MASTER THREAD: 2021 Model 3 - Charge data, battery discussion etc

[AAKEE]

I just did read @TimothyHW3’s post again, I now see that you probably did not mean my calculation but to @voldar’s question?

In my post before I had my calculation for my 100-0% drive, and I took it as a answer to that. Original answer was to @voldar so in that case we more or less say the same thing.

 

[TimothyHW3]

Nominal remaining 77.9, so 36.0 kWh used.

The full pack when new was’nt showing on these

You can check this new Nyland video, where he had about 500-800Wh loss. Check begin and towards the end, which coincides almost perfectly with my rule of thumb for about 0.5-1kWh in Summer at around 120km/h(he was driving a bit slower)

 

[voldar]

Not sure your explanation is true.
When charging a Tesla on a CCS DCFC - using a CCS adaptor - you can see the kWh the DCFC is giving you and what the Tesla reads as getting into the battery.
I will pay attention next time I do this and I'll let you know.

I just checked the charge on a CCS : the same amount of kW reported by the CCS DCFC station was reported by the Tesla.

At the same time, the kWh reported as added by the Tesla are different than those presented by the DCFC : 36 kWh vs 38.561 kWh
Maybe the difference is what went in the buffer but not shown by Tesla as added kWh ? @TimothyHW3

 

[AAKEE]

I just checked the charge on a CCS : the same amount of kW reported by the CCS DCFC station was reported by the Tesla.

The charging power has been reported the same on a charger and the car.

But If you charge with 1 kW for one hour the battery will not have 1 kWh more energy.
There is losses in the charging process, heating the battery. The car is also awake which costs energy.

View attachment 940908

At the same time, the kWh reported as added by the Tesla are different than those presented by the DCFC : 36 kWh vs 38.561 kWh
Maybe the difference is what went in the buffer but not shown by Tesla as added kWh ?

Nothing really goes into the buffer, if you do not have driven to a lower SOC than 0%

In the picture the Tesla says ”+34kWh” but the Charging station says 36.765 kWh if I do not read that display wrong.

You bought 36.765 kWh.
The nominal full pack increased 34x 0.955= 32.47 kWh.
The car overreports the charged by 1/0.955 which means it shows the charged energy including the buffer to be the whole battery capacity from 0% - 100% displayed.

 

[AAKEE]

You can check this new Nyland video…which coincides almost perfectly with my rule of thumb for about 0.5-1kWh

This is probably going to have to be splitted into two or three posts to keep it readable.

To start with the heat loss, any heat loss is in direct proportion to the internal resistance. We can even calculate the electrical heat loss: Heat loss = I^2 x Internal resistance.

As the heat loss is squared to the Current ( I ), it will be four times higher at doubled power.

From 80 to 120 km/h we go from about 120Wh/km to about 162.5 Wh/km.
Thats a increase of 35% per km, but as the speed is increased by 50% the time for each km is only 66.7%.
The power needed for 80 will be 80x120= 9.6kW.
The power needed for 120 will be 120x165= 19.44kW.
19.44/9.6= 2.02, squared is 4.
The heat loss at 120 will be four times the heat loss at 80.

The internal resistance is dependent on the battery temperature. Thats even the reason for preconditioning before Supercharging.
This is a Panasonic NCR18650B tested at different SOC and temperatures.
17C means about 55 Ohms at SOC 40-80%
37C means about 43-44 Ohms at SOC 40-80%

The difference in internal resistance, for example after a recent charge or supercharge short before the drive.
There is a 25% difference between 17 to 37C.
Coming out of a supercharge with 58C cell temp, will give us about 38 Ohms, which means that the IR is 30% lower than at 17C.
A 30% reduction in IR will reduce the losses with 30%.

IR incresases with time, both from cycles and storage. In general the IR increase from cycles is about proportional to the degradation.
For calendar aging, the higher the SOC, the higher the increase in IR. Also, the higher the temperature, the higher the IR increase.

The -1A is about 0.3C so not far away from driving on a highway.
At low SOC (40% and below) the IR increase after 10 months is about 15% at 25C
At high SOC, 80-90% the increase is at about 30% for same time and temp.
The increase looks square root dependant so after longer time, the difference will be about double at high SOC vs low SOC.

Cycles also increase the IR.

