Wiki Sudden Loss Of Range With 2019.16.x Software

[xanadufl]

I have not been able to 100% confirm anything as of yet. This is definitely a pretty complex change to the SoC calculation system overall.

First, for quite some time (~5 years or so) Tesla has used their battery management system to calculate out a lot of variables about the entire system in a very granular way. A lot of these variables are deduced from various readings and are either not measured directly with sensors or otherwise impossible to measure anyway. Nevertheless, the BMS calculates this data.

One of the data bits that Tesla calculates these days, with a pretty high degree of accuracy, is the SoC and capacity of individual cell groups within the pack. This is an indirectly calculated value. They also calculate a bunch of other variables for each cell group, including estimated internal resistance, power dissipation, a couple of lifetime stress factors, and more recently a few new variables I haven't been able to figure out what they are with certainty.

However, in the handful of data logs I've gathered from affected 85 vehicles, the issue that is outward facing (loss of range) is due to one or more cell groups showing a lower max capacity than other groups. This also seems to correlate a bit with a couple of the new variables, but, again, not really sure what they are (not sure of scaling, either, so really difficult to determine what they're measuring/computing here). Only one of these vehicles did I have both before and after logs, and in that case the groups in question were on par with the other groups up until the update that caused this issue.

Long story short, this is definitely caused by the a recent software change, and is due to some new variable they're calculating. I'm not 100% sure what those variables are, however, but my gut is inclined to give them the benefit of the doubt on this one for the time being. My notes on the ongoing BMS software changes over the years have almost always been to improve some aspect of the system, unlike things like the horrible decline in the UI, for example. Either from a usability standpoint (such tweaking variables to eke out a higher charge rate, or make thermal management a little more efficient) or a safety/reliability standpoint (such as modeling and estimating the stress on cell level fusing to prevent physical damage and subsequent capacity loss).

Tesla's BMS is pretty incredible. They know their batteries, and they can infer a lot about their condition as a result. The BMS models so many different variables, most of which are not exposed to the user or even on CAN in any way without some prodding and/or modification. To my knowledge, there isn't a better BMS setup out there.

This particular situation doesn't seem to be a screw up... if it's reducing the max charge, it's doing it for a reason. I do think Tesla should make that reason known, however, to affected owners. My suspicion is that doing so would open them up to large warranty replacement costs, though... and I'm not really sure where that would sit legally overall. If the reduction is due to some kind of variable that's a result of regular lithium ion degradation from normal use, then, while crappy for the owner, it may be for the best. If it's due to some now-detectable defect, however, I'd say Tesla should be liable to correct the issue with a replacement pack.

This is some speculation, but in either case, I'm inclined to believe that there is a potential safety issue involved here... and Tesla's silence on the situation with lack of a clear response to affected owners leads me to believe that the issue lies in the now-detectable defect category. Again, speculation... but it fits.

All of that said, I went and reset the NVRAM of my one customer's BMS who was affected by this, as an experiment of sorts (at their request after discussing the situation in detail). Basically, the BMS will recalibrate and recalculate all of its internal variables over the next couple of weeks. I modified the software to expose pretty much everything possible for logging, and I'm hoping I'll be able to better monitor it and get a better idea what's going on over the next few weeks, assuming the issue resurfaces.

Great post I also am very interested in learning how this all pans out. Please keep me in the loop. ([email protected])

 

[jerry33]

My wife noticed the AC running like a daemon right after the 2019.16 update and thought there was something wrong. It sometimes buzzes like a chainsaw. Yesterday we took the kids to the mall and I got a notification the AC was turned off, because it had been on for 4 hours. No one turned it on! WTF? Fortunately it only reduced the charge by about 2%. It's interesting we've seen no range reduction, but we're definitely noticing a change in the vehicle's behavior. We're up to 2019.20.4.2 now and the new behavior continues.

Is preconditioning on? Is overheat protection on? Both these will run the A/C automatically.

