Only 3% battery degradation on M3LR (E5D battery) after +3 years and 75.000 Km!

[zef3215]

Hmm - I think you just demonstrated how difficult it is to estimate your battery capacity with significant accuracy. It looks like your battery is an LG M48 like my car (and for @Bouba). You mention that your FPWN is 74.5 kWh (same as mine). That makes 1% battery, 0.74 kWh or thereabouts.

First off, purely as an example, depending on the accuracy of a specific type of data measurement (which are often subject to rounding), measurements that seem different could in reality be very similar. I refer to your 3% and 5% above - it would not take much of a measurement variation and then data rounding to make those practically the same.

Next, when did you take the SMT readings? Straight away or a few minutes after Bluetooth connection? Sometimes it takes a while for SMT to get a current value from the CAN bus and sometimes it will only do that if the car has been driven. It depends on the parameter, but, you could have errors there too.

I appreciate all that sounds a bit bla bla, but the example is rational.

I use NFP data over time in order to assess battery capacity, It appears good for +/- 0.5 to 1 kWh error on total capacity. I could comfort that data with the SMT CAC values (when they were working in SMT before last December!). The other ways of estimating capacity seem to give about a 1 kWh error as discussed in previous posts. On that basis I would be inclined to believe your NFP calculation of 6.7% (but that's my opinion only and happy to be called out). Logically that value would also depend on lifetime average SoC, average storage temperature and n° of charge cycles as per @AAKEE posts. In the end best to charge to 100% and drive to display 0% when it's moderately warm, avoiding phantom drain wherever possible, then you'll know for sure for the current battery capacity.

What I don't get is the result from the health test. The "HV Battery Health Test Confusion" talked around that without arriving at a conclusion. I wonder if it's actually measuring other parameters Tesla considers critical to a healthy pack - things like pack imbalance where a cell is significantly down on the others in the same module? There's a commercial post discussing this here

Thank you for sharing your insights here. Yes, I’m aware that SMT needs a bit of time to “stabilise” so the readings are taken after driving quite a bit.

Once aspect which we all need to consider is that, on Tesla there is a buffer energy in the battery - 3,2kWh below zero for M3 LR with LG battery. So, 1% when NEE is more or less 0,713 and decreasing according with degradation.

 

[Bouba]

Why do we need a buffer ?....is it for a technical reason...or psychology ?....me thinks that having a reserve under zero...of completely unknown quantity...is worse than a definite zero now you don’t move

 

[AAKEE]

Thank you for sharing your insights here. Yes, I’m aware that SMT needs a bit of time to “stabilise” so the readings are taken after driving quite a bit.

Once aspect which we all need to consider is that, on Tesla there is a buffer energy in the battery - 3,2kWh below zero for M3 LR with LG battery. So, 1% when NEE is more or less 0,713 and decreasing according with degradation.

The buffer is 4.5%, not a fixed kWh value.

1% IS (not guessing here) 69.5x 0.955/100 = 0.663725 kWh.

The car displays 100-0% from full to the buffer. Thats 69.5 x 0.955 = 66.3725 kWh (split that by hundred = what 1% displayed range is worth).

Nominal capacity x 0.045 = buffer size.

SMT do not need any time to stabilize.
It reads the data straight out of the BMS in the car.

 

[Steve446]

Bet Tesla was smart enough to use that fact to ”stow away a little degradation”.

Possibly. So, where is the criteria (actual situation) that makes Tesla move to a battery replacement. The rules say 70% Surely there are several criterial that provoke a battery replacement:
- >70% "degradation" (how is that measured)
- major cell imbalance (BMS errors?).
The car in question appears to have a "degradation" assessed by NFP greater than the 3% health test assessment...

 

[Steve446]

SMT do not need any time to stabilize.
It reads the data straight out of the BMS in the car.

I don't want to get lost in the details but sorry that's not entirely my experience! When my car has just woken up it takes a few minutes to acquire the actual current values for some of the parameters, others I agree are straight away.

1% IS (not guessing here) 69.5x 0.955/100 = 0.663725 kWh.

Yes, agreed, but that's not 1% of FPWN if you wish to assess "degradation" from some starting point like FPWN

 

[AAKEE]

The car in question appears to have a "degradation" assessed by NFP greater than the 3% health test assessment...

