Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register
  • The latest TMC Podcast (#14) is now available on YouTube and all major podcast networks. We covered FSD Beta's exciting v11 update, Enhanced Autopilot coming to the U.S. and Canada, and more!

Battery capacity loss question

What "reasonable point of view" are you looking for? People to say "yeah its wrong!!" ?

I'm hoping somebody on this board will be able to help answer the questions I asked in my post at the top of this thread. Not blame me for not reading enough posts (I have read many here), telling me "don't worry be happy" or suggesting I sell my car.

Whole both you and @AlanSubie4Life took a stab at this, you both referenced anecdotes/posts on this forum, which suffer from selection bias (amongst other issues). I am interested in finding what Tesla has put out there on this issue, beyond the warranty. It's not the same thing.

Your responses have other inaccuracies which are not worth debating here (just one example - Tesla support has specifically told me I should NOT interpret anything from the fully-charged mileage because of how the algorithm to compute that number works). This is another reason why I'm hoping others can share info that comes direct from Tesla, and not armchair speculation/"research".
 
Last edited:

WhiteWi

Active Member
Supporting Member
Feb 21, 2021
1,897
1,892
Planet X
I will give you example of my battery Guess O meter aka battery charge meter. I have 2020 M3 and about 6 month ago it dropped all the way to 278-279 miles at 100% (310 when bought the car), Skip to now and it shows 292 miles at 100%.
We started to use car more and changed our charging routine plus warmer weather now. That is why I said don’t worry be happy unless you see sudden drop below warranty threshold. In most cases battery just dies and Tesla replaces it before you get to lose 30%. No need to get all worked up about things out of our control.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
11,932
15,459
San Diego
just one example - Tesla support has specifically told me I should NOT interpret anything from the fully-charged mileage because of how the algorithm to compute that number works

One issue here is that you are more inclined to believe Tesla Support than you are to believe a bunch of randos on the Internet. Big mistake!
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
11,932
15,459
San Diego
One issue here is that you are more inclined to believe Tesla Support than you are to believe a bunch of randos on the Internet. Big mistake!
Just following up on this, in a more serious tone…. In fact, you don’t have to believe anyone! Nearly all the information on how the miles display works on the car is actually able to be determined empirically. You don’t have to have anyone tell you how it works. Even the buffer % can be nearly exactly determined empirically from the car (the 1% “heat losses” interfere with that exact measurement)! That’s the best part. There are confirming tidbits from Tesla which they file with the EPA, so no ambiguity with those, and a few subtle little details, which take a while to work out.

But you can figure out the exact numbers yourself, if you’re persistent, curious, very observant, and with some aptitude for running careful experiments, as you drive your car.

In the end it’s very simple though. Everything posted in this forum on the way this works can be confirmed empirically (and it’s been described exactly how here multiple times). You don’t have to just believe it!

So good luck! Don’t believe anyone! Prove it to yourself.
 
Completely normal. And looking at miles in this way you are doing is the best way to estimate capacity loss. (Just make sure you know the original rating for your vehicle - covered earlier in this Model Y thread or others - and there are sometimes some subtle details which hide a small % of initial loss; these are discussed elsewhere - but for the most part taking ratio of current 100% to original EPA 100% gives a good estimate with foregoing caveats). The estimate bounces around a few %, so just slap some error bars on your capacity loss.

As long as you're above 70% you're good to go. It's extremely common to see 10% loss at your vehicle's age and mileage (better results are also very common). You can see this in this forum and oodles of stories in the Model 3 forum as well as @jjrandorin says. Not going to link to them - you'll have to take my word for it. It's extremely normal.

If you want to slow it down (less impactful now since the loss will be much slower from this point anyway), just charge to 50% or so regularly, and keep cycle depth to a minimum (charge often to 50%); general Lithium-ion battery characteristics suggest that could be the best strategy. This reduces calendar aging (nothing to do with the miles on the vehicle). If 50% doesn't work for you, don't bother, and charge to the level you need to comfortably meet all your daily needs.

At the moment, capacity loss of 15% seems to kind of be the upper limit (this upper limit is increasing every day). Reports of 20% loss are very uncommon, at least at this point in time. I assume we'll get to that point eventually (time!), but not there yet.

