Pt.2: Taycan lets you drive with shorted out battery modules [VIDEO]

[Rik_CT4s]

In my experience with around 300 Taycans repaired at my garage and around 500 Taycan VINs that I’ve printed PCSS reports for forum members… Out of every 10 VINs 8 are flagged for ARB6.

So yes all those cars flagged by ARB6 sooner or later will end up like this. Matter of time only. Not short term of course but we’re talking years!

For example, my car is a MY22 TS CT (production date nov 2021) and is stated as WRS0....however, these LG batteries come out of the same factory and other cars do have WRS6 or other numbers.

Does WRS0 warrant that nothing will happen to this battery?...while essentially all can be flawed! I do not understand this WRS0 (all should be fine approach).

Besides: asking for a friend
How can one go from WRS0 to WRS6 to help it a bit! My friend wants a brand new J1.2 Turbo S battery badly and tune it thereafter!!
Once again, asking for a friend.

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[ct14garage]

For example, my car is a MