MS Refresh threshold

[zivac87]

I have had 99.0 nominal remaining, 98.4 nominal full pack, and my car still showed 560km (= 348miles), so it most probably never exceeds 348 mi / 560km on 21” selection.

It's only showing over 560 km in Tessie, but never in car. My car finally started dropping range at 21.000 km and it happened really steep. Its showing 545 km now with 94.3 kWh nominal.

Can you check one thing, when parked at roughly 63% SoC, car will drop/adjust at least 2-3% within 1 hour after brief sleep. It is happening every time at that SoC since car was new, not sure why BMS is not learning anything. It's always shown in energy app - park tab. There are other BMS adjustments but they are usually around 1%; not as noticeable for most.

 

[AAKEE]

It's only showing over 560 km in Tessie, but never in car. My car finally started dropping range at 21.000 km and it happened really steep. Its showing 545 km now with 94.3 kWh nominal.

Yes, I know the issue from Teslafi.
Teslafi get the range in hundreds of km, but the SOC only in whole no digit value.
Teslafi jumps up and down due to the half perfent rounding up and down but the range values from scan myctesla logged with teslalogger is very stable.

But in car 560km is the solid max.

Can you check one thing, when parked at roughly 63% SoC, car will drop/adjust at least 2-3% within 1 hour after brief sleep. It is happening every time at that SoC since car was new, not sure why BMS is not learning anything. It's always shown in energy app - park tab. There are other BMS adjustments but they are usually around 1%; not as noticeable for most.

I already know my SOC is very stable, I can show data on it.
Since the day the nominal full pack reached 98 kWh which from other calculations is/was correct, even after a long drive, when I park the SOC stays virtually the same.
When the BMS underestimated the capacity it always increased after a longer drive.
Using scan my tesla and SOC with .1 resolution I see this very clear.

This is the arriving from a 45+45km drive with sebtry on during the shopping visit (1hr).
At about 16 (4pm) I arrived at home.
Teslafi shows 40% but the BMS value was 39.9%.
1 1/2 hour later I went to the car to check again, and then had 39.8%. (Still shows 40% on teslafi).
The SOC level do not matter for me, I mostly charge to 55% but I might have a sleep at around 63% from a trip, I’ll look for it.

I guess the 3% loss includes a drive before?
Sounds like a capacity overestimation.

When driving the SOC is preliminary and calculated via energy content minus used energy.
When parking, and sleeping the battery voltage can be measued (in sleep the OCV can be measured), after this the SOC is adjusted.
I do not have any own data on overestimates, but on underestimates.

One thing you can do is check the SOC, and also the range (use km, as it is the highest resolution).
Check it when parking andvthen check it after 15-20 minutes.
Both my MSP and M3P have adjustet the big adjustment before it falls asleep.

What happens when you charge? Not a 1-5% charge but 30% or more?
If you set for example 70%, what is the displayed SOC about 20-30min after the charge?

 

[zivac87]

I understand concept of underestimating/overestimating after charge.

Sometimes I charge from 40-70% and after brief sleep BMS reads 72%. Sometimes I charge to 60% and car reads 59%.

But this weird bug happens every time when I park at around 63%, no matter if I charged car to 80% then drive it and park at 63% or when I charge from 55% to 65%, then drive few miles and let it sit to 63%. It always accounts for standby drain in park time, and it always happens at that SoC within 1 or 2 hours after waking car.

It's weird Tesla didn't notice that. That is another reason why I keep my car under 60%, my standby drain is minimal, BMS calculation is most precise around that level for my MSP.

I would be interested if it happens to you as well and to check what exactly causes that behaviour.

 

[AAKEE]

I had no close to 63%.
A couple at 60 and one at 69%.

All had eiter the same SOC after the charge or 1% loss (earlier when the BMS underestimated).

 

[zivac87]

unfortunately

whenever I keep it under 60% BMS is almost spot on, always charges to exact % and "standby loss" (BMS correction would be better name IMO) is minimal.

If you ever park between 60-65% let me know what happened.

 

[aerodyne]

Recently tried the Recurrent and Tessi Apps.

I like Teslafi better, but these new apps give some data that Teslafi does not.

For instance, it shows the average new pack had 96.3KwH, and my current capacity as 94.1 KwH or 396 miles. Dividing the first by the second gives EPA consumption for my '22 MS LR of 237.8 wh/mi.

Multiplying the consumption by the EPA range of 405 gives 96.24 Kwh.

Not sure how the buffer, which I have heard is anywhere from 1.5 to 4.5%, plays into this.

 

[AAKEE]

Recently tried the Recurrent and Tessi Apps.

I like Teslafi better, but these new apps give some data that Teslafi does not.

For instance, it shows the average new pack had 96.3KwH, and my current capacity as 94.1 KwH or 396 miles. Dividing the first by the second gives EPA consumption for my '22 MS LR of 237.8 wh/mi.

Multiplying the consumption by the EPA range of 405 gives 96.24 Kwh.

Not sure how the buffer, which I have heard is anywhere from 1.5 to 4.5%, plays into this.

The buffer is always 4.5%
It does not change percent wise but the size vary to be 4.5%.

All of the battery incl. the buffer is counted at 100% to reach the EPA range.

The actual consumption driving to be able to reach the EPA range when reaching 0% displayed needs to be 4.5% lower than the EPA consumption.

Above the treshold, the car increases the Wh/mile to stay at the EPA number at 100%.