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V10 and Battery "Degradation"

Thunder7ga

Member
May 20, 2018
325
279
Johns Creek, GA
Over the last few months, I had been one of those that saw a large decline in reported battery health/degradation. I had even contacted Tesla where they said they looked at my battery remotely and saw no issues, but also said they have a known bug in how the car calculates range. My car is a supercommuter car, so it uses between 50-60% of its battery every workday and at the low point it was reporting its 100% range at around 295 (with a spike to 290) as recently as 10/6.

As the below chart shows, since I got v10 on 9/29, the reported range has been heading back to about where I was expecting it since I got v10.

FusionCharts.jpg
 
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ewoodrick

Well-Known Member
Apr 13, 2018
5,285
3,732
Buford, GA
You are looking at an estimated number. Also, if you were to read any of the many threads on this exact same subject, you'll see that Tesla is correct.
Just look at the big changes. I bet they correspond to software updates
 

KenC

Active Member
Sep 4, 2018
3,609
3,280
Maine
Over the last few months, I had been one of those that saw a large decline in reported battery health/degradation. I had even contacted Tesla where they said they looked at my battery remotely and saw no issues, but also said they have a known bug in how the car calculates range. My car is a supercommuter car, so it uses between 50-60% of its battery every workday and at the low point it was reporting its 100% range at around 295 (with a spike to 290) as recently as 10/6.

As the below chart shows, since I got v10 on 9/29, the reported range has been heading back to about where I was expecting it since I got v10.

View attachment 465196
Look how rock-steady your estimate was until 22k miles! Then the blip up when the 325 mile range was released, which precipitated the long slow decline into the 290s. Wondering if the BMS estimate was just wandering/drifting, slowly getting more and more wrong, until the V10 release, forced a recalibration, and it relatively quickly is finding its way back to 310.

I'm assuming you exported your csv data from somewhere and put it into a spreadsheet? Doesn't look like one of the 3rd-party apps.
 

earthwormjim

Member
Jun 25, 2019
165
167
California
Well this seems encouraging for me, especially that I'm not alone with this sudden drop. My SR+ had been showing a 220 mile range maximum right around when I updated to V10.

I opened a ticket and got the typical insulting canned response, stating I probably have my maximum charge set to 90%...

Online chat was slightly more helpful, they remote diagnosed the car supposedly, saying nothing was wrong but suggested "re-calibrating" the battery charge controller.

I tried the whole re-calibration procedure, charging to 100% and discharging to sub 20%, seems to slowly be recovering some range. Now the car charges to 224 miles. Online chat suggested doing this 3 times back to back, so we'll see how it goes.
 

Watts_Up

Active Member
Mar 4, 2019
3,442
2,343
In a galaxy far, far away
I assume that the mileage reported on this graph is the "Estimated Range" that the car displays after charging?

The various irregular pics show clearly that the calculation estimate get affected by software updates, otherwise you should get a smother variation.

It would be more realistic to charge the car to 100%, drive at constant speed until you get 10% and measure the distance and the power usage.

This is the methodology recommended by Bjørn Nyland

I don't have often the occasion to drive from 100% to 10%, so I personally measure, with a Watmeter,
how much energy is needed to recharge from 10% to 100%.

Of course some of the energy is lost to convert the 240V AC to 400 V DC, but the losses
can be estimated by comparing the provided energy with the energy used by the car to go from 100% to 10%.

Also, the losses are proportional to the energy needed to charge the car.

Doing so, I think that I get a more realistic value of the battery degradation by measuring the actual battery capacity changes.
 
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earthwormjim

Member
Jun 25, 2019
165
167
California
My SR+ is displaying SR- range, exactly 220 miles after V10 update, which does work out to about 5kwh loss in battery capacity.

Tesla support suggested doing the whole battery reset thing, charge too 100%, discharge to 10%, 3 times.

I'm on round 2 (currently charging), round one seems to have increased my range to 224 miles.
 

glide

Active Member
Jun 6, 2018
3,290
3,393
USA
My SR+ is displaying SR- range, exactly 220 miles after V10 update, which does work out to about 5kwh loss in battery capacity.

Tesla support suggested doing the whole battery reset thing, charge too 100%, discharge to 10%, 3 times.

I'm on round 2 (currently charging), round one seems to have increased my range to 224 miles.

The displayed range does not reflect whether you are being subjected to Tesla’s voltage limitation. Watch the whole video.

The entire fleet is impacted by this and all cars will eventually experience a significant range loss of Tesla isn’t held to account for this.
 

