Wiki Sudden Loss Of Range With 2019.16.x Software

[AdamInFlag]

Hi everyone,

I've been a longtime silent lurker, but this topic certainly has grabbed my attention a lot and so I decided to make a lengthy post in the German Tesla forum (tff-forum.de) a few days back. It was well recieved and several members suggested I also post my findings here, which is what I'm going to do now.

Short background about myself: I have a MSc in chemistry with focus on functional materials and while my research topic right now is not about batteries, I regularly read research about Li-ion technology and consider myself to beat least somewhat knowledgeable in the topic. I also tinker with some applications for 18650 cells as a hobby and regularly read some discussions in the Second Life Storage forum where members are making stationary solar storage and similar things from discarded laptop and tool batteries. Whether this makes sense or is safe might be worthy of discussion, however you cannot deny that the members have collected a lot of knowledge about failure modes of 18650 batteries over the years.

Anyway, all the talk about Li plating and dendrite formation reminded me about a well-known problem in that community. A few years back, many members started to notice that older Sanyo 18650 cells often start to heat up upon charging. The cell looks fine at first glance (normal voltage, low internal resistance, reasonable capacity) and starts the charging process normally. However, once the charge voltage reaches around 4.0V, the cell begins heating up, often leading to dangerously hot temperatures of 80°C or higher. The reason is a parasitic internal current that soon exceeds the charging current making a full charge impossible. At first, only Sanyo UR18650A cells seemed to be affected, however by now examples are known from nearly all older Sanyo cell types as well as some Panasonic, Sony and LG batteries. All reasoning about the underlying causes was speculation until one member who investigated the problem on his job posted one very interesting contribution: Red Sanyo 18650 Cells Getting Hot While Charging - Page 10
Short summary: If charging conditions deviate a little bit from the norm (temperature too high, too much time spent at high SoC), micro-dendrites form between cathode and anode, leading to an internal short-circut. This is the exact failure mode of Li plating. The effect usually vanishes after cooling down and the cells stabilize between 3.95 and 4.05V. It might even disappear completely for a few cycles, but eventually always comes back. Also, the onset is relatively independent from age (both temporal and cycling) and can occur as early as after one year. The effect starts to manifest as an elevated self-discharge rate and worsens from there. As a safety measure, the original poster recommends charging only to 4.10V (corresponds to a "standard charge" in Tesla terms) and reducing charging current and temperature while charging. No failures were observed with these precautionary measures.

Let's just hypothetically assume, Tesla found exactly such a problem in some batteries. How would that manifest?

- Balancing problems and self-discharge at high SoCs lead to some cars being unable to charge to 100%
- High SoCs suddenly make the cooling system work much more than usual due to heat generation
- In the worst case, single cells cross the threshold to thermal runaway and cause cars to burn up
- Tesla takes notice and distributes new software that looks for elevated self-discharge and sets charging voltage to 4.1V or lower on those cars. DC charging speed is reduced for all cars as a precautionary measure.

Correct me if I' wrong, but this seems to be pretty much exactly what is happening.

I will tell you in all honesty: As a Tesla fan, having ordered a Model 3 and holding TSLA shares, I very much hope that Tesla will find a solution to the problem. But everything looks very sketchy. Not only for Tesla, but for a lot of others as well. Panasonic might have to take partial blame - they must have known about the safety problems with their UR18650 cells for at least ten years, but never even notified their customers. And most other battery giants have been shown to deliver cells with similar problems (albeit not in the magnitude seen at Sanyo). I wish Tesla would just come forward with a meaningful statement.

I want to make clear that I do absolutely not suggest that most older Tesla packs are defective or dangerous. If I had to guess I would think that in very few select cases, problems as described above were observed and Tesla, fearing a PR nightmare, decided to play it safe with all packs that even remotely look like they might develop that issue in the future while they are working on a tool to reliably weed out any seriously damaged packs. Tesla batteries have been shown to be able to lead long and safe lives with minimal degradation repeatedly. A few black sheep do not change that big picture, as long as Tesla is able to identify them correctly.

What are your opinions?

Thank you for the incredibly informative first post!

If I'm understanding this correctly, while this is certainly a failure mode that is well understood in all Li-ion cells, there seems to be some cells that are affected at certain conditions (ie, temp, charge rate, charge state and time at high SOC) and others that are largely unaffected. Presuming that this is in fact the failure mode the the current software is attempting to detect and placing a limit on the top charge voltage, it's apparent that not all 18650 cells used in the 85/60/70 batteries have been affected at the specs that Tesla has had to date (note that my 2015 85D has not been affected by a range reduction). I think what may drive the ultimate outcome of the lawsuit is if the result you described is considered to be "normal degradation", or if it is considered to be defective cells that would lead to this result. If Tesla had instituted a voltage cap based on some measured property of the battery pack from day one, they would have had a better argument that this is part of normal degradation. However, the fact that it appears they didn't anticipate this failure mode at the the specified conditions that they originally implemented doesn't bode well for that argument.