It seems to be that case every time.

The real degradation is higher than the service mode test.

 

[AAKEE]

I don't want to get lost in the details but sorry that's not entirely my experience! When my car has just woken up it takes a few minutes to acquire the actual current values for some of the parameters, others I agree are straight away.

What OBD-dongle do you use?
A high speed version?

I have the ODBLink MX+ always connected and a samsung tablett that wakes up Scan My Tesla when the USB-outlet is powered.

Not unusual for me to change the preset like ”battery” to ”BMS” or ”all” at the same time I enter the car.
The ”all” list fills up in a few seconds, with all values there.
At least I havent seen any case of it taking minutes to get the values.

 

[AlanSubie4Life]

"HV Battery Health Test Confusion" posts #10, 27 and 33 from @AlanSubie4Life. He also suggests using the energy screen method after a full charge. You mentioned that you also had SMT so you can use Full Pack When New and Nominal Full Pack to estimate current battery capacity.

Yeah I think it's pretty clear from that thread what I think of the Battery Health Test, lol. It doesn't matter what it puts out, it's of no consequence and is entirely depending on what is chosen as the denominator. It's not even determinative of whether or not you have a warranty claim (it's likely not used for that purpose, plus I don't think a vehicle has ever reached the warranty claim threshold, or come close (certainly hasn't been a report here that I can recall), so it's kind of academic).

Just use the energy screen method or SMT.

As usual, have to be careful about using Full Pack When New (it's just a hard-coded value close to the starting capacity but doesn't necessarily represent an accurate starting capacity (it could be higher or lower than typical starting capacity). For this particular (LG?) pack, I think this was around the time they were locking out the Panasonic packs but not locking out these? Anyway someone would have to review the history to determine where typical vehicles actually started.

We don't have EPA tests to rely on AFAIK either, @AAKEE, because this particular vehicle's results were not released in the US. I think. I'm sure there is a test result but not public domain.

Seems like it was ballpark 75kWh as I recall (not the 74.5kWh FPWN hard-coded value). But there are SMT scans & pictures posted on this website from brand new cars matching this description, which could be looked up by those so-inclined. Just have to find the right thread (from around that time). Lots of captures.

The degradation threshold can be calculated too, by those so inclined. The method there is well established but you actually have to know what the true maximum displayed miles is (probably also in that old thread).

I seem to remember claims that LG NMC (this pack?) are slightly slower to lose capacity, presumably due to chemistry differences affecting the growth rate of SEI. But anyway 7.5% after a few years is pretty good.

 

[AAKEE]

For this particular (LG?) pack, I think this was around the time they were locking out the Panasonic packs but not locking out these? Anyway someone would have to review the history to determine where typical vehicles actually started.

The Panasonic was locked to ~ 75kWh to match these cars with the same WLTP.

We don't have EPA tests to rely on AFAIK either, @AAKEE, because this particular vehicle's results were not released in the US. I think. I'm sure there is a test result but not public domain.

Seems like it was ballpark 75kWh as I recall (not the 74.5kWh FPWN hard-coded value). But there are SMT scans & pictures posted on this website from brand new cars matching this description, which could be looked up by those so-inclined. Just have to find the right thread (from around that time). Lots of captures.

Yes, the top value often was around 75 kWh.

The degradation threshold can be calculated too, by those so inclined. The method there is well established but you actually have to know what the true maximum displayed miles is (probably also in that old thread).

I do not think they use any other setting for displayed range than in the cars than the 82 pack with the 79kWh threshold.

Max range varied and the battery often started slightly low and sometimes reached about 75kWh NFP.
Still 543-545km range (74.5kWh) was the most common I think.

I seem to remember claims that LG NMC (this pack?) are slightly slower to lose capacity, presumably due to chemistry differences affecting the growth rate of SEI. But anyway 7.5% after a few years is pretty good.

Its the newer LG 78.8kWh pack with 4% aluminum added to the chemistry that holds up better.
That 74.5kWh pack follows the Panna 77.8 rather close in degradation (percent wise).

