I find displayed 100% range (both usable as per app and absolute as per both available in TeslaFi) fluctuates significantly even over relatively short periods of time. It is however also quite seasonal although how much of this is temperature and how much seasonal tyres I am not sure - after a seasonal tyre swap the car looks like it recalibrates itself next drive, ie don’t drive hard for next few miles message.
Our 2019LR had 310 miles from new. 4-1/2 years later it’s normally somewhere in the 280, but has dropped into the high 270’s at times, or risen into low 290’s.
But tbh, it’s all finger in the air as the BMS is just making a best guess at what’s available and in car or in app, also making some adjustments for usable energy which is normally simplified into the one display value and occasional snowflake.
There are probably better ways to get a better range reading (energy graph) but as long as our ‘100%’ range fluctuates within the normal empirical values, I’m comfortable with that, especially as ours sits within the TeslaFi range for other similar cars within its fleet.
Whilst there is some battery degradation going on since new, the vast majority of the range fluctuations is down to BMS.
At the end of the day, the usable range will be influenced by many variables, and the car/app display is not taking most of those into account.
FWIW horizontal lines above/below green (fleet average) line is 300 miles upper, 280 miles lower. Car when new was 310.
There may be some argument that we have just had a warmer winter than previous, but that’s probably stretching what can be concluded from the graph.
What can be gleaned from the fleet average is that after an initial range drop, average range pretty much flat lines.