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

[outdoors]

This is my best guess of what happened. I am quite confident that the constant did NOT change on this update, based on discussions at the time with owners where I asked this specific question. I think the rated line has always been at 239Wh/mi (234Wh/mi constant). Before and after update.

One had to be paying to each release notes. The rated range line has never changed on my 2017 3. Mine was included, but slightly less, as mine was slightly less than to begin with. Not from experience, just from remembering the situation and numbers. I saw the notes, and saw the range, but I don't think anyone was excluded.

 

[nicksp]

No I don't. However, there are a lot of reasons why people would not notice this change.

Actually I've figured this out before, but what I said above is wrong.

Specifically this is wrong:



This 295 to 310 could NOT happen. If below 310miles before the update, people would not see any change when making the update!

Most likely (since the LR RWD always had over 330 miles in the EPA test), Tesla just had the degradation threshold set to 310 miles, from the beginning. This means that people with LR RWD happily had 310 miles until their capacity dropped below 310mi*234Wh/mi = 72.5kWh (takes a year or more in some cases).

Most vehicles were still above 72.5kWh when the update came along in less than a year after the vehicle release. Maybe some had started to show a little capacity loss, for example 72kWh would give 308 miles.

But when the update came along, anyone above 72.5kWh would have seen their max range go up a bit. Maybe from 310 to 315, for example, if their car was a year old with 73.7kWh estimate.

Anyway, net result is some people would see basically no change with the update. Many would see very little change. (They might see 315 and think they "didn't get the update."). People with the oldest most degraded vehicles, below 72.5kWh, would see no change!

Furthermore, many would not be paying attention to their 100% charge, and only pay attention after the update. So it would be hard to see the change.

Would have to search out TeslaFi captures of a person before and after the update to see whether what I am saying is consistent.

This is my best guess of what happened. I am quite confident that the constant did NOT change on this update, based on discussions at the time with owners where I asked this specific question. I think the rated line has always been at 239Wh/mi (234Wh/mi constant). Before and after update.

(As a refresher on degradation threshold: Remember that the way it works is it crams all the energy into the available miles, so if you are above the threshold, your miles will be more energetic. For example, if you have 78kWh with a 72.5kWh/310mi degradation threshold, each rated mile will contain 252Wh (78kWh/310mi), while after you get to 72.5kWh, you'll get 234Wh per mile. And below that you'll just start losing rated miles. So it's not really like a top buffer where when you start driving you won't see any change in your miles until you get below 72.5kWh of remaining energy. It's a top buffer of sorts, but it doesn't work that way. Miles start clicking off as soon as you start driving. Just more slowly than they would for someone in a car below the threshold.)

Thanks. Great explanation.

 

[AAKEE]

Anyway, net result is some people would see basically no change with the update. Many would see very little change. (They might see 315 and think they "didn't get the update.").

Anyone claiming not to have gotten the range update should perform a full charge, and post pictures of the range at 100% and also pictures of the energy screen.
From this we can find the capacity, and also the constant (which was not changed, as per the findings).

When we have this data we can show that:
- The range update would not be noticed if the car was below the old degradation threshold.
- The degradation will not be even close to as low as it looks range wise.

 

[navguy12]

Yeah it is a myth as far as I know.

People think they didn’t get it because they had already degraded below the new 310 miles. That’s my theory.

I haven’t seen any TeslaFi captures showing no change to range on the update. (Everyone should have seen a change - some people would go from 295 to 310 for example.)

I was one of the cars that never saw anything over 499 km (May 2018 build, delivered 01 Jun 2018).

Unfortunately, the screen shots from summers of 2018 and 2019 are gone, but it never read anything over 499 km at anytime.

Summer of 2020 (two years old) showing 499 km:

Summer of 2021 (three years old) showing 499 km:

Summer of 2022 (four years old) showing 495 km:

Fall of 2023 (five years and four and a half months) showing 478 km while still accepting six amps:

A slow top up this past Monday morning, while preparing for a trip, showed 480 km and still accepting a charge (sorry, no screen shot).

Edit: clarity.

 

[AAKEE]

I was one of the cars that never saw anything over 499 km (May 2018 build, delivered 01 Jun 2018).



A slow top up this past Monday morning, while preparing for a trip, showed 480 km and still accepting a charge (sorry, no screen shot).

480 km means about 69.8 kWh capacity, so about 10% loss of capacity.

 

[navguy12]

Most likely (since the LR RWD always had over 330 miles in the EPA test), Tesla just had the degradation threshold set to 310 miles, from the beginning.

This makes sense. In any event, my car stayed at 499 km well into its third year of age.

 

[navguy12]

Anyone claiming not to have gotten the range update should perform a full charge, and post pictures of the range at 100% and also pictures of the energy screen.
From this we can find the capacity, and also the constant (which was not changed, as per the findings).

When we have this data we can show that:
- The range update would not be noticed if the car was below the old degradation threshold.
- The degradation will not be even close to as low as it looks range wise.

I have another long trip in nine days; I’ll try and remember to take the shots (at my 100% SOC) you recommend and I’ll post them here and you can interpret the data.

 

[AlanSubie4Life]

I was one of the cars that never saw anything over 499 km (May 2018 build, delivered 01 Jun 2018).

Unfortunately, the screen shots from summers of 2018 and 2019 are gone, but it never read anything over 499 km at anytime.

Summer of 2020 (two years old) showing 499 km:

View attachment 1006722


Summer of 2021 (three years old) showing 499 km:

View attachment 1006723

Summer of 2022 (four years old) showing 495 km:

View attachment 1006724

Fall of 2023 (five years and four and a half months) showing 478 km while still accepting six amps:

View attachment 1006725

A slow top up this past Monday morning, while preparing for a trip, showed 480 km and still accepting a charge (sorry, no screen shot).

Edit: clarity.

I know you did it to just show the date (but note the date is already displayed at the top of the screen) - but for the summer 2020/2021, can you show that the battery icon is full for both of those 499km values? Just for the record.

You are in Canada (but were you always, do you have a US market car?), so I do wonder if it was handled differently there (you never got the bump to the degradation threshold). Not that it would matter at all to anything, as described above - the change didn't change anything except the degradation threshold, which doesn't change the baseline constant, doesn't change range, and doesn't change energy available. (That's my claim anyway - it just changes the maximum number that can be displayed.). But it would make me wrong! Some people actually didn't get the degradation threshold increase!

I would agree your evidence shows you never got the degradation threshold adjustment. I don't know if there are any Canadian 2018 LR RWD owners who got the update.

Also as @AAKEE suggested, I guess a picture showing your rated line is at 239Wh/mi… you could just take a picture of the energy screen capturing the projected range, recent efficiency, and the rated miles remaining (battery icon), which would allow us to derive the 234Wh/mi constant (just to be sure, not that I have any doubts!). That would show line is at 239Wh/mi as expected.

Anyway even if some people did not get the update, the 310mi/325mi thing doesn’t matter for calculating capacity loss, as long as you are below both of those numbers. Potentially vehicle that never got the threshold update and still shows a steady 310miles could have more energy than a straight energy screen calculation would suggest.

But it has been so long this situation would be fairly uncommon (a vehicle with more than 72.5kWh). And it would be easy to see that your range just refuses to budge, which means you are above the threshold.

Regardless the starting energy to use for these vehicles is 78kWh (not 76kWh). EPA test got 78-79kWh.

 

[Bouba]

For all theses cars that got (or did not get) the range increase....which battery did they have ?

 

[AlanSubie4Life]

For all theses cars that got (or did not get) the range increase....which battery did they have ?

77.8kWh. Same as the other LR cars. Though the wiring harnesses may or may not have differed (one motor vs two etc.)

They started with that energy available and it was never unlocked, etc. It just went down with age as expected. It would have been illegal for Tesla to do otherwise (they cannot lock out energy).