 

[Regaj]

Some attributes read by SMT are asleep until the car is activated by being put into Drive. But in my experience Nominal Remaining is not among those. It is read instantly and reliably when SMT is fired up. SMT is simply displaying what the BMS is reporting. If the car had to be driven before the BMS could report Nominal Remaining, the cabin display wouldn't be able to show SOC, nor would your app be able to report it.

As to any delta between Nominal Remaining as reported by SMT and the Service Menu Battery Health Test, I'd be inclined to put more trust in Nominal Remaining, as that's what the BMS is actually reporting. The Health Test appears to have some other variables baked in.

I've never heard of a Tesla battery being replaced under warranty based purely on hitting that 30% degradation threshold. Lots of packs have been replaced under warranty... but in every case I've heard of the failed pack exhibited other symptoms and threw one or more error codes.

 

[Steve446]

What OBD-dongle do you use?
A high speed version?

I have the ODBLink MX+ always connected and a samsung tablett that wakes up Scan My Tesla when the USB-outlet is powered.

Not unusual for me to change the preset like ”battery” to ”BMS” or ”all” at the same time I enter the car.
The ”all” list fills up in a few seconds, with all values there.
At least I havent seen any case of it taking minutes to get the values.

As supplied from SMT's e-shop Jan 2022, a Nexus Nexlink Bluetooth 5. From reviews it's middle way "high speed" between the LX lower speed and the MX+ I think you have. When the app is launched on my Galaxy S22 with the car awake it's always fast to load a complete page such as Temps or Battery which are the ones I routinely use to extract my SMT data. However, some of the individual parameters on those pages will show the value last received from the CAN bus during a previous session, most are correct immediately, a few take anything up to 20-30 seconds. Some like the odo and CAC (before it stopped working) only show after a drive. I use the Perf page when driving, left permanently on some are correct immediately some are not - all the values are real time after 20 to 30 seconds. I'm quite happy with it, the only issue I've ever seen is it sometimes freezes on a longer journey - needing an app restart to make it work.

 

[Steve446]

Some attributes read by SMT are asleep until the car is activated by being put into Drive. But in my experience Nominal Remaining is not among those. It is read instantly and reliably when SMT is fired up. SMT is simply displaying what the BMS is reporting. If the car had to be driven before the BMS could report Nominal Remaining, the cabin display wouldn't be able to show SOC, nor would your app be able to report it.

As to any delta between Nominal Remaining as reported by SMT and the Service Menu Battery Health Test, I'd be inclined to put more trust in Nominal Remaining, as that's what the BMS is actually reporting. The Health Test appears to have some other variables baked in.

I've never heard of a Tesla battery being replaced under warranty based purely on hitting that 30% degradation threshold. Lots of packs have been replaced under warranty... but in every case I've heard of the failed pack exhibited other symptoms and threw one or more error codes.

Yes agreed; in my case I'm talking about when the car is first woken up. When SMT is started I always get a mostly complete page of data immediately in for example Temps or Battery it's just that some appear and some are updated from old values ~20 seconds afterwards. I never bothered really to check which ones except for those that are annoying to wait for such as outside temperature and cell temp.

 

[AAKEE]

As supplied from SMT's e-shop Jan 2022, a Nexus Nexlink Bluetooth 5. From reviews it's middle way "high speed" between the LX lower speed and the MX+ I think you have. When the app is launched on my Galaxy S22 with the car awake it's always fast to load a complete page such as Temps or Battery which are the ones I routinely use to extract my SMT data. However, some of the individual parameters on those pages will show the value last received from the CAN bus during a previous session, most are correct immediately, a few take anything up to 20-30 seconds. Some like the odo and CAC (before it stopped working) only show after a drive. I use the Perf page when driving, left permanently on some are correct immediately some are not - all the values are real time after 20 to 30 seconds. I'm quite happy with it, the only issue I've ever seen is it sometimes freezes on a longer journey - needing an app restart to make it work.

I have an interrupt cable. that I used in the M3P after a tip from @eivissa. I had in in hte M3P and it from time to time needed reset several time during on e hours drive and sometimes not even once a week. For the MSP i mounted it first but I have only seen one drop out so far so I removed it (hard to know if it is on or off, having the OBDLink MX+ hidden under the mobile charging cabinet.
I removed the interrupt cable a few months ago, doenst seem to need it.

