I’ve got the Tessie app and I’ve been looking at my degradation. It’s showing 8.4%, with 72.1kwh usable. This seems correct as I drained the car down to 8% and charged up to 100% (specifically to check the math) and it only took 66kw. I’ve got 1200 miles on the car. Am I going nuts and overreacting on what might just be the BMS not having enough data points? I’m going to be quite disappointed if I actually am at 8.4% on a new car
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New M3 Performance 8.4% degradation?
- Thread starter Steven Matsko
- Start date
How old is the car? Whbat date is the manufacturing date set to?
If it is new, like not more than a few months, you probably have not lost that much. It is probably a BMS calibration issue. Give the car some time to measure the battery capacity.
If the car has been driven little but has a year or so of life it is very possible that the capacity has dropped considerably due to calendar aging, specially if the car has been standing with high SOC like 80-90% in a varm environment.
If it is new, like not more than a few months, you probably have not lost that much. It is probably a BMS calibration issue. Give the car some time to measure the battery capacity.
If the car has been driven little but has a year or so of life it is very possible that the capacity has dropped considerably due to calendar aging, specially if the car has been standing with high SOC like 80-90% in a varm environment.
Tom_JS
Member
Well, I wouldn’t panic… yet. I have a M3LR with about 10,000 miles over 10 months and I’m at about 2.5% degraded so I’d keep an eye on it and remember, you have 120,000 mile warrantee on that battery. So if worse comes to worse it will be replaced free of charge.
zef3215
Member
My 2021 M3LR delivered in December 2020 with LG battery showed 2,5% degradation after first summer and about 20.000Km. Next year, it went to 2,7% and is there since with 55.000km on the odometer. The car reports 515-520km of full range while new it was reporting 534Km. I hardly fast charge, go over 90% or stay below 10% for long amount of time. So far, I’m impressed and that 15-20Km of lost range is not noticeable in real life.
Most 82kWh batteries start at 80-81 kWh in the M3P. Some less than that.
The easiest way to check is to refer to the displayed range at 100% charge (at the battery icon).
If the car hasnt been standing for a long time waiting for you to buy it, you should not have that amount of degradation.
If you always have sentry mode active, the car do never sleep. Sleep is needed to measure the battery capacity thoroughly.
You could make sure to
Charge up and leave the car with 80/90/100% for a couple of hours ( lets make that three hours) with sentry mode off, and than get it to low SOC, like 5-10% or so, and let it sleep 3 hours there as well.
After this charge to 70-90% and let it sleep. Theres a good chance that you will see higher range / lower ”degradation” after this.
To keep the degradation low, there is some really good tricks that can be done.
If you like to read about it, search here on TMC for calendar aging and my nick @AAKEE.
AlanSubie4Life
Efficiency Obsessed Member
We’ve seen a few examples of some new cars that have low rated range. Some of them have recovered, some have been somewhat on the low side consistently (though somewhat recovered).
If I bought a new car I would always check the projected range before taking delivery and reject anything out of hand that doesn’t look right. Even if it is “just” a BMS issue I wouldn’t want to deal with the hassle and concern. Easy enough to do the basic checks before delivery if they have a reasonable SOC at delivery.
Anyway let us know how it turns out after a few cycles per advice above.
I assume you are at about 295 miles at 100%, instead of the 315 you should have.
Was the 66kWh measured by the Tessie app (this initially confused me and I had to delete a lot of stuff from my post)? Hopefully it was not what was displayed on the vehicle screen for a 92% charge addition. (That would imply a lower usable capacity than 72kWh.)
That’s pretty bad and hopefully it will recover. I would describe it as abnormal, but unlikely to indicate any issue with your battery (other than it potentially being limited in capacity). But time will tell!
It’s entirely possible it will just be something you have to live with, though it may be that subsequently you see slower capacity loss than most. Maybe they put an old unused pack in your car.
Could also be totally a BMS issue. I don’t think it is possible to rule either one out except through the passage of time and maybe some investigation.
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Sorry for the confusion, I probably should’ve added a bit more context. Tessie measured my capacity at 72.1 kwh which it claims a new pack should be around 78.8. The 66kw is what I was able to add to my pack by charging from 8% to 100% which if extrapolated out comes out to roughly 71.7kwh for a 100% charge. I’m really banking on it being the bms cause otherwise I’ll be getting shafted once it actually begins to do the standard degradation on top of what I already may or may not have
AlanSubie4Life
Efficiency Obsessed Member
Third-party tools only have numbers to work with so they can be confusing.
82.1kWh is the nameplate rating for that pack but it is not achieved. 95.5% of this is 78.4kWh usable which I assume is what Tessie is reporting (78.8kWh - no idea what that is).
Where do you see the 66kWh reported? On the charging screen in the car? Or in an app somewhere.
Anyway your pack to display 315 rated miles must have over 80.6kWh. (Due to rounding can be a little less of course.) That is the key starting point. That is 77kWh usable and where you (should have) started.