 

[DJRas]

There lies the issue (pun intended.) The method of calculating the range did not change (or at least that's not the beef.) The maximum charge was reduced by software limiting the maximum voltage of the battery. There is no way that is normal degradation, as normal degradation does not reduce the maximum voltage to which the battery can be charged and doesn't involve software limits. If they have found there is an issue with the battery that requires them to reduce the maximum voltage to which the battery can safely be charged they should be forthcoming with that information to owners, rather than attempt to deflect the issue through smoke and mirrors about driving habits and range calculations.

The people who can no longer make trips they have previously been able to make (I believe there are at least 3 in this thread) certainly deserve to be told why, in the course of a single software update, they find their cars to be significantly limited for their usage. I specifically bought an 85 over a 70 to allow me to more comfortably make a regular trip without having to stop for supercharging. So far my range hasn't changed, so I'm not expecting anything, but I fully support those affected being told why.

I work in the computer industry. We sometimes have to release patches that introduce performance degradation in order to mitigate security issues. We would never release such patches without communicating the impact. Thinking about it... We probably did way back when (roaring 80s or so) and got our butts roasted over it by customers and developed policies about being transparent. Devaluing something you've sold simply doesn't go over well with savvy customers.

One other thing I'm wondering is if Tesla was more transparent about the issue would they get more slack? What if they said something like, "affected owners will be receive lifetime telematics with no restrictions", or "any affected owner will be given free supercharging if they ever purchase a new vehicle", or other meaningful, yet non-crippling perks? Would most impacted owners accept this in the interests of supporting the company's well being?

Your second option is totally unacceptable. My car 2014 S 85 new was $99,000 including lifetime unlimited Supercharging. Today worth maybe $25,000 with a degraded battery and 136,000 miles. A new 100 would be well over $120,000. So, pay them another $100,000 just to get the range back (and a little more) that i lost through a software update???⁸
I DON'T THINK SO!!!!

 

[Droschke]

I don't even know why Tesla has forums on its site. It just serves to make them look bad when they pull censorship stunts like this.

That forum started when Tesla was all new and all praise. Every owner was a VIP customer, with their kWh untouched

 

[DILIE]

Is preconditioning on? Is overheat protection on? Both these will run the A/C automatically.

Yes, overheat protection is enabled, but it wasn't hot enough for it to need to run for 4 hours straight. The high on the 4th was right around 90F. I turned AC back on as we walked out to the parking lot (an hour after it turned itself off earlier) and the car was comfortable by the time we reached it.

 

[jerry33]

Yes, overheat protection is enabled, but it wasn't hot enough for it to need to run for 4 hours straight. The high on the 4th was right around 90F. I turned AC back on as we walked out to the parking lot (an hour after it turned itself off earlier) and the car was comfortable by the time we reached it.

That's weird. By any chance did the "leave on" happened to get pressed. Doesn't seem like it from your original post. Also, did you just upgrade, and after the upgrade did you reboot? Sometimes a reboot is needed after an upgrade to reset everything. If none of those apply, it's best to call service and have them check the logs.

 

[tga]

Is everyone that is impacted by dropped range also impacted with slower supercharging?

Im not impacted by the range and I now have a higher top supercharging speed of 130 kW instead of 120.

One thing to note - I have seen surprisingly different SC speeds at different stations. To minimize variables, only compare sessions at the same station. FWIW, I've never seen 130kW - highest I've ever gotten was 118kW.

...as well as an on-board algorithm that constantly learns your driving habits and adjusts the predicted range accordingly.

Since we're talking about rated range, this statement from support is patently false. Cluelessness? Outright lying? Who knows...

Rated and ideal range are based on a fixed Wh/mi rating. Your driving habits have nothing to do with it. Estimated range (displayed in the energy app and the nav system's estimate arrival) does take your usage into account, however.

