Data Suggests Tesla Battery Packs Will Retain 80% Capacity At 521,000 Miles



Battery cell production at the Tesla Gigafactory in Nevada.

Updated research shows that Tesla batteries may honestly last just about forever.

Nothing lasts forever, but based on new information, a lithium-ion battery pack in a Tesla vehicle could potentially outlast its owner, not to mention the rest of the car, and quadruple the life of an ICE vehicle. The updated study posted on the Dutch-Belgium Tesla forum tracks 900 Tesla drivers around the globe in regards to their battery degradation. It shows that after 521,952 miles (840,000 km) the battery should maintain 80 percent of its original capacity.

According to the U.S. Department of Transportation, the average American drives 13, 476 miles per year. Let’s make it easier and significantly overstated and say that we drive about 20,000 miles each year. So, 500,000 miles would take us at least 25 years, although people have been known to rack up many miles in a shorter time period (but it’s really rare). Keep in mind this is only taking the battery down to 80 percent. To deplete a Tesla battery completely could truly take more than a lifetime.

The spreadsheet shown below was first drafted by Matteo but is now updated by Maarten Steinbuch (via Teslarati):


Tesla battery degradation chart via Matteo and Steinbuch

As you can see, the spreadsheet simply plots points to signify each owner’s remaining battery capacity. Though there are surely some points that are outside of the norm, this makes it easy to see trends. Whether or not you agree with the study, or believe in its validity or scientific merits, it’s perhaps the best model out there to give Tesla buyers/owners an idea of battery/range/performance degradation over time.

Tesla Model 3

According to Tesla, the Model 3 will use the automaker’s new 2170 cells, which could potentially last even longer than the 18650 cells referenced in the study.

An average ICE car is expected to exceed 100,000 miles. At around 150,000 miles (or less), most ICE cars are deemed “done”. Again, there are many exceptions, but the point is valid. Essentially, it loses an average of 1 percent every 30,000 miles. However, according to Steinbuch, at 150,000 miles the average Tesla battery still has about 92 percent of its original capacity.

Following this trend brings him to the conclusion of 20 percent degradation over 500,000+ miles, with 80 percent capacity still available. Hypothetically, a Tesla battery would be “incapacitated” at three million miles, though this could likely never be tested, and you couldn’t really use the car regularly once the battery degraded down into the numbers well below 50 percent capacity. It’s still an interesting stat, for sure.

It’s important to note that this study is based on Tesla’s current 18650 battery cells. The Model 3 will use the new 2170 cells, which are more energy dense and efficient. While no study has been performed on the 2170 cells, you can bet that they may last longer than the earlier cells.

Ben Sullins of Teslanomics visited this subject not long ago, prior to the recent research update. Check it out below:

Sources: Teslarati, Teslanomics

Categories: Tesla

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68 Comments on "Data Suggests Tesla Battery Packs Will Retain 80% Capacity At 521,000 Miles"

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There goes another FUDster argument against PEVs by the shills for Big Oil!

I’m pretty sure that virtually all well designed battery packs will be perfectly serviceable until they reach the end of their calendar lives.

it all comes down to usage. Lion batteries have a definite life span based on charging. Full discharge and full, fast recharge will shorten the life while small to moderate discharge and slow recharge overnight and the battery will last a long time.

There’s no magical Tesla battery or anyone else’s, basic Lion tech.

The “average” 521,000 miles with 80% degradation is based on the average Tesla usage which no doubt fits the long life parameters for Lion batteries, small to moderate discharge and slow recharge.

One can plan their battery longevity by matching up to their usage.

It’s not just based on charging. Lifetime is also based on calender time, environmental temperature, and extreme discharge events.

Calender-based lifetime is the least predictable factor, because the degradation is usually quite sudden and can’t be extrapolated. We’ll just have to wait to get definitive data on that.

Fortunately, all data points to long life, so EV proponents can easily tell the doubters that there’s no proof of batteries needing replacement every few years.

