Wiki Sudden Loss Of Range With 2019.16.x Software

[Droschke]

Kind of getting tired at Tesla lack of transparency! Aren't people with newer cars not noticing?

You'll be surprised to know how many owners are still unaware of these _gates. In another thread, an active poster with two model S cars (2013 S85 and 2018 S100D) is just reporting as being surprised to find out about his 2013 model S pumps running at higher SoC. Most people do not notice.

You are correct, the post#1 battery capacity calculation estimates the total capacity, including the reserved buffer (4 kWh).

 

[mymagiccarpet]

You'll be surprised to know how many owners are still unaware of these _gates. In another thread, an active poster with two model S cars (2013 S85 and 2018 S100D) is just reporting as being surprised to find out about his 2013 model S pumps running at higher SoC. Most people do not notice.

You are correct, the post#1 battery capacity calculation estimates the total capacity, including the reserved buffer (4 kWh).

Since we are on the topic of pump...I charged the car to 90% and it really did charge to "new" 90 of 201mi. Whether this will go away again, or is there to stay, only Tesla knows. And I really appreciate their abundant communication about the issue.

Got home with 195, parked and left it over night, pump, or some other device was running actively. When I got in the car the next morning, it was at 174 (78ish %). It's obviously no good charging above that, it's totally wasteful unless you need it right away. Whenever you charge above 78% and park, they should have a popup that says "you just wasted your money". I get popups for other things, so why not for this.
The interesting question is the limit at 78%? What changes there?

This is nuts. I can count so many ways in which they crippled this car with the infamous FW update.

 

[BigNick]

From what I've observed with TM-Spy on my car, 80% SoC is very close to 4.00V, so maybe the BMS is trying to keep battery voltages just below 4V, possibly 3.98V to 3.99V?
(Speculation, I have not reverse-engineered any BMS code.)

 

[FooFenix]

From what I've observed with TM-Spy on my car, 80% SoC is very close to 4.00V, so maybe the BMS is trying to keep battery voltages just below 4V, possibly 3.98V to 3.99V?
(Speculation, I have not reverse-engineered any BMS code.)

It seems indeed that the BMS does have "targets" it's trying to keep by running the pumps... but I've been wondering whether those targets are likely to be voltage(s).

Could it perhaps be that the BMS is actually trying to keep Temperature targets and what we observe is a consequence of that? Higher SoC usually requires (recent) harging, which implies heating up the cells (more or less, depending on rate).

To me it seems feasible that we have a correlation here: when the pack has been charging beyond 80%, it is likely to exceed the temp targets. On go the pumps to cool the cells down below the BMS's target, which happens to bring the SoC below 80%.

Again, it's just a hypothesis! Thoughts?

 

[Florian500]

AFAIK the S85 has only 34 sensors to "measure" temperatures in ~7000 cells. Two per module and cooling fluid in and out of the whole pack.
Maybe the pumps run to speed up temperature distribution in the pack. To move energy away from single, undetectable hotspots.

 

[Chaserr]

It's highly likely the targets are temperature and volts are only capped in cars that are identified as having out of control situations that would result in fire (like david's confirmed capping with short circuits both detected and intentionally hidden). The fact that Tesla has an intentionally coded response to such dangerous problems and it is to hide it says as much as the fact that his errors were suppressed as soon as he shared them - months after they were first documented in private. Hiding those shorts is their goal - they aren't going to fix the problem.

Early hypotheses regarding dendrites wouldn't impact the entire fleet simultaneously and draingate cooling seems to be as universal as chargegate throttling. Both chargegate and draingate could be mitigating lithium plating - a precursor to dendrites and more universally probable. Lithium plating can also cause fires and is almost expected in older batteries charged at high C like we were encouraged to do. Lithium plating can also reach self-heating cascade temperatures if the cells are as cool as 95F (cooled than skin temperature!) which perfectly explains draingate. Higher states of charge can self heat and older cells have higher internal resistances that would multiply self heating problems.

If you lok at every gate, they are all 100% aimed at thermal reductions. Voltages lower = temps lower. Slowed charge = less heat. Draingate is actively lowering temps to absurdly low numbers.

Tesla told us why the day 2019.16 was released. Fires. They have never taken back those words, because they are still true. We'll find out the official cover story sooner or later, but until our batteries are replaced they are going to keep taking more invasive steps to reduce thermal events without admitting anything new.

 

[Droschke]

It seems indeed that the BMS does have "targets" it's trying to keep by running the pumps... but I've been wondering whether those targets are likely to be voltage(s).

Could it perhaps be that the BMS is actually trying to keep Temperature targets and what we observe is a consequence of that? Higher SoC usually requires (recent) harging, which implies heating up the cells (more or less, depending on rate).

