Battery degradation, real or imagined?

littlD

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#41
I've shared this a number of times just to illustrate how much the estimated range can vary, 307 after 31,000+ miles is where I am at the moment, at 285 I did my first 20% - 100% - 20% - 100% BMS recalibration. I do one every 3 months now.

screenshot-49-png.26895
 

Bigriver

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#42
In all this, I understand the estimated remaining range is just that...estimated. However, if I continually drive at an efficiency rate below the rated, I would estimate I should consume less range than I have traveled.
Exactly. I find this is not always the case and I am somewhat puzzled by this too. I’ve been gathering data for quite some time and maybe some time I’ll get a chance to assemble it and see if it makes any sense. The bottom line is that I can have a low Wh/mile on a drive and still use more rated miles than actual miles. And I’m referring to just the driving portion - rated miles and actual miles when I start and stop. One thing I do know is that there is not a single Wh/mile value that is the “break even” point when the change in rated miles is the actual miles driven. I’m anxious to look at my data to see if I can see any correlation to temperature, speed, or other parameters.
 

mswlogo

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#43
Exactly. I find this is not always the case and I am somewhat puzzled by this too. I’ve been gathering data for quite some time and maybe some time I’ll get a chance to assemble it and see if it makes any sense. The bottom line is that I can have a low Wh/mile on a drive and still use more rated miles than actual miles. And I’m referring to just the driving portion - rated miles and actual miles when I start and stop. One thing I do know is that there is not a single Wh/mile value that is the “break even” point when the change in rated miles is the actual miles driven. I’m anxious to look at my data to see if I can see any correlation to temperature, speed, or other parameters.
I never find that to be the case. The wh/mi is calculated from the same “source” the range is calculated from. If I’m below 240 wh/mi my range drops slower than the miles driven. This is only while driving. It can drop outside of driving for many reasons that I try to minimize.
 

Scubastevo80

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#44
Following along. I’ve tried 4 times (before heading out on road trips) to charge my AWD to 100%, but have never hit 310. 304 initially, 300 last. My daily commute is 150 miles. I charge to 90% daily, and repeat with scheduled charging starting at 8PM. Charge finishes around 2/3AM and I’m back on the road at 4:15AM. What’s odd, is my starting range at 90% is now down to 266mi today (vs 279). Compounding my concern is the the efficiency vs use. Rated efficiency is 240w/mi, right? So assuming my commute was exactly 240w/mi, the 150 mile commute should put remaining range at 116mi (266-150)? Well, even though my efficiency was 237, I’ve only got 94 miles of range left. I’m trying to figure this out but struggling.
I'll have to try the 20%-100%-20% method suggested by another member on here. I'm just over 9k miles and also charge to 90% about 2x a week (run the car down to anywhere between 40-90 miles usually) and was getting about 278-9 at that number. After the recent software updates and the last two charges, I've been getting 270 miles. I also looked at the Stats app and my battery health indicator showed 308-309 which has suddendly dropped off to 298-300. This is odd to me given my wh/mi has gone down significantly now that the weather is warmer here.

I wonder if the article below that said Model S owners with the 85 kw battery are noticing range drop was a bit early as this could be impacting Model 3's as well. My wife's S 85D hasn't had any range drop, but my 3 certainly has.
https://electrek.co/2019/06/20/tesla-battery-range-drop-software-update-longevity/
 

MelindaV

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#45
I'll have to try the 20%-100%-20% method suggested by another member on here. I'm just over 9k miles and also charge to 90% about 2x a week (run the car down to anywhere between 40-90 miles usually) and was getting about 278-9 at that number. After the recent software updates and the last two charges, I've been getting 270 miles. I also looked at the Stats app and my battery health indicator showed 308-309 which has suddendly dropped off to 298-300. This is odd to me given my wh/mi has gone down significantly now that the weather is warmer here.