CDN-Build

Member
Aug 15, 2018
65
40
Cambridge
I’ve seen the video. I love this guy. His videos are usually pretty informative.

but; Before we see 300 posts stating we should all unite and sue Tesla, it’s best to first educate ourselves right.
Assuming this is accurate information, Tesla would likely only be doing this to protect the batteries. They sure wouldn’t do it to hurt the batteries.
At worst, we have slightly less range by a few percent to protect our batteries.

not saying it’s an ideal scenario if accurate, but if it is, which would you prefer, more Battery degradation over time, or a few percent less range. ?

many here only charge to 80% to protect the battery already. So charge to 82%. :)
On the trips that you need 100%, it’s a rare case that that small percentage loss will be a deal breaker.

just my thoughts.
 
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,001
12,052
San Diego
So now we have 70kW packs for those with LR versions.

My pack has 70.4kWh for discharge, per the trip meter, and 75kWh for charging, per the charging screen. (306rmi * 230Wh/rmi, or 245Wh/rmi.) These numbers are extrapolated, but over a range of state of charge from 21 miles to 306 miles.

The most I've ever seen is 310rmi * 230Wh/rmi = 71.3kWh (or 76kWh for a charging event). So not much change. Not sure why people are so fired up about this video - they really need to dig up the prior video showing the 240Wh/rmi (150Wh/rkm) constant from Bjorn that he claims he measured (too lazy to do it myself).
 

nightfly

Member
Apr 1, 2016
90
30
San Diego, CA
There's precedent for a class action. See Hyundai class action lawsuit where they advertised a certain MPG but cars got no way near that. So given the fact that Tesla uses software updates to significantly impact the primary feature of their auto mobiles - range - they are likely looking at a doozy of a lawsuit regardless if some individuals care or not or are/aren't impacted.

If you ever plan on selling your M3 - this will reduce its value.

~6% hit to range along with expected degradation of ~5% nominal...not good.

I’ve seen the video. I love this guy. His videos are usually pretty informative.

but; Before we see 300 posts stating we should all unite and sue Tesla, it’s best to first educate ourselves right.
Assuming this is accurate information, Tesla would likely only be doing this to protect the batteries. They sure wouldn’t do it to hurt the batteries.
At worst, we have slightly less range by a few percent to protect our batteries.

not saying it’s an ideal scenario if accurate, but if it is, which would you prefer, more Battery degradation over time, or a few percent less range. ?

many here only charge to 80% to protect the battery already. So charge to 82%. :)
On the trips that you need 100%, it’s a rare case that that small percentage loss will be a deal breaker.

just my thoughts.
 
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earthwormjim

Member
Jun 25, 2019
165
167
California
The displayed range does not reflect whether you are being subjected to Tesla’s voltage limitation. Watch the whole video.

The entire fleet is impacted by this and all cars will eventually experience a significant range loss of Tesla isn’t held to account for this.

Correct, however my actual real world usage does. 100% to 10% displayed battery usage showed ~40kwh of used consumption. The SR+ has a 53.5kwh battery, and roughly 50kwh or so are supposed to be usable. Based on my energy consumption and battery %, I only have 44-45kwh of usable battery capacity.
 
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,001
12,052
San Diego
Correct, however my actual real world usage does. 100% to 10% displayed battery usage showed ~40kwh of used consumption. The SR+ has a 53kwh battery, and roughly 50kwh are supposed to be usable. Based on my energy consumption and battery %, i only have 44-45kwh of usable battery capacity.

Was that a single uninterrupted (no stops allowed) trip, with % taken immediately after placing car in Park at the end? Your rated miles of 220 rmi should give you:

209Wh/rmi * 220rmi = 46kWh (discharging, trip meter)

219Wh/rmi * 220rmi = 48.2kWh (charging, charging info page while still plugged in, with charge session stopped)

And your trip of 90% usage should have shown 220*0.9*209Wh/rmi = 41.4kWh (But note that using % exposes you to potentially significant rounding error.)

224rmi would be 46.8kWh/49kWh.

240rmi would be 50.2kWh/52.6kWh
 
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earthwormjim

Member
Jun 25, 2019
165
167
California
Was that a single uninterrupted (no stops allowed) trip, with % taken immediately after placing car in Park at the end? Your rated miles of 220 rmi should give you:

209Wh/rmi * 220rmi = 46kWh (discharging, trip meter)

219Wh/rmi * 220rmi = 48.2kWh (charging, charging info page while still plugged in, with charge session stopped)

And your trip of 90% usage should have shown 220*0.9*209Wh/rmi = 41.4kWh

224rmi would be 46.8kWh/49kWh.

240rmi would be 50.2kWh/52.6kWh

Car was stopped for about 30 min half way through, that hardly seems relevant though. The car isn't going to magically consume the missing 5kwh of battery capacity sitting off for 30 minutes. I don't know why you're throwing in wh/mi when I clarified actual displayed battery %.

100% of battery capacity to 10%, as in that is the exact % displaying on the car's display, not range/240 or range/220, yielded ~40kwh in the displayed consumption on the car. Car was driven about 190 miles total, so wh/mi was lower than my usual daily commute of 210wh/mi. I did not look at charging power consumption.

Even if you round up or down a whole percentage point, you're not going to reveal the missing 5kwh.
 
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AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,001
12,052
San Diego
I don't know why you're throwing in wh/mi.

I didn't, I threw in the constant of 209Wh/rmi (or 219Wh/rmi for the charging event on the SR/SR+). Nowhere above is Wh/mi mentioned. ;)

90% of battery capacity to 10%, as in that is the exact % displaying on the car's display, not range/240 or range/220, yielded ~40kwh in the displayed consumption on the car.

Yeah, there could be some small rounding error. Likely was from 100%, but could have been to 10.49%. (0.3kWh error)

Obviously, you do have battery capacity loss (at least temporary) - of at least 16/240 = 6.7%. (3.3kWh discharge/3.5kWh charging)

Just was curious about the exact conditions. The 30 minutes could have resulted in an additional uncounted 0.2kWh of error, depending on the conditions. And you said ~40kWh (could easily have been higher - have to multiply miles traveled by Wh/mi, not read off the kWh displayed since last charge, due to rounding error). We are looking for a 41.4kWh number for 90% of the capacity, so ~40kWh + 0.5kWh ~= 41.4kWh. It all seems conceivable.

Next big charging event, make a note of the charging kWh and the miles added. You have to stop the session from the screen, note the miles (or kWh) added, then change the Display to % (or Miles), and then note the kWh (or miles) added. I don't think you can unplug the car until after you gather that data otherwise it disappears.

It should be a ratio of 219Wh/rmi for charging AFAIK.
 
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earthwormjim

Member
Jun 25, 2019
165
167
California
I didn't, I threw in the constant of 209Wh/rmi (or 219Wh/rmi for the charging event on the SR/SR+). Nowhere above is Wh/mi mentioned. ;)



Yeah, there could be some small rounding error. Likely was from 100%, but could have been to 10.49%. (0.3kWh error)

Obviously, you do have battery capacity loss (at least temporary) - of at least 16/240 = 6.7%. (3.3kWh discharge/3.5kWh charging)

Just was curious about the exact conditions. The 30 minutes could have resulted in an additional uncounted 0.2kWh of error, depending on the conditions. And you said ~40kWh (could easily have been higher - have to multiply miles traveled by Wh/mi, not read off the kWh displayed since last charge, due to rounding error. We are looking for a 41.4kWh number, so ~40kWh + 0.5kWh ~= 41.4kWh. It all seems conceivable.

Next big charging event, make a note of the charging kWh and the miles added. You have to stop the session from the screen, note the miles (or kWh) added, then change the Display to % (or Miles), and then note the kWh (or miles) added. I don't think you can unplug the car until after you gather that data otherwise it disappears.

It should be a ratio of 219Wh/rmi for charging AFAIK.

Had a power interrupt today, so I won't have a complete picture...

Yeah, I'm not expecting to get exactly 50kwh, or find exactly 5kwh of missing capacity or even that it is 5kwh I'm missing, but a significant amount is missing, something between 5-10%. 10% is what separates the SR from the SR+, so I'm not exactly happy here that I have a seemingly partially crippled SR+. Those extra miles were part of why I paid the difference in price, there are a couple drives a year, where those extra miles make the drive possible without needing to charge.

But, we'll see if charging then discharging works out. So far it seems to have netted me some increased range.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
10,001
12,052
San Diego
Yeah, I'm not expecting to get exactly 50kwh, or find exactly 5kwh of missing capacity or even that it is 5kwh I'm missing, but a significant amount is missing, something between 5-10%. 10% is what separates the SR from the SR+, so I'm not exactly happy here that I have a seemingly partially crippled SR+. Those extra miles were part of why I paid the difference in price, there are a couple drives a year, where those extra miles make the drive possible without needing to charge.

For sure. It's a significant loss - I was really more interested in the precise numbers, to be able to double check the constants. Hopefully it is temporary. Sounds like there are a lot of SR/SR+ owners affected in the same way. And LR to be honest.
 

CDN-Build

Member
Aug 15, 2018
65
40
Cambridge
There's precedent for a class action. See Hyundai class action lawsuit where they advertised a certain MPG but cars got no way near that. So given the fact that Tesla uses software updates to significantly impact the primary feature of their auto mobiles - range - they are likely looking at a doozy of a lawsuit regardless if some individuals care or not or are/aren't impacted.

If you ever plan on selling your M3 - this will reduce its value.

~6% hit to range along with expected degradation of ~5% nominal...not good.

And there it is. :)
No facts yet. One YouTube video, not even thoroughly educated on the facts yet, and boom. Class action law suit. Lol
 

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