To me it seems feasible that we have a correlation here: when the pack has been charging beyond 80%, it is likely to exceed the temp targets. On go the pumps to cool the cells down below the BMS's target, which happens to bring the SoC below 80%.

Again, it's just a hypothesis! Thoughts?

This is all you need:

"Tesla confirmed they are releasing a BMS software update to revise the 'charge and thermal management settings' ..."

The link below and similar references have been posted and discussed here numerous times:

Tesla is updating its battery software following a car fire, claims improve longevity - Electrek

 

[DJRas]

As you charge above 80% the battery temperature DROPS as the current drops.

 

[mymagiccarpet]

It seems indeed that the BMS does have "targets" it's trying to keep by running the pumps... but I've been wondering whether those targets are likely to be voltage(s).

Could it perhaps be that the BMS is actually trying to keep Temperature targets and what we observe is a consequence of that? Higher SoC usually requires (recent) harging, which implies heating up the cells (more or less, depending on rate).

To me it seems feasible that we have a correlation here: when the pack has been charging beyond 80%, it is likely to exceed the temp targets. On go the pumps to cool the cells down below the BMS's target, which happens to bring the SoC below 80%.

Again, it's just a hypothesis! Thoughts?

78% ish is pretty consistent throughout the year. There seems to be no correlation with external temp, and likely battery temp, b/c when it's hot, fans will turn on even if I just open the door of the car, and they'll run pretty heavy after pulling into the garage. However, when it's 40s, fans' wont be on, but pump will run consistently throughout the year whether its hot or cold, and always to around 78%. Also, last winter, it would be running throughout the night until morning when it's 30s and 40s in the garage. I would expect that it can bring down the temp faster when it's cold and stop at different percentage, but it doesn't. This is my observation, but there could be some correlation to temp, i just don't think it is the primary factor.
Seems more likely it's just draining the battery. I'll give you capacity back, but you have to use it right away.

 

[Droschke]

As you charge above 80% the battery temperature DROPS as the current drops.

View attachment 585913

That tells me even with the drop in the battery temperature above 80% SoC the pack may still not assumed to be in a "safe" state without the draingate effect in place.

 

[Chaserr]

That tells me even with the drop in the battery temperature above 80% SoC the pack may still not assumed to be in a "safe" state without the draingate effect in place.

Detection of Lithium Plating During Thermally Transient Charging of Li-Ion Batteries
Draingate cooling looks like it is tailored to mitigate self-heating thermal events caused by plating.

Lithium plating hazards in our batteries also perfectly describes warmer no-regen behavior post batterygate
How Observable Is Lithium Plating? Differential Voltage Analysis to Identify and Quantify Lithium Plating Following Fast Charging of Cold Lithium-Ion Batteries - IOPscience

It is all about "safety" without actually being safe and legal by telling us about the problem. If they complied with the law we'd all have recalled batteries by now. Note recalled doesn't mean replaced - they just need to follow the law and make sure at risk hazards are removed from the road - unaffected cars can once again be restored to fully usable function. I still assume they have no ability to make this determination or all batteries are faulty because the gates are still here and we have not been mailed anything approved by the NHTSA informing us of what has been done to us "temporarily" while we wait for the real fix. A recall could be as simple as "everyone is downgraded until you update to 2020.X which will determine whether you need a battery replacement" - Tesla might even have illegally released an update that does this long ago with "improved diagnostics" - how many batteries were ID'd for instant replacement when that rolled out? That could have been a recall in compliance with the law if they had bothered to inform through the NHTSA who can mandate and track who has been checked for recall alert conditions and who is still in potential danger.

 

[trayloader]

Weak shorts for short shorts comes to mind.

 

[Chaserr]

I assume David's concealed short circuit alert is on the extreme and irreversible endzone of the plating spectrum if not dendrite penetration. Every battery can get plating and it can be managed and reversed with proper thermal control if utilized from the very beginning. The links I've been providing show how it's possible to control the process safely and why Tesla probably didn't know that until recently. If you check the dates almost all publications that go deep into this are post-batterygate.

 

[fbitz777]

You are correct, the post#1 battery capacity calculation estimates the total capacity, including the reserved buffer (4 kWh).

All this is telling me is that if you drive at rated Wh/mi you will not achieve the rated range....how does Tesla get the EPA get that range then (maybe Tesla has a special EPA mode)
Note that usually when I get to zero SOC I am typically able to run another 8-12 miles on my car...maybe that's what they do.

 

[Droschke]

All this is telling me is that if you drive at rated Wh/mi you will not achieve the rated range....how does Tesla get the EPA get that range then (maybe Tesla has a special EPA mode)
Note that usually when I get to zero SOC I am typically able to run another 8-12 miles on my car...maybe that's what they do.

