Wiki Sudden Loss Of Range With 2019.16.x Software

[Matias]

What's interesting is it's starting to look like those that already have moderate degradation are the ones NOT effected.

240 miles on an 85D is already 11% degradation which is crazy high after only 45K miles. I have more than double your miles and have less than half the degradation you have.

EU range for 85D was 430 when new. As I wrote earlier, my vin 79XXX 90% charge range is now 370 kms, so 100 % would be 411 kms, so less than 5% degradation. And no changes recently. Firmware is 2019.20.1.

 

[Matias]

It looks like your car new was supposed to have 253 miles of range. Now you are down 15% from that at 215. That sounds reasonable for a vehicle that is 5 years old with 112k miles. My theory is the BMS has been miscalculating your actual degradation all along.

That is interesting theory, because if that is correct, we have evacuated Tesla’s battery degradation to be less than it actually is.

 

[sorka]

It looks like your car new was supposed to have 253 miles of range. Now you are down 15% from that at 215. That sounds reasonable for a vehicle that is 5 years old with 112k miles. My theory is the BMS has been miscalculating your actual degradation all along.

You clearly haven't read the facts around the issue. It has nothing to do with range calculation. Effected batteries are not charging to 100% even though they display 100%. The proof the the cornerstone fact in this entire thread which you've completely missed.

 

[Droschke]

It’s highly unlikely that your battery would have no degradation at all.

Agree.

It’s more likely that some bug they had was not properly degrading the rated miles and these software versions fixed the bug.

My RM has dropped by over 30 miles on a low mileage car (43k miles). That's more than 10%. This is not normal degradation.

Unfortunately people are seeing the proper degradation applied all at once instead of over a period of years.

The evidence so far is showing this is not the case. The impacted cars are prevented from charging to the maximum remaining capacity.

If this is the case, then Tesla was over charging based on real degradation, which was a safety hazard.

This is not a bug fix. It's also impacting the cars that have already been experiencing degradation.

 

[sorka]

No, he had 240 miles at 90% charge. That extrapolates to a full charge of 266 miles, which is (I think) only 1.3% degradation off of the original 270 miles rated. for the S85D.

Bruce.

Ahh. Totally missed that. Can I thumbs down my own post

 

[sorka]

I heated the battery to Max (109.2F to 112.7F when reported “Ready”) and made a 0-60 run at a reported 90% SOC):

If you're still pulling 1525 amps, then the drop in power is not due to software. So how many amps are you pulling wide open throttle as you pass 40 mph?

Also, battery temp(as long as it's not really cold) and SOC(as long as it's not below 30%) won't make any difference in amps drawn so don't go max battery just to pull that number.

 

[sorka]

More data.
I got my own CANBUS reader and checked during charging.
The speculation that thos update reduced the 100% charge state to 3.9 volts (instead of 4.2 volts) is incorrect. My car got to about 4.1 volts while charging at 97% (2kW charge rate regulated by the car).
However, the battery now reports the "nominal full pack" is now 64.3 kWh minus 4kWh reserve and "usable full pack" 60.3 kWh.

I also hooked up to someone elses 2014 S 85 that has not been updated (2018.26 rev). He has 103,000 miles on his odometer and a "nominal full pack" 72.8 kWh, "usable full pack" 68.8 kWh with a maximum rated range of 247 miles.

This is where MY car was prior to the update. Unfortunately, i don't have CANBUS data on my car prior to the update. But, it certainly appears that with this update Tesla removed 8.5kWh capacity from MY battery.

It's not a fixed 3.9 volts. Everyone is effected to different degrees. Some not at all. Some severely.

You're effected as well as you'd be closed to 4.18 volts at 97% rather than 4.1. So your 100% is now closer to 92% of whatever remaining capacity you have.

 

[Droschke]

Battery pumps and powertrain pumps were running after charging complete, and some 0,8A were pulled from the HV battery when reading.

Would be interesting to see your status after the next supercharging.

 

[VT_EE]

You clearly haven't read the facts around the issue. It has nothing to do with range calculation. Effected batteries are not charging to 100% even though they display 100%. The proof the the cornerstone fact in this entire thread which you've completely missed.

