Is this normal battery degradation?

[Jonnymack74]

Hi
My 2019 75D should have a usable kwh of 72.5 (unless I'm mistaken)
Today on a road trip from 100% charge I reached 50% but had only consumed 29kwh which NY this math would give me a total of 58kwh of usable battery. Is this kind of degradation normal for a car of this age?

 

[Anth89]

Hello

72.5 KWh is a value for new cars and considers a safety buffer (4-5 KWh).
Furthermore the dashboard may forget some consumption, for example when you're stopped.
Therefore your values seem absolutely normal.

On my 100D (2017, 190 000 km) SMT reports now around 88-89 KWh usable capacity (supposed to be 97 KWh when brand new), but the same calculation than yours gives me usually 80-81 KWh.

 

[Jonnymack74]

Hello

72.5 KWh is a value for new cars and considers a safety buffer (4-5 KWh).
Furthermore the dashboard may forget some consumption, for example when you're stopped.
Therefore your values seem absolutely normal.

On my 100D (2017, 190 000 km) SMT reports now around 88-89 KWh usable capacity (supposed to be 97 KWh when brand new), but the same calculation than yours gives me usually 80-81 KWh.

You've done 190k km? That's a lot. Mine is almost 59k miles. It's almost 20% so feels like a lot of degredation

 

[Anth89]

It feels a lot but it is not correct.

You probably do not have more than 5% to 7%. The way you are measuring (through the consumption read on the dashboard) cannot allow you to measure degradation, for various reasons: consumption on the dashboard does not consider when the vehicle is idle, battery has a safety buffer, reference capacity is measure with ideal conditions (temperature etc.).

On my own case your calculation would lead to 17% (81/97). But the real calculation is 89/97 = 92% of initial capacity - 8% degradation.

There are many topics about that, most reliable ways to measure degradation is using tools like ScanMyTesla or Tessie.

 

[Jonnymack74]

I've just got tessie and it says my degradation is 8%. I'll see how this plays out over next couple weeks

 

[AAKEE]

I've just got tessie and it says my degradation is 8%. I'll see how this plays out over next couple weeks

The 75D was 75kWh total, about 72.6 ”usable” (actually all 75 was usable, the term usable is misused).

Youre probanly at ~ 12% degradation from the 75 kWh new.

You could perform a energy graph calc.
Average x estimated range x 100 / SOC % = capacity in Wh.

 

[Jonnymack74]

According to tessie my battery capacity just went up 65 3 to 65.4 now it's had a couple of charges since I got the app. Is this the norm? I'm debating on whether to keep the app as 15 quid a month is ridiculous

 

[AAKEE]

According to tessie my battery capacity just went up 65 3 to 65.4 now it's had a couple of charges since I got the app. Is this the norm? I'm debating on whether to keep the app as 15 quid a month is ridiculous

Tessie is often good at finding the same capacity the BMS estimates.
(Tessie sometimes suck at the original capacity, rendering people think they have lower degradation than the real one. I do not use Tessie myself but they still seem to list my cars origin capacity at 96.2kWh.
The EPA test shows 99-100kWh for this pack and my pack is at 97 kWh after 1 year three months and 22K km from build date, so in Tessie terms my pack is better than a new one )

You could get scan my tesla.
It is a single payment for the app, not expensive, and you need a small harness, not expensive either. With that you can read the data directly from the source.

I do not know if Tessie needs some charges to better estimate the capacity but in general even the cars BMS will vary the estimate slightly from day to day.
(The actual battery capacity can vary slightly up and down as it can sometimes recover slight capacity loss. This is not the same as a BMS Calibration where the range might increase from helping the bms better estimate the capacity, but that also might make the BMS read a higher capacity.)

 

[aerodyne]

According to tessie my battery capacity just went up 65 3 to 65.4 now it's had a couple of charges since I got the app. Is this the norm? I'm debating on whether to keep the app as 15 quid a month is ridiculous

Variation is not unusual, and can be caused by temperature changes and BMS calibration.

See image below.

You could get a free app like Recurrent, which while not not very precise, shows your capacity and charging history, something I'd like to see if I was interested in buying your car.

Not mentioned earlier is Teslafi. About 40 "Quid" a year. Lots of useful features. It does track the range pretty well over time compared to SMT, and has a fleet comparison as shown below: