Maximum battery charge level reduced

[RonE]

Issue: Maximum battery charge level reduced - No error messages​

Sorry if this is a repeat question but new to site and didn’t find an answer…

I have a 2020 Model S Long Range Plus. Bought when one year old with 6,600 miles… don’t know prior charging habits If it makes a difference. Milage rating appears to be B/T 402 & 405 depending what article you may read.

BACKGROUND & ISSUE:
Over a 15 month period, we had drove the car nearly 6,000 miles and only used a supercharger twice to familiarize ourselves with the process. Otherwise, we always charged at home on a 50 amp circuit and never charged over 80% setting. That said, even though charging was set at 80%, it routinely topped off B/T 346 & 348... obviously over 80% but I just assumed this was likely normal.

Then came June 2022 @ 12,450 miles - I charged the car at home to the 80% setting which topped off at 346. For the first time ever, we took the car on a road trip. After driving 160 miles directly to Monterey, Ca., I stopped at a Supercharger near our hotel to top off the charge. THE CHARGING STOPPED AT 307 MILES. There have been no error messages or any other changes to indicate a problem. Since that time, charging now routinely tops off B/T 303 & 308 which is now mildly below the 403/405 80% limit for the Long Range Plus.

So, any idea what happened here?? Why was it charging consistently over 80% and then, why suddenly it charges consistently to below 80%? Any reason for concern? Charging at 304 mile is of no consequence for us given our driving habits, however; I want to make sure we are not harming the car by not addressing this changing issue further.

Thanks for any input…

 

[aerodyne]

Issue: Maximum battery charge level reduced - No error messages​

Sorry if this is a repeat question but new to site and didn’t find an answer…

I have a 2020 Model S Long Range Plus. Bought when one year old with 6,600 miles… don’t know prior charging habits If it makes a difference. Milage rating appears to be B/T 402 & 405 depending what article you may read.

BACKGROUND & ISSUE:
Over a 15 month period, we had drove the car nearly 6,000 miles and only used a supercharger twice to familiarize ourselves with the process. Otherwise, we always charged at home on a 50 amp circuit and never charged over 80% setting. That said, even though charging was set at 80%, it routinely topped off B/T 346 & 348... obviously over 80% but I just assumed this was likely normal.

Then came June 2022 @ 12,450 miles - I charged the car at home to the 80% setting which topped off at 346. For the first time ever, we took the car on a road trip. After driving 160 miles directly to Monterey, Ca., I stopped at a Supercharger near our hotel to top off the charge. THE CHARGING STOPPED AT 307 MILES. There have been no error messages or any other changes to indicate a problem. Since that time, charging now routinely tops off B/T 303 & 308 which is now mildly below the 403/405 80% limit for the Long Range Plus.

So, any idea what happened here?? Why was it charging consistently over 80% and then, why suddenly it charges consistently to below 80%? Any reason for concern? Charging at 304 mile is of no consequence for us given our driving habits, however; I want to make sure we are not harming the car by not addressing this changing issue further.

Thanks for any input…

Probably just the BMS recalibrated after so many home charge cycles.

6% degradation, if it is that, is not unheard of after 2 years.

You should not worry about the battery, esp if you charge at home to 80%. the BMS will take care of the battery.

In the unlikely event your capacity decreases rapidly, you may have a defective pack which will eventually fail, hopefully under warranty.

If you can't avoid thinking about it suggest load the 2022.44.25 update which allows you to view both 12v and HV pack health.

 

[Tam]

Issue: Maximum battery charge level reduced - No error messages​

Sorry if this is a repeat question but new to site and didn’t find an answer…

I have a 2020 Model S Long Range Plus. Bought when one year old with 6,600 miles… don’t know prior charging habits If it makes a difference. Milage rating appears to be B/T 402 & 405 depending what article you may read.

The EPA says its range is rated for 402 miles.

...never charged over 80% setting...

Any reference for why not?

Tesla Service center prefers 90%:
https://youtu.be/G5t1YOHQhlc?t=122

...THE CHARGING STOPPED AT 307 MILES...

80% of 402 is 321 miles.

307 miles is the estimated calculation of the Battery Management System. It is not precise as you wish as if it's just a simple calculation.

There is nothing wrong with that number due to the nature of "estimation".

...Why was it charging consistently over 80% and then, why suddenly it charges consistently to below 80%?...

As you can read from the Service Center receipt, the best way to reduce its inaccurate estimation is to set your charge at 90%. That's the reference point so it can guess better.

Any reason for concern?

None. It's expected.

...I want to make sure we are not harming the car by not addressing this changing issue further. ..

You are doing fine. You are not harming your battery at all. It's about the accuracy of the guessing system but your battery is fine regardless how the system guesses a number for you.

The warranty covers 70% of capacity or 281 miles.

If you set your charge at 100% in a warm day and it only shows below 281 miles, then it's time to file for a warranty claim.

Your current worse fear of 307 miles is way over 281 miles to file a warranty claim.

 

[RonE]

Thank you for the timely replies…
Tam - I get everything you say. As to why 80% changing limit; as I recall all the reading I did around the time I was buying car and subsequently, it said for the health of the battery to limit charging to 80% unless otherwise needed for travel and charge every night to maintain the health of the battery. Now, along with link you provided, I see recommendations at 90%. Likewise, I see suggestions to let battery drain down before recharging which is in conflict with what my Tesla owners manual say… which is to plug in every night. Any input on that one Thanks!

 

[Tam]

...I see suggestions to let battery drain down before recharging which is in conflict with what my Tesla owners manual say…

Correct. Shallower discharge is much better than deep discharge. Grinding down your battery with deeper discharge shortens your battery life.

For example, if I consume 10% daily and start at 80%, I should plug it in daily, so the difference is only 10% from 80 to 70%.

However, the bad way is to wait for 6 days and wear it down from 80% to 20%, then replug it in, the difference is now 60%. If you have a choice, you should choose to wear down 10% every day rather than the deeper 60% after 6 days.

which is to plug in every night. Any input on that one Thanks!

Correct. That's what the manual says. There's no advantage to waiting.

 

[aerodyne]

Thank you for the timely replies…
Tam - I get everything you say. As to why 80% changing limit; as I recall all the reading I did around the time I was buying car and subsequently, it said for the health of the battery to limit charging to 80% unless otherwise needed for travel and charge every night to maintain the health of the battery. Now, along with link you provided, I see recommendations at 90%. Likewise, I see suggestions to let battery drain down before recharging which is in conflict with what my Tesla owners manual say… which is to plug in every night. Any input on that one Thanks!

The 90% or greater applied to the 2170 cells, M3/MY, to enable better pack calibration, not cell health.

For the 18650 cells on the MS/MX, no need to ever charge above 80%, no harm is storing at 50-60%.

Elon said so years ago, and I've got the Teslafi stats to back it up.