Bought a 40.5k miles 2020 Model 3 with significant Battery degradation. What can I do?

[augustov58]

Hello all!,

I am a first-time Tesla owner. I would like to know your opinion on my findings.

As I mentioned, I just purchased a certified preowned Model 3 with 40.500 miles through the tesla.com website. I did a good research about Teslas and, among other EVs I considered it the best option.

My experience is mixed. The car looks really good and is in very good shape, also thought I found a very good deal with tesla warranty and the car specs being a Standard Range plus, with 19" wheels and enhanced AP.

My first problem came when we started driving the car. My wife started hearing a weird noise when moving slowly or starting to move. I found out that the lug nuts in the 4 wheels were loose, especially the rear passenger-side one where the noise was coming from. I tightened the lug nuts myself and called Tesla service immediately to check the car in case anything had suffered.

My second problem is that I noticed a really low range in my car after a week of driving and wanted to obtain some guidance. I have downloaded the Tessie app to check and also performed a battery health test in service mode to test against the Tessie app. Here are my findings and some other stats:

-Battery degradation according to Tessie: 15.9%
-Battery health according to health Test on the car: 85% (or 15% degradation)
-Car calculated Range 217mi. (217/250*100 = 86.8% so math kinda checks out)
-Average efficiency according to Tessie app: 75% or 287Wh/mi. This is counting other factors based on my real world use. Which means I get around 162.75mi of real range(0.75*217mi). To my surprise, less range can be driven
-Battery total full load when charged 45.4Kwh. Rated is 54Kwh ( 45.4/54*100 = ~84% Again math maths)

I live in Florida and the weather is really hot during the summer I understand have a big impact in efficiency

I understand I have battery coverage under 100.000 miles if my battery range drops under 70%. But in any case, this seems out of the normal of what I have seen around and by the app and other stats. What can I do to improve my situation based on the information provided? See attached pictures of my health test and Tessie app stats

 

[flixden]

One of these days we need to add an addendum to this method in the sticky… This method will be limited to the lesser of the pack capacity and the degradation threshold. In the case of your car this is ~79kWh, the degradation threshold.

Your actual capacity may be higher right now (very likely is 1-2kWh higher but can only be determined with SMT or very careful observation).

I am getting values between 78.4 and 79.5 with this method.
So with the degradation threshold, the results shouldn't change for a while right?
Is SMT just an app?

 

[ZenRockGarden]

@AAKEE : what kind of degradation should I expect after one year with the SOC being around 50% most of the time?
And what really is the average degradation being reported for the M3/MY?
I calculated my MY's battery capacity to be right around 79kWh with 1k miles on the Odo using the method ahown here:
Calculating Your Battery's Estimated Capacity Using the Car's Energy Screen
Is this a reliable and fairly accurate method?

He literally gave you a decent estimate. It's mostly just calendar aging which is in this ballpark:

5% after one year​

7% after two years​

8.7% after three years​

10% after four years​

11.2% after five years​

12.2% after six years​

13.2% after seven years​

14.1% after eight years.​

 

[AlanSubie4Life]

I am getting values between 78.4 and 79.5 with this method.
So with the degradation threshold, the results shouldn't change for a while right?
Is SMT just an app?

Yeah that variation is expected due to rounding error. Right, the method should only show a change once you start to lose rated range (capacity loss will start and affect your real max achievable range before that, of course - that started as soon as your battery was manufactured).

SMT - Scan My Tesla

 

[flixden]

He literally gave you a decent estimate. It's mostly just calendar aging which is in this ballpark:

5% after one year​

7% after two years​

8.7% after three years​

10% after four years​

11.2% after five years​

12.2% after six years​

13.2% after seven years​

14.1% after eight years.​

Yeah, I saw that. But I was looking for an expected total number, not just calendar aging.

 

[AAKEE]

I think we agree. Note that the above chart would need to be adjusted for the number of cycles since it takes twice as many shallow-cycles to go the same distance as a twice as deep cycle.

The chart use Full Equivalent Cycles (FCE).
This means that it is already compensated for the different depth of discharge (DoD).

One FCE = The same energy amount as one full 100-0% cycle.
One FCE is for example 10 cycles if the DoD is 10%.

Researchers mostly use FCE in their graphs as you otherwise can not se whats better directly in a chart.

 

[AAKEE]

@AAKEE : what kind of degradation should I expect after one year with the SOC being around 50% most of the time?

You can search the forum.
Search for calendar aging and AAKEE, I have written a lot about it.

Calendar aging depends on time x temperature x SOC.
Low temperature and low SOC is good.

If you have an average cell temp of 25C you look at about 5% if the SOC is mostly above 55%
It would be 5.5% after 12 months (chart is 12 months). The rate of the Calendar aging decreses with the square root of time.

This behaviour is verified in many research tests, even with cells taken out of a almost new Tesla vehicle.

I can calculate the expected degradation for you if I get a few facts from you.