Battery Degradation question

[AAKEE]

yeah teslafi has the same issue which is why calculated consumption and chargerange is never correct.

The most accurate way is to read out the kwh with SMT to be honest.

Yes, I will do this again on another car in the near future that uses Tessie to ”prove the issue”.

In other forums, Swedish and Swedish tesla groups on Facebook the standard is that people discuss best charging behaviour for battery longevity.
When I tell about the low SOC benifits, the most usual answer is “I charge to 90% (or 80%) and I only have 3% degradation”

Checking it up, they more or less always have a lot more degradation. So they live up in the blue, lured by apps showing faulty values.

Tessie has a part in their homesite that they call “minimizing battery degradation” where they did not read Teslas charging advise correctly and also, appearently, went on some of the Elon Musk Twitter statements like “should I charge to 80-30 or 90-40?” and took the answer like it as the best charging level in all situations.
People find this, and refer to it as ”truth”
(”Its stated on the Tessie site so it is valid).

 

[PonseyScheme]

My '22 MYP purchased in Nov 21 is showing a degradation of 7.3% - I live in TX, and we've had some brutally high temps. I rarely ever supercharge and only charge at home. I usually charge 80% in most situations. But as of recently, degradation was usually at 6.2% and max mileage is around 270 miles at 100%. How much stock should I put in the app? I believe the BMS is calculating more on temps? Thoughts?

 

[Bouba]

My '22 MYP purchased in Nov 21 is showing a degradation of 7.3% - I live in TX, and we've had some brutally high temps. I rarely ever supercharge and only charge at home. I usually charge 80% in most situations. But as of recently, degradation was usually at 6.2% and max mileage is around 270 miles at 100%. How much stock should I put in the app? I believe the BMS is calculating more on temps? Thoughts?

If you did an aggressive program of battery restoration....getting the charge as low as possible for several hours, charging fully and repeating it over a period of time...you might just recover some of your loss.
Also, when my car thought that I needed to replace my tires, my loss was about four percent, as soon as I entered that I have rotated them my loss dropped to two percent...so there are probably tricks that you can do to ameliorate your loss

 

[robl45]

Tesla said that doesn’t work. They also said the tessie app is wrong. I don’t know who to believe but they said my battery was normal for its age

 

[Bouba]

Tesla said that doesn’t work. They also said the tessie app is wrong. I don’t know who to believe but they said my battery was normal for its age

There are many people here that can testify that it does work and have posted recipes....in fact the car will do it for you because they have included it...so it would seem strange that they say it doesn’t work. The Tesla staff always say that any non Tesla app or any information on the internet is wrong...it’s their standard response

 

[AAKEE]

My '22 MYP purchased in Nov 21 is showing a degradation of 7.3% - I live in TX, and we've had some brutally high temps. I rarely ever supercharge and only charge at home. I usually charge 80% in most situations. But as of recently, degradation was usually at 6.2% and max mileage is around 270 miles at 100%. How much stock should I put in the app? I believe the BMS is calculating more on temps? Thoughts?

I threw in 81 kWh starting point, 30C average (maybe to high?) 80% end of day SOC 65% and start charging at arrival after work. Total miles just about average.

It looks like you should be at about 73kWh.
The degradation treshold is about 80.5kWh I think it would put you at about 275 mi range (not really knowing the degradation threshold, and the EPA range, 303 miles?

 

[AAKEE]

How much stock should I put in the app? I believe the BMS is calculating more on temps? Thoughts?

Which app? Teslas own. The slider do not always show the correct range at 100%.

The BMS measures the capacity by comparing the measured delta SOC (change in SOC) with the energy used.

During the drive (or charge) the SOC is estimated. True SOC is measured by the cell voltage and we need the cell to rest to get a proper voltage.

During the drive, the BMS use the estimated capacity and known SOC before the drive to calculate actual energy in the battery.
For example, 80kWh capacity and 100% SOC means 80kWh nominal remaining.
When the car has used 40kWh, we think we have 50% left ((80-40)/80).
When parking, or just after the real SOC can be measured and the SOC updated if there was a difference.
Overestimated capacity = SOC falls after the drive.
Underestimated, SOC climbs aftercthe drive.