 

[Matias]

Some suspect, that Tesla is censoring its own site regarding this. There’s at least one thread on official Tesla forum about this
Quick drop in range after 2016.16.2 update | Tesla

 

[xbox4me62]

Is there another thread specifically discussing reduced supercharging speeds? I have a Dec 2013 P85+ and yesterday pulling into a supercharger at 47% SOC with navigation on (presumably to preheat battery) I only got less than 35kw from 50% - 90% SOC. This has happened twice now at two separate superchargers. This has basically made long distance driving impossible now.

EDIT: First time was at a 72kw urban charger (unpaired). Second time was at a standard 120kw charger with no cars next to me.

 

[Lukez]

Yes, overheat protection is enabled, but it wasn't hot enough for it to need to run for 4 hours straight. The high on the 4th was right around 90F. I turned AC back on as we walked out to the parking lot (an hour after it turned itself off earlier) and the car was comfortable by the time we reached it.

Do you have range mode on by chance?

 

[DILIE]

That's weird. By any chance did the "leave on" happened to get pressed. Doesn't seem like it from your original post. Also, did you just upgrade, and after the upgrade did you reboot? Sometimes a reboot is needed after an upgrade to reset everything. If none of those apply, it's best to call service and have them check the logs.

Not even aware there is a "leave on" button, so not used for sure; did you mean Dog Mode? [Edit] Ha! Just saw the "Leave Climate On" selection (along with Dog Mod) in a screenshot in another thread, just by chance. [/Edit] Definitely did not use it. Have been through several upgrades recently as we worked our way up to 20.4.2. I generally do not reboot manually after upgrades. May try one to see if it changes the cooling behavior.

Do you have range mode on by chance?

No, have never used it, but seems it wouldn't cause this behavior (use more energy to cool.)

 

[Chaserr]

I'm experiencing the severely slowed charging speeds as well, and also noticed the all-night loud AC fan running. My AC system is absurdly loud and makes clickety-clack vibrations at 10-11 fan speeds, so I never *EVER* set it that high but it did that on its own for hours in my 70 degree climate controlled garage a couple of times after this malware update, even after I got up and made sure the car was off, didn't have Keep Climate On, and the fob wasn't anywhere near the car because it's gotten that loud and I wanted to sleep. Tesla of course said everything was normal, but reading this now I'm agreeing that maybe were using that loud fan and compressor as a power waste to get the SOC under the newly lowered cap.

 

[Lukez]

Not even aware there is a "leave on" button, so not used for sure; did you mean Dog Mode? Definitely did not use it. Have been through several upgrades recently as we worked our way up to 20.4.2. I generally do not reboot manually after upgrades. May try one to see if it changes the cooling behavior.


No, have never used it, but seems it wouldn't cause this behavior (use more energy to cool.)

I notice it doing excessive cooling at superchargers only when I had range mode on so was wondering if you happened to have it on

 

[Guy V]

There lies the issue (pun intended.) The method of calculating the range did not change (or at least that's not the beef.) The maximum charge was reduced by software limiting the maximum voltage of the battery. There is no way that is normal degradation, as normal degradation does not reduce the maximum voltage to which the battery can be charged and doesn't involve software limits. If they have found there is an issue with the battery that requires them to reduce the maximum voltage to which the battery can safely be charged they should be forthcoming with that information to owners, rather than attempt to deflect the issue through smoke and mirrors about driving habits and range calculations.

The people who can no longer make trips they have previously been able to make (I believe there are at least 3 in this thread) certainly deserve to be told why, in the course of a single software update, they find their cars to be significantly limited for their usage. I specifically bought an 85 over a 70 to allow me to more comfortably make a regular trip without having to stop for supercharging. So far my range hasn't changed, so I'm not expecting anything, but I fully support those affected being told why.

I work in the computer industry. We sometimes have to release patches that introduce performance degradation in order to mitigate security issues. We would never release such patches without communicating the impact. Thinking about it... We probably did way back when (roaring 80s or so) and got our butts roasted over it by customers and developed policies about being transparent. Devaluing something you've sold simply doesn't go over well with savvy customers.