I wonder if the article below that said Model S owners with the 85 kw battery are noticing range drop was a bit early as this could be impacting Model 3's as well. My wife's S 85D hasn't had any range drop, but my 3 certainly has.
https://electrek.co/2019/06/20/tesla-battery-range-drop-software-update-longevity/
I tried the 5%-100% charge cycle 3 times in a row without any change. For mine, the range took a drop with 2019.8.5 (or 2019.12.1.1 - they were both installed within a charge of each other).
for the 7000 miles prior to 2019.8.5, I regularly was at 306-309. When charging from a low charge rate to 100%, the percentage and kWh added equated out to the battery at 100% being 73kWh. When looking at a similar charge from prior to 2019.8.5, the kWh added equated to just over 75kWh. the 2kWh difference is essentially the drop in max rated range I am seeing.
screen-shot-2019-06-19-at-6-08-17-am-png.27037
 

garsh

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#46
I tried the 5%-100% charge cycle 3 times in a row without any change. For mine, the range took a drop with 2019.8.5 (or 2019.12.1.1 - they were both installed within a charge of each other).
for the 7000 miles prior to 2019.8.5, I regularly was at 306-309. When charging from a low charge rate to 100%, the percentage and kWh added equated out to the battery at 100% being 73kWh. When looking at a similar charge from prior to 2019.8.5, the kWh added equated to just over 75kWh. the 2kWh difference is essentially the drop in max rated range I am seeing.
View attachment 27037
I wonder if you are the recipient of an earlier version of the "battery protecting" changes that early Model S owners are now reporting.

Tesla owners see battery range drop after software update to ‘improve longevity’
 

MelindaV

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#47

garsh

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#48
IDK, there are enough 3s that had a similar drop around 12.1.x as mine, there was something in the FW that impacted some/many similarly.
I'm wondering if Tesla made some update to the firmware to help "protect" what they deem to be "at-risk" packs, by scaling back how high they'll charge them.

If that is the case, I still wouldn't be happy with the resulting max range decrease, but it would make me feel a lot better than thinking that my battery has suddenly undergone a severe degradation.
 

MelindaV

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#49
ironic thing for mine, which is totally coincidental, is on the chart I posted a few posts up, the point where the sudden drop happened was following the charge I had while at a hotel in seattle. Plugged in that night and the max range was still set to 95% from the charge prior to leaving. So when we got to the room, from the app, I moved the change limit down to 85%, and while at breakfast before leaving, bumped it back up to 95%. when my traveling companion asked, I said you don't want the battery sitting idle near 100%.
I will forever know my battery range dipped when the Cubs came to town.
 

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#51
For those doing charges from low percentages to 90% or higher to try and reclaim range, Tesla service told me that it is important to let the car sit idle for an hour or two before charging and after charging has completed, because it is only after those idle times that the BMS takes new sensor readings. I do not know exactly how long it has to be idle, I don't know if it can be plugged in (but I'd really hope so), just that driving and then immediately starting to charge, or driving immediately after completing a charge will not let the BMS update it's knowledge about the battery.

Anyway, I don't know if that's true, or if service was just giving me homework so I'd cancel my appointment and try charging in their recommended way for a month before making another appointment.

Their instructions were: drive to below 40% charge, let the car sit idle, charge to 90%, let the car sit idle. Repeat.

My current estimated 100% charge is 262 miles, and a 90% charge is 237. I've lost 2 miles of range since starting this procedure.
 

MelindaV

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#52
For those doing charges from low percentages to 90% or higher to try and reclaim range, Tesla service told me that it is important to let the car sit idle for an hour or two before charging and after charging has completed, because it is only after those idle times that the BMS takes new sensor readings. I do not know exactly how long it has to be idle, I don't know if it can be plugged in (but I'd really hope so), just that driving and then immediately starting to charge, or driving immediately after completing a charge will not let the BMS update it's knowledge about the battery.

Anyway, I don't know if that's true, or if service was just giving me homework so I'd cancel my appointment and try charging in their recommended way for a month before making another appointment.

Their instructions were: drive to below 40% charge, let the car sit idle, charge to 90%, let the car sit idle. Repeat.

My current estimated 100% charge is 262 miles, and a 90% charge is 237. I've lost 2 miles of range since starting this procedure.
I wish there was some universal answer from them. My service guy said to plug it in and charge to 90%, and let it sit plugged in as long as possible - like a week ( :oops: yeah - they suggested it sit undriven for a week). For the last 2 weekends, I've been plugging it in friday night when I get home and not driving it over the weekend. Since starting this, it's also dropped another mile or two.
 

