Battery Degradation question

[AlanSubie4Life]

View attachment 972433View attachment 972434

So roughly between 75.5kWh and 79kWh. (Too low an SOC to be particularly useful as you said.)

When you do this at a higher SOC, can you also (meaning an additional picture) tap the battery on the screen to swap to rated miles? This will let us also get the constant (which may be different (larger) than the other 2023 vehicle, which would screw up projections based on 221Wh/rmi). We do need % still, as in your pictures above.

At 100% at some point would be awesome, but 80-90% also fine. Or even something like 60% in the interim if that is your charge level (would cut the error roughly in half and certainly provide sufficient sig figs (3) for the constant).

 

[Kelculate]

Thanks. Sure, will do that. Probably do 80% tomorrow. May do 100% next week if I take a road trip.

 

[Bouba]

What does ‘rated’ miles mean ?

 

[AlanSubie4Life]

What does ‘rated’ miles mean ?

The EPA miles. When I say “rmi” I mean rated miles, which have units of energy (they do not have units of distance).

For Teslas (so far, could change any time!), each rated mile has a specific energy content based on:
1) The energy content of the pack for that car when new (actually it is chosen to be a fixed “degradation threshold,” which is typically a little lower than what a brand-new car has). Technically it is the greater of these two values (Pack Energy, Degradation Threshold), but relatively quickly is just the DT.
2) The number of miles displayed on the Monroney (“window”) sticker, which is what the EPA rating is. (Also “EPA est.” on website - NOT the “est.” numbers)
3) A scaling factor for the buffer (e.g. 0.955 for Model 3).

So for Model 3, each displayed usable rated mile (rmi) is:
0.955* (Pack Degradation Threshold Energy) / EPA miles

 

[AAKEE]

Feb 2022 MSLR, 9,700 miles in 13 months. Tessie says 4.4% degradation and is more degradation than fleet average. Super charged twice just to 80%. I was charging at home to 89% but have changed to 75%.View attachment 923902

A bit of a bump on a old post.
Just found this, and when this thread was started I did not know very much about MS battery and BMS.

The refresh (Palladium) MS has a 99.4 kWh battery. We know this from both the EPA test which got 99.3-99.4kWh out of the pack and from checking with Scan My Tesla.
Full pack when new is 99.4 kWh. So the battery starts at that point.

Most cars seem to reach above 98 kWh so the 96.3 kWh Tessie has as the starting point is not correct.
I would set that value to 99.4, as it is the branded starting point and also what the EPA test showed.

Tessie use to state ”usable capacity” but the number you see is the total capacity.
The Tessie app has changed the term to ”capacity” I think.

My MSP started at 95.3kWh nominal full pack, but it was obvious that the real capacity was at least 98 kWh from start.
After a few weeks it reached 98kWh and has topped at 98.4kWh. (Calendar aging starts when the cell is manufactured or about when the car is built so we might not see the nominal full pack number).

The buffer works just like model 3/Y, it is 4.5% of the nominal full pack number.
The buffer is included in all numbers above, including the Tessie numbers.

 

[Kelculate]

Here we go. Looks like it is at 77.8kWh. Full is 78.1kWh, is that correct?

 

[AAKEE]

Here we go. Looks like it is at 77.8kWh. Full is 78.1kWh, is that correct?

The calculation 77.8 kWh is correct.

If the battery is the LG NMCA, it is 78.8 kWh Full Pack When New.
They mostly reach (tops out at) 79-79.1kWh after a few months here in europe.

 

[Kelculate]

The calculation 77.8 kWh is correct.

If the battery is the LG NMCA, it is 78.8 kWh Full Pack When New.
They mostly reach (tops out at) 79-79.1kWh after a few months here in europe.

Thanks. So the degradation is normal for my car? Also can you explain why the battery capacity would increase after a few months?

 

[AAKEE]

Thanks. So the degradation is normal for my car?

Yes, no problems at all.

If it is the LG NMCA, they are really stable.
Recently got message from a friend that got a Model 3 with the LG NMCA a bit over one year ago, maybe 1.5 years.
He havs followed my low SOC stategy and still has 78.0kWh nominal full pack, so only lost 0.8 kWh after ~ 1-1.5 years and 41000km.

Also can you explain why the battery capacity would increase after a few months?

Batteries is cycled on a very specific scheme to start working as a battery.
There is a possibility that LG has not cycled them to the level where they are at their top capacity.

In the EPA test report Tesla state for the model S refresh battery (Panasonic 18650):

3.02 Battery pre‐conditioning procedures
The lithium ion battery cells are cycled by the battery cell manufacturer before they are assembled into battery packs. There is no further pre‐conditioning necessary.