My car has been affected by the reduced supercharger speeds (as I think all cars have - it appears even the 100Ds are showing a reduced charge rate during the taper, even if the low SOC charge rate has been bumped). I'm wondering what the odds are that we ever see a return to the original rates? This may depend upon how past history informs if this is ever going to become an issue in any given battery pack. In other words, it hasn't been an issue in mine over 67K mi, so can I please have 40 min 10-80% back please?

 

[CuriousG]

Based on my conversation with the attorney a couple of days ago, he has gotten numerous engagement letters from clients and is in discussions with many, many more potential clients. The complaint was not yet served on Tesla when we spoke.

I’m still on the fence, waiting to see how much mileage is recovered with software 2019.28.2.5. I had my car at Tesla today and requested that they perform the CAC test on the battery but they declined to do it. They said Tesla wants to wait on the test as long as mileage is being recovered. Once mileage stops being added to the battery they said they will revisit the request for the test.

After my initial sudden 26 miles battery loss it stabilized. Then started to happen again and lost another 4 miles then stabilized again. I have since gained back 1,2,1 mile(s) in the last 3 sessions before it has settled again and hasn't changed in the last 3 charge sessions.

Now I'm having weird issues now with my MCU and binnacle where I can't connect to my car through the Tesla app but can connect with my other car. Called Tesla support to try whatever remedies that may have and nothing worked that I haven't tried already. Last night I received 2019.28.3.1 on the Model 3 and tested out the new profile option that locks to your phone. In doing so, I had to unplug the car to test and so it opened the charge port on the Model S when I unplugged. So I noticed that the binnacle stayed on the whole time 30+ min later. It took me having to open my door and closing it again for the display to finally turn off.

Fortunately, I have a mobile service person coming tomorrow to look at some minor issues with the 3 so I'll have them look at the S at the time time.

 

[swegman]

I am still on the fence as well, hoping they might do the right thing and give back what they stole, but this slow charging REALLY sucks
I should start billing them for the extra charging time at the standard shop rate.

My concern is that Tesla is basically the only game in town for servicing the car. In the 6+ years I’ve owned the car, Tesla has always treated me fairly, even going beyond and above what they had to without charging me. I don’t want to end up on some list where they refuse to service my car or charge for things they previously billed to goodwill. I’m waiting to see whether they do the right thing and “give back” the range that was taken away.

Btw, I ordered a diagnostic scanner and cable today, and will buy ScanMyTesla and an Android phone (a local Walmart had the Samsung J3 for $25) so I can personally monitor the health of the battery.

 

[Droschke]

Now I'm having weird issues now with my MCU and binnacle where I can't connect to my car through the Tesla app but can connect with my other car. Called Tesla support to try whatever remedies that may have and nothing worked that I haven't tried already. Last night I received 2019.28.3.1 on the Model 3 and tested out the new profile option that locks to your phone. In doing so, I had to unplug the car to test and so it opened the charge port on the Model S when I unplugged. So I noticed that the binnacle stayed on the whole time 30+ min later. It took me having to open my door and closing it again for the display to finally turn off.

I seriously think Tesla updates needs to follow with a "Customer QA Feedback form", where the owners would submit the results of their QA testing in behalf of Tesla, submitted back to Tesla

 

[Droschke]

Tesla has always treated me fairly, even going beyond and above what they had to without charging me.

They still really do that for you?

That used to be the case for me as well, but not anymore since the whole "Service" paradigm has drastically changed in recent years.

 

[Evoforce]

I have also been on the fence yet about joining the suit. I have really been hoping that Tesla would reach out to all of its customers and especially those affected and personally inform us what is exactly going on. I have started to turn blue in the face... still holding my breath...

 

[Ferrycraigs]

O

There's at least one report somewhere in the last 200 pages of this thread with a canbus scan showing that peak current was not reduced, so the only thing causing loss of power vs before 16.1 is the cap in charging. i.e. every SOC percent displayed now is less than the true SOC of the battery as compared to before 16.1.

f course there are two, concurrent, problems. Batterygate which sees the capacity capped, and Chargegate which sees a dramatic curtailing of charging speeds. So a lot of Alchemist42’s comments may relate more to chargegate than batterygate. But it is a very interesting read, particularly as I am affected by batterygate yet have not operated my battery under the conditions described. So whilst I find the conjecture very persuasive, I am still attracted to some early batteries containing slightly sub standard cells that are liable to deteriorate more quickly than standard cells.

 

[swegman]

They still really do that for you?

Yes. The latest being about 2-1/2 weeks ago. While in another state, the car wouldn’t shift into Drive or Reverse. Called them, they sent a tow truck to get my car and take it to the nearest service center and provided me with a Tesla loaner. When I picked up my car, they handed me the fob and said have a good trip. I asked if there was any paperwork to sign, figuring I would at least have to pay for the tow and the deductible. They said nope, nothing to pay.

I’ve had door handles, touchscreens, fog lights, several charge ports, broken sun visor, etc replaced all for free. It can be difficult at times to reach a live person when having an issue. But that’s the only issue I’ve had with Tesla service..

 

[Droschke]

I’ve had door handles, touchscreens, fog lights, several charge ports, broken sun visor, etc replaced all for free.

In or out of warranty window?

 

[Ferrycraigs]

Great.