I clearly understand what is going on as I’ve read this entire thread and am somewhat versed in electrical engineering. I find it fascinating. They do appear to be limiting how high the battery can charge. The BMS should be monitoring the battery for evidence of battery degradation and adjusting the max charging accordingly to maintain safety. A comment earlier stated that it seems people who have experienced “normal” degradation are not having the sudden loss issue after the recent software update. From what I’ve gathered in this thread, most people experiencing little to no rates mileage loss, even after years of use and tens of thousands of miles, are the ones getting hit. The lack of degradation over the years seems highly dubious unless Tesla has magical batteries nobody else has. We also know all this started after some older Tesla fires which caused Tesla to examine the BMS software. So, my current theory is a bug in the BMS software continued to allow charging as if there was no degradation because the BMS didn’t recognize there was actually degradation. Perhaps this is the cause of a few of the fires. I am looking forward to wk0057’s analysis on what is actually happening. If my theory is remotely correct, good luck suing as the plaintiff would most likely have to prove their “accurate” battery degradation is significantly worse than than the fleet average over the same number of years. None of this excuses Tesla’s utter lack of communication and non-existent PR department.

 

[electronblue]

None of this excuses Tesla’s utter lack of communication and non-existent PR department.

Your message had a lot merit up to the point where you seem to suggest lack of PR department is the reason Tesla is keeping quiet about this. That is just naive in my view.

It seems very likely to me Tesla keeps quiet about negative issues because they feel it is in their interest to do so.

 

[David99]

More data.
I got my own CANBUS reader and checked during charging.
The speculation that thos update reduced the 100% charge state to 3.9 volts (instead of 4.2 volts) is incorrect. My car got to about 4.1 volts while charging at 97% (2kW charge rate regulated by the car).
However, the battery now reports the "nominal full pack" is now 64.3 kWh minus 4kWh reserve and "usable full pack" 60.3 kWh.

I also hooked up to someone elses 2014 S 85 that has not been updated (2018.26 rev). He has 103,000 miles on his odometer and a "nominal full pack" 72.8 kWh, "usable full pack" 68.8 kWh with a maximum rated range of 247 miles.

This is where MY car was prior to the update. Unfortunately, i don't have CANBUS data on my car prior to the update. But, it certainly appears that with this update Tesla removed 8.5kWh capacity from MY battery.

Actually 4.1 Volt at 97% while charging is too low to be correct. At 97% the voltage is as close to 4.2 as it gets. I believe the theory that Tesla caps the max charge limit is correct. This is exactly what the software limited battery packs were doing. That's really wrong. They can't just take away battery capacity. It's like stealing.

 

[sorka]

I clearly understand what is going on as I’ve read this entire thread and am somewhat versed in electrical engineering. I find it fascinating. They do appear to be limiting how high the battery can charge. The BMS should be monitoring the battery for evidence of battery degradation and adjusting the max charging accordingly to maintain safety. A comment earlier stated that it seems people who have experienced “normal” degradation are not having the sudden loss issue after the recent software update. From what I’ve gathered in this thread, most people experiencing little to no rates mileage loss, even after years of use and tens of thousands of miles, are the ones getting hit. The lack of degradation over the years seems highly dubious unless Tesla has magical batteries nobody else has. We also know all this started after some older Tesla fires which caused Tesla to examine the BMS software. So, my current theory is a bug in the BMS software continued to allow charging as if there was no degradation because the BMS didn’t recognize there was actually degradation. Perhaps this is the cause of a few of the fires. I am looking forward to wk0057’s analysis on what is actually happening. If my theory is remotely correct, good luck suing as the plaintiff would most likely have to prove their “accurate” battery degradation is significantly worse than than the fleet average over the same number of years. None of this excuses Tesla’s utter lack of communication and non-existent PR department.

I called BS on your statement because any NORMALLY degraded lithium ion cell can still be safely charged to 4.2 volts even if it's degraded to 50% of it's original capacity. If Tesla is limiting the charge because of some unsafe condition they're now detecting via software then it isn't NORMAL degradation and they need to replace the battery if it's still under warranty.

At the very least, they need to not LIE about the SOC and call 3.9 or 4.0 volts 100% when it isn't. They could display the actual SOC and state on the display that the charge is limited due to it being unsafe to charge higher.

By showing 100% when it isn't actually really is a complete LIE.

 

[VT_EE]

Your message had a lot merit up to the point where you seem to suggest lack of PR department is the reason Tesla is keeping quiet about this. That is just naive in my view.

It seems very likely to me Tesla keeps quiet about negative issues because they feel it is in their interest to do so.

The lack of a functional PR department would certainly explain why Tesla communication for ALL issues is horrible. If one does exist, they are either terrible at their at their job or handicapped by someone. This line of thinking is no more naive than your assumption of nefarious intent. Past Tesla history dictates they pretty don’t communicate any bug fixes.