The same is stated for the model 3’s with Panasonic.

Still, it is possible that there can be a break in period needed for the LG battery.

It could also be a matter of that the BMS need sone time to measure the real capacity.

I wote for that they need to be cycled a bit further to reach maximum capacity.

 

[zoomer0056]

77.8kWh

How is this number calculated from the gragh?

 

[AAKEE]

How is this number calculated from the gragh?

Average x calculated range x 100 / SOC = Watt hours

 

[Kelculate]

Thanks. Do I need to do anything to cycle the battery for it to reach the maximum capacity? Or just try to keep SOC low during storage?

 

[Kimmi]

Looks like the place to post this? Does using the battery check in Service Mode cause battery degradation? No problems, just asking. 2021, December 2020 build, LW AWD with 26K miles and lifetime kWh of 261. Stats reports Full Battery Capacity as 73kWh.

 

[AAKEE]

Thanks. Do I need to do anything to cycle the battery for it to reach the maximum capacity? Or just try to keep SOC low during storage?

Just keep it at 60% or below when not needing more and use it as usual. If you need more, use more and 100% charges wont heart either if needed.
I do not know your cars age but depending on usage they seem to top out after 1-2, maybe 3 months.
Perhaps not all reach 79 kWh, it might depend on the usage/cycles. I do not know.

In the long run, the top kWh value will not matter.

 

[KenBlub]

Yes, no problems at all.

If it is the LG NMCA, they are really stable.
Recently got message from a friend that got a Model 3 with the LG NMCA a bit over one year ago, maybe 1.5 years.
He havs followed my low SOC stategy and still has 78.0kWh nominal full pack, so only lost 0.8 kWh after ~ 1-1.5 years and 41000km.



Batteries is cycled on a very specific scheme to start working as a battery.
There is a possibility that LG has not cycled them to the level where they are at their top capacity.

In the EPA test report Tesla state for the model S refresh battery (Panasonic 18650):


The same is stated for the model 3’s with Panasonic.

Still, it is possible that there can be a break in period needed for the LG battery.

It could also be a matter of that the BMS need sone time to measure the real capacity.

I wote for that they need to be cycled a bit further to reach maximum capacity.

This happened to me. I picked up my LR a week ago. SOC was 90%. Had a 200+ mile trip home. Car said I needed to stop at a SC on the way. While driving home, I looked and the SC stop was gone and I made it home with 17% SOC. Battery capacity has gone up in past week per energy graph calculations

 

[AlanSubie4Life]

Looks like it is at 77.8kWh. Full is 78.1kWh, is that correct?

The calculation 77.8 kWh is correct.

So the degradation is normal for my car?

Do I need to do anything to cycle the battery for it to reach the maximum capacity

Ok: Remember, the method provides only the degradation threshold (not the battery capacity) when your car does not show any range loss.

Note that the degradation threshold is not necessarily equal to the "Full Pack When New" hard-coded value (in fact it usually isn't these days, though it was for a while in 2020 on the LR AWD vehicles).

Since you haven't charged to 100% in these pictures, we can't definitively say you have no range loss, but 266rmi @ 80% projects to 332.5, so you probably are still at the max of 333 rated miles.

So, if you have NOT lost range, the value of 77.8kWh using the energy screen method, only indicates that your battery has at LEAST that amount of energy. (Aside: the way this works is if you have more than this threshold of energy, the energy content of each rated mile is increased, hiding the extra capacity by shoving it into a fixed number of maxed-out miles (in this case max is 333).)

In addition, the constant here calculates to be 234Wh/mi (interestingly identical to the 2018/2019 Model 3 LR RWD). It is DIFFERENT than the other 2023 vehicle (79kWh/358rmi = 221Wh/mi). Note the rated line in the pictures is at about 239Wh/mi (252Wh/mi and 232Wh/mi are nearly equidistant, with 232Wh/mi being closer), which is what you'd expect for 234Wh/mi (the rated line is always 5Wh/mi higher for some reason). So that confirms the straight calculation (not really necessary to confirm, but just pointing it out).

So:
We can't see that you have any degradation. If you get 333 miles at 100%, then you do not have any appreciable capacity loss (at least, not any below the degradation threshold - of course you can lose some, and just not see the loss, as long as you stay above the threshold).

And for the record, the current 333-mile Model 3 Long Range has a degradation threshold of 77.8kWh, and a constant of 234Wh/mi. It's possible for these values to change later.

