Battery charging over its set point?

[appleguru]

My car was is in for service, and was allowed to sit in the cold for a while... the battery got very low, down to about 8% SoC at around -5 degrees C. Car showed a range of 9 miles at its lowest before it was plugged in:

The car was then plugged in, with a charging setpoint of 90%. It charged at 40A/208V for around 7 hours until it was done (around midnight) but remained plugged in until morning.

About an hour after charging was complete though, a very strange thing happened: the range jumped from 221 miles (90%) to 236 miles (96%).

It appears the miles per % did not change, but the BMS just decided that it was at a higher state of charge than it originally thought. Has anyone else seen this happen? Is this a good recalibration or a bad one?

Here’s the data from teslafi showing exactly when the change happened:

The “under the hood” logs show a "BMS_w145_SW_socChange" message in the charging session. Any insight anyone could provide would be greatly appreciated.

 

[scaesare]

I have had that happen, but it's only been by a percent or so... I attributed it to the temperature rising such that the pack voltage may have fluctuated some, along with perhaps some recalibration the car did at the time.

Your 6% is a pretty big jump... but then again you started with a much lower state of charge and temp than I did, so perhaps that's why...

 

[Pale_Rider]

Yeah I hadn’t it happen about a month ago. Charged 3% over for what ever reason. Hasn’t happened again.

 

[boaterva]

I've seen this happen several times when the car got 'confused'. I think I've figured it out that some app was in use that never let the car sleep, as it wasn't doing so on TeslaFi. I.e., I set up something like one of the stats apps (not TeslaFi, it has its own sleep parameters, of course), and never turned it off. So, the car was awake forever. Then, somehow, it gets upset and normal operations don't work.

Not sure why this would be the case, but it did happen several times over the last 18 months. A new software release did this also, which is why I always reboot on new software loads, which also clears it.

Not to say these are the causes for your issue, but just FYI.