One other thing I'm wondering is if Tesla was more transparent about the issue would they get more slack? What if they said something like, "affected owners will be receive lifetime telematics with no restrictions", or "any affected owner will be given free supercharging if they ever purchase a new vehicle", or other meaningful, yet non-crippling perks? Would most impacted owners accept this in the interests of supporting the company's well being?

I'm afraid that makes you an exception.

 

[Guy V]

Anyone affected could you please check if you get sizable Regen at 100 percent indicated SOC....I lost 5 miles rated range after update and that (217 miles) has been stable for last 1000 miles ...however I get good Regen at 100 percent and Full Regen at 98 percent....used to see these dashed lines on the energy graph for quite a while before.

Conclusion: my de-rating has been achieved by Tesla not letting car charge as much as before the update.

I recently noticed a regen limit line after a 90+% charge and surprisingly that the regen meter would not nearly approach the limit even on maximum downhill regen.

 

[AmpedRealtor]

The wh / mile constant has nothing to do with the battery.

It does inasmuch as the constant was determined by performing an EPA test on the vehicle/battery combo.

 

[Guy V]

I don’t know how you can witness all this @neroden and still think Tesla is only ”failing to communicate”.

Their actions on their own forum — if true — seem to again suggest sweeping this topic under the rug quite intentionally, which would support more the thesis that they are choosing not to communicate about this, instead of failing to. Having your own forum is quite useful too, because then you can control the message...

As for a speculated $90 million cost in battery replacements, for a company that has been denying much cheaper Yellow Band screen replacements and has been saving toilet paper costs and struggling with service center service volume, do you really think avoiding that warranty cost would not enter their calculations at Tesla?

Besides Tesla is communicating about this. They clearly have a corporate message that amounts to ”nothing to see here”. To me it seems they are sweeping this one under the rug and hoping it stays there, which given the age of the cars it might. The hordes of Model 3 enthusiasts — and its value to the company — are the perfect smokescreen for any such small issues with Model S/X.

I would say it looks like a company in high-concern mode after discovering a potentially major significant issue that they do not have enough information about yet to be sure they can make definitive statements that will not come back to haunt them, and that they are doing whatever they think feasible to ensure mitigation to prevent something really bad happening before they can sort it out.

I am sure they are working wholeheartedly, if not frantically, to come to a practical, optimal resolution for everyone. I am 100% wishing them the very best of luck!

 

[jerry33]

I notice it doing excessive cooling at superchargers only when I had range mode on so was wondering if you happened to have it on

I've found that range mode only helps for short trips in cold weather. (I understand this is different on trips if you have an AWD S or X). So 90% of the time I leave it off because it allows the battery to go to the max allowed temps rather than keeping it more constant.

 

[electronblue]

I would say it looks like a company in high-concern mode after discovering a potentially major significant issue that they do not have enough information about yet to be sure they can make definitive statements that will not come back to haunt them, and that they are doing whatever they think feasible to ensure mitigation to prevent something really bad happening before they can sort it out.

I am sure they are working wholeheartedly, if not frantically, to come to a practical, optimal resolution for everyone. I am 100% wishing them the very best of luck!

Or they could just tell what they know now and tell us which part is uncertain instead of sneaking a major range and charging change without so much as a mention in the release notes.

If history is any guide we’ll probably never know or hear from Tesla unless they are forced by a court or somesuch.

 

[Guy V]

Or they could just tell what they know now and tell us which part is uncertain instead of sneaking a major range and charging change without so much as a mention in the release notes.

If history is any guide we’ll probably never know or hear from Tesla unless they are forced by a court or somesuch.

They definitely did make a public statement:

“We are revising charge and thermal management settings on Model S and Model X vehicles via an over-the-air software update that will begin rolling out today, to help further protect the battery and improve battery longevity,”

Data that is not analyzed is not information. They need to analyze, test, link it it to results and completely verify, not announce suppositions, or they will certainly be accused of providing misinformation or outright lying if any part or what they reveal should turn out to be wrong.

They have said what they believe they can without running headlong into a legal and PR minefield.