For charging, its the same but the other way around.

Lets say we have 30% SOC and set the charge level to 80%.

The BMS calculates 50% charging of 80kWh battery so it sets a value for to charge complete= 40 kWh.
When charging the SOC is calculated so not exact.
After the charge stopped, the BMS messures the SOC and adjust if needed.

If the battery capacity was overestimated the displayed SOC will climb above the set limit.
If the battery capacity was underestimated the displayed SOC will decrease after being measured.

Charging to planned 80% but measuring 79% after the charge means that the capacity is larger than the estimation and probably the estimated capacity (nominal full pack) will be increased.
Hitting the exact same SOC number as the planned on the charging means the capacity estimate is spot on.

 

[Bouba]

Charging to planned 80% but measuring 79% after the charge means that the capacity is larger than the estimation and probably the estimated capacity (nominal full pack) will be increased.
Hitting the exact same SOC number as the planned on the charging means the capacity estimate is spot on.

That is very interesting...I did not know that...thank you

 

[DayTrippin]

My '22 MYP purchased in Nov 21 is showing a degradation of 7.3% - I live in TX, and we've had some brutally high temps. I rarely ever supercharge and only charge at home. I usually charge 80% in most situations. But as of recently, degradation was usually at 6.2% and max mileage is around 270 miles at 100%. How much stock should I put in the app? I believe the BMS is calculating more on temps? Thoughts?

I would give recurrentauto.com a try and have them log data for you and give you an estimation of degradation. I am in Texas and not seeing anywhere that amount of degradation. I normally keep my resting charge rate at 50% and only charge above that just enough to cover my trip and almost never above 80%.

How many miles on yours? I am at 10k miles and 18 months. I am showing less than 1% degradation on my M3 LR. My MS LR was similar degradation with similar mileage and delivery a month earlier than than the 3.

AAKEE probably tracks this info as closely as anyone here.

 

[PonseyScheme]

I would give recurrentauto.com a try and have them log data for you and give you an estimation of degradation. I am in Texas and not seeing anywhere that amount of degradation. I normally keep my resting charge rate at 50% and only charge above that just enough to cover my trip and almost never above 80%.

How many miles on yours? I am at 10k miles and 18 months. I am showing less than 1% degradation on my M3 LR. My MS LR was similar degradation with similar mileage and delivery a month earlier than than the 3.

AAKEE probably tracks this info as closely as anyone here.

I have a little over 20K miles. Here in North Texas - its been brutally hot and I've had to keep climate on at times to keep it from getting too hot in the car. Not sure if that takes into account of how the BMS is then calculated.

 

[PonseyScheme]

I threw in 81 kWh starting point, 30C average (maybe to high?) 80% end of day SOC 65% and start charging at arrival after work. Total miles just about average.

It looks like you should be at about 73kWh.
The degradation treshold is about 80.5kWh I think it would put you at about 275 mi range (not really knowing the degradation threshold, and the EPA range, 303 miles?
View attachment 970794

Thanks for running the calcs, the remaining capacity according to Tessie is 73.2Kwh - again I have a feeling that doesn't seem right. Also, it calculates based on 79KWH - is 81KWH based on with the buffer?

 

[AAKEE]

Thanks for running the calcs, the remaining capacity according to Tessie is 73.2Kwh - again I have a feeling that doesn't seem right. Also, it calculates based on 79KWH - is 81KWH based on with the buffer?

Tessie is very often wrong on the initial capacity. They had a mix up of total capacity and usable earlier.

A ’22 MYP has a battery with 82.1 kWh full pack when new.
I think the EPA test showed a output of about 81 kWh for the MYP. The dis.epa.gov is not available rigt now for me.

The original capacity was 82.1 kWh, and the EPA test showed at least 80.7 kWh or so drawn from the battery.
You can change it by pressing on the value.

The about 73 kWh calc I did was based on the environmental effect and the SOC values you gave etc.
As the calculated value and Tessie agrees as well, I’d guess its close to the reality.

 

[PonseyScheme]

Tessie is very often wrong on the initial capacity. They had a mix up of total capacity and usable earlier.

