Range Loss Over Time, What Can Be Expected, Efficiency, How to Maintain Battery Health

[vickh]

Another data point I'm @190 out of the original 220.

6/`19 SR delivery @ 22k miles.

Debating whether to join class action

 

[scottf200]

Looking at TeslaFI battery report (TeslaFi.com Tesla Model S 3 X Y Data Logger) there is a distinct 7-mile range drop between
2021.12.25.7 and
2021.24.3 from the graph and table data below.
All these are normal workday drives ~104 miles (~52 miles each way).
Anyone else seeing that?
P.S. There was a TeslaFI chart thread but it was locked down otherwise I would have posted there.

 

[Jeremy3292]

Charged my M3 to 100% just before a long trip today and at 100% it still said it had 35 min remaining. Any thoughts on this? Perhaps this is the "hidden" capacity that is optically locked?

@AAKEE @AlanSubie4Life @eivissa

 

[AlanSubie4Life]

Charged my M3 to 100% just before a long trip today and at 100% it still said it had 35 min remaining. Any thoughts on this? Perhaps this is the "hidden" capacity that is optically locked?

View attachment 712042

@AAKEE @AlanSubie4Life @eivissa

No. It is likely re-estimating NFP, balancing, etc. Even batteries below the capacity threshold can show this behavior, I think.

If it were the "optical lock," and there were actually a large buffer above 100%, then you would logically expect to have to drive for some time before seeing a reduction in rated miles, or %. But you'll see the miles start to tick off nearly right away.

But you can confirm! After charging to 100%, and waiting for it to complete, start driving right away (can't lose any unmetered energy), and keep an eye on the trip meter. You'll drop about 1% when you've used up about 0.5-1kWh. Or if you switch to rated miles, you'll see miles start to tick off once your trip meter shows 0.2-0.4kWh of use. These are rough numbers - in reality I think it is possible to charge up to 101% or something (I've seen this reported in some SMT captures (the UI will not exceed 100%) but not sure the significance), but no more than that.

If it were a large upper buffer (and we're talking about as much as 2-3kWh here for an 80-81kWh battery with a 77.8kWh degradation threshold), then you would see that much on the trip meter consumption before seeing a decrement in the miles. (You won't see this, I don't think.)

But you should check and let us know. If you actually meter out 2-3kWh of use before seeing a drop in your rated miles, I'd have to change my understanding of the framework. That would be completely inconsistent with my understanding of how it works.

Changing to rated miles (Energy Display -> Distance) makes it easiest to do this experiment.

Again, my current understanding is simply that the energy content of each rated mile is expanded right now. They'll gradually reduce in size over the coming year (or whatever) until you hit the degradation threshold, whereupon their energy content will become constant.

 

[Jeremy3292]

No. It is likely re-estimating NFP, balancing, etc. Even batteries below the capacity threshold can show this behavior, I think.

If it were the "optical lock," and there were actually a large buffer above 100%, then you would logically expect to have to drive for some time before seeing a reduction in rated miles, or %. But you'll see the miles start to tick off nearly right away.

But you can confirm! After charging to 100%, and waiting for it to complete, start driving right away (can't lose any unmetered energy), and keep an eye on the trip meter. You'll drop about 1% when you've used up about 0.5-1kWh. Or if you switch to rated miles, you'll see miles start to tick off once your trip meter shows 0.2-0.4kWh of use. These are rough numbers - in reality I think it is possible to charge up to 101% or something (I've seen this reported in some SMT captures (the UI will not exceed 100%) but not sure the significance), but no more than that.

If it were a large upper buffer (and we're talking about as much as 2-3kWh here for an 80-81kWh battery with a 77.8kWh degradation threshold), then you would see that much on the trip meter consumption before seeing a decrement in the miles. (You won't see this, I don't think.)

But you should check and let us know. If you actually meter out 2-3kWh of use before seeing a drop in your rated miles, I'd have to change my understanding of the framework. That would be completely inconsistent with my understanding of how it works.

Changing to rated miles (Energy Display -> Distance) makes it easiest to do this experiment.