 

[sorka]

Actually 4.1 Volt at 97% while charging is too low to be correct. At 97% the voltage is as close to 4.2 as it gets. I believe the theory that Tesla caps the max charge limit is correct. This is exactly what the software limited battery packs were doing. That's really wrong. They can't just take away battery capacity. It's like stealing.

That's right. The voltage displayed while charging is not any indication of current state of charge. You need to let the cell settle for a few minutes after charging finishes.

 

[electronblue]

The lack of a functional PR department would certainly explain why Tesla communication for ALL issues is horrible. If one does exist, they are either terrible at their at their job or handicapped by someone. This line of thinking is no more naive than your assumption of nefarious intent. Past Tesla history dictates they pretty don’t communicate any bug fixes.

I think past Tesla history of silently limiting launches, performance and DC charging to avoid warranty claims suggests a strong likelihood of intent.

Pack Performance and Launch Mode Limits

If you fast charge, Tesla will permanently throttle charging

There are many more such examples which fit the idea that negative news are deliberately not communicated while the smallest bit of positive ones have PR all over it (say, games).

As for not communicating bug fixes while they communicate feature changes it goes to the same core issue in my view. Tesla often seems to choose not to communicate negative issues. Nothing to do with lack of PR or comms personnel, but a choice it seems.

 

[VT_EE]

I called BS on your statement because any NORMALLY degraded lithium ion cell can still be safely charged to 4.2 volts even if it's degraded to 50% of it's original capacity. If Tesla is limiting the charge because of some unsafe condition they're now detecting via software then it isn't NORMAL degradation and they need to replace the battery if it's still under warranty.

At the very least, they need to not LIE about the SOC and call 3.9 or 4.0 volts 100% when it isn't. They could display the actual SOC and state on the display that the charge is limited due to it being unsafe to charge higher.

By showing 100% when it isn't actually really is a complete LIE.

Who said the display has to show “100%” of the original full capacity? I personally would want to know when my useable (post normal degradation) battery is at 100%, otherwise as your battery ages the % keeps getting lower and you have no idea when a charge is actually done. What’s the point of charging to full and having the display say 85%? If you want to see how many actual miles are available, which would give you an indication of degradation from new, then change it to the mileage reading. It almost seems like some people on this forum think the “fuel gauge” in a Tesla should work like a gas tank fuel gauge.

 

[David99]

The lack of degradation over the years seems highly dubious unless Tesla has magical batteries nobody else has. We also know all this started after some older Tesla fires which caused Tesla to examine the BMS software. So, my current theory is a bug in the BMS software continued to allow charging as if there was no degradation because the BMS didn’t recognize there was

I don't think that's true. We have data from thousands of cars collected by different people. We have a good idea what normal degradation is. Tesla's batteries are very good but not magic.

I have approx 11% degradation after 212k miles. That's right around the average for similar cars. Not too long ago I did a test driving the car to the point where it shut down. Had the BMS misjudged degradation I would have been stranded long before 0, but I could go 3 miles after it showed zero. I regularly drive my car down to single digit range left. The BMS is correct in calculatiing the availabe capacity. The change in Voltage when charging to 100% also confirms that Tesla is artificially reducing the capacity. So I think there is good evidence that it's not a BMS bug that calculated the capacity wrong.

I think the answer is in finding out what makes the affected cars differnt than those not affected (which is still the majority).

 

[VT_EE]

I called BS on your statement because any NORMALLY degraded lithium ion cell can still be safely charged to 4.2 volts even if it's degraded to 50% of it's original capacity. If Tesla is limiting the charge because of some unsafe condition they're now detecting via software then it isn't NORMAL degradation and they need to replace the battery if it's still under warranty.

At the very least, they need to not LIE about the SOC and call 3.9 or 4.0 volts 100% when it isn't. They could display the actual SOC and state on the display that the charge is limited due to it being unsafe to charge higher.

By showing 100% when it isn't actually really is a complete LIE.

Nobody on this forum knows what “normal” is for the specific chemistry and cell design Tesla uses. Anyone claiming otherwise is making a lot of assumptions. BUT, assumptions are what make this forum so interesting and teases out ideas.

 

[David99]

Nobody on this forum knows what “normal” is for the specific chemistry and cell design Tesla uses.

Having collected data from thousands of cars is a good start. Having data from people who have done long term tests with Tesla cells is another.

 

[electronblue]

Nobody on this forum knows what “normal” is for the specific chemistry and cell design Tesla uses. Anyone claiming otherwise is making a lot of assumptions. BUT, assumptions are what make this forum so interesting and teases out ideas.

Since Tesla does not seem to be transparent, assumptions and own research is all we have.

History has shown Tesla is not likely to tell us if something is wrong. We have to find out ourselves.