Most do not have anywhere 521k miles on them, it’s an extrapolation/guess…could be worse, could end up being even better (but I doubt it, that’s not how physics tends to work – something starts to get old, which then causes other things to age quicker). For example, maybe the A/C and heating will require more energy over time, thus lowering range and putting more stress on the battery. Maybe the battery cooling system will not work as well after 5-10 years, causing the battery to degrade quicker.

If this Data is even remotely accurate, then LG may have a little more competition from the Panasonic/Tesla Gigafactory expansion, that is taking place.


There’s a quote somewhere where Elon says NCA (Tesla automotive cells)is good for 1600 cycles and NMC is good for 5000.

LG’s cells are NMC. LG cells have twice the cycle life of Tesla’s NCA automotive cells.

………..but it may come down to calendar life in the end and not cycle life for these cells.

While NMC cells should provide for better cycle life, we have seen NMC automotive cells with poor cycle life. The cell degradation in Kia Soul EV’s, using Idaho National Labs AVT data shows 6-8% degradation between 4,000 and 11-12,000 miles on their 4 test vehicles. That’s terrible – about Nissan Leaf 1st gen terrible. The Soul EV uses SK Innovations NMC cells.

It may be at full charge cycles, NMC cells last longer than NCA, but backing off the charge cycle SoC window doesn’t necessarily provide for linear results.

Ive done some testing myself and under the same conditions, LG NMC cells last atleast 5X longer than Panasonics NCA cells. Cells were same energy density for comparison.

500K miles for a 250 miles battery is only 2,000 cycles.

That is well within “expectation” of a good battery design that is well protected.

Of course, that is assuming that there are no other factors impacting it such as aging (if it takes 20 years to get there) or excessive use of DCFC.

Again, another result driven by larger battery pack and good TMS.

The battery degradation chart generally first goes down a bit, then stays pretty linear (like we can see in the chart in the article).

But then at a certain point it drops like a rock. It is that point that is interesting, not how it would look if it continued to be linear like it won’t do forever.

That point is very likely to be way after most retire their vehicle based on miles anyway though.
Keep these charts coming, it would be interesting to see how old the vehicles are too because I believe that age will kill the battery before miles do.

This is why I think basically most Model S / X are destined to become a taxi in later life. Especially the ones with free lifetime supercharging.

In cost, and limited frequency, battery replacement won’t be any more a consideration than engine replacement.

My gut says, 80-90% don’t reach 500k miles before their batteries are re-purposed for storage, cars break for other reasons, or Tesla shuts them off ;). I think at 400k Musk shows up on the 17″ screen, arms folded, knodding “upgrade time”.

Then he sings “Daisy.”

That would be a hilarious easter egg.

A few have a capacity of more than 100%? Error?

A lot of them actually.

But that is purely based on range predictor which is about as useful as anyone’s guess.

If that is the “range estimator”, the actually degradation “could” be MUCH WORSE.

The better study would have been total available kWh left vs. new. But that would require far more complex work for the owners.

We know at least 2 cases where high mileage Tesla wasn’t displaying the range correctly (higher than it has).

Yes, there are cars with up to 102.5 percent range according to this graph. This is because the baseline (100%) isn’t the actual starting point for each car individually. It is a statistically calculated start point for all cars. The individual points describe each individual car’s actual measured capacity compared to the theoretical 100%, measured including additional variables, like battery temperature. Due to variations in battery production, a small percent of cars WILL have a few percentage variance from the baseline. That is normal and expected. Building battery cells isn’t like making exact digital copies of software. Every battery isn’t exactly identical, and they only need to fall within the tolerable range specified in the design specifications. Also, while each point is represented as a single point, there is actually slight variances inherent in the measurement. For example, the exact same car would get different range numbers with each 20 degree change in temperature. So a few percentage point outlier data point can reflect changes in charging conditions as well. Exceptions from the norm actually prove the rule. If you find yourself getting caught up in the outlier data that may be a few percentage points out of the norm,… Read more »

I was startled to see a graph, just a couple of days ago, indicating that li-ion batteries actually have a significantly higher capacity above room temperature! That maxes out at ~140° F. But the batteries age much faster when discharging at that temperature, so that’s not a good tradeoff.

