Model 3 Performance Battery Degradation One Month (Story)

[VLTWGGN]

A few weeks back I had a lot of worries about battery degradation on my model 3. The car was only charging to about 280 miles which is almost 10% loss. Even had the service center check the car when it was in for other service but they said everything was ok. I have a very short commute of 12 miles and was charging everyday.

Some things I have learned.

The miles reading is based on calculated battery capacity only. It does not vary with driving style or temperature.

It appears the Tesla BMS (Battery Management System) will loose some calibration if you are shallow charging.

The analogy I would use is if you are trying to find the capacity of a bucket that hold 5 gallons (20 quarts) only using 1 quart of water. If you only add a quart and measure the height change to estimate the capacity any error in the height measurement is multiplied by 20. If you use 2 gallons to estimate the total capacity any error is multiplied only 2.5 times. This is greatly over simplifying but explains what I believe is going on. This is why shallow charging leads to these errors.

The charging cycle allows the BMS to measure the energy (water) going into the battery with the change in the overall voltage (height) of the battery to estimate capacity. My guess is the Tesla BMS errors to the low side to be sure the actual range is never underestimated.

I have been following advice I saw to only charge when you are below 100 miles. I am charging to 80%. So now most cycles are about 30% to 80%. The extrapolated charge is back to 308 miles with 247 miles of charge at 80%. I charged one time to 100% @ 307 miles. It took a few cycles to have it correct. The car has almost 7K miles.

Hope this helps anyone concerned about the battery capacity.

This is EXACTLY what I'm experiencing right now. My car only charges to about 282 at 100% and this seemingly happened overnight. I'll implement this 30-80% method and see if we can re-calibrate it.

 

[tracksyde]

One person (djgarret21) in the 42.3 thread saw their estimated 100% range go from 301 to 313 after updating to 42.3:

Model 3 Software Update 2018.42.x

Anyone here with 42.3 that has seem something similar?

My first charge (to 80%) after 39.7 only went to 240 miles (~300mi at 100%). I'm currently on 42.2 and there hasnt been much change. If anything, my estimated 100% range has dropped a bit to maybe ~298 miles.

 

[007Bond]

One person (djgarret21) in the 42.3 thread saw their estimated 100% range go from 301 to 313 after updating to 42.3:

Model 3 Software Update 2018.42.x

Anyone here with 42.3 that has seem something similar?

My first charge (to 80%) after 39.7 only went to 240 miles (~300mi at 100%). I'm currently on 42.2 and there hasnt been much change. If anything, my estimated 100% range has dropped a bit to maybe ~298 miles.

Thanks for posting this it goes with the point I was just going to make.

Don't you all think Tesla needs to come up with a better way to display range in mile???

Come on all this calibration is crazy, I mean sure us guys on here we all get into all this stuff. But Tesla is marketing this car at the masses. The average person buying a Model 3 who is not into cars like us is not going to do any recalibration. They are just going to do what the manual says, charge and drive. So if Tesla does not want to lose the common buyer they need to fix things like this.

Now I see average housewifes with kids in a model 3, guys that have no idea about electric cars, they just bought it, my neighbor has no idea he just plugs it in and drives it has no interested in all the tech stuff. So ppl like this are not interested is recalibrating anything, they bought the car to replace their daily driver. This is the market Tesla targeted, not us guys that would all jump at the chance to be Beta testers.

So I ask again don't you think Tesla needs to fix this?

Maybe Tesla should have more indicators like some others do, Range in miles, battery health, charge level.

All I can say is showing charge level and range in miles is not working if it needs to be recalibrated all the time.

 

[diamond.g]

Thanks for posting this it goes with the point I was just going to make.

Don't you all think Tesla needs to come up with a better way to display range in mile???

Come on all this calibration is crazy, I mean sure us guys on here we all get into all this stuff. But Tesla is marketing this car at the masses. The average person buying a Model 3 who is not into cars like us is not going to do any recalibration. They are just going to do what the manual says, charge and drive. So if Tesla does not want to lose the common buyer they need to fix things like this.

Now I see average housewifes with kids in a model 3, guys that have no idea about electric cars, they just bought it, my neighbor has no idea he just plugs it in and drives it has no interested in all the tech stuff. So ppl like this are not interested is recalibrating anything, they bought the car to replace their daily driver. This is the market Tesla targeted, not us guys that would all jump at the chance to be Beta testers.