It's intriguing that the rated range has dropped so much. There's been nearly no change in capacity. I wonder if they decided to stop doing the ~0.747 scalar based on 5-cycle results? (This would mean real-world range is likely very similar between this vehicle and the 358-mile one.)
358rmi * 0.7/0.747 = 335.5rmi, so it nearly works out, especially if you consider the other pack is 79+kWh and this one is probably a little less.

Thanks for the pictures, this was very helpful to understanding what the deal is with this vehicle.

 

[AAKEE]

Ok

It's intriguing that the rated range has dropped so much. There's been nearly no change in capacity. I wonder if they decided to stop doing the ~0.747 scalar based on 5-cycle results? (This would mean real-world range is likely very similar between this vehicle and the 358-mile one.)
358rmi * 0.7/0.747 = 335.5rmi, so it nearly works out, especially if you consider the other pack is 79+kWh and this one is probably a little less.

Good catch with the efficiency and treshold!

Yes, its a bit strange if it is the same LG battery as we have gotten in Europe since two years.
Here we (still EPA rated Wh/mile) get up to 358/576km displayed.
My friends is at 78 kWh and show 569km(354 mi).

I can not think of the effeiciency beeing
reduced that much ( probably bot reduced at all), so as you say the new m3 should do a real range of about 79/82 of the old car…

 

[Bouba]

Ok: Remember, the method provides only the degradation threshold (not the battery capacity) when your car does not show any range loss.

Note that the degradation threshold is not necessarily equal to the "Full Pack When New" hard-coded value (in fact it usually isn't these days, though it was for a while in 2020 on the LR AWD vehicles).

Since you haven't charged to 100% in these pictures, we can't definitively say you have no range loss, but 266rmi @ 80% projects to 332.5, so you probably are still at the max of 333 rated miles.

So, if you have NOT lost range, the value of 77.8kWh using the energy screen method, only indicates that your battery has at LEAST that amount of energy. (Aside: the way this works is if you have more than this threshold of energy, the energy content of each rated mile is increased, hiding the extra capacity by shoving it into a fixed number of maxed-out miles (in this case max is 333).)

In addition, the constant here calculates to be 234Wh/mi (interestingly identical to the 2018/2019 Model 3 LR RWD). It is DIFFERENT than the other 2023 vehicle (79kWh/358rmi = 221Wh/mi). Note the rated line in the pictures is at about 239Wh/mi (252Wh/mi and 232Wh/mi are nearly equidistant, with 232Wh/mi being closer), which is what you'd expect for 234Wh/mi (the rated line is always 5Wh/mi higher for some reason). So that confirms the straight calculation (not really necessary to confirm, but just pointing it out).

So:
We can't see that you have any degradation. If you get 333 miles at 100%, then you do not have any appreciable capacity loss (at least, not any below the degradation threshold - of course you can lose some, and just not see the loss, as long as you stay above the threshold).

And for the record, the current 333-mile Model 3 Long Range has a degradation threshold of 77.8kWh, and a constant of 234Wh/mi. It's possible for these values to change later.

It's intriguing that the rated range has dropped so much. There's been nearly no change in capacity. I wonder if they decided to stop doing the ~0.747 scalar based on 5-cycle results? (This would mean real-world range is likely very similar between this vehicle and the 358-mile one.)
358rmi * 0.7/0.747 = 335.5rmi, so it nearly works out, especially if you consider the other pack is 79+kWh and this one is probably a little less.

Thanks for the pictures, this was very helpful to understanding what the deal is with this vehicle.

I never realized that the line was 5 kw over EPA...thank you..very interesting

 

[AlanSubie4Life]

I never realized that the line was 5 kw over EPA...thank you..very interesting

Yeah, there's no proof from the pictures per se; this is just eyeballing it, but if the owner "drove to the line," getting exact overlap, it would be at about 239Wh/mi. It's clearly higher than 234Wh/mi in any case, as one would expect. (234Wh/mi is 77.8kWh/333rmi, just to remind of the origin of that value. It's also available from 232Wh/mi * 268mi / 266rmi = 234Wh/mi; these calculations are equivalent due to how the screen works.)

 

[Kelculate]

Good catch with the efficiency and treshold!

Yes, its a bit strange if it is the same LG battery as we have gotten in Europe since two years.
Here we (still EPA rated Wh/mile) get up to 358/576km displayed.
My friends is at 78 kWh and show 569km(354 mi).

I can not think of the effeiciency beeing
reduced that much ( probably bot reduced at all), so as you say the new m3 should do a real range of about 79/82 of the old car…

Finally charged my car (2023 M3LR dual motor) to 100%. Still showing the same 77.8kWh and ~333mi rated range. Wonder if any other owner sees the same