Again, my current understanding is simply that the energy content of each rated mile is expanded right now. They'll gradually reduce in size over the coming year (or whatever) until you hit the degradation threshold, whereupon their energy content will become constant.

Yes, you were correct. It went from 100% down to 99% very shortly after leaving work. Or 353 rated miles down to 351 quickly. I toggle back-and-forth.

Random interesting tidbit: I have some free supercharging miles and when I charged at the supercharger today it only used 68 free miles for a 34% charging session (50% to 84%). That means Tesla is rating those free miles at 200 miles “per tank” or one full charge. That is a nice benefit to the consumer. I expected them to use EPA rated miles, 34% = 120 free miles used.

 

[upsss]

Wouldn't it better for the battery if you limit the charging current lat say from 32A to 20A assuming you can keep it charging for a longer period of time?

 

[Candleflame]

i also lost 8km (5miles) on 24.3 from 12.25.7 -> which is probs same percentage as you as I have a LR.

 

[MaxRSM]

y I think it is possible to charge up to 101% or something

My Model 3 LR ( September 2019 ) is losing Kwh like a crazy in last months.
Last week was at 68.6 Kwh.
I have tried to charge it to 100% and leave to that for the night to force BMS to recalibrate.
At some point it showed 101% , LOL.
Next morning nominal full pack was up to 69.4 Kwh.
Now i'm discharging 10% every day and in 2-3 days i'll reach 60% and then i'll go up again at 100%.

 

[AlanSubie4Life]

My Model 3 LR ( September 2019 ) is losing Kwh like a crazy in last months.
Last week was at 68.6 Kwh.
I have tried to charge it to 100% and leave to that for the night to force BMS to recalibrate.
At some point it showed 101% , LOL.
Next morning nominal full pack was up to 69.4 Kwh.
Now i'm discharging 10% every day and in 2-3 days i'll reach 60% and then i'll go up again at 100%.


View attachment 712785

Yes, SMT calculates SOC as Usable Remaining/(NFP-Buffer) and reports with 3 significant figures, as far as I can tell, which would be (Nominal Remaining - Buffer)/(NFP-Buffer), which would be 65.9kWh/(68.6kWh-3.1kWh) = 100.6%, or 101%.

So for instances where NFP is lower than Nominal Remaining, which does happen (not sure when and exactly how much NFP is adjusted - as you saw it went up overnight as it re-evaluated the situation), you get over 100%.

 

[ericl]

2018 M3 LR AWD. Did I recalibrate wrong? Usually 90% is around 270 using %. Switched to miles and charged to full 100% today and its 280???? Full range I believe is 310.

 

[GreenHokie]

In my experience, calibration doesn’t help. I normally charge to 90% which gets me around 240 miles of reported range. If I slide the charge % to 100 in the Tesla app, it will estimate/show around 260-270 miles as the resulting range. My original range limit was 310 miles.

So, if you’re still getting 280 miles at 90%, then you’re probably doing better than most, especially with a 2018 model. So, be happy and just enjoy the vehicle!!

 

[ericl]

In my experience, calibration doesn’t help. I normally charge to 90% which gets me around 240 miles of reported range. If I slide the charge % to 100 in the Tesla app, it will estimate/show around 260-270 miles as the resulting range. My original range limit was 310 miles.

So, if you’re still getting 280 miles at 90%, then you’re probably doing better than most, especially with a 2018 model. So, be happy and just enjoy the vehicle!!

Haven't charged this car to 100% in 4 months. Was going to see what the difference is between chill and sport mode, but the estimator is all funky which doesn't help.

 

[GreenHokie]

Yeah, I no longer stress/care about what the vehicle reports for the range. Has zero impact on my driving habits, even on longer trips. Sure, I’d love to see my vehicle report 310 as the available miles when I move the slider to 100%. But, I’m also OK with seeing 260-270 miles.

I never charge to 100% period. There are zero real world situations where the additional mileage at 100% makes any difference in my drive/trip, compared to charging it to just 90%. So, why even bother charging it to 100% (and risk potentially harming/degrading the battery pack)?… is my philosophy.

 

[stevesark]

Yeah, I no longer stress/care about what the vehicle reports for the range. Has zero impact on my driving habits, even on longer trips. Sure, I’d love to see my vehicle report 310 as the available miles when I move the slider to 100%. But, I’m also OK with seeing 260-270 miles.

