Wiki Sudden Loss Of Range With 2019.16.x Software

[DJRas]

Ok... so i took a flight this week and parked at the airport for 4 1/2 days. When I parked I had 100 miles (46%) remaing rated range. When i returned I had 74 miles (34%) rated range. All precondition, thermal protection and everything else I can think of turned off.

I then drove 55 mikes to a Supercharger station in 55 minutes and had 4 miles (2%) rated remaining. From TM-SPY you can see my battery pretty off-balance (132mv) after 3 minutes waiting before starting SuC.
Charging to 90% at 72 kW charging station predicted 1 hour and that is about what it took.

Now the interesting bit.
While charging I was watching the displayed miles added and kWh added on the dash. The miles added exactly matched the miles added in BMS (ScanMyTesla) data.
HOWEVER, the kWh added did NOT match. The displayed kWh added was exactly miles added times 0.295 (magic number). At the end the display showed 192 miles (teslafi said 192.28) added and 57 kWh added. BUT the BMS said only 53.2 kWh were added (53.2/192.3 = 0.276 MY magic multiplier).

 

[AmpedRealtor]

Ok... so i took a flight this week and parked at the airport for 4 1/2 days. When I parked I had 100 miles (46%) remaing rated range. When i returned I had 74 miles (34%) rated range. All precondition, thermal protection and everything else I can think of turned off.

I then drove 55 mikes to a Supercharger station in 55 minutes and had 4 miles (2%) rated remaining. From TM-SPY you can see my battery pretty off-balance (132mv) after 3 minutes waiting before starting SuC.
Charging to 90% at 72 kW charging station predicted 1 hour and that is about what it took.

Now the interesting bit.
While charging I was watching the displayed miles added and kWh added on the dash. The miles added exactly matched the miles added in BMS (ScanMyTesla) data.
HOWEVER, the kWh added did NOT match. The displayed kWh added was exactly miles added times 0.295 (magic number). At the end the display showed 192 miles (teslafi said 192.28) added and 57 kWh added. BUT the BMS said only 53.2 kWh were added (53.2/192.3 = 0.276 MY magic multiplier).

Seems like the discrepancy is equal to the buffer size.

 

[DJRas]

Seems like the discrepancy is equal to the buffer size.

No... the BMS shows 53.2 kWh added to both the usable and nominal remaining.

At 2% rated (8.1%) nominal the BMS showed 1.2 kWh and 5.2 nominal.
The dash showed 4 miles remaining.
So, if they are including the 4kWh buffer then 5.2 kWh/4 miles 1.3 Wh/mi.

 

[DJRas]

Further information from last night.
My 2% usable (8.1% nominal) battery voltage was 3.169 avg (3.087 minimum).

My 90.07% usable (90.7% nominal) battery voltage was 4.003 avg (3.998 minimum).

Those of you that understand Li battery voltage to State of Charge are welcome to comment... PLEASE comment!

 

[AmpedRealtor]

No... the BMS shows 53.2 kWh added to both the usable and nominal remaining.

IOW your display is showing 57 kWh added while "the BMS" is showing 53 kWh added. By "BMS" you mean the numbers as reported by your app, using a dongle of some kind to read the BMS data. Is it possible that the data provided to your dongle has changed or is being misread? When you say BMS, you really mean the numbers shown by your app. How do you know the app is correct? It's entirely possible that Tesla changed the way the BMS reports data in one of the recent software updates, in a manner that is incompatible with your app.

What I find interesting is that the discrepancy between what is displayed on your vehicle screen and what your app calls "BMS" is almost exactly 4 kWh, which many say is the size of the buffer. That's all I'm pointing out.

 

[DJRas]

IOW your display is showing 57 kWh added while "the BMS" is showing 53 kWh added. By "BMS" you mean the numbers as reported by your app, using a dongle of some kind to read the BMS data. Is it possible that the data provided to your dongle has changed or is being misread? When you say BMS, you really mean the numbers shown by your app. How do you know the app is correct? It's entirely possible that Tesla changed the way the BMS reports data in one of the recent software updates, in a manner that is incompatible with your app.

The BMS shows 2 sets of battery capacity Nominal (includes the 4 kWh buffer) and Usable (Nominal minus 4kWh).
Both show 53.2 kWh added from 5.2 kWh to 58.4 Nominal (including the 4 kWh) and 1.2 kWh to 54.4 kWh.

Additionally, Teslafi reports 56.51 kWh added (rounded to 57 kWh displayed on dash) so the more precise delta is 3.3 kWh... not the 4.0 kWh buffer.

Just a coincidence that at the end there was about 4 kWh delta.
Part way during the charge the delta was less.
At 74 miles added (22 kWh added 74 * 0.295 = 22]) the BMS reported 20.5 kWh added
At 137 miles added (41 kWh added [137 * 0.295 = 41] )the BMS reported 38.0 kWh added

Looking at one end of the data has fooled many people.