I believe the advertised numbers were more achievable than what they now appear to be. I know that was the case with my car on the road trips I took when the car was new and before things started to get shady.

 

[Chaserr]

EPA ratings are done in a climate controlled garage at slower speeds than we usually drive with lights, AC, radio and everything else turned off. The EPA's tests are so tightly controlled Tesla got more range by checking the logs of an EPA test done with a door open and making them retest with it closed again. We open and close doors constantly, so we lose that range in every day driving. They also do the tests in 1 or 2 big cycles so there is less vampire losses, and they definitely don't submit cars to be tested with batterygate or draingate turned on.

They do it for gas cars the same way and thats where the phrase "Your mileage may vary" came from. It doesn't represent any person's driving but it does help compare one car to another on equal terms.

 

[mymagiccarpet]

EPA ratings are done in a climate controlled garage at slower speeds than we usually drive with lights, AC, radio and everything else turned off. The EPA's tests are so tightly controlled Tesla got more range by checking the logs of an EPA test done with a door open and making them retest with it closed again. We open and close doors constantly, so we lose that range in every day driving. They also do the tests in 1 or 2 big cycles so there is less vampire losses, and they definitely don't submit cars to be tested with batterygate or draingate turned on.

They do it for gas cars the same way and thats where the phrase "Your mileage may vary" came from. It doesn't represent any person's driving but it does help compare one car to another on equal terms.

Testing was thoroughly revised in 2008 to be more realistic, and all new cars mpg was revised that year, mostly going down as would be expected. Speeds have been increased, and they have AC and cold test. However, understanding what's actually reported is a bit tricky.
Here is more details: Detailed Test Information - click on tabs to get more detailed explanation.
And what's different with EV/PHEV testing - this one is worth a read (I don't want to interpret it): https://www.fueleconomy.gov/feg/pdfs/EPA test procedure for EVs-PHEVs-11-14-2017.pdf
I can't tell which method Tesla uses to derive their rating, but as usual, it's convoluted.

 

[Smiles83]

EPA ratings are done in a climate controlled garage at slower speeds than we usually drive with lights, AC, radio and everything else turned off. The EPA's tests are so tightly controlled Tesla got more range by checking the logs of an EPA test done with a door open and making them retest with it closed again. We open and close doors constantly, so we lose that range in every day driving. They also do the tests in 1 or 2 big cycles so there is less vampire losses, and they definitely don't submit cars to be tested with batterygate or draingate turned on.

They do it for gas cars the same way and thats where the phrase "Your mileage may vary" came from. It doesn't represent any person's driving but it does help compare one car to another on equal terms.

The doors were left open for the entire night causing the car to not totally turn off and losing 1-2%, makes sense they would want to retest to the same standard.

 

[mymagiccarpet]

The doors were left open for the entire night causing the car to not totally turn off and losing 1-2%, makes sense they would want to retest to the same standard.

Just a bunch of complainers...didn't they tell us some small number of customers may see small drop in their range.
If 10-12% battery loss is small drop in range, what's the problem with door being open?

 

[wk057]

The pumps always run at full speed (or near full) during high rate charging, high rate discharging, and above a threshold of SoC vs Temp. If you look at CAN data (or the diag screen) you can see that usually this is done with the battery loop isolated (as in, not attempting to cool or heat the cells). This is simply to help equalize the temperature of the cells throughout the pack, and this mechanism is present in even the earliest firmware versions I've examined (6+ years old now). Nothing new.

Basically, the more thermal variation there is between the cells, the more variation there is in how much power each cell will output (load) or accept (charge). This translate to a higher voltage imbalance over time. Equalizing the temperatures of the cells slows any voltage/capacity imbalance between cell groups that could be caused by thermal variations.

This is also why in my solar setup I put the pairs of modules that were in series on the same horizontal plane, since this would work out to roughly the same air temperature since they were at the same level... and it actually worked out quite nicely, as I've never had any major imbalances in any strings despite using no liquid cooling. (My highest charge/discharge rate is about 1/3C, so definitely not a huge factor). (Edit: Just to note, the system just reached 5.5 years of continuous operation, with over 200 MWh produced.)

There's some links and a graphic in a post above that are completely irrelevant. As always, take such things with a grain of salt... or a pile. The above info is referring to cells charged at freezing temperatures at high rates... which is known to cause damage, degradation, and otherwise be unsafe. The temperatures above freezing that they are referring to appear to be the permitted self-heating targets for the cells under charge/discharge when starting at freezing. Fortunately, since day 1, Tesla has included protections to prevent the battery from ever being subject to those conditions. The cells are never charged when below an unsafe temp, and the max charge current is monitored vs temperature at the millisecond level... so, as noted and as usual, irrelevant information.