

      https://en.wikipedia.org/wiki/Molten-salt_battery

      1. speculawyer says:

        European Think City EVs used a ZEBRA molten-salt battery.

  11. Mark.ca says:

    There was a similar incident last year in US where they replaced the battery but the issue was software related and battery was still only 6% down after 200k miles. This is probably the same issue and it looks like in this case they just fixed the glitch. This is incredibly low levels of degradation.

    1. ffbj says:

      I was thinking similar. Great deal for Taxi drivers where a lot of your expense is fuel and many costs are fixed.
      8 years or unlimited miles, like a gift from the gods.

    2. ModernMarvelFan says:

      “but the issue was software related and battery was still only 6% down after 200k miles”

      “only” 6% reported by the range estimation. That leads the operator of the Model S to run out of charge couple times. So, that clearly shows the so called 6% range loss is INACCURATE or under-estimating at best.

      This just shows all those “claimed” range loss based on “range estimator” is full of inaccuracy.

      If one wants to find if any true range is lost, it needs to do a full charge to discharge cycle to see the amount of kWh discharged and how that compared with “new”.

      1. Pushmi-Pullyu says:

        The fact that in some cases, the BMS of an EV has been shown to be giving false readings about charge level isn’t a good reason to ignore the evidence that is presented to us. It’s good to cite such hopefully rare cases as a logical reason for some degree of skepticism, but asserting that we should ignore the data we have is counter-productive.

        Now, if you could give us the margin for error, or the standard deviation in the data, then that would be useful.

        1. ModernMarvelFan says:

          Since the ONLY vehicle that showed 6% and 200K miles was the ONE vehicle that had the wrong range reading AND had its battery pack replaced, it appears the correlation was 100%.

          Now, with this data point, which also has its battery pack serviced as well. Even though we don’t know what was actually serviced, but it appears that both case of high mileage battery packs needed services to them regardless.

          I would like to see any other data point that shows any other Tesla Model S with more than 200k miles that doesn’t need any kind of services to its battery pack. Is there one beside those two?

      2. Mark.ca says:

        “If one wants to find if any true range is lost, it needs to do a full charge to discharge cycle to see the amount of kWh discharged and how that compared with “new”.”
        I definitely agree with you on that one! It’s not something an average Joe would do, unfortunately.

  12. SparkEV says:

    A guy in SparkEV forum drove over 80K miles with his 2014 SparkEV, and recently charged from empty to full for 21 kWh as reported by Chargepoint. Using 85% as charging efficiency, that works out to 17.85 kWh. Since 2014 had about 19.5 kWh usable capacity, he’s lost bit under 10%.

    But SparkEV has about 1/5 the battery. 80K miles is equivalent to 400K miles on 100 kWh battery car for 10% degradation. Actually, SparkEV would be worse charge-discharge cycles since it likely goes through deeper discharge cycles for having small battery as well as much higher DCFC charging C rate.

    While I’d like to believe SparkEV is extraordinarily great (which is true), it may be that all EV with decent TMS perform almost as well. So a 100 kWh Tesla losing 7% in 250K miles may be just “ok”, not extraordinary.

    1. ModernMarvelFan says:

      80K miles on a 80 mile ish EV is about 1,000 cycles which is same as a 250K miles on a 250 miles ish EV…

      1000 cycles = ~ <10% loss is pretty much "on track" in a well managed battery.

      Of course, that is assuming the degradation is "dominated" by cycling, not by aging. If cycling is low and time is long, then aging due to time might start to dominate. We don't know about time related aging on those batteries yet.

      1. SparkEV says:

        Aha. You are correct, I hadn’t considered efficiency advantage for SparkEV. But considering far more abuse SparkEV battery would suffer with much deeper discharge and much higher C rate DCFC, ~10% loss isn’t bad at all with similar number of charge cycles. I think this shows that age related degradation is the dominant factor with decent TMS.

  13. Jonathan B says:

    We all know that the bigger the back the less it will cycle and the longer it will last. Yes 7% at this many miles is very good, but this is Finland. Even with a TMS that’s a pretty kind climate for degradation. Furthermore the pack is young. The average driver will not put this many miles on their car in only a few years. It will take them 15 years to put 250K miles on it. To say that a Tesla in the US will last 250K miles with only 7% degradation is not entirely accurate. Also, I’m not sure about how the unused capacity is eaten away it on different models. Tesla has some models that have greater reserve capacities, and thus would provide a better buffer for degradation.

    1. speculawyer says:

      Yep…and this is probably another thing that Tesla did right. With a very large battery, the typical daily driving will hardly stress it at all such that capacity drops only a small amount.

      Smaller batteries that frequently got from full to near empty are much more stressed.

    2. Pushmi-Pullyu says:

      “Tesla has some models that have greater reserve capacities, and thus would provide a better buffer for degradation.”

      Which models? Are you talking only about the difference between the Roadster and later models? I assume all the Model S’s and Model X’s have a reserve capacity that’s the same percentage of the pack size. If that’s not true, then I’d like to know more.

      Would you please present the evidence or cite your source?

      1. Dave86 says:

        Tesla originally came out with a 40KWH Model S that actually had a 60KWH battery. So few Tesla customers wanted the 40KWH version that Tesla found it cheaper to software limit a 60KWH battery than engineer a true 40KWH battery.

  14. Four Electrics says:

    Simplest explanation is that Tesla replaced the entire pack. At one point they were replacing one out of every 20.

    1. pjwood1 says:

      cite your source

      1. Get Real says:

        His source is his rear-end and as a serial anti-Tesla troll he is talking out of it.

  15. Tom says:

    An interesting article on Tesla’s overall warranty cost structure. It would seem reasonable based off what I’ve read that complete failures of the electric motors are more common in the initial stages of the vehicle’s life (so far that is…it’ll get better) than say catastrophic failure of an ICE engine. Electric things tend to have a spike at the beginning of life.

    But it would seem that overall cost is lower. Presumably this has several reasons (as often discussed).
    1. Fewer parts overall vs a regular car.
    2. OTA updates and diagnostics allow Tesla to determine/fix the vast majority of issues without touching the vehicle. Compare this to bringing a vehicle in for diagnostics and swap of trivial parts on a regular car.
    3. Even if the electric motor fails outright, the ‘fix’ would seem to most often just be take that one out and put a new one in which is likely dramatically easier to do than trouble shooting an ICE, then tearing apart the engine and replacing the part. Not unlike a modern computer.

    The graph is a nice graph.
    https://seekingalpha.com/article/4100969-teslas-build-quality-improved-significantly

  16. Jake Brake says:

    If this is the case, competitors batteries should be good for 1 billion miles.

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