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The 66kw is what I was able to put into the battery pack when charging from 8% to 100%. As far as display miles, I’ll have to get back on that as I always leave it in % mode and I have the car set for 18 wheels since I installed some(I’ll change it back to 20 to see what I’ll get on the miles reading). I’ll update my findings as time goes on. Here’s a screenshot of Tessie too
Attachments
Made an error. I conflated the 78.8 number as factory when that appears to be my actual max of the pack vs factory 82.1. Still, 72.1 usable
Gauss Guzzler
Safety Score = 42
The car estimates battery degradation on its own, and obviously Tessie doesn't have any information or insight that the car doesn't. So if you want to know today's BMS estimate of battery capacity just charge to 100% and compare the available range to the rated range. For a new 3P that should be around 307-315 miles, possibly less if you've done something to the tires or aerodynamics.
And if you really want the best possible estimate of degradation, do that 8%-100% thing again but this time using the built-in degradation analysis available within service mode.
And if you really want the best possible estimate of degradation, do that 8%-100% thing again but this time using the built-in degradation analysis available within service mode.
AlanSubie4Life
Efficiency Obsessed Member
Yes, this is what the OP should do. It's easiest. Tesla keeps it super simple and doesn't hide anything. It should be 315 miles, no less, for a new P.
And it will NOT be affected by tire selection or aerodynamics.
315 miles indicates a capacity of at least ~80.6kWh. That value includes the buffer, so translates to usable capacity of 95.5% of that, which is 77kWh.
This stuff is very deterministic. The only thing that is not deterministic is the BMS estimate, which is the very best estimate in the world of your pack's capacity. This estimate is reflected in the rated range at 100%, which should be compared to 315 rated miles in the case of this Model 3 Performance.
I can confidently say that their data is completely wrong.
I honestly can't make sense of any of their numbers. I can't make anything fit with what we concretely know to be exactly correct about this pack.
78.8kWh - your current pack capacity? Or what they think you started with (which would definitely be wrong as discussed)?
72.1kWh -> your "usable"
91.6% of the original
307 rated miles
78.8kWh your pack capacity? (As discussed this is not where your pack started, so that interpretation would be wrong.)
307 rated miles => 307/315 * 80.6kWh = 78.5kWh (2.5% loss, could be completely reasonable)
91.6% of the original would be 0.916*80.6kWh = 73.8kWh. Where did 91.6% come from?
72.1kWh "usable" => 72.1kWh/0.955 = 75.5kWh. WTF?
So literally nothing makes sense. I'd check to make sure Tessie is configured correctly and knows which vehicle you have. And again, the most useful thing is just to extrapolate your 100% charge value (or charge to 100% and see what it is).
Again, the usable is always 95.5% of the full pack capacity. That is rock solid true for any Model 3 except the LFPs. It's just always the case.
It's probably possible to translate the incorrect Tessie numbers though a mapping function, once you understand how they are reporting it incorrectly, going forward. Good times!
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I have never understood how the programmers behind tessie thinks.
I have seen many examples of strange numbers and very confused owners.
”Usable” in Tessie language seems to include the buffer.
78.8 kWh is the Nominal Full Pack of the bigger LG pack put in cars built in China and Germany. Not applicable in this case.
(78.8 is also my M3P’s Nonimal full pack
)
AlanSubie4Life
Efficiency Obsessed Member
Doing your best to stay right on that capacity loss curve!(78.8 is also my M3P’s Nonimal full pack
Actually its a balanced action!
Doing what is possible without affecting the ownership negative or making it awkward to be an EV owner.
Still charge full more often than many others do (some 30+ of full charges)
Still Supercharhing whenever needed (17-18% is Supercharging for me)
We did get som info today in the Tessie Vendors thread: Vendor - Official Tessie app talk
The usable capacity number is measured in a way that it includes the buffer, so it is total current capacity accordning to Tessie.
In the @Steven Matsko case, its on the low side but we all hold our thumbs for this value to creep up.
Thats the blue capacity number in the meter.
The usable capacity number is measured in a way that it includes the buffer, so it is total current capacity accordning to Tessie.
In the @Steven Matsko case, its on the low side but we all hold our thumbs for this value to creep up.
Thanks for the update @AAKEE. Tomorrow I’ll be able to do a charge from close to 0 up to 100 and we’ll see how it response to having more info on the lower end for the bms. If I still see no difference I’ll have to just update my findings in a couple months once I’ve got more miles on it. I do appreciate everyone’s insights and reply’s
Quick update. Charged to full (99%, wouldn’t go higher), Tesla showed 315 on the range indicator. With the additional data Tessie now shows 3.1% degradation. Tessie tells me that 77.5 kWh were added from 4-99%. I think all is well! Might have been a combination of lack of low end and high end bms data as well as lack of overall data for Tessie. Cheers!
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