Battery health tracking SS

[AAKEE]

@AAKEE - any chance you could do a work up on my battery / predicated degradation, please? Mag date July 2023, MY AWD SR, Dallas TC, parker in garage, charge to 50% most days, charge on level 2 at home, charge mostly over night before I leave home, mileage is 2,765.

Thats ~ 66.5 kWh capacity, I do not have exact starting number for that pack.

 

[Owner4523]

Thats ~ 66.5 kWh capacity, I do not have exact starting number for that pack.

Here is what Tessie shows. Are you able to do a prediction regarding degradation?

 

[AAKEE]

Here is what Tessie shows. Are you able to do a prediction regarding degradation?

34% SOC opts for a little rounding error, but it should be in the whereabouts of 0.5/34, so 1.5%

 

[AlanSubie4Life]

66.5 kWh capacity, I do not have exact starting number for that pack.

It is around 68kWh. Recharge event was 77kWh. 92s9p 4680 AFAIK. Bandoliers of 69 elements. Three modules of 23s9p, each composed of three bandoliers, with every three consecutive elements of the 69 bandolier elements incorporated into a parallel brick (3x3p =9p).

 

[Owner4523]

34% SOC opts for a little rounding error, but it should be in the whereabouts of 0.5/34, so 1.5%

Thanks, is that pretty good or on average? When I charge to 50% the display says 140 or 139 by the way.

Are you able to predict where you think thing s will be in 12 months?

 

[Owner4523]

It is around 68kWh. Recharge event was 77kWh. 92s9p 4680 AFAIK. Bandoliers of 69 elements. Three modules of 23s9p, each composed of three bandoliers, with every three consecutive elements of the 69 bandolier elements incorporated into a parallel brick (3x3p =9p).

Thanks, do you think I should change this number?

 

[AlanSubie4Life]

Thanks, do you think I should change this number?

Yeah I would change it to 68kWh or maybe 68.5kWh. Would have to have someone with SMT or you would need to meter it really carefully yourself, if you are above the threshold, to get a good estimate.

 

[Owner4523]

Yeah I would change it to 68kWh or maybe 68.5kWh. Would have to have someone with SMT or you would need to meter it really carefully yourself, if you are above the threshold, to get a good estimate.

Hmm...are you sure it's not more like 67.4 or 67.8?

 

[AAKEE]

Here is what Tessie shows. Are you able to do a prediction regarding degradation?

From what I found online, 67.5 kWh seem to be nominal full pack on almost new car. Maybe slightly higher full pack when new, 67 kWh?

These 4680 cells are Panasonic/Tesla NMC builds and we do not have any data on these, but using this chart with about average data on NMC:

Its about the same as NCA so ~ 2.7% calendar aging for the first year.

Initial capacity 67.5-67kWh might end up at ~ 65-65.2kWh after one year, with the average 25C cell temp and at or below 50% most of the time.
Cyclic aging probably is ~ negligable or 0.25% or so.
I did not check the Dallas average annual temp, byt having been there I know it probably is warmer on average than the average place for a car. So we might need to calculate with increased Calendar aging due to the warmer climate. On the other hand, as it is a new battery typet hey might have been able to reduve the calendar aging.

It would be possible

 

[AlanSubie4Life]

Hmm...are you sure it's not more like 67.4 or 67.8?

That would be lower than expected. It is possible it is that low, but the EPA doc does not have this number readily presented for this vehicle. I use 89% as a charging efficiency which fits fairly well with existing data. That takes the 78kWh to 68.5kWh.

I think taking 68kWh as the starting point would be fine. At some point it is splitting hairs.

If we had a starting capacity from EPA like we do for nearly every other vehicle then we could use that.

I can’t remember if you did the screen captures (pictures) to get the charging constant and the degradation threshold for your 4680 Y, I think in the other thread. Where I gave instructions. Possible I just missed your response.

Anyway that probably works out to around 67.5kWh is my guess.

EDIT: your picture above with 94 miles is not ideal since we’d like at least three digits. But anyway calculate that (Proj * Recent / Rated Miles ) = 241Wh/mi

And 279 rated miles when new gives 67.1kWh for the threshold.

The problem is we do not have enough accuracy on that 241Wh/mi number. You could convert to km display or do a higher charge (55%, switch to km display, retake).

 

[AlanSubie4Life]

That takes the 78kWh to 68.5kWh.

Typo - meant 77kWh for AC recharge energy in EPA doc as covered earlier.

 

[AAKEE]

That would be lower than expected. It is possible it is that low, but the EPA doc does not have this number readily presented for this vehicle. I use 89% as a charging efficiency which fits fairly well with existing data. That takes the 78kWh to 68.5kWh.

I did use 11.5% losses, so 0.885 which I got as an average from the other Y versions.
Also used 76.5kWh recharge energy (there’s two tests if I remember it, recharge 76.5 and 77kWh.)
76.5 did give 67.7kWh.


I did find this (using Tes-Lax) on on youtube showing this the moment before disconnecting the SuC. (The car is at ~ 10K miles).

I think taking 68kWh as the starting point would be fine. At some point it is splitting hairs.

Yes, we are about at the right spot anyway.

 

[AlanSubie4Life]

Also used 76.5kWh recharge energy (there’s two tests if I remember it, recharge 76.5 and 77kWh.)
76.5 did give 67.7kWh.

Yeah there was 77.2kWh and 76.5kWh.

So 0.885 is 67.7kWh to 68.3kWh.

Tesla being very secretive with the 4680 capacities, .

Anyway it would be great to get @Owner4523 to get some slightly higher SOC pictures in miles/km mode just to finalize this. But it does look like the current situation is:
181Wh/mi*125Wh/mi/94rmi * 279rmi = 67.2kWh for threshold.

And about 241Wh/rmi for the constant. So 230Wh/mi for parity.

Anyway higher numbers would be better. I suspect the threshold is closer to 67.4kWh.

And a new pack around 68kWh

 

[AAKEE]

Yeah there was 77.2kWh and 76.5kWh.

So 0.885 is 67.7kWh to 68.3kWh.

Tesla being very secretive with the 4680 capacities, .

Anyway it would be great to get @Owner4523 to get some slightly higher SOC pictures in miles/km mode just to finalize this. But it does look like the current situation is:
181Wh/mi*125Wh/mi/94rmi * 279rmi = 67.2kWh for threshold.

And about 241Wh/rmi for the constant. So 230Wh/mi for parity.

Anyway higher numbers would be better. I suspect the threshold is closer to 67.4kWh.

And a new pack around 68kWh

Yes, if we use the 330’ range for the 2170L@ 80.7 kWh compared to 279 miles, it looks like 68.2 kWh. With the same wheels they should weigh about the same and the consumption should be close between?

 

[Owner4523]

Yeah there was 77.2kWh and 76.5kWh.

So 0.885 is 67.7kWh to 68.3kWh.

Tesla being very secretive with the 4680 capacities, .

Anyway it would be great to get @Owner4523 to get some slightly higher SOC pictures in miles/km mode just to finalize this. But it does look like the current situation is:
181Wh/mi*125Wh/mi/94rmi * 279rmi = 67.2kWh for threshold.

And about 241Wh/rmi for the constant. So 230Wh/mi for parity.

Anyway higher numbers would be better. I suspect the threshold is closer to 67.4kWh.

And a new pack around 68kWh

Thanks for taking the time to give me this insight. ! I'm going on a road trip tomorrow and will take / share some more pictures.

 

[Owner4523]

Thanks for taking the time to give me this insight. ! I'm going on a road trip tomorrow and will take / share some more pictures.

Yeah there was 77.2kWh and 76.5kWh.

So 0.885 is 67.7kWh to 68.3kWh.

Tesla being very secretive with the 4680 capacities, .

Anyway it would be great to get @Owner4523 to get some slightly higher SOC pictures in miles/km mode just to finalize this. But it does look like the current situation is:
181Wh/mi*125Wh/mi/94rmi * 279rmi = 67.2kWh for threshold.

And about 241Wh/rmi for the constant. So 230Wh/mi for parity.

Anyway higher numbers would be better. I suspect the threshold is closer to 67.4kWh.

And a new pack around 68kWh

Here's are some updated pictures.

 

[AlanSubie4Life]

Here's are some updated pictures.View attachment 1024592View attachment 1024593View attachment 1024594View attachment 1024595View attachment 1024596View attachment 1024597View attachment 1024598View attachment 1024599View attachment 1024600View attachment 1024601View attachment 1024601

For safety reasons and for accuracy, I would recommend taking these picture when:
1) the car is parked
2) the car is unplugged.

Making calculations:
But anyway, the above numbers all point to a degradation threshold as high as 67.7kWh or as low as 67.5kWh. (From the first couple pics.). Constant is 241.8-242.8Wh/mi

And your pack capacity is around 67.4kWh-67.5kWh (it is hard to tell precisely but it seems you may still have 279 miles range at 100%, which implies it could still exceed the threshold). If you can check your 100% charge on the road trip, that would be easiest to way to see it.

If you do get another high stationary SOC reading, definitely if you take a picture it would help.

But summary is your battery is very near the full health value currently. It likely started above 67.5kWh, and 68kWh seems reasonable given the age of the vehicle.

Remember once you exceed the threshold of ~67.5kWh, you won’t display miles in excess of 279 rated miles.

 

[Owner4523]

For safety reasons and for accuracy, I would recommend taking these picture when:
1) the car is parked
2) the car is unplugged.

Making calculations:
But anyway, the above numbers all point to a degradation threshold as high as 67.7kWh or as low as 67.5kWh. (From the first couple pics.). Constant is 241.8-242.8Wh/mi

And your pack capacity is around 67.4kWh-67.5kWh (it is hard to tell precisely but it seems you may still have 279 miles range at 100%, which implies it could still exceed the threshold). If you can check your 100% charge on the road trip, that would be easiest to way to see it.

If you do get another high stationary SOC reading, definitely if you take a picture it would help.

But summary is your battery is very near the full health value currently. It likely started above 67.5kWh, and 68kWh seems reasonable given the age of the vehicle.

Remember once you exceed the threshold of ~67.5kWh, you won’t display miles in excess of 279 rated miles.

Thank you! Here are a few more pictures.

 

[AAKEE]

Thank you! Here are a few more pictures. View attachment 1024802View attachment 1024803

The selection down right must be *average range*, otherwise the data can not be used for this purpose.

 

[AlanSubie4Life]

Thank you! Here are a few more pictures. View attachment 1024802View attachment 1024803

So close! As @AAKEE says, must be “average.” Hoping to see that 100% number if you get a chance on the roadtrip (a great time for nearly harmless 100% charges).