In response to @Alchemist42, you said "Not all cars have gotten reduced DC charge speed."

But those cars that are capacity capped are also reporting charging speed cap. Of course not "all cars" seeing charging speed reduction.

I am one of perhaps a few that is capacity capped but not charge rate capped. But that could easily be because I have stopped updating, as I fear the chargerate cap is possibly in the next update.

 

[swegman]

In or out of warranty window?

Out.

Maybe it’s because I’m nice to the staff at the service centers. I bring donuts for them whenever I have issues.

 

[Droschke]

Out.

Maybe it’s because I’m nice to the staff at the service centers. I bring donuts for them whenever I have issues.

Wow, I had no idea boxes of donuts would get me free door handles, touchscreens, fog lights, several charge ports and broken sun visor out of warranty! Must be some delicious donuts you are buying

But seriously, I'm currently in the extended warranty window and I might try the donuts trick to get the $200 fee waived.

On Edit: Corrected the fee to $200

 

[swegman]

.. to get the $250 fee waived.

Was the out of pocket fee increased from $200 to $250? I thought it was a. $200 deductible.

Anyway, after leaving Tesla today I charged the car after driving about 50 miles. My 89% charge rate increased by another 2 miles to 207 miles. Remote S now says the battery has a 69 kWh capacity, a gain of 3 kWh so far. Still need to gain back 20 miles at the 89% charge rate to be back to where I was before the battery capacity reduction.

 

[Droschke]

Was the out of pocket fee increased from $200 to $250? I thought it was a. $200 deductible.

Anyway, after leaving Tesla today I charged the car after driving about 50 miles. My 89% charge rate increased by another 2 miles to 207 miles. Remote S now says the battery has a 69 kWh capacity, a gain of 3 kWh so far. Still need to gain back 20 miles at the 89% charge rate to be back to where I was before the battery capacity reduction.

Thanks for the correction regarding the fee. I've already edited my post to show $200.

I'm also in the same boat, need another 20 miles back (have gained 10).

Question: How do you set the charge limit slider on the touch screen to 89% exactly?

 

[swegman]

Question: How do you set the charge limit slider on the touch screen to 89% exactly?

The Remote S (now called Tesla Remote) app allows you to set the charge percentage in 1% increments. Tesla defined (at least when I originally bought the car, and maybe still) a 90% to 100% charge as being for trips and that charging up to these levels should not be done on a regular basis. Thus I set my charge rate to 89%, which is within Tesla’s preferred daily charge level.

 

[Guy V]

Based on my conversation with the attorney a couple of days ago, he has gotten numerous engagement letters from clients and is in discussions with many, many more potential clients. The complaint was not yet served on Tesla when we spoke.

I’m still on the fence, waiting to see how much mileage is recovered with software 2019.28.2.5. I had my car at Tesla today and requested that they perform the CAC test on the battery but they declined to do it. They said Tesla wants to wait on the test as long as mileage is being recovered. Once mileage stops being added to the battery they said they will revisit the request for the test.

Very interesting, "many, many more" is somewhat at odds with a "very small percentage".

 

[MikeyC]

They know exactly how much you charge, whether it’s AC or DC and to what level the car was charged. So they could see that I always charge to 89% indicated range and that the rated miles for 89% has increased slightly.

This is probably my biggest problem with Tesla. They monitor every move you make and can tell you how and what you did in "their" car minute by minute... but you'll never really figure out exactly what they did to the car with updates or why, like even via posting a (real) changelog. I wouldn't be surprised if you go in for abnormal seat wear and the response is "We see that you farted 17 times in your seat in 17,000 miles. We're sorry but that voids your warranty."

Mike

 

[Jlwine]

Life and work have had me busy, so I cannot believe that in my few visits here in over the last few months, I have not seen this thread. What I have done in that time is taken my car into Tesla twice complaining about sounded lost of range and slowness while supercharging, and never did they mention that others have made similar complaints. Pretty damn irritating. I have a 75kWh batter and my drop wasn’t as much as some of yours, “just” about 16-17 miles, but it was very sudden. Now I know it was related to an update. I received another software update last night, I am going to try and fully charge tonight and see what happens.

BTW, have others noticed seemingly reduced re-gen as well, excuse me—for asking if this has already been discussed a lot, I realize
I have a lot more reading to do.

 

[swegman]

Very interesting, "many, many more" is somewhat at odds with a "very small percentage".

It’s definitely much more than the few cars Tesla asserts. As a general rule, if a company says a problem affects only 1-2 percent of their customers, it’s likely that the real number is 10-20% of the customers are affected.

 

[Ferrycraigs]

I had my car at Tesla today and requested that they perform the CAC test on the battery but they declined to do it. They said Tesla wants to wait on the test as long as mileage is being recovered. Once mileage stops being added to the battery they said they will revisit the request for the test.

That’s an interesting stance. How are we meant to know when that point (mileage stops being recovered) is reached? And who here has confidence that the Vmax might not be tweaked again at some point in the future? The obvious question is why would they not want to do the test as presumably it supports their position that our batteries are all fine. Sounds very much like kicking the can down the street and not wanting to make more hard evidence available.