 

[navguy12]

I know you did it to just show the date (but note the date is already displayed at the top of the screen) - but for the summer 2020/2021, can you show that the battery icon is full for both of those 499km values? Just for the record.

You are in Canada (but were you always, do you have a US market car?), so I do wonder if it was handled differently there (you never got the bump to the degradation threshold). Not that it would matter at all to anything, as described above - the change didn't change anything except the degradation threshold, which doesn't change the baseline constant, doesn't change range, and doesn't change energy available. (That's my claim anyway - it just changes the maximum number that can be displayed.). But it would make me wrong! Some people actually didn't get the degradation threshold increase!

I would agree your evidence shows you never got the degradation threshold adjustment. I don't know if there are any Canadian 2018 LR RWD owners who got the update.

Also as @AAKEE suggested, I guess a picture showing your rated line is at 239Wh/mi… you could just take a picture of the energy screen capturing the projected range, recent efficiency, and the rated miles remaining (battery icon), which would allow us to derive the 234Wh/mi constant (just to be sure, not that I have any doubts!). That would show line is at 239Wh/mi as expected.

Anyway even if some people did not get the update, the 310mi/325mi thing doesn’t matter for calculating capacity loss, as long as you are below both of those numbers. Potentially vehicle that never got the threshold update and still shows a steady 310miles could have more energy than a straight energy screen calculation would suggest.

But it has been so long this situation would be fairly uncommon (a vehicle with more than 72.5kWh). And it would be easy to see that your range just refuses to budge, which means you are above the threshold.

Regardless the starting energy to use for these vehicles is 78kWh (not 76kWh). EPA test got 78-79kWh.

I know you did it to just show the date (but note the date is already displayed at the top of the screen) - but for the summer 2020/2021, can you show that the battery icon is full for both of those 499km values? Just for the record.

You are in Canada (but were you always, do you have a US market car?)

Yes, always in Canada. I have a Canadian market car delivered in Toronto on 01 Jun 2018.

Also as @AAKEE suggested, I guess a picture showing your rated line is at 239Wh/mi… you could just take a picture of the energy screen capturing the projected range, recent efficiency, and the rated miles remaining (battery icon), which would allow us to derive the 234Wh/mi constant (just to be sure, not that I have any doubts!). That would show line is at 239Wh/mi as expected.

Yes, I‘ll take a picture of that page…does it have to be at 100% SOC or can any SOC serve the same purpose?

 

[AlanSubie4Life]

View attachment 1006821


View attachment 1006820



Yes, always in Canada. I have a Canadian market car delivered in Toronto on 01 Jun 2018.




Yes, I‘ll take a picture of that page…does it have to be at 100% SOC or can any SOC serve the same purpose?

Thanks! Any SOC, just be sure it is displaying miles, not percentage, for this purpose. Higher SOC gives a bit better accuracy but as long as you have three digits on all three numbers it’ll be fine (so over 100km projected range, over 100Wh/km recent efficiency, and over 100km rated range remaining).

Anyway the product proj range * recent efficiency / (rated range) should equal 234Wh/rmi (145Wh/rkm).

It does seem that maybe Canadian cars never got the memo. Maybe it was not limited to just Canadian, but that would not make that much sense. Anyway, thanks for the info - good to see strong evidence that some did not ever get the adjustment to the threshold. And as expected, your car did not lose range for years - which adds extra credence to the working theory that the threshold change was the only adjustment made. If you had got the update, you would have seen range decline (from higher levels) much earlier (though it would have converged and seen 495km in summer 2022 and would have the same range now)!

 

[navguy12]

Anyway the product proj range * recent efficiency / (rated range) should equal 234Wh/rmi (145Wh/rkm).

Hopefully the following data makes sense to you.