I didn’t realize that li-ion battery capacity was so temperature dependent. That also helps explain why they lose capacity when it’s very cold.

I think I get your point or agree with your point.

But I am not sure if I agree with the usage of the word “capacity” in this case. Yes, the amount of “energy” available from the battery varies with temperature. But that is “different” from the word “capacity” implied in the sense that “amount of energy content” changed. Capacity usually means at a “rated temperature”.

Just about all devices performance vary with temperature. Electric motor, ICE engine power output all vary with temperature as well. But their “power rating” doesn’t change usually since those “power rating” are listed at a specific temperature range (even altitude for ICE).

Ah, my error MMF. You’re right, it’s not that capacity rises with temperature. It was “discharge capacity” that was being graphed… or what I think most people would call maximum power. I didn’t look closely enough at the data that was being graphed.

[Miss Emily Litella voice:] Nevermind!

Yes, that is correct (in message).

I still think the best graph is this one, because it puts everything in the proper context:

Somm said:

“A few have a capacity of more than 100%? Error?”

In addition to the variables Nix details, there’s one other factor making this subject a real can of worms:

What the car displays as charge level is (at least theoretically) the fraction of usable capacity of the pack. No EV maker uses the full nameplate capacity of the battery cells, as rated by the manufacturer. Charging li-ion batteries to full nameplate capacity, and discharging them to 0%, ages them far faster than necessary. So all EV makers design their cars to retain at least a few percent (maybe at least 2-3%?) reserve, a gap between usable capacity and full nameplate capacity, both at the “top” and “bottom”.

So yes, it’s possible for a Tesla car to have a charge level slightly above 100% usable capacity… but still less than full capacity.

With a Leaf it can be 80% in 40,000 miles.

And 50% after 150K miles…

Yep. My 12 Leaf was down to 85% in 26k miles. At that rate, it would have hit 80% around 35k miles.

It’s almost like the capacity of these batteries depends more on age and other factors than miles driven!

*My* 2012 Leaf is down to around 85% (I have two bars missing, and my Leafspy adaptor went missing awhile ago), and it’s done about 75,000 miles.

My Leaf has also lived its entire life in the perfect environment of the Pacific Northwest, so there’s that.

Where did you get this data?

I’m at 14% down on capacity (Leaf Spy Pro) on a 2013 Leaf SV, coming up on 49 k miles in 50 months of in service driving. Most Leaf smaller battery packs (24kWh), all without thermal management, will degrade at roughly twice the rate of Tesla thermally managed packs of at least twice the size.

That is a good data point, not all Leaf packs fade fast but in hot weather they do. The design was poor, they packed them in their with inadequate heat sinking nor cooling.

The article makes as much sense as driving on highway looking at rear view mirror only.

I would suggest to read some popular articles about calendar life of Li Ion batteries first before making outlandish claims about outliving owner. Or even Tesla’s own blog for that matter.

Nice to finally have a figure to point to for average cycle life. But two caveats:

1. This ignores calendar life, or “shelf life”. Li-ion batteries have a calendar life that’s an entirely separate limit from cycle life. Even just sitting on a shelf and never being used, the batteries will eventually hit the limit of calendar life; capacity drops off a cliff. And nobody seems to know when that will happen. Will Tesla’s battery packs last 25 years without hitting the calendar life limit? I don’t know, and probably you don’t, either.

2. The average cycle life is just that: The average. As you can clearly see from the graph above, there are outlier cases. I’m fairly sure it’s the usual bell curve distribution. So while the average expected range to 80% capacity may be 521,000 miles, some people’s battery packs will age faster… and some will age slower.

I think the key is that if the battery lasts even 10 years, by the time you need to replace it you should be able to do so relatively inexpensively. If they last 15 years, much the better.

Nothing lasts forever. The battery just has to last long enough.

Li-Ions don’t age the way that trendline shows. It has to be due to a change in usage.