I never charge to 100% period. There are zero real world situations where the additional mileage at 100% makes any difference in my drive/trip, compared to charging it to just 90%. So, why even bother charging it to 100% (and risk potentially harming/degrading the battery pack)?… is my philosophy.

I concur, thought it mattered on long trips, but it really doesn't. Once I finally took a long trip, realized my butt/legs needed a break before the car needed charging.

 

[ericl]

Yeah, I no longer stress/care about what the vehicle reports for the range. Has zero impact on my driving habits, even on longer trips. Sure, I’d love to see my vehicle report 310 as the available miles when I move the slider to 100%. But, I’m also OK with seeing 260-270 miles.

I never charge to 100% period. There are zero real world situations where the additional mileage at 100% makes any difference in my drive/trip, compared to charging it to just 90%. So, why even bother charging it to 100% (and risk potentially harming/degrading the battery pack)?… is my philosophy.

M3 has lost % more in 3 years than my MS in 7 years lol.

 

[AlanSubie4Life]

Was going to see what the difference is between chill and sport mode

Will make no difference. The miles are a display of energy, they have nothing to do with modes - the only thing that changes miles is on 2020 LR AWD Performance (and maybe regular...can't remember) vehicles where 18"/19"/20" wheels affect the constant but it's just bookkeeping and makes no difference to the energy.

M3 has lost % more in 3 years than my MS in 7 years lol.

Haha. Different cells. Not clear how much lower the degradation threshold was than the original capacity for Model S, either. That could in theory hide a lot of initial capacity loss and you'd never know it (without SMT, or calculating your current capacity and comparing to likely initial starting capacity based on other user captures and/or the EPA test results). (But it may well be the cell difference - the 2170L cells arguably are doing better so far, but the data is very very limited. So the 18650s may have been more robust for some reason.)

Anyway, 280 is slightly low, but you might see it bump up a few miles after sitting there a while (but this is not worth it of course). This is about 11% capacity loss. 68.6kWh vs. your starting ~78kWh.

I'm at 285-290. A perfectly normal result. There are people who have 310 rated miles still though, haha (less than 3% capacity loss - effectively the max original mileage was 318 miles, but it maxed out at 310 and extra capacity was hidden via the degradation threshold and expanded rated mile energy content)!

 

[299792458]

Fun little experiment to try:

My projected range had been trending down over the summer, to around 278. I generally finish my daily driving between 6:00 - 8:00 PM, and have been immediately charging to 90%. Recently, I had a new low where my range had shown 275. I then changed my charge level to 80% and enabled scheduled charging to start at 3:00 AM every day, and within a few days it bounced back up to ~290 miles.

For context, my projected range has had various fluctuations of about +/- 5 miles over the past 2 years (the period I’ve been using TeslaFi), with the average being about 285. I’ve used various charging methods, but typically have been charging to 90% daily on a Tesla Wall Charger.

So after a little over 2 weeks, estimated 100% (TeslaFi) range is around 292 now. I just realized there was an additional variable that I can't account for, which was software upgrade 2021.24.10 happening right around the same time I went to scheduled charging and 80%. 2018 Performance, VIN 63,xxx, and now 61K miles.

 

[djchromatic]

I bought my car used about a year ago. From what I’ve read it should have had around 260 mile range originally. I don’t remember ever seeing the total range being higher than 235 miles since I’ve owned it? Has it degraded that much?

 

[ericl]

Okay I totally freaked out because the M3 doesn't show the miles like my MS does. Switched back to %. Looks like I haven't really lost much range because I was still hitting "310" in January before I switched to %.

M3:
100% --> 88%
46 miles driven.

That gives me an effective range of 383 miles somehow (I drive like a grandpa).

 

[AlanSubie4Life]

I bought my car used about a year ago. From what I’ve read it should have had around 260 mile range originally. I don’t remember ever seeing the total range being higher than 235 miles since I’ve owned it? Has it degraded that much?

Sounds like a 2020, so it started at 250. Maybe 2019. 2019 started at 240.

In either case you are doing great.