A ’22 MYP has a battery with 82.1 kWh full pack when new.
I think the EPA test showed a output of about 81 kWh for the MYP. The dis.epa.gov is not available rigt now for me.

The original capacity was 82.1 kWh, and the EPA test showed at least 80.7 kWh or so drawn from the battery.
You can change it by pressing on the value.

The about 73 kWh calc I did was based on the environmental effect and the SOC values you gave etc.
As the calculated value and Tessie agrees as well, I’d guess its close to the reality.

That's incredibly disappointing if that is true from Tessie. Would that change again once cooler temps set in? Also, changing it from 79Kwh to 82Kwh show a larger deficit? I guess here on out I will charge to 60% and see if that recalibrates to BMS as opposed to 80%. Here I thought not supercharging and not putting it 100% still bit me in the ass.

 

[Kelculate]

Anyone using Recurrent on the 2023 M3 LR? Tesla advertised 333mi range but EPA actually says 363mi. Recurrent is reporting my new car (manufactured 08/23) at 334mi but considers that degraded based on 363mi. Anyone seeing the same or did my battery really degrade that much despite being kept at 40% or lower SOC overnight

 

[AAKEE]

Anyone using Recurrent on the 2023 M3 LR? Tesla advertised 333mi range but EPA actually says 363mi. Recurrent is reporting my new car (manufactured 08/23) at 334mi but considers that degraded based on 363mi. Anyone seeing the same or did my battery really degrade that much despite being kept at 40% or lower SOC overnight

Where did you find the actual EPA range?
In the registration papers?

It did not degrade like that.

It must be a mixup by someone (do not rely on numbers like capacity or EPA from app vendors like tessie initially, probably same for recurrent).

You could do a energy graph calculation to see the capacity.

 

[Kelculate]

363 mi is the number on Recurrent for my car "EPA: 363 mi". At 2023 Tesla Model 3 Long Range AWD it is still 358mi. The Monroney sticker shows 333mi though.

To do energy graph calculation, I'll need to charge to 80% or more. So I'll wait for a time when I need to charge the car that much.

 

[AlanSubie4Life]

The Monroney sticker shows 333mi though.

That is what takes priority. You have the newer 2023 with the smaller battery, which is not yet posted to fueleconomy.gov (and may never be, showing up only next year, in the next few months).

To do energy graph calculation, I'll need to charge to 80% or more. So I'll wait for a time when I need to charge the car that much.

You don’t have to; just makes the result more accurate. A low accuracy result would still be good (the error is bounded). At the moment, it’ll probably yield about 75kWh - would be great to see if for this brand new vehicle because it would give degradation threshold and the constant. Which probably some people already know but I do not. The constant might be the same as prior 2023 vehicle; the threshold certainly will not be.

But yes, likely would want it repeated later at higher SOC for better accuracy, at a time you more going to draw it down in short order.

 

[AAKEE]

363 mi is the number on Recurrent for my car "EPA: 363 mi". At 2023 Tesla Model 3 Long Range AWD it is still 358mi. The Monroney sticker shows 333mi though.

To do energy graph calculation, I'll need to charge to 80% or more. So I'll wait for a time when I need to charge the car that much.

Tesla has made a change to the new model 3 LR in US.
They most problably changed to another battery. Most people think it is the LG 78.8 kWh battery.

If the sticker says 333 it most probably is the new version with the lower range (due to s smaller battery).

A photo of the energy screen that also shows the SOC will sort everything out.
We will help with that.
Anyway, there is no chance you lost a lot of capacity in very short time.

 

[AAKEE]

At the moment, it’ll probably yield about 75kWh - would be great to see if for this brand new vehicle because it would give degradation threshold and the constant. Which probably some people already know but I do not. The constant might be the same as prior 2023 vehicle; the threshold certainly will not be.

73.7 kWh is what I get from the 334 miles.
It looks very low to be the LG 78.8 kWh.
(In Europe, the WLTP/EPA equivalent is built on the high number when the battery reach the higher capacity).
It smells like these cells not is the LG 78.8kWh. Either the 74.5 kWh LG or a new NMC lower capacity cell, in the same manner as the 4680 with NMC.

 

[Kelculate]