The few times Tesla has addressed battery degradation, they have simply lied and dismissed it.

[D Good]

A bit of a rant, a bit of a question, and a bit of discussion.

Tesla is in denial about battery degradation. Just the other day, on Jay Leno discussing the new model 3, Lars (the head vehicle engineer) completely dismissed Jay's genuine question about battery degradation. He stated something to the effect of the batteries only losing "like 4 percent" of their capacity over multiple years. As we all know, this simply is NOT true.

Tesla needs to attract customers, I get that, but lying to their face about a key part of owning an electric vehicle is not the answer. How will the customer feel when they start to realize their car is losing range? The won't feel good, and they may become an owner with a negative outlook on electric vehicles.

Take this video:

I know the car in the video has been "abused". However, I own this exact model, and I can attest to the huge degradation. My car (2021 LR model 3 78kwh battery-same as in the video) has 48k miles, and it is reporting 63.7 kWh usable, which is the exact same whopping 15% degradation as seen in the video based on a 74.7 kWh original usable pack. THIS IS A VERY NOTICEABLE AMOUNT OF DEGRADATION AFTER JUST 48K MILES. I have recently gone off to college about 2 hours away from my house, and when I travel home, I notice that the car would only have about a 220 mile range at 75mph, and sometimes it will dip below 200 if I do 80 (64000KWh/330Wh/mi at 80MPH = 193miles). The car's battery has not been abused. About 50/50 supercharging and AC charging. Is this normal? I know it's not.

Could the problem be with the 2021 model 3 LR? Maybe. What I am more worried about is the fact that I am supposedly in the significant minority being a "pessimist" about battery degradation. It is a very real (and sometimes extreme) problem that Tesla refuses to address.

For a car advertised with 353 miles (yeah, they went crazy on the 2021 models for some reason) I have been deeply disappointed. I know the advertised range is impossible, but to get only about 60% of the advertised range? Hmmmm.

This is why we need a "500 mile" EV. 500 miles means 350 miles.

P.S. At this point, I essentially have significantly less daily range than a modern LFP rear wheel drive. the LFP can get the full 60KWh every day, whereas I can only use
(63.7 * 0.8) = 50.1 kWh. Also my car is significantly less efficient, making the problem worse. Ridiculous.

 

[ucmndd]

P.S. At this point, I essentially have significantly less daily range than a modern LFP rear wheel drive. the LFP can get the full 60KWh every day, whereas I can only use
(63.7 * 0.8) = 50.1 kWh. Also my car is significantly less efficient, making the problem worse. Ridiculous.

Setting aside the rest of your rant - if you need more range, charge more. This argument that your range is lower because you refuse to change above 80% is nonsense. If you need more range, you have it literally any time you need it.

As for me - I put almost 200,000 miles on a 2016 Model S 75. It had about 12% degradation when I sold it. Supercharged regularly. Charged to 100% whenever I needed to, 90% on most days. In all a perfectly reasonable and pleasant experience over 7 years.

For what it’s worth - my 2023 Model 3 RWD is only good for ~200 miles also at typical highway speeds.

 

[D Good]

Setting aside the rest of your rant - if you need more range, charge more. This argument that your range is lower because you refuse to change above 80% is nonsense. If you need more range, you have it literally any time you need it.

As for me - I put almost 200,000 miles on a 2016 Model S 75. It had about 12% degradation when I sold it. Supercharged regularly. Charged to 100% whenever I needed to, 90% on most days. In all a perfectly reasonable and pleasant experience over 7 years.

For what it’s worth - my 2023 Model 3 RWD is only good for ~200 miles also at typical highway speeds.

Exactly. I bought a long range. My car should not have equivalent to standard-range range after just 3 years of regular use.

And to the point of above 80%, yes I am absolutely willing to use it, but 80% is what is “recommended” (it used to be 90%, who knows what happened there). Charging over 80% supposedly induces significantly more degradation. When the “recommended” limit was 90%, I charged it to 90% often. Could Tesla have realized 90% wasn’t much better than 100% and that’s why they changed the recommended daily charge level?

 

[AlanSubie4Life]

Charging over 80% supposedly induces significantly more degradation. When the “recommended” limit was 90%, I charged it to 90% often. Could Tesla have realized 90% wasn’t much better than 100% and that’s why they changed the recommended daily charge level?

Pretty well established that you should keep your time-averaged charge level below about 55% for your type of pack (LFP can be kept a bit higher, but not applicable here). Going to 80%, 90%, 100% not an issue at all, just don’t leave it sitting there.

15% is on the high side. So your energy screen method is reporting about 67kWh?