-The heat loss will be very dependent on the speed, due to the I^2 part.
-The heat loss will also depend on the cell temperature.
-The heat loss will also depend on the battery age and how it was used (mostly high or low SOC).

There is many variables that affect the actual heat loss as we can see above.

 

[AAKEE]

This is next part of the trilogy.

SOC.

SOC can hardly be measured during a drive. The voltage droop from power varies too much to give a rigid number.
SOC is defined by the OCV voltage.
During the drive the car calculates the SOC, as it cant really be measured.

As an example, a 80 kWh battery (forget about buffers for now). The BMS knows (or thinks) the battery capacity.
For a full charge, se have 80kWh om board.
After the drive have used 40kWh we can calculate that 50% was used and there is 50% left, should be 40 kWh as we used 40 kWh.
These 50% SOC is preliminary, as we could not measure it but only do a approximate calc.

When we stop and the car gets a few minutes or drive really slow, the car could maybe be able to see a bigger difference in voltage and do a preliminary adjustment to the SOC after the drive. These differences could come from using battery power in a higher rate then the specification* says but it could also come from a BMS that has the wrong idea of the battery capacity.

If the BMS *thinks* 80kWh as in the example above, and measures 40kWh used, the BMS would state 50% preliminary SOC.
If we drive slow, stop and or eventually park, the car can measure the SOC, and if 45% SOC now was measured, there is a 5% difference of ”lost energy”.
We could have a increased heat loss, but we also could have a BMS that has the wrong capacity number.
If the real battery capacity is 72.7 kWh instead, the numbers match.
We have ”lost” 40kWh/ 55% of 72.7, thats 72.7-40= 32.7 kWh still there.
32.7/72.7 = 45%.

The BMS does it like this, except for the capacity calculation I did in the lower part.
Using for example teslafi graphic logs it is easy to see when the SOC jumps up or down after a longer drive, due to the capacity calculation being wrong, offsetting the numbers.

SOC during the drive is calculated, and it is calculated from the used energy so the numbers on the display and the delta in nominal full pack should match quite well.
Driving fast (high power) will make the SOC measurements/ adjustment hard so during the drive these should match fairly well.
Stopping or slow drive might cause a adjustment if the difference is high/obvious.
Parking with a sleep and OCV will update the SOC tho the real number.

 

[AAKEE]

Third part

The todays drive.

Charged to stop at 100%, also did let the car fall asleep briefly to better be able to calculate the numbers.
Started at 78.1 nominal remaining.

At 100 km

Used energy 100x174 = 17.4kWh
Difference in Nominal remaining 78.1-60.6= 17.5. The SMT photo was taken after the display and the SMT only updates each 0.2 kWh.

At 200km

Used energy 200x177= 35.4 kWh
Difference in nominal full pack = 35.6 kWh

Arrival at a grocery shop.
First stop on this drive.

Used energy 248x174= 43.2kWh
Difference in nominal full pack = 78.1-34.8= 43.3 kWh.
Only 0.1 kWh delta, and the nominal remaining mostly updates in 0.2 kWh steps.

This stop was a 15 min shopping stop, with sentry and dog mode active.
After this the final 7km drive, and immediatly when stopping it looked like this:

Used energy 255x174= 44.4 kWh.
Difference in nominal remaining 78.1-33.4= 44.7.
The delta is 0.3kWh and this includes the 20 min stop with dog mode and sentry (+9C outside so some heat was needed, tve car showed battery power 0.96 kW when I arrived). This might be somewhere around 0.2 to 0.3kWh during the shopping.

After unloading the car and taking the stuff inside, but not long after the parking it looked like this:

Used energy (still)44.4kWh.
Difference in nominal remaining = 78.1-34.1= 44.0 kWh.
Note that the difference in nominal remaining is 0.4 kWh lower than the energy used.
The SOC was adjusted up (BMS underestimating the capacity) from 40.1 to 41.1 = 1% or 0.75 kWh.

In this drive, we could see a delta in nominal remaining of 0.1 after using roughly 60%, and after adjusting for the 20 minutes dog mode we actually did loose either 0.0 or 0.1kWh to heat losses.

My car have much lower IR than the average M3P 2021, due to the low SOC strategy. Other cars might have higher losses.