So I ask again don't you think Tesla needs to fix this?

Maybe Tesla should have more indicators like some others do, Range in miles, battery health, charge level.

All I can say is showing charge level and range in miles is not working if it needs to be recalibrated all the time.

It is possible they will go the Apple route and only show the percentage, leaving you to have to open the Energy app to see how far you can go based on how you are driving.

 

[TexasEV]

Thanks for posting this it goes with the point I was just going to make.

Don't you all think Tesla needs to come up with a better way to display range in mile???

Come on all this calibration is crazy, I mean sure us guys on here we all get into all this stuff. But Tesla is marketing this car at the masses. The average person buying a Model 3 who is not into cars like us is not going to do any recalibration. They are just going to do what the manual says, charge and drive. So if Tesla does not want to lose the common buyer they need to fix things like this.

Now I see average housewifes with kids in a model 3, guys that have no idea about electric cars, they just bought it, my neighbor has no idea he just plugs it in and drives it has no interested in all the tech stuff. So ppl like this are not interested is recalibrating anything, they bought the car to replace their daily driver. This is the market Tesla targeted, not us guys that would all jump at the chance to be Beta testers.

So I ask again don't you think Tesla needs to fix this?

Maybe Tesla should have more indicators like some others do, Range in miles, battery health, charge level.

All I can say is showing charge level and range in miles is not working if it needs to be recalibrated all the time.

The “common buyer” isn’t affected at all, because they’re not obsessed about the battery and how accurate the range is. When driving around town who cares if, for example, a 260 mile reported range is really 255 or 260 or 265? He’ll be home before the car even drops below 200 miles. Who even looks at the battery meter when driving around town when you have a 310 mile range car? This isn’t a Leaf. The range only matters when driving long distance, and it’s not going to affect where you supercharge whether your estimated charge at arrival is really 22% rather than 20%, or whatever. Chill out and enjoy the car.

 

[Eno Deb]

So I ask again don't you think Tesla needs to fix this?

Maybe Tesla should have more indicators like some others do, Range in miles, battery health, charge level.

All I can say is showing charge level and range in miles is not working if it needs to be recalibrated all the time.

Not sure what you mean. They can try to make the battery estimator more accurate (if the thread linked above is correct, they may have done just that in firmware 42.3). But determining the SoC of a battery will always be only an estimate. There is no 100% accurate way to do this.

I honestly don't understand why people are obsessing about this so much. The estimator does not affect the actual capacity, so the full range is there if you need it.

 

[gtmotor]

Just for reference mine showed 314 miles when new at 100%. I shallow charge it everyday, now it shows 297 after 10k miles.

 

[MP3Mike]

Just for reference mine showed 314 miles when new at 100%. I shallow charge it everyday, now it shows 297 after 10k miles.

Have you updated to 2018.42.3 or higher already? If not, let us know how it changes once you do.

 

[M109Rider]

Just updated to 2018.42.3 this morning.
This was my SOC this morning.
This is my SOC the first charge after the update.
Seems like it may have made a difference.

 

[gtmotor]

Have you updated to 2018.42.3 or higher already? If not, let us know how it changes once you do.

I'm on 42.2 . I'll see if it changes after the update

 

[Candleflame]

Not sure what you mean. They can try to make the battery estimator more accurate (if the thread linked above is correct, they may have done just that in firmware 42.3). But determining the SoC of a battery will always be only an estimate. There is no 100% accurate way to do this.

I honestly don't understand why people are obsessing about this so much. The estimator does not affect the actual capacity, so the full range is there if you need it.

I disagree. Until the driving computer tells you when cells are failing (leading to a warranty case) it is essential that we know how much range there is as this is the only way to know if something is off.
Tesla can see how many cells are faulty but won't tell you.

 

[djgarrett21]

One person (djgarret21) in the 42.3 thread saw their estimated 100% range go from 301 to 313 after updating to 42.3:

Model 3 Software Update 2018.42.x

Anyone here with 42.3 that has seem something similar?

My first charge (to 80%) after 39.7 only went to 240 miles (~300mi at 100%). I'm currently on 42.2 and there hasnt been much change. If anything, my estimated 100% range has dropped a bit to maybe ~298 miles.

That's me. I got the update notification while my car was charging maybe that has something to do with it? I think someone else noticed a bump to their rated range on 42.3, not sure where I saw the post.