 

[D Good]

Pretty well established that you should keep your time-averaged charge level below about 55% for your type of pack (LFP can be kept a bit higher, but not applicable here). Going to 80%, 90%, 100% not an issue at all, just don’t leave it sitting there.

15% is on the high side. So your energy screen method is reporting about 67kWh?

Never done the energy screen method. This is from driving 100% to 0. I will do this too and report back.
If the degradation is truly this high, that would be really disappointing. I have a new performance 3 on order but I am keeping this LR as well. I’m definitely going to baby the pack in the performance whenever possible if it’s truly this bad.

 

[AlanSubie4Life]

Never done the energy screen method. This is from driving 100% to 0. I will do this too and report back.
If the degradation is truly this high, that would be really disappointing. I have a new performance 3 on order but I am keeping this LR as well. I’m definitely going to baby the pack in the performance whenever possible if it’s truly this bad.

You can just use your projected 100% charge rated miles too and compare to 353, which was 77.8kWh (the degradation threshold) - so take the ratio and multiply by 77.8kWh to give your current capacity. It's all equivalent - you'll find this gives exactly the same answer as the energy screen method.

I'd expect you're at more like 320 rated miles at 100%; that would be more typical. But outliers do happen.

The metering only works if you do it continuously with no stopping, watch out for rounding error, and extrapolate and account for the buffer.

It's easier to just get the answer and forget about the metering (but they will line up, within a few % - there can be dead reckoning error or error in the BMS estimate).

 

[jjrandorin]

I'd expect you're at more like 320 rated miles at 100%; that would be more typical.

In another thread, the OP said:

This is not the right way to calculate degradation. You have to actually drive the car 100% to zero percent (you could also just use 50% of the battery and double it, but this is less accurate) and see how many kWh you pulled. My car (the one discussed above with extreme degradation) still says I should have 323 miles of range. However, this is completely false based on the number of KWh I pulled 100 to 0.

 

[AlanSubie4Life]

In another thread, the OP said:

Makes sense. So @D Good is measuring the useful kWh wrong, most likely. Just missing some of it.

This is 323/353*77.8kWh = 71.2kWh.

So usable would be 68kWh. That's what should be able to be metered on a continuous drive without any stopping, without any time spent in park, from 100% to 0%. Within 1-2kWh or so. Wouldn't be surprised to get as low as 66kWh on occasion.

 

[D Good]

Thank yall so much for the encouragement. The way I learned to do battery degradation was from (I think) the YouTuber Bjorn who does the classic 100 to 0 like I did (admittedly with some fancy equipment). The miles number at 100 percent fluctuates (as is normal) so I am reluctant to rule trust just doing a percent difference from 353. In fact, I don’t think my car even ever said 353 miles in the first place (I had no idea what I was doing with the car when I first got it and didn’t know what to check etc). I know that Kyle Connor from out of spec says that there can be significant heat loss that throws off the measurement in the trips card if you do the 100 to 0 test at over 50 mph. Could that be what’s happening? Also, the often incorrect Tessie app says 67.3 kWh, whatever you can take from that.

 

[AlanSubie4Life]

I know that Kyle Connor from out of spec says that there can be significant heat loss that throws off the measurement in the trips card if you do the 100 to 0 test at over 50 mph. Could that be what’s happening?

Yes. It’s not that significant though - I’ve never seen more than about 1% when I have actually been paying attention.

Also, the often incorrect Tessie app says 67.3 kWh, whatever you can take from that.

Seems too low based on what you have said elsewhere.

The miles number at 100 percent fluctuates (as is normal) so I am reluctant to rule trust just doing a percent difference from 353

Guess it depends on the car. Mine has been in the extremely tight range of 286 to 294 miles for the last three years, for example. Never seen anything outside of this extremely small range. This is just 2kWh difference, max. And usually it’s more like half of that variation!

 

[D Good]

Did the energy screen calculation. Got 69.23 KWh. Worse than I would want, but not terrible.

 

[AlanSubie4Life]

Did the energy screen calculation. Got 69.23 KWh. Worse than I would want, but not terrible.

This would suggest 314 miles (69.23kWh/77.8kWh*353mi) at 100% which is quite a bit different than the 323 miles you quoted elsewhere (which would be 71.2kWh). (These numbers both include the buffer so usable is 95.5% of that.)

The method is usually much more accurate than this. Do you have the data you used, along with an SOC%/rated miles number (so we can simultaneously extrapolate your rated miles at 100%)?

