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Model 3 Performance Battery Degradation One Month (Story)
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Sounds like a software issue then since your extrapolated range was 292 before, right?
They have been testing the 3 for over a year. They know patterns for 1 month in, 2 months in... I don’t debate that they may be lacking 2+ year statistics on the exact battery. I don’t buy this guy’s story. Exactly what are his credentials? It seems silly not to use convenient nightly timed charging just because one is paranoid about degradation and wants to know exact end of charge SOC.
SunCharged
Member
292 before is correct. I’ll call Tesla in a little while and see what they think.
Dr. J
Active Member
Not to be argumentative, @ViviV, but wouldn't the EPA data (29kWh/100 mi, above in the @MP3Mike post) for the AWD imply an even higher usage for the P3D, i.e. significantly higher than the 256 Wh/mi in your scenario? Just trying to reconcile data that seems at odds. May not be relevant.
The AWD Model 3s use ~12% more power than the RWD Model 3. (And the 2018 RWD Model 3 is ~4% more efficient than the 2017 RWD Model 3.)
I appreciate your taking the time/effort to reach out to Tesla and find someone who knows something about this, and then relaying that info to forums like this (regardless of whether the person you talked to, who obviously felt he/she knew what they were talking about, did actually know what they were talking about - you did your best at least in trying to track down a person to help out with this!). That's time out of your day, no doubt, just to even get to a person in the organization that at least is supposed to know something about this subject. So, thanks for your efforts in this regard.
Sadly, it's my experience that you just don't know what/who to believe, even if they sincerely think they know what they're talking about, and even if they're directly employed by the company that should know what it's talking about. That's life, and therefore it's my opinion that it's good to adjust one's expectations and evaluations of such info based on this reality.
I'm more inclined to go with the Tesla documentation that instructs us to plug in every night, though I might try to charge to 80% now, instead of my typical 70-75%. One thing I noted, is when I did a 10-100% charge, and my range estimate popped up from 291 to 300, when I then reverted back to 70/75% SOC limit, my extrapolated range dropped back down to 292/293. Maybe the car/software just has problems in estimating range, even if based on a static rated range formula, when you charge to only 70-ish. It's all anecdotal, but I seem to see folks talking about charging to 80-90% who are still reporting near fully-spec'd range
TT97
Active Member
I was trying to find the sources but was not able to find so I am replying based on my memory. I believe the EPA measures Wh/mi (kWh/100 mi) based on electricity from the plug (AC) vs. the cars measuring Wh/mi based on battery usage (DC). There is a loss factor when charging (varies, but roughly 10%) - Based on 10% loss, the 290 Wh/mi from the EPA is really 261 Wh/mi at the battery (close enough to 256 for gov't work).
If anyone can confirm (or debunk), I would appreciate.
Dr. J
Active Member
Talkin' out my armpit here, so to speak, but I doubt that ramping the battery SOC way down then way up is actually affecting its range. More likely, it's allowing a more accurate estimate of true range. Also, we know from Mr Dahn that Li ion batteries like being mostly near the middle of the battery's SOC. Ergo, ramping the battery SOC way down then way up is not doing any good to *actual* range and may be (minutely, perhaps) causing harm to the battery's longevity. Is it worth it, to get a better estimate of range? (Not to me, but I have a RWD that I have yet to take on a road trip.) I'm aiming at 60% SOC on a daily basis, taking it up higher only if I find out I need it. I will do a 100% charge when I have to make it to Childress, TX (and again in Amarillo) on the way to Colorado, but not after Wichita Falls and Clayton, NM superchargers come online.
No, the 10-100% charge cycle isn't meant to actually affect range, I understand that. It's all about calibration of the range estimate that's displayed - as you say it's allowing a more accurate estimate of the true range of your car, and that's exactly why I did that cycle, once. That upped my estimated range from 291 to 300 flat, which at least partially validates that doing such a cycle might bring the BMS back into a more accurate calibration. However, after doing that cycle, a week later my car has drifted back down to around 291-293 extrapolated total range, after resuming my regular habit of daily charging to 70-75%.
And so, especially when you consider that apparently my RWD "secretly" really has a rated range of 330-ish (see, e.g., all that talk of the EPA range being in the low 330's for RWD, but Tesla purposely used a lower 310 number), an estimated range in the low 290's starts to look a little alarming, approaching 10% off that EPA "secret" range number.
Overall, my concern is knowing if my battery is healthy or not, since, next to my house (and son), this is my largest financial outlay/investment (and it's not a lease, so I'm holding onto it for the long term, so battery problems are my problems; not the lessor's). That's why it's nice to have the thing calibrated so it is doing its best to give you an accurate *rated* range, at least every now and then. In the end, I'll just be watching things closely, and monitoring the displayed rated range, as the miles tick off (currently at slightly over 5,500). Current data points are just the start of a larger data set that will be used to track how my battery is doing as time goes on (and miles go by).
If I had a P3D+ or something, I'd probably not worry - low 290's would be A-OK. But my RWD version is not all that . . .
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Keep in mind that the EPA numbers are from the wall including charging losses. So not comparable to what you see in the car.
ViviV
Member
@FSKT I have a P3D+ and I am not OK with 290 for 100% in a new car.
I got the rated Wh/mi for my car as 256 from the energy graph. I altered my speed until I was able to get the average dotted line to be exactly superimposed on the solid rated line so the dotted line is not seen. I'd be curious what others are seeing for rated.
gzerninplatz
Member
Re not using shore power if charged up to set limit - that quote was about using SCHEDULED charging, which is used to avoid using power when it is expensive, so it makes sense that it would not use shore power at all until the scheduled time. Non-scheduled charging will use shore power as needed, when needed...
ghostbusta
Member
Mine is still at 246 at 80%, drive < 20 miles daily and plug in every night. Almost at 400 miles now, not too concerned for now, never charged to 100%.
This morning, after charging to exactly 75% (as I have done for the past several days, and driving about 35 miles per day), I was at 216 miles, which works out to 288 miles calculated full range (216 / .75 = 288). Just two days ago, it was at 293, and four or so days before that, it was up at 300.
Last time I got down to a calculated 291 range, I did the 10-100% charge cycle (well, not exactly 10%, I think I got it down to 15%, and based on my use/needs I just couldn't have it go lower without *really* going lower). After about 24 hrs from doing that cycle, my range popped to 300. And now it's drifted down again, past 291, down to 288. I do not have V9 software yet.
Conventional wisdom is that "displayed range = Rated Range" and is not adversely affected by driving habits, up/down kwh/mi numbers, *or* cold weather. So a displayed range of 288, and falling, starts to look odd when it's a number that should not *at all* be affected by temperature or how hard/soft I'm driving the vehicle (ave 254 wh/mi btw).
I'm not going to do another re-balancing at this stage (seems one shouldn't have to rebalance once every two weeks, after all). I want to do just how Low my car can Go, in terms of calculated full range, when I use the car in a manner that at least is supposed to be the best for the battery (70-75-ish%, daily charging). If it plummets into the 270's under this regime, then I'll go back to Tesla SC and complain.
Last time I got down to a calculated 291 range, I did the 10-100% charge cycle (well, not exactly 10%, I think I got it down to 15%, and based on my use/needs I just couldn't have it go lower without *really* going lower). After about 24 hrs from doing that cycle, my range popped to 300. And now it's drifted down again, past 291, down to 288. I do not have V9 software yet.
Conventional wisdom is that "displayed range = Rated Range" and is not adversely affected by driving habits, up/down kwh/mi numbers, *or* cold weather. So a displayed range of 288, and falling, starts to look odd when it's a number that should not *at all* be affected by temperature or how hard/soft I'm driving the vehicle (ave 254 wh/mi btw).
I'm not going to do another re-balancing at this stage (seems one shouldn't have to rebalance once every two weeks, after all). I want to do just how Low my car can Go, in terms of calculated full range, when I use the car in a manner that at least is supposed to be the best for the battery (70-75-ish%, daily charging). If it plummets into the 270's under this regime, then I'll go back to Tesla SC and complain.
Do you charge to 80% daily? Your approx 20 miles/day is not too far off from my 30-ish/day, and I have been charging mostly to 75%, and I'm down to a calculated range of 288. That's 30 miles less than where you are . . . .
You were doing well until you said “cold weather”. Battery capacity is lower in cold weather, and the rated miles displayed has always reflected that. A 100% charge in cold weather will show fewer miles of range than in warm weather. There has never been any dispute about this. Search the hundreds of posts on this topic over the years for details.
OK, thanks. I'm still trying to get a handle on this, and I've run across posts that say cold weather shouldn't affect rated range displayed, though obviously it affects actual range significantly. So, based on your reply I'll adjust my assessment of the CW to reflect that in cold weather the displayed rated range can be lower.
But . . . How cold are we talking? In my area, the highs have been around 75-85 for the past few months. Evening temps can dip down to the high 40's only very lately (as in 48, 49); otherwise lows have been mostly in the mid-50's to upper 60's over the life of my car.
In other words, this isn't exactly Fargo, ND weather here in Nor Cal. You can indeed find a million (literally I think a million) posts about folks in Minnesota, etc. where they're wondering why their range has dropped when it's 15 degrees outside, but those posts carry little relevance to my situation.
So bottom line then, how cold should it get before I can start attributing any part of my current 22 mile range reduction to temperature? If it goes from 85-75 degrees, is that at all meaningful in terms of range you should see displayed? Because that's exactly the temperature band my car has been in its entire life so far.
As a last data point, I did a 10-100% cycle to achieve only 291 miles full range, I did that cycling when my days averaged highs in the low 80's, and yet Tesla Dublin said that my 310-291 drop probably was all due to temperature decrease.
Does this sound right to you?
PS - I see in some searches of cold-related range issues, that S's and X's will actually tell you that the cold is affecting range, and will even tell you how much. I also understand Model 3's will show a little blue snowflake next to the range when the car senses that temperature is affecting range. I have never seen the blue snowflake on my display. Ever.
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