JML

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#53
I wish there was some universal answer from them. My service guy said to plug it in and charge to 90%, and let it sit plugged in as long as possible - like a week ( :oops: yeah - they suggested it sit undriven for a week). For the last 2 weekends, I've been plugging it in friday night when I get home and not driving it over the weekend. Since starting this, it's also dropped another mile or two.
Mine did sit undriven for over a week while I waited for the rear glass to get replaced. During that entire time it was plugged in, but set to 70% charge. During that time the a 100% charge went from 274 to 268 miles. So far this month I've been loosing more than 0.5 mile per day from my max charge. If it continues at this rate I have about 3 months until I'll trigger the 70% capacity retention warranty. I'm really curious if they'll try to get out of that by blaming it on a software bug.
 

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#54
I have been experimenting with the perceived degradation for some time now. I have been getting about 10% below rated range per charge, i.e getting about 255 miles actual driving from a 277 miles charge (I charge to 90%). The on board trip meters had consumption ranges from 230 Wh/mi - 266 Wh/mi, but the range loss was around 25- 27 miles.
After the 2019.20.1 upgrade (May be completely coincidental), i have started getting nearly close to the rated value.
newrange-jpg.27066



I got about 267 driven miles to a rated 275, i.e a loss of 8 miles or 3%.
I am doing some more measurements now and see if this is persistent.
Did anyone else notice similar improvements in the latest update?
 

Dr. J

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#55
I have been experimenting with the perceived degradation for some time now. I have been getting about 10% below rated range per charge, i.e getting about 255 miles actual driving from a 277 miles charge (I charge to 90%). The on board trip meters had consumption ranges from 230 Wh/mi - 266 Wh/mi, but the range loss was around 25- 27 miles.
After the 2019.20.1 upgrade (May be completely coincidental), i have started getting nearly close to the rated value.
View attachment 27066


I got about 267 driven miles to a rated 275, i.e a loss of 8 miles or 3%.
I am doing some more measurements now and see if this is persistent.
Did anyone else notice similar improvements in the latest update?
This doesn't sound like battery degradation and its reversal. It sounds more like higher consumption in colder weather, lower consumption in warmer weather. Is there a reason to believe otherwise?
 

ddatta

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#56
This doesn't sound like battery degradation and its reversal. It sounds more like higher consumption in colder weather, lower consumption in warmer weather. Is there a reason to believe otherwise?
Not really sure if it is warmer vs colder or the degradation was "percieved". The measurements I had given earlier were all on 50 degrees plus weather, in the past couple of months.
I still am trying to get a rationale for "phantom drain", when I do not have sentry mode, "keep climate control on" or any other features turned on by default, and keeping the speeds low so that the consumption is ~250 Wh/mi.
As i said, i'll run some more experiments to verify, but before this, i was unable to get close to the rated range, however carefully i drove.

In the winter, my efficiency was about 30% off the rated range, as expected with the heaters on.
 

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#57
My car had been charging to 294 to 295 at 100%. I made a mistake and let it charge to 100% and sit overnight. Normally I make sure it doesn’t sit at 100% for more than an hour. Anyway, it charged to 299. Three different discharge to below 20% and charge to 100% cycles had done nothing. So now I am only down by 11 miles.
 

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#58
Teslafi reports 325. The car says 313. Who do I trust? At this point I don’t think Teslafi.
 

MelindaV

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#59
Teslafi reports 325. The car says 313. Who do I trust? At this point I don’t think Teslafi.
are you looking at the Estimated range in Teslafi, vs the Rated range in the car? Teslafi lists both and in my case, they have always matched 100% of the time. (Teslafi is pulling the data from the API, not doing any calculations on their own.)
 

HCD3

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#60
are you looking at the Estimated range in Teslafi, vs the Rated range in the car? Teslafi lists both and in my case, they have always matched 100% of the time. (Teslafi is pulling the data from the API, not doing any calculations on their own.)
Thanks Mel no. The car at 80 %, which is what I charge to every day says 257 to 260. That plus 20 % comes out to 313 or thereabouts. Let me know if my math is not correct.