 

[UncleCreepy]

FWIW: without using any more or less fancy app, my 2020 LR AWD started at 504 km displayed range. Now, 144,000 km (89,500 miles) later, 100% charge equals 474 km. Maybe there is more to it, but to me, that's 6% less mileage than what I had when the car was new. I can live with that. I regularly charge the car to more than the recommended level but I start driving right after I reach my target, and then arrive at home at the recommended 80% (or 90% when that was the recommended maximum).
To me, range continues to be a non-issue.

 

[AlanSubie4Life]

FWIW: without using any more or less fancy app, my 2020 LR AWD started at 504 km displayed range. Now, 144,000 km (89,500 miles) later, 100% charge equals 474 km. Maybe there is more to it, but to me, that's 6% less mileage than what I had when the car was new. I can live with that. I regularly charge the car to more than the recommended level but I start driving right after I reach my target, and then arrive at home at the recommended 80% (or 90% when that was the recommended maximum).
To me, range continues to be a non-issue.

474km => 474km/516km*77.8kWh = 71.5kWh

8.1% capacity loss.

Probably the initial low value of 504km popped up to close to 516km before decaying down from there. But without tracking, hard to say. (It's an abnormally low initial value.)

The relatively cool temperatures (on average) help.

 

[D Good]

This would suggest 314 miles (69.23kWh/77.8kWh*353mi) at 100% which is quite a bit different than the 323 miles you quoted elsewhere (which would be 71.2kWh). (These numbers both include the buffer so usable is 95.5% of that.)

The method is usually much more accurate than this. Do you have the data you used, along with an SOC%/rated miles number (so we can simultaneously extrapolate your rated miles at 100%)?

267 miles, 86 %. Charged the car to 100% today and it said 318 miles. Again, this number has fluctuated for me in the past slightly so I’m not confused as to why it’s off by a bit. Further, a percent is actually quite a large “window” to be in. 267 at the bottom of 86% vs the top of 86% can create variety in the extrapolation.

 

[D Good]

Overall, I’m not particularly happy with the degradation. As an aspiring engineer, it’s something I just am going to think about and notice. I’ve always kept my car in % mode as the miles is completely useless. I’m going to unfortunately have to baby the performance I have on order as I don’t want to really have to be thinking like this again. Also apparently the 82kwh Panasonic batteries degrade much more too. What ever happened to this “million mile” battery?

 

[AlanSubie4Life]

267 miles, 86 %. Charged the car to 100% today and it said 318 miles. Again, this number has fluctuated for me in the past slightly so I’m not confused as to why it’s off by a bit. Further, a percent is actually quite a large “window” to be in. 267 at the bottom of 86% vs the top of 86% can create variety in the extrapolation.

Yeah all in the ballpark of what I would expect. 318/353*77.8kWh = 70kWh.

I’ve always kept my car in % mode as the miles is completely useless.

Miles denote energy. (They are units of energy.)

 

[3sr+buyer]

I’ve always kept my car in % mode as the miles is completely useless.

The miles at the top of the screen are a measure of remaining battery capacity. That number can be useful for tracking capacity loss over time.

Note that this is different from most other EVs where the miles number adjusts based on recent economy. On Tesla cars, this "guess-o-meter" miles is on the energy screen's consumption graph.

 

[karlos22]

stop looking at the range indicator at 100%. If your car had 10-20% degradation you wouldn’t even notice unless you frequently drive insanely long distances. Even then it doesn’t really matter apart from a few minutes more at the supercharger.

Set it to % and forget about it.

 

[DrChaos]

Overall, I’m not particularly happy with the degradation. As an aspiring engineer, it’s something I just am going to think about and notice. I’ve always kept my car in % mode as the miles is completely useless. I’m going to unfortunately have to baby the performance I have on order as I don’t want to really have to be thinking like this again. Also apparently the 82kwh Panasonic batteries degrade much more too. What ever happened to this “million mile” battery?

Higher state of charge on average and 50% supercharging doesn't help on preserving battery life.

The "million mile battery" was a very high purity NMC battery developed in Jeff Dahn's lab and not charged up to as high voltage as usual for NMC, and was measuring cyclic aging rate. It wasn't a production battery. The science there was that with a good enough control of chemistry and lower top charge the NMC battery can be as good on cyclic aging as LFP. Commercially they will still stick with LFP for frequent cycling uses (energy storage & buses) because it's cheap now from China.

We know now that it's calendar aging that mostly drives battery degradation unless you drive a ton (like commercially), though high current supercharging isn't great either. Yes, higher initial energy cells like NCA can degrade more. The upside with calendar aging is that it slows down with time.

The NCA battery isn't universally bad. I keep my charge limit at 50% all but probably 20 days per year and never supercharge, and my degradation is about 3.8% after 2 years (extrapolating or looking at range at 100%, or using energy screen) and has been almost zero over last year.