Battery degradation already?

[Sixer]

My 3 SR+ is now 6 months old and I’ve only covered 4000 miles. I barely use superchargers but regularly charge though out the week.

On Elon’s advice that 90% is generally ok I switched to charging to 90% rather than 80%. I updated recently to 12.5 and have started seeing something strange going on. My available range has recently (past two weeks) gone from 207 available miles to 197 when charging to 90%. I have moved this back to 80% today but am I seeing battery degradation already? At that rate it’s a bit alarming.

 

[Tessaract]

It's not battery degradation, merely Battery Management System calibration. There are other posts in this forum (don't have the link off the top) that detail exactly how to allow the BMS to properly recalibrate.

 

[Sixer]

I think I may just ignore it and switch to percentage

 

[Adopado]

I think I may just ignore it and switch to percentage

Definitely a good idea! I agree with the comment above ... it's much more likely to be battery management calibration.

 

[booyaka76]

I think I may just ignore it and switch to percentage

100% do this - switch to %, charge when you need to, end of. Don't over think it.

 

[Mr H]

Run it down to 10% and leave it there for a couple of hours to balance the cells, then charge to 90% and it should be ok

 

[LEE3]

It feels like they could add a function for the car to routinely do this collaboration as part of an update.

 

[Twiglett]

the only thing that will make this feel like degradation is to ignore the myriad of posts on here that explains what is going on and that it isn't degradation.
TLDR?
Your battery isn't degrading.
My two year old model 3 has 33k mile and pretty much every "degradation event" I've seen is linked to a new software update.
Over two years it has gone down and gone up - which means it can't be "degradation"
Set in on percentage and ignore it and be happy.

 

[Adopado]

It feels like they could add a function for the car to routinely do this collaboration as part of an update.

As far as I understand it the car does do it already. If you use the car normally the battery management should recover capacity as part of a normal usage cycle. The "problem" only arises because we tend to be hyper-sensitive and spot when a number onscreen is lower than it was before. In reality little has changed other than the number on the screen. We can take some actions to prompt the car to recalibrate ... and that makes us feel better ... but if you didn't do anything I am confident that the system would ultimately sort itself out without intervention. This is different to a true degradation, which can occur in some instances but normally after higher mileages and with older design battery packs.

 

[pow216]

Worry about it when you can’t get to where you need to get to!

 

[tsh2]

I don't think it is possible to calibrate the capacity if you stay in the 20-80% range (when the cell voltage shows only weak correlation with state of charge). So regular short cycles result in a dead reckoning approach. In order to re-calibrate, you need to balance (sit near one end or the other for long enough) and also cover most of the capacity range. The end result is that unless you have done this recently, the mileage number displayed is guesswork.

There is a slight caution - if you spend 3 months in the 70-80% range, don't trust the first long run from 80% to give you 80% range. Charging to 90% or more should always mean a real 90% though - here the cell voltage does give the BMS enough information.

 

[MrBadger]

I thought that cell balancing was only last few % SOC, ie, squeezing the last few electrons into the battery metaphorically so to speak.

BMS recalibration I believe kicks in <20% and >90% or there abouts, hence recommendations to let car SOC enter within these limits when battery values seem awry.

I think both are needed on occasional basis to maintain good correlation.