The following data is based on 70% SOC:

The SOC as a rated range (?) (I never use this data, only the percentage data):

Projected range based on most recent 25 km (230 km x 211 Wh/km) = 48,530/334 km = 145.3 Wh/km:

Projected range based on most recent 50 km (258 km x 188 Wh/km) = 48,504/334 km = 145.2 Wh/km

Projected range based on most recent 10 km (215 km x 225 Wh/km) = 48,375/334 km = 144.8 Wh/km

 

[AlanSubie4Life]

Hopefully the following data makes sense to you.

The following data is based on 70% SOC:

View attachment 1006877

The SOC as a rated range (?) (I never use this data, only the percentage data):

View attachment 1006878

Projected range based on most recent 25 km (230 km x 211 Wh/km) = 48,530/334 km = 145.3 Wh/km:

View attachment 1006879

Projected range based on most recent 50 km (258 km x 188 Wh/km) = 48,504/334 km = 145.2 Wh/km

View attachment 1006880

Projected range based on most recent 10 km (215 km x 225 Wh/km) = 48,375/334 km = 144.8 Wh/km

View attachment 1006881

Yep. All checks out. 145Wh/km.

145Wh/km *499km = 72.4kWh

Thanks again for the interesting info. Again: Maybe in the US some people did NOT get the update…but as you can see, it makes no difference, except in the display (if you have more than 72.5kWh).

 

[nicksp]

Yep. All checks out. 145Wh/km.

145Wh/km *499km = 72.4kWh

Thanks again for the interesting info. Again: Maybe in the US some people did NOT get the update…but as you can see, it makes no difference, except in the display (if you have more than 72.5kWh).

In terms of kwh, the battery has degraded approximately 6kwh. But then how come the range is down that little from original 499 kms to 480kms?

 

[AAKEE]

In terms of kwh, the battery has degraded approximately 6kwh. But then how come the range is down that little from original 499 kms to 480kms?

Nope, the current capacity is about 69.3 kWh.
211Wh/km x 230 / 70% SOC = 69.3 kWh.

69.3/77.8 = 11%.

Thats close to the degradation level I was talking about earlier

 

[AlanSubie4Life]

In terms of kwh, the battery has degraded approximately 6kwh. But then how come the range is down that little from original 499 kms to 480kms?

The calculation I was making was for the degradation threshold (constant * max miles ever displayed). Not the current capacity (constant * current miles/km at 100%). (478km*145Wh/km = 69.3kWh)

Sorry; that was not clear (only clear from context, when reading other posts)!

The degradation threshold is where the rated range will start to visibly display capacity loss (even though capacity loss starts immediately). In this case it took several years (2021/2022) before capacity loss started to show, even though 7% of capacity had been lost that point. This is hidden through rated miles that have 7% less energy when at the capacity-loss/degradation threshold (145Wh/km) vs. when new (156Wh/km). (Displayed rated miles actually have 4.5% less energy than each of these numbers of course due to the buffer.)

 

[pdx_m3s]

Coming up on 5 years with my 2019 SR+ (Panasonic 2170 cells... the good ones).

After a couple deep discharges and charges to over 90%, I'm sitting at ~5% degradation.

Over its life, the car has been charged to about 60% on average, daily. I charge higher as needed. Less than 10 total Supercharging sessions.

 

[AlanSubie4Life]

Coming up on 5 years with my 2019 SR+ (Panasonic 2170 cells... the good ones).

After a couple deep discharges and charges to over 90%, I'm sitting at ~5% degradation.

Over its life, the car has been charged to about 60% on average, daily. I charge higher as needed. Less than 10 total Supercharging sessions.

228 rated miles at 100% is really very good! (49.9kWh)
Plenty of cars in hotter climates seemed to do a lot worse (several reports of 200-210 miles after a year).

 

[pdx_m3s]

228 rated miles at 100% is really very good! (49.9kWh)
Plenty of cars in hotter climates seemed to do a lot worse (several reports of 200-210 miles after a year).

Temperature seems to be a major factor.

I just do what we know works for Li-ion cells... avoid, where possible, high extended temps and high SOC. You will always find me parked under shade if possible haha.