 

[Julienx2k2]

The BMS shows 2 sets of battery capacity Nominal (includes the 4 kWh buffer) and Usable (Nominal minus 4kWh).
Both show 53.2 kWh added from 5.2 kWh to 58.4 Nominal (including the 4 kWh) and 1.2 kWh to 54.4 kWh.

Additionally, Teslafi reports 56.51 kWh added (rounded to 57 kWh displayed on dash) so the more precise delta is 3.3 kWh... not the 4.0 kWh buffer.

Just a coincidence that at the end there was about 4 kWh delta.
Part way during the charge the delta was less.
At 74 miles added (22 kWh added 74 * 0.295 = 22]) the BMS reported 20.5 kWh added
At 137 miles added (41 kWh added [137 * 0.295 = 41] )the BMS reported 38.0 kWh added

Looking at one end of the data has fooled many people.

The kWh added shown on the display do not account for losses during charging, the same way that kWh used displayed after a trip on the dash do not account for losses during discharge.

Round trip efficiency of batteries is under 10% and that is confirmed by these numbers.

What you add to your battery during charge is the "typical km" mulitplied by the magic constant (189 wh/km for my tms p85+).
So charging efficiency is this figure divided by the displayed "added kWh". Typically I get 5-7% calculated losses at a supercharger, all fine

To calculate losses during discharge, I look at the "used kWh" on the dash and compare that to the reduction in "typical km" I had during the trip (multiplied by your magic constant). There I typically get 1-3%.


I am right now on a long road trip through Europe and log all these data, so far its been quite consistent.

By the way and related to the OP, I have not observed any reduction in available battery capacity. I m still around 70kWh like before the update. I have a tms P85+ from 2013 with 200.000km, most of it on supercharger and with a dozen times charging at 100%. Software version 2019.20.4.2
If anything this shows that how much you have supercharged does not suffice to trigger the capacity capping.

 

[Julienx2k2]

Just to be clear: contents of my post are my own informed opinion.
And I realize theres a typo, indeed its not the round trip efficiency that is under 10%, its the round trip losses

 

[DJRas]

The kWh added shown on the display do not account for losses during charging, the same way that kWh used displayed after a trip on the dash do not account for losses during discharge.

Round trip efficiency of batteries is under 10% and that is confirmed by these numbers.

What you add to your battery during charge is the "typical km" mulitplied by the magic constant (189 wh/km for my tms p85+).
So charging efficiency is this figure divided by the displayed "added kWh". Typically I get 5-7% calculated losses at a supercharger, all fine

To calculate losses during discharge, I look at the "used kWh" on the dash and compare that to the reduction in "typical km" I had during the trip (multiplied by your magic constant). There I typically get 1-3%.


I am right now on a long road trip through Europe and log all these data, so far its been quite consistent.

By the way and related to the OP, I have not observed any reduction in available battery capacity. I m still around 70kWh like before the update. I have a tms P85+ from 2013 with 200.000km, most of it on supercharger and with a dozen times charging at 100%. Software version 2019.20.4.2
If anything this shows that how much you have supercharged does not suffice to trigger the capacity capping.

Well... Teslafi shows 58.3 kWh used to get 56.51 added. That is your 3 % loss. So that would be the extra power required for heating or cooling the pack, etc.
The 0.295 Wh/mile multiplied by the miles added exactly matches the kWh added on the display for all State of Charge. Whether at the start or 10 minutes in when the pumps kicked on 100%.

 

[Julienx2k2]

Well... Teslafi shows 58.3 kWh used to get 56.51 added. That is your 3 % loss. So that would be the extra power required for heating or cooling the pack, etc.
The 0.295 Wh/mile multiplied by the miles added exactly matches the kWh added on the display for all State of Charge. Whether at the start or 10 minutes in when the pumps kicked on 100%.

Interesting as well is that the screenshots you have taken show that if you look at the delta in Nominal Charge Remaining indeed you get your 53.2 kWh added you have mentioned above. But if you look at the delta in Charge Total rows, you get 61927 - 61869 = 58 kWh.

So what is the correct amount of energy stored on your battery during its charge from 2% to 90%? The car display (+57kWh), TeslaFi (+56.5kWh), the Charge Remaining row from the BMS readings (+53.3kWh) or the Total Charge row from the BMS readings (+58kWh)? All that is quite confusing lol

 

[DJRas]

Interesting as well is that the screenshots you have taken show that if you look at the delta in Nominal Charge Remaining indeed you get your 53.2 kWh added you have mentioned above. But if you look at the delta in Charge Total rows, you get 61927 - 61869 = 58 kWh.