Li-Ions will age more rapidly as they get older because the rising internal impedance means you use more charge to do the same things, thus accelerating wear. The higher impedance also means more internal head created during charging and discharging and this can also accelerate wear if it isn’t managed well.

Still, it looks like these batteries are doing more than well enough to justify the existence of EVs on a lifespan basis.

That is entirely incorrect, Unlucky. As li-ion batteries are subjected to the sort of cycling they get in an EV, they lose capacity faster for the first few hundred cycles, then the loss gradually tapers off to nearly a flat line.

That is exactly what we see here, altho the differences in the data points are hugely exaggerated because the bottom of the graph is cut off, so the tapering off of loss vs. cycles is also hugely exaggerated. In fact, 85% of the graph is cut off, making this one of the worst examples of exaggeration I’ve ever seen in a non-technical article!

Pushy, you are correct at this point in the data. But I think he is talking about the rapid drop-off that happens as a battery reaches end-of life.

At some point on this graph, after it follows this current trend line for some time, it will bend down at an increasingly steeper rate as cells approach failure.

There just isn’t enough data yet to see when that point may be that this will begin to happen. It may be over half a million miles. Maybe more, maybe less. But this current graph won’t continue on this same curve for eternity. At some point it will bend down at an accelerated pace as failure begets further failure.

The data just hasn’t hit that point yet, indicating that it will likely be many more miles before that starts to happen.


Well said!

“At some point on this graph, after it follows this current trend line for some time, it will bend down at an increasingly steeper rate as cells approach failure.”

Correct me if I’m wrong, Nix, but what you’re talking about there is the pack hitting the limit of calendar life. That is a separate issue from cycle life, which is what I was talking about. I’ve explained the difference in previous posts to this very discussion, altho you may not have read my previous posts before responding to this one, due to the way responses are threaded here.

I don’t want to put words in his mouth, but I’m interpreting his comments to be both calendar and cycles combined, with the graph continuing further to the right.

In their current form, these data points include both calendar and cycle losses. They haven’t isolated out either effect separately (that could actually be fairly easily done with data on vehicle age and sufficient data points…)

I think he is not questioning the data so far already on the graph. I think he is objecting to the assumption that it will be a simple curved graph like it is now, continuing forever along the same curve.

Instead the shape will resemble more like the S-curve that Tesla uses for the Model 3 ramp-up (except going down instead of up).

As cars lose range both due to calendar and cycles (it doesn’t matter which), the data points will scatter down on a steeper angle than what we see so far in the data we have now.

Or at least, if that is indeed what he is trying to say, that would be the part that I would agree with….

I hope this makes sense.

Misleading in many ways.
Calendar life is an issue, obviously this is not represented in this graph as Tesla S is a pretty young car. Especially for regions with warm climate this curve will look a lot worse over the years. You will only retain as much of your battery if you
– live in moderate or cool climate
– drive a lot in a short time span
– get no dead cells or other components

Then again the curve always will go to a steep decline some time after going flat at first. Linear approximation might not be correct (we do not know when the steep and sudden decline will set in, but it will).

You should not expect your battery will last 500.000km considering average use cases. You will not be able to drive your battery for 15 years or more!

“You will not be able to drive your battery for 15 years or more!”

You don’t know that.

You don’t know what the calendar life is for the li-ion battery cells which Tesla is using, any more than I do. I wouldn’t be at all surprised to see the average calendar life turn out to be 20 years or even more.

And calendar life will almost certainly vary by the exact chemistry used in the batteries.

Exactly right.

The data should really be tested for multiple variables, instead of a single variable.

– Distance (proxy for # of cycles)
– Climate (Temp.)
– Age

For eg. 500 miles @ 20% degradation may happen if that is all driven in first 5 years – how about 25 ?

Moreover – nobody seems to know/care about the sudden degradation after some point. This is also what makes secondary use of batteries somewhat dubious.