In case of a BMS overestimating the capacity se would see a drop in SOC and following this a drop in nominal remaining (nominal remaining is SOC x nominal full pack so when the SOC lowers the nominal remaining also does).
This means a car with a overestimating BMS probably would show a higher difference in nominal remaining than the used energy, as the faulty updated SOC will reduce the nominal remaining shortly after the drive.
The faulty number is actually the nominal remaining being to high before the drive, but this is not noticed until the SOC is lower than expected after the drive.

Its not easy to calculate the heat loss, as there are numerous factors affecting this.
Its also not safe to say that the difference between nominal remaining and used energy is heat losses. It can be a BMS calibration issue, and will be if the BMS is off. There might be some part heat loss and some BMS calibration. Not easy to say.

 

[AAKEE]

I did the return drive today:

Used energy: 47.2 kWh
Difference in nominal remaining: 47.9 kWh.
So this time, more losses.

This drive was 88 km/h average (the earlier was 84km/h. 5% faster, 13% higher power.
Consumption was 191 wh/km = 10% higher, slightly faster and strong headwind.
Higher power (13%) yeilds 28% higher heat loss from power only.

This time the car was charge with the UMC at 13A 230V, so only 3kW.
It was. 5h 20 min from the charge was finished, so the battery started at 12C and ended up at 30C. Average celltemp during the drive about 19C.

The earlier drive started at cell temp 34C (just finished carging to 100% with WC 11 kW), and kept an average about 33-35 C during the drive. )

 

[TimothyHW3]

Difference in nominal remaining

Nominal remaining is not what the car uses, but the value under "ideal remaining". Nominal remaining is not relevant... This also varies by temperature, especially in winter ideal remaining is way lower. Unfortunately the dev from smt doesn't include this value under battery so you have to copy it from All to Battery tab.
So repeat the test with ideal remaining

In future just do a full run from 100% to about 5% like Nyland does on a highway with at least 120km/h and then we can talk. The Tesla km reporting is also sometimes wrong depending on the wheels so that might scew the results. However you turn it, the best you can get is minimal loss on very slow driving with good conditions and no head wind.

On a normal highway run you can expect 1kWh less and on the German highway or in winter - from 1.5kWh loss to infinity...

 

[AAKEE]

I actually did a 240km drive to work using 65% two days ago.

(The Energy is wrong, disregard, byt average speed should match. Its a 300m height gain on this drive).
More or less all 110km, except out of my town and through the target town and also two villages on the way
Average speed 95 km/h but I used the AP with 110 km/h for about 225 km
Start 63.2 nominal remaining.

End: 14.8

Difference : 48.4 kWh

Used energy: 40.04kWh, so a 0.36 kWh diff.

 

[TimothyHW3]

Start 63.2 nominal remaining

Again, ideal remaining, not nominal should be used...

Look, I get that at these speeds there is minimal loss. I actually had a run the other day of 155km at low speeds on "curvy, humpy" roads. I started full and spent 21 kWh according to the BC and the ideal remaining delta was actually lower not higher 20.7kWh.

So I guess some regen wasn't accounted for or the BMS didn't calculate the full capacity in the beginning correctly. Anyways, if I do the run all the way to zero I will see the delta and in the winter it will be a different story.

I see you do these runs in Sweden, repeat that test in the winter time.

 

[AAKEE]

Again, ideal remaining, not nominal should be used...
I see you do these runs in Sweden, repeat that test in the winter time.

I have seen a 2kWh difference on the same drive as above (well, the other direction).
The car was charged with the UMC 2kW, so only 9C cell temp at the start and very cold weather. (I even think it was more than 2kWh, I have the data for that drive).

 

[ran349]

Again, ideal remaining, not nominal should be used...

The SMT app shows SOC and SOC expected under the battery tab. Both are wrong in the general sense. They can be correct if nominal remaining and or expected remaining happen to match ideal remaining.

The SMT developer should just show one SOC value, based on ideal remaining, and just call it SOC, under the battery tab. That would avoid confusion on the subject, and that would be the value that matches the car displayed SOC.

At least that is the way it works on my MS. It sounds like you have verified that is how it works on the M3 as well.

 

[AAKEE]

The SMT app shows SOC and SOC expected under the battery tab. Both are wrong in the general sense. They can be correct if nominal remaining and or expected remaining happen to match ideal remaining.

The SMT developer should just show one SOC value, based on ideal remaining, and just call it SOC, under the battery tab. That would avoid confusion on the subject, and that would be the value that matches the car displayed SOC.