I guess having a 3 hand SMT that will cause the need to reboot the OBD-dongle from time to time?

I just when to my MSP and checked the values, I can as before not see anything taking noticable time to appear or update. The tablet i always have in the car is on but sleeping and it wakes itself and starts SMT when the car wakes. The unlock when I comes cloes to the car wakes the tablet and by the time I get in the seat, the SMT is on, connecting to the OBDLink and next thing the values are there. I think it was about the same in the M3P.

For the performance page, some values aren't present until they "happen". If 0-60mph/ 0-100kph or 1/4 mile takes too long, I think I know the answer .
Just kidding, I have an home made page that was used on the M3P with the tablet in front of the wheels. 0-100 wasnt shown was driven between apps restarts until 0-100 was performed. There are several values like that that need to have a value to be shown.

 

[Steve446]

I have an interrupt cable. that I used in the M3P after a tip from @eivissa.

I have used the cable that was supplied with the OBD2 dongle (oups, "harness", I should remember my international English ). What is an interrupt cable?

 

[AAKEE]

I have used the cable that was supplied with the OBD2 dongle (oups, "harness", I should remember my international English ). What is an interrupt cable?

Like this (amazon has it). It has an on/off button so if/when the connection stops to the SMT, the interrupt cable is switched off and then on and the connection reestablishes. (my version has a pushbutton instead of the side to side switch on the pic).

 

[Steve446]

Like this (amazon has it). It has an on/off button so if/when the connection stops to the SMT, the interrupt cable is switched off and then on and the connection reestablishes. (my version has a pushbutton instead of the side to side switch on the pic).
View attachment 1014679

Ordered it thank you same push button was the cheapest version on Amazon.fr €8.59

 

[Steve446]

As usual, have to be careful about using Full Pack When New (it's just a hard-coded value close to the starting capacity but doesn't necessarily represent an accurate starting capacity (it could be higher or lower than typical starting capacity). For this particular (LG?) pack, I think this was around the time they were locking out the Panasonic packs but not locking out these? Anyway someone would have to review the history to determine where typical vehicles actually started.

Yes thanks for the comments, I appreciate though that it's a hard coded value. As far as I can tell from my vehicle's French registration document and EU homologation it's an LG M48; "75" kWh). I've always used it (74.5) as a starting reference point for capacity comparison though (right or wrongly). The first ever rated Range I had new was 544 km and energy screen 74 (end Sept '21) when I added SMT in Jan '22 it was 543 and NFP 74. Always been down ever since

 

[AAKEE]

Yes thanks for the comments, I appreciate though that it's a hard coded value. As far as I can tell from my vehicle's French registration document and EU homologation it's an LG M48; "75" kWh). I've always used it (74.5) as a starting reference point for capacity comparison though (right or wrongly). The first ever rated Range I had new was 544 km and energy screen 74 (end Sept '21) when I added SMT in Jan '22 it was 543 and NFP 74. Always been down ever since

Yes, NMC seems to need a little more cycling than made during the manufacturing process to reach the max capacity.
It is very clear for the LG M-50 (78.8) that it starts low and need cycles to reach the full capacity, at least for the BMS to find the capacity).
I have seen a few M-48 (74.5) also increase the capacity after a while. As it seems, if you mostly charge high to 80-90% the capacity will go down instead of increasing.
There is a few research reports that support this, where the capacity increases initially specially if ysing lower SOC.

(I saw very low initial capacity in my Plaid, but I did a check that was not dependent on the BMS values and found the capacity to be 98-98.2kWh or so, while the BMS was saying 95.7. So in that case it was the BMS that needed to learn and not the batteries needing a break-in.)

 

[yessuz]

Interesting.

My M3 LR (2022) now showsbased in Teslamate, that after 2 years and 43k miles I lost ~ 7 kwh of capacity.

I did not run the battery health test though

 

[AlanSubie4Life]

Interesting.

My M3 LR (2022) now showsbased in Teslamate, that after 2 years and 43k miles I lost ~ 7 kwh of capacity.

I did not run the battery health test though

Just use the energy screen. You started around 80-81kWh.