So what is the correct amount of energy stored on your battery during its charge from 2% to 90%? The car display (+57kWh), TeslaFi (+56.5kWh), the Charge Remaining row from the BMS readings (+53.3kWh) or the Total Charge row from the BMS readings (+58kWh)? All that is quite confusing lol

Yes, Teslafi shows 58.3 kWh used to add 56.51 - 97% efficiency.
The Usable Remaing in the ScanMyTesla is used for Range remaining and Percent SoC. These numbers ALWAYS match the displayed percent and miles on the dashboard.

Therefore, I BELIEVE that 53.2 kWh were actually added using 58.3 kWh to get there (91% efficiency).

 

[sorka]

The study you linked is more related to Li-metal electrodes. Pulses from regen braking (same for boost phase at SuC) at low temperatures are part of the problem, not the solution.

I've done a TON of regen braking over the years coming back from skiing on very cold batteries. Cold enough that regen is always completely limited to none until the battery warmed up just enough to allow a little at which point the rest of battery heating is just from regen.

This is 6 or 7 times a ski season. If this is truly the cause then I'd expect to see a massive drop in range should I be unable to prevent v9 from installing.

 

[tga]

I've done a TON of regen braking over the years coming back from skiing on very cold batteries. Cold enough that regen is always completely limited to none until the battery warmed up just enough to allow a little at which point the rest of battery heating is just from regen.

This is 6 or 7 times a ski season. If this is truly the cause then I'd expect to see a massive drop in range should I be unable to prevent v9 from installing.

I have a decent downhill stretch leaving my house, so no regen on cold NH mornings. I started delaying my charge so I'd have a warm battery when I left in the morning. I've done that almost daily for three winters.

I haven't seen any common factors with the impacted cars yet. I'm starting to think there's a batch of bad cells that got mixed into the bad packs.

 

[Blu Zap]

I haven't seen any common factors with the impacted cars yet. I'm starting to think there's a batch of bad cells that got mixed into the bad packs.

Tesla has found an issue with a certain batch/version of the 85kWh battery. Looks like the car fires in Singapore and Hong Kong brought this to their attention. Their band-aid is to reduce range and not allow these particular versions of the 85 kWh batteries to fully charge. This defect is covered up and has not been announced by Tesla. Otherwise they would have to do warranty replacements of he effected batteries.

 

[tga]

Tesla has found an issue with a certain batch/version of the 85kWh battery. Looks like the car fires in Singapore and Hong Kong brought this to their attention. Their band-aid is to reduce range and not allow these particular versions of the 85 kWh batteries to fully charge. This defect is covered up and has not been announced by Tesla. Otherwise they would have to do warranty replacements of he effected batteries.

Right. What I meant is there doesn't seem to be any common cause, which has been much of the recent focus of this thread. Lots/little supercharging, hot/cold weather, etc. There seems to be no common cause. Hence my thought that there may be a bad run of cells/manufacturing defect as the root cause, not owner's usage patterns.

 

[sorka]

I haven't seen any common factors with the impacted cars yet. I'm starting to think there's a batch of bad cells that got mixed into the bad packs.

Except that the effected batteries so far seem to cover at least 3 years of production, right?

 

[mjmiron]

I have a 2015S 85D and after the latest update in June I too lost 25-30 miles of range I am extremely upset especially about the lack of information from Tesla. Like some prior folks stated they have completely reduced the usability of our cars. I paid for the larger battery for the extra range to compensate for loss in the winter as well as not having to charge as often. I would be open to a class action if one is started. I called my service center in MN and they told me it was the first time they had heard about this waiting for a call back. It does not seem like a huge deal but the cost for a 60 battery versus a 85 is a lot and imho folks buy the larger battery for increased range. Tesla needs to fix this not limit our mileage. I drive 20k miles a year and lower mileage equals more charging and less efficiency. They need to upgrade the battery to a 90 or 100 battery if they are going to take away my range not limit it.

 

[PetriKarj]

The study you linked is more related to Li-metal electrodes. Pulses from regen braking (same for boost phase at SuC) at low temperatures are part of the problem, not the solution.

Please point me then to right reading ...

 

[Blu Zap]

There seems to be no common cause. Hence my thought that there may be a bad run of cells/manufacturing defect as the root cause, not owner's usage patterns.

@tga I am with you. I believe it is more Tesla's cover up and not informing owners, is bigger than the actual cause. I can appreciate that Tesla is keeping our vehicles from bursting into flames as happened to the Model S 85s in Hong Kong an Singapore. But by software limiting our respective battery capacities and not telling us smacks of a cover up. One that really appears to be avoiding their battery warranty obligation.

 

[Matias]

Also, I get the power limit line around 300kw no matter what my stare of charge when accelerating. No more flooring it to get on the freeway.

This is clearly a defect. Have you reported this to Tesla?