Battery Degradation Year 1

[LiquidXTC]

As I close in on a year of ownership and just over 22k miles, this is the degradation report from Tessie and Recurrent.

 

[AAKEE]

As I close in on a year of ownership and just over 22k miles, this is the degradation report from Tessie and Recurrent.
View attachment 937601View attachment 937602

You need to set the initial capacity to 82.1 kWh in the center of the meter, tap onnit and change.

 

[LiquidXTC]

 

[rwojo]

@AAKEE you sure that's what should be done for Tessie? On a new car will immediately show something like 4-5% degradation and way below the fleet average.

 

[LiquidXTC]

You need to set the initial capacity to 82.1 kWh in the center of the meter, tap onnit and change.

Good catch, I was confused why it was so high, it was changed at some point and I never noticed.

 

[LiquidXTC]

Here is what Tessie shows.

 

[AAKEE]

@AAKEE you sure that's what should be done for Tessie? On a new car will immediately show something like 4-5% degradation and way below the fleet average.

The way Tessie use the data, it is the full capacity including the buffer it ”senses”.

Even if the term usable capavity is used, it is the capacity inliding the buffer it gets from the car.

All values are very off, until you use the total capacity.
For the 82.1 kWh batt, we could argue to set 80.5, as most cars with that battery starts there according to the BMS.
(But I had “nominal capacity” 81.6 and nominal remaining 82.0kWh, so…)

As tessie often is wrong about the initial capacity the tessie “average curve” is affected from that issue.

With all problems comming from the use of Tessie, i wouldnt recommend it.
Very often people have like ”3% degradation” according to Tessie.
When checking the Bms data, the truth is 7 or 10% or so.

 

[AAKEE]

Here is what Tessie shows.
View attachment 937617

Your car is one year old I guess from the thread name?
If its a model 3 or Y in US, 2022 or so, its a panasonic 82.1 kwh battery.

Did you have about 358 miles as the ”new car range” (EPA range = 358 miles?)

 

[AAKEE]

@AAKEE you sure that's what should be done for Tessie? On a new car will immediately show something like 4-5% degradation and way below the fleet average.

We can do some calculations from @LiquidXTC’s car, if he likes to share.

A 2022 model 3 LR / P in us has a panasonic 82.1 kWh battery.
If you use a tool to scan the BMS canbus data you will find that the BMS says ”full pack when new” 82.1 kWh.
In the Performance you need about 80.7 kWh to see the full range.
In the Long Range you need about 79-79.1 or so for the full 358 miles.
One can discuss what value should be set, but if a value below 80.7 kWh is set for the Performance, or 79.1 kWh for the Long Range, that lover value is not sufficient to reach the EPA rating that the car was delivered with.

I have a 2021 model 3 P (Panasonic 82.1 kWh pack) presently with about 78.8 or so nominal full pack. If I get tessie and set 77.8 kWh, my battery would have grown 1 kWh since new (2 1/2 years and 62.000km).

For my own calculation I use 82.1 kWh as the base.

There is numerous issues with this.
Most common is discussions sbout low SOC stategy and low degradation.
The average Tessie user climbs in ”I always chargé to 80-90% and have only 2-3% degradation”
”Why use low SOC when I charge to 90% and still have lower degradstion than you”.

When looking at the data the real degradation often is much more, like 7-10%.

In the case below, its the 82.1 kWh batt.
Thats a 7% loss from the 82.1 mark.

I recently checked up a ABRP equivalent to this above by using maximum range and known values. The ABRP used a strange suspect orogin capacity, and also the sctual capacity was suspect.

After the checks from the cars data, it was obvious that ABRP did not know what they where doing. The stated degradation number was bogus.

 

[AAKEE]

Here is what

I could try calculate the expected degradation/ capacity on your car.

Need, manufacturing month or purchase month.
The Regular set charging level you use.
End of the day SOC, before charging.
When you start the charging a regular day
Is the car in a garsge or outside?
Current odometer.
The climate, warm or cold?

 

[LiquidXTC]

I could try calculate the expected degradation/ capacity on your car.

Need, manufacturing month or purchase month. 5/22
The Regular set charging level you use. 78%
End of the day SOC, before charging. 48%
When you start the charging a regular day 8pm
Is the car in a garsge or outside? carport
Current odometer. 22,048 miles
The climate, warm or cold? warm

 

[AAKEE]

Almost missed the data posted!

Need, manufacturing month or purchase month. 5/22
The Regular set charging level you use. 78%
End of the day SOC, before charging. 48%
When you start the charging a regular day 8pm
Is the car in a garsge or outside? carport
Current odometer. 22,048 miles
The climate, warm or cold? warm

Forgot to ask the average consumption since new, so I guessed. Doesnt change the cyclic wear noticable.
Looked up georgia and used 20C/about 68F as the annual average temp.

Remember; this is not the truth, is the expected capacity from calendar+cyclic aging.
For initial capacity, 82.1kWh

77.4kWh should be about 351 miles at full charge.

 

[rwojo]

Almost missed the data posted!


Forgot to ask the average consumption since new, so I guessed. Doesnt change the cyclic wear noticable.
Looked up georgia and used 20C/about 68F as the annual average temp.

Remember; this is not the truth, is the expected capacity from calendar+cyclic aging.
For initial capacity, 82.1kWh
View attachment 937858

77.4kWh should be about 351 miles at full charge.

@AAKEE Is this an Excel/Google Sheet you can share as a template?

 

[UncleCreepy]

Without Tessie, Excel or other fancy stuff:
Initial range at 100%: 504 km (313 miles)
Current range at 100%: 462 km (287 miles)
So I lost 8.3% of range after 109,400 km (68k miles) in three and a half years. I can life with that

 

[AAKEE]

@AAKEE Is this an Excel/Google Sheet you can share as a template?

I will set it up as a homepage eventually.
I do not think I will share it as it is today.

 

[AAKEE]

Without Tessie, Excel or other fancy stuff:
Initial range at 100%: 504 km (313 miles)
Current range at 100%: 462 km (287 miles)
So I lost 8.3% of range after 109,400 km (68k miles) in three and a half years. I can life with that

Wjhat model/variant and what EPA range?

Model 3 LR AWD? Same constant for the EPA, I guess. 2020?

In that case, 462 km = 70.3 kWh, out of 77.8 kWh initial capacity.

 

[UncleCreepy]

Wjhat model/variant and what EPA range?

See my signature. It's a Model 3 AWD, first registered in December 2019. Not sure what the EPA range was at the time. I believe it was 322 miles but I'm not entirely sure.

 

[AlanSubie4Life]

I believe it was 322 miles but I'm not entirely sure.

310 miles, degradation threshold 76kWh, constant 245Wh/mi. Started around 77.8kWh.

 

[AlanSubie4Life]

310 miles, degradation threshold 76kWh, constant 245Wh/mi. Started around 77.8kWh.

Oops. 2020….so all of that is wrong. I saw 2019 and just reacted, lol.

322 as you say. Started around 77.8kWh Threshold 77.8kWh. 241.5Wh/mi or so.

 

[UncleCreepy]

Oops. 2020….so all of that is wrong. I saw 2019 and just reacted, lol.

322 as you say. Started around 77.8kWh Threshold 77.8kWh. 241.5Wh/mi or so.

Not sure how you can calculate my average consumption with the numbers I provided but you are almost spot on. Over the last 45k miles my average consumption was 238 Wh/mile. Sadly I don't have the lifetime consumption anymore since my car once had that dreaded error where it forgets all of its settings. I could recover most of them but the trip counters were gone.