At least that is the way it works on my MS. It sounds like you have verified that is how it works on the M3 as well.

The SOC value (SOC only, without prefixes etc) match my cars displayed SOC.

 

[sonoransky]

I'm a new owner of the 2023 Tesla Model 3 Long Range. I'm in the US and attempting to confirm the battery that is in the car. A Tesla representative pulled up the car (pre-delivery) and indicated it was a LG (non LFP) battery. He referenced a battery code that included "M50". I pulled up the following URL for research ... Tesla-Info It shows the M50 is considered "BT43" which is the Made in China battery that was used for the Model 3 Long Range in Europe. This site goes on to say ... "BT43 which is the LG Chem M50 79kWh battery with 2170 NMC cells, coded 5L". It also references a range of 374 miles and a 0-60 of 4.2 seconds.

If you pull up the United Kingdom Tesla website, it shows the current Tesla Model 3 Long Range WLTP rated at 374 miles with a 0-60 of 4.2 seconds.

I'm leaning towards the battery in my car being the same as what is currently in the European version. I'm assuming this is why the US version of this car is only eligible for half of the tax rebate (Made in China battery).

I have only owned the car a few days. The range seems significantly higher than the 333 posted on the US Tesla website. I'm sure it's possible I am in a transitional car (pre refresh). Thanks.

 

[AAKEE]

I'm a new owner of the 2023 Tesla Model 3 Long Range. I'm in the US and attempting to confirm the battery that is in the car. A Tesla representative pulled up the car (pre-delivery) and indicated it was a LG (non LFP) battery. He referenced a battery code that included "M50". I pulled up the following URL for research ... Tesla-Info It shows the M50 is considered "BT43" which is the Made in China battery that was used for the Model 3 Long Range in Europe. This site goes on to say ... "BT43 which is the LG Chem M50 79kWh battery with 2170 NMC cells, coded 5L".

Its not impossible that Tesla need to use LG batteriea to cope with the supply needs.

At least until now any US LR or P had Panasonic batteries only.

If you get a LG, they arent bad.
Slightly less capacity but they seem to hold up very well. Possibly a better battery in the long run.

We also know that Tesla representatives in many cases have had very little knowledge compared to for example this forum.
If he looked up confirmed data it probably is correct but if he made a wild guess…

 

[RVAC]

I'm a new owner of the 2023 Tesla Model 3 Long Range. I'm in the US and attempting to confirm the battery that is in the car. A Tesla representative pulled up the car (pre-delivery) and indicated it was a LG (non LFP) battery. He referenced a battery code that included "M50". I pulled up the following URL for research ... Tesla-Info It shows the M50 is considered "BT43" which is the Made in China battery that was used for the Model 3 Long Range in Europe. This site goes on to say ... "BT43 which is the LG Chem M50 79kWh battery with 2170 NMC cells, coded 5L". It also references a range of 374 miles and a 0-60 of 4.2 seconds.

If you pull up the United Kingdom Tesla website, it shows the current Tesla Model 3 Long Range WLTP rated at 374 miles with a 0-60 of 4.2 seconds.

I'm leaning towards the battery in my car being the same as what is currently in the European version. I'm assuming this is why the US version of this car is only eligible for half of the tax rebate (Made in China battery).

I have only owned the car a few days. The range seems significantly higher than the 333 posted on the US Tesla website. I'm sure it's possible I am in a transitional car (pre refresh). Thanks.

Is it a US manufactured car?

 

[sonoransky]

Is it a US manufactured car?

My apologies for listing my post in the wrong thread. Just noticed this thread is focused on 2021's. Moderators, feel free to move if necessary.

To answer your question, I believe it's just the battery that comes from China.

 

[Apprunner]

My apologies for listing my post in the wrong thread. Just noticed this thread is focused on 2021's. Moderators, feel free to move if necessary.

To answer your question, I believe it's just the battery that comes from China.

Thanks for the info. I was skeptical that this was an LFP battery that was improved. Not surprised at all that its the LG pack.

 

[AAKEE]

My apologies for listing my post in the wrong thread. Just noticed this thread is focused on 2021's. Moderators, feel free to move if necessary.

To answer your question, I believe it's just the battery that comes from China.

Theres just was a post in a Swedish facebook forum about the EPA range for model Y’s are adjusted down in USA, this might be a correction for starting to use the LG batteries that is slightly smaller.