Weird experience in state of charge (M3 SR 2024)

[ThisStockGood]

I arrived at my destination at about 5 % SOC after driving 250 km. Two hours later I come back to my car and the SOC is suddenly 12 %. It has not been plugged and the temperature has been the same all day.

Any guesses why?

I am aware of the fact that LFP pack are worse than NCL batteries regarding guessing the current state of charge, but from 5 % to 12 %? I think it sounds like a lot.

The car is brand new. It has been supercharged to 100 % once.

 

[Rocky_H]

The state of charge can drift up or down by a few percent after it's parked as the temperature shifts some, and if the car has been able to shut off for a while, so it can remeasure the battery state unloaded. And this % move will usually be more when the state of charge is very low, because the batteries have a steeper voltage change at the low end like that.