Wiki Sudden Loss Of Range With 2019.16.x Software

[Droschke]

FYI, Austin claims there's no way that Tesla is locking out range at the top. I asked him to explain the sudden large drops in rated range for those reporting this. He said you can't trust anything you read in a forum. The internet is full of misinformation and most of it is false.

Don't know who Austin is and about his credentials/credibility. In fact, who cares what he says. I've lost 30 miles in just one month, as have others.

 

[Droschke]

Be aware that charging 90 to 95% is slower, and 95 to 100% is much, much slower, and for me terminated @97% @ 3amps, consistent across 3 cycles.
Regen is also now limited above 93% (temps are consistent in so cal).

This is my experience as well.

 

[sorka]

Don't know who Austin is and about his credentials/credibility. In fact, who cares what he says. I've lost 30 miles in just one month, as have others.

That's my point

 

[Droschke]

The capacity continues to drop (S 85 12/2014).

View attachment 420838

This seems to be even more alarming. So, we really do not know what the ultimate loss would be for the impacted cars.

 

[ran349]

One thing is for sure, in the short term, after I'm forced on the update, I will continually adjust the charge up as required to reach an ACTUAL 90% charge since that's what I need in order to have a reasonable emergency return buffer on my commute.

FYI, Austin claims there's no way that Tesla is locking out range at the top. I asked him to explain the sudden large drops in rated range for those reporting this. He said you can't trust anything you read in a forum. The internet is full of misinformation and most of it is false.

I haven't heard that excuse in years.

Who are Steven and Austin? Are they claiming that Tesla never intentionally limits the range?

 

[DJRas]

I too have a sudden drop starting in May.
I took it to Oceanside Service Center 2 days ago (without this graph). They did a simple BMS reading and said the pack was normal and the degradation was ok.
After remembering i had Teslafi info and printed this graph i took it in again today. They said they will do an actual battery test tomorrow.
I'll also let them know about this post.

 

[David99]

After reading this discussion and reading the data from an affected car (not mine) I believe it is a software issue. Something triggers the software/BMS to miscalculate capacity. Batteries do not degrade all of a sudden after being stable for years. And the fact that we have a good number of cars seeing the same starting around the same time indicates it's a software issue.

 

[sorka]

After reading this discussion and reading the data from an affected car (not mine) I believe it is a software issue. Something triggers the software/BMS to miscalculate capacity. Batteries do not degrade all of a sudden after being stable for years. And the fact that we have a good number of cars seeing the same starting around the same time indicates it's a software issue.

Well of course it's a software issue. Already established firmly here. The question is this a bug or intentional. The fact that the BMS is allowed to report higher SOC than the actual cell voltage indicates is not an accidental kind of mistake. I've been a paid software engineer for 32 years and I know the difference.

 

[faughtz]

After reading this discussion and reading the data from an affected car (not mine) I believe it is a software issue. Something triggers the software/BMS to miscalculate capacity. Batteries do not degrade all of a sudden after being stable for years. And the fact that we have a good number of cars seeing the same starting around the same time indicates it's a software issue.

Look at my posts 61 and 65 above. I think if I had continued to talk battery and degradation, TESLA would have continued to say the battery was ok.

Once I pointed to the software, they agreed and stopped replying.

 

[sorka]

Can the OP please ask the mod to rename this thread to something like "Sudden loss of range with 16.x software update" ?

 

[bhzmark]

Something triggers the software/BMS to miscalculate capacity.

I agree -- that is likely. A question though is whether the miscalculation was before, and now with the update it's fixed, or it was the calculation accurate before, and now it is miscalculating? how to tell?

 

[TJtv]

Someone with root access must be able to see what changes were made in 16.x and hopefully be able to figure that out.

 

[DJRas]

It is tied to 2 software updates
2019.16.1.1 and 2019.16.2

 

[Droschke]

Can the OP please ask the mod to rename this thread to something like "Sudden loss of range with 16.x software update" ?

That's what I was going to ask @Dutchmeeuw to do. This needs more visibility since it's not only the 85kWh packs.

 

[Droschke]

I agree -- that is likely. A question though is whether the miscalculation was before, and now with the update it's fixed, or it was the calculation accurate before, and now it is miscalculating? how to tell?

Or, there is no miscalculation at all. Rather, a "new" calculation to limit the battery exposure to fire, etc. Like you said, we do not know.

 

[Droschke]

It is tied to 2 software updates
2019.16.1.1 and 2019.16.2

Correct.

 

[sorka]

I agree -- that is likely. A question though is whether the miscalculation was before, and now with the update it's fixed, or it was the calculation accurate before, and now it is miscalculating? how to tell?

That's easy. Lithium cell voltage correlates to SOC. 4.2 volts is always 100% charged while just under 4.1 volts is always 90% charged. The bug be it intentional or not is now applying a mapping, based on something the BMS doesn't like, and lying about the actual SOC hence one owner posted a canbus capture showing 3.9 volts at 100%. 3.9 volts is not 100% with any lithium ion chemistry. As a cell loses capacity, it's voltage correlation to SOC doesn't change. A cell that only has 50% capacity left, serious degradation, still shows 4.2 volts fully charged.

That said different formulations do have slightly different SOC vs voltage graphs but I can guarantee you there wasn't a cell chemistry change via software update

 

[sorka]

Or, there is no miscalculation at all. Rather, a "new" calculation to limit the battery exposure to fire, etc. Like you said, we do not know.

Sure, but then why lie about the capacity. Why not stop charging at say 90 or 93% or whatever it is the BMS determines is now safe for the current condition of the battery and then display a message that the charge was limited due to safety?

I can tell you why. They'd be flooded with guaranteed warranty claims since this isn't degradation at all but new limits tesla has decided to to put in retroactively to slow down battery degradation.

This way Tesla can hide what their doing especially if they phase it in over several months to hide the fact that it was tied to one software update.

 

[sorka]

I just want to be doubly clear again. If Tesla believes there's a safety issue with older batteries and needs to limit their charge, I have no issue with that. They should do so. But they should not lie about the SOC. They should limit SOC, say they are doing so on the display, and then display a message to come in for service so the battery can be replaced UNDER WARRANTY if it's within the 8 years.

What they are doing here is beyond slimy.

 

[Droschke]

Sure, but then why lie about the capacity. Why not stop charging at say 90 or 93% or whatever it is the BMS determines is now safe for the current condition of the battery and then display a message that the charge was limited due to safety?

I can tell you why. They'd be flooded with guaranteed warranty claims since this isn't degradation at all but new limits tesla has decided to to put in retroactively to slow down battery degradation.

This way Tesla can hide what their doing especially if they phase it in over several months to hide the fact that it was tied to one software update.

Excellent point.