Enjoy your car! Sounds like it is doing great. Just a little harder to make it between long Supercharger gaps (in some cases impossible).
So, my 04/2019 LR Dual Motor with 80k kms is now at 82% capacity, at first I thought it was a calibration error but this was a road trip without stopping confirming the BMS calibration. Usually I can make this run with 10-15% remaining on arrival.

Service gives me this is normal fleet degradation and I don’t buy it.

Charge daily at home overnight to 80% and run it down to 50-60%

Only charge to 100% when immediately leaving on a road trip.

Supercharging very rarely.
 

Attachments

  • A487D5B7-F27A-42E3-A044-A87AEDA99A2E.jpeg
    A487D5B7-F27A-42E3-A044-A87AEDA99A2E.jpeg
    326.3 KB · Views: 32
  • Like
Reactions: modlyowner

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
11,932
15,459
San Diego
So, my 04/2019 LR Dual Motor with 80k kms is now at 82% capacity, at first I thought it was a calibration error but this was a road trip without stopping confirming the BMS calibration. Usually I can make this run with 10-15% remaining on arrival.

Service gives me this is normal fleet degradation and I don’t buy it.

Charge daily at home overnight to 80% and run it down to 50-60%

Only charge to 100% when immediately leaving on a road trip.

Supercharging very rarely.
Seems fine. Hard to tell from what you posted what your actual capacity is, but it is worst case, assuming you started at 100% and drove continuously, without stopping even briefly, to 1%:

384km*160Wh/km/0.99/0.955/78kWh = 83.3%, 65kWh. 427 rated km at 100%.

So 17% capacity loss worst case. Below average but hard to tell from your data whether that is what it is.
 
Last edited:
  • Like
Reactions: WhiteWi
Seems fine. Hard to tell from what you posted what your actual capacity is, but it is worst case, assuming you started at 100% and drove continuously, without stopping even briefly, to 1%:

384km*160Wh/km/0.99/0.955/78kWh = 83.3%, 65kWh. 427 rated km at 100%.

So 17% capacity loss worst case. Below average but hard to tell from your data whether that is what it is.
Yea this is close to my quick calc and the BMS calc currently is 417. I hate to say but this is drastically worse than my expectations. I was hoping that after this run the BMS would recalculate and revive missing capacity but no luck 😭.
 
  • Like
Reactions: modlyowner

AAKEE

Member
Jan 8, 2021
836
1,125
Sweden
So, my 04/2019 LR Dual Motor with 80k kms is now at 82% capacity, at first I thought it was a calibration error but this was a road trip without stopping confirming the BMS calibration. Usually I can make this run with 10-15% remaining on arrival.

Three years with a battery regularly charged to 80% that stands with 80% during the nights will cause quite some degradation from calendar aging.

Vancouver climate? Hot cold?

If the climate is average the calendar aging probably would cause 10-12% degradation during this time even if the car was not driven at all. Add a half to one percent degradation each year for the cycles/driving and you probably have a average nulber of degradation.

I did not read the whole thread, if you did do a BMS calibration or a full discharge run you might find the ”true” residual capacity of the battery.
 
... the battery should retain 90% of capacity by 200k miles (Tesla: Battery Capacity Retention Averages 90% After 200,000 Miles). This is obviously very different than what I have been told by Tesla support and the common knowledge on this board.
I've never heard that a battery should retain 90% of capacity over 200,000 miles! And "should retain 90%" is not the same as "retention averages 90%". You know, you're not going to get anyone all excited about you being in the lower part of that "average", as it is normal. I tell people that it is common for a battery to lose five percent of capacity the first year and one percent each year thereafter, but "common", again, is not any guarantee of anything. Batteries degrade over TIME, not mileage, so I would think that my battery would still hold 90% of capacity if I ran 200,000 miles in one year, but NOT if I ran 200,000 miles in TEN years.

If you bought your car knowing that you absolutely had to have 200 miles of range MINIMUM, the fault is yours, because it is widely understood that batteries lose range over time.
 
Last edited:

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


SUPPORT TMC
Top