Actually, the NCA chemistry is very heat tolerant. Lab testing at 50 degrees C shows really not much difference over 25 degrees C. As for calendar life, the same kind of cell construction is used in the stationary storage packs and Tesla has stated that the design lifespan is 12-15 years and some might last 20+.

Also, it is possible to do module level repair on the Tesla battery pack and I suspect people will end up doing that. And there is likely a robust aftermarket for cell modules that have problems but can be disassembled for the cells to be re-purposed.

Its just slightly better in calender life (worse in cycle life) than nmc, but i would not Fall that heat resistant at all:

Tech01x – has Tesla said the energy storage cells are NCA? They clearly said the original Power Walls and Packs were NMC. I’ve never heard them say one way or the other about 2nd gen packs.

Kurt Kelty’s presentation this spring made it sound like the GF is NCA-only. And those cells presumably went into energy storage products (ex-Australia). But he never said that outright and I’ve not heard anyone else say it, either.

“Following this trend brings him to the conclusion of 80 percent degradation over 500,000+ miles.”

So the key word is “following this trend”…

I think that is a false assumption. The trend is linear for now until aging induced factors start to impact the battery in later life.

Many LEAF supported claimed that LEAF battery won’t degrade faster when it gets older and it will level out. But it turns that it dove off a cliff and accelerated degradation (Steve Marsh’s LEAF is a clear good example).

I think we will truly find out the degradation in the next 10 years when all the data are in.

Of course, by then, people can just argue that “technology has improved” since then so the “older data” no longer applies.

Now, if we have some 9 years old Tesla Roadster battery data, it would be very interesting.

I haven’t read any reports of early Roadsters showing the signs of rapid capacity loss associated with end of calendar life, so I assume even those earliest batteries have not yet started to hit the limit of calendar life.

And as I recall, Tesla claims the calendar life will be even better for the chemistry used in the new 2170 cells.

It is only 9 years. We will see in the next 10-15 years.

Of course, Roadster sample size is pretty small though.

Entirely true, especially regarding the low number of Roadsters sold in the first year of production, 2008.

I’m no statistician, but I’d think we would want an unbiased sample size of at least 200 before we could express any confidence that the data was a close approximation to reality. (Plus, getting a truly unbiased sample might not be easy. Opt-in surveys are never unbiased.)

It is indeed premature to say we know for how long this graph will continue on the current path. But we do have some clues. The first being the 80% battery loss statistic. The whole reason 80% is used when talking about the useful life of batteries, is that typically batteries don’t enter their death spiral of increased rate of failure until AFTER they drop below that 80% point. So when predicting the the impact of miles alone (which is not actually isolated in this data), it is more likely than not that the graph would continue on the current trajectory until it reaches that 80% point. But this data as presented is the sum of both calendar and mileage losses. And most cars will likely start suffering calendar loss before they are driven 500K+ miles. So nothing can be read into the current data either for or against the batteries lasting a specific number of years. With that said, if they isolated the data further, to just calculate the impact of charge cycles, this curve has a fairly high level of confidence to keep this rate up until at least 80%, before turning into a steeper downward drop sometime… Read more »

I could see that they raise the curve of how long vehicles last. If there was such a thing anti planned obsolescence, that’s what I think Tesla is aiming at.
It certainly differentiates their vehicles from traditional vehicles, which are engineered to have parts fail, after a time.

There’s nothing special about Tesla’s batteries except that they have switched from laptops to a different format for the Model 3. Now comes word that Mercedes will get a new , higher nickel content battery that claims a driving range of 430 miles. Tesla has no battery patents nor trademarks – they design cars, not batteries. Now comes depressing word that Tesla’s gigafactories can’t make batteries as cheap as the leading Japanese battery maker – this after Musk claimed his factories could cut the price by a third. Bummer!!

Isn’t the leading Japanese battery maker Panasonic who Tesla have partnered with for the Gigafactory?

If you’re talking about LG, they’re Korean.

“higher nickel content battery that claims a driving range of 430 miles”
My laptop batteries can do that too…i just have to use more of them.

kent beuchert said: “There’s nothing special about Tesla’s batteries except that they have switched from laptops to a different format for the Model 3.” The engineering of the battery pack, and the effectiveness of the battery thermal management system (TMS), probably has a bigger effect on battery life than the exact chemistry used in the cells, which varies from one model of EV to another, and often even from year to year within the same model. Tesla has a pretty good TMS. Some people think the TMS that GM uses in the Volt is even better. “Now comes word that Mercedes will get a new, higher nickel content battery that claims a driving range of 430 miles.” Those who have been following the evolution of EVs for years know better than to believe claims of breakthru battery tech from any source, even well-established companies. Such claims are usually — in fact, almost always — total and complete B.S. “Tesla has no battery patents nor trademarks – they design cars, not batteries. Incorrect. Tesla has several patents related to the internal design of battery cells. See, for example: Tesla Inc. also has a very sophisticated battery analysis lab. Panasonic is… Read more »

Laptops don’t use high energy NCA cells because it is too risky to use them without a thermal management system. The original LiCo cells used in the Roadster were pretty close to some laptop cells, but that’s almost a decade ago. Things have diverged significantly.

And as others have noted, the leading Japanese cell manufacturer is Panasonic, and that is who Tesla partnered with at the Gigafactory.

Almost everything you have stated is wrong… that’s quite an accomplishment.

Yes like most anti-EV trolls, kent beuchert is remarkably consisten t in being wrong on virtually all his utterances here.

One simply has to google his name to see that he an been an anti-EV, anti-Tesla and anti-RE troll for a long time.

Thanks for the footwork and the warning. now I know to avoid…

Is there any info for how long EV buyers keep their vehicles? They do not seem to keep them very long…

Usually the people who buy a new vehicle and drive it into the ground are the ones buying the very cheap Versa/Yaris/Fit etc…

Well there is Tesloop which has a number of high mileage vehicles, one over 300k. They did a comparison of service with Mercedes, and found the Tesla about 1/10 the cost, to maintain.

“and found the Tesla about 1/10 the cost, to maintain”
Tell that to your ICE friends! This is not even about Tesla as pretty much all ev share this quality.

“While no study has been performed on the 2170 cells, you can bet that they may last longer than the earlier cells.”

In the absence of any science, I don’t see how we can conclude that they would last longer. It’s very possible the extra density and larger size of the 2170’s would make them degrade quicker (i.e. if heat is unable to escape as easily).

“While no study has been performed on the 2170 cells, you can bet that they may last longer than the earlier cells.”

I don’t know what’s worse about that sentence: The grammar or the logic!

Now, as I recall, Elon did say that the Gigafactory battery cells will (or should) last longer, and it’s nearly impossible to believe that Tesla hasn’t performed its own accelerated aging tests on the 2170 cells. So to claim “no study has been performed on the 2170 cells” is almost certainly not true.

I’m guessing what the writer actually meant was that no study of the 2170 cells has been publicly reported, and likely won’t for some years.

How are all the batteries that got replaced represented on this chart? If the answer is “they are ignored”, how can it have any predictive value?

Is there some reason to think that the number of Model S and Model X Tesla battery packs which have been replaced, is a statistically significant number? If so, then I’d appreciate it if you’d cite your source.

So far as I know, that’s pretty rare.

Plug-in America does some surveys. I count 29 pack replacements out of 281 respondents. A few of those were replaced twice. This data is incomplete. It’s not a random sampling and we don’t know what percentage of users had a pack replaced after they filled out the survey.

I first saw a list like this a couple years ago and it seems the percentage was higher, though I might be thinking of drive unit replacements.

Anecdotally, both well known high mileage Model Ss (Quebec taxi and Tesloop) had batteries replaced.

I think Tesla does an incredible job of managing a pretty tricky chemistry. But I also think this 80% at 521k miles claim is completely irresponsible.


Capacity isn’t the only variable. The batteries will fail in other ways

Odds are the way the world/physics works, they’ll degrade faster after X miles and Y years and/or have some other issue from vibration or other factor before reaching 25 years old or 500k miles.