Here is what I've noticed on 42.3 thus far:
-Charging terminates 1% before the set level, e.g. set charge to 80% but car stops charging at 79%.
-My rated range is 312+ after updating to 42.3. Previous to that I was hovering around 301

 

[Eno Deb]

I disagree. Until the driving computer tells you when cells are failing (leading to a warranty case) it is essential that we know how much range there is as this is the only way to know if something is off.
Tesla can see how many cells are faulty but won't tell you.

Well, you can disagree all you like, but it is still a fact that the battery state is just estimated and not 100% accurate. Here is a recent overview paper describing some of the issues and the complexity of the estimation methods:

Critical Review on the Battery State of Charge Estimation Methods for Electric Vehicles - IEEE Journals & Magazine

You will not be able to reliably diagnose potential battery issues just from the range estimator. You can see an example in the post above, where apparently a software upgrade has significantly changed the displayed range. At the end of the day you depend on what Tesla is willing to show you and what you actually achieve driving.

 

[DR61]

I had been getting 270 mi at 90% and 298 mi at 100%. Update yesterday to 42.4 from 42.2 and this AM a charge to 90% indicates 275 miles. Seems calibration has changed.

 

[MP3Mike]

Tesla can see how many cells are faulty but won't tell you.

No they can't. They might be able to see how many bricks are performing poorly, but they can't identify individual cells that are faulty.

The pack has 4,416 cells but Tesla can only monitor the 96 bricks. (Each brick is made up of 46 cells in parallel.)

 

[tomas]

Thanks for posting this it goes with the point I was just going to make.

Don't you all think Tesla needs to come up with a better way to display range in mile???

Come on all this calibration is crazy, I mean sure us guys on here we all get into all this stuff. But Tesla is marketing this car at the masses. The average person buying a Model 3 who is not into cars like us is not going to do any recalibration. They are just going to do what the manual says, charge and drive. So if Tesla does not want to lose the common buyer they need to fix things like this.

Now I see average housewifes with kids in a model 3, guys that have no idea about electric cars, they just bought it, my neighbor has no idea he just plugs it in and drives it has no interested in all the tech stuff. So ppl like this are not interested is recalibrating anything, they bought the car to replace their daily driver. This is the market Tesla targeted, not us guys that would all jump at the chance to be Beta testers.

So I ask again don't you think Tesla needs to fix this?

Maybe Tesla should have more indicators like some others do, Range in miles, battery health, charge level.

All I can say is showing charge level and range in miles is not working if it needs to be recalibrated all the time.

I recommend staying patient for a 6 months. When the S was first introduced, many people were experiencing varying rated range numbers, and there was the same talk. Over a year or so, Tesla was able to tweak the range estimation algorithm via software releases... and you seldom hear concerns with the S. The 3 has a different battery... and I suspect they will have to tweak range estimation based on experience with the 3 fleet.

 

[Candleflame]

No they can't. They might be able to see how many bricks are performing poorly, but they can't identify individual cells that are faulty.

The pack has 4,416 cells but Tesla can only monitor the 96 bricks. (Each brick is made up of 46 cells in parallel.)

yeh sorry thats what i meant. obviously not every single cell is being monitored. But the car will not tell you if one of those bricks fails. you have to call tesla to do an over air cell inspection from software.

 

[Candleflame]

Well, you can disagree all you like, but it is still a fact that the battery state is just estimated and not 100% accurate. Here is a recent overview paper describing some of the issues and the complexity of the estimation methods:

Critical Review on the Battery State of Charge Estimation Methods for Electric Vehicles - IEEE Journals & Magazine

You will not be able to reliably diagnose potential battery issues just from the range estimator. You can see an example in the post above, where apparently a software upgrade has significantly changed the displayed range. At the end of the day you depend on what Tesla is willing to show you and what you actually achieve driving.

when 40 miles is missing and you have recalibrated the range then there is definetly something off and will promt you to call tesla.

 

[TANGO SUKKA]

2855 miles on my car. usually charge to 90% and by the end of the day im around 40-50%. I supercharge like once a week. Yesterday I supercharged my car to 100% to see what the range was, and it's still 310.

 

[MP3Mike]

yeh sorry thats what i meant. obviously not every single cell is being monitored. But the car will not tell you if one of those bricks fails. you have to call tesla to do an over air cell inspection from software.

If a brick fails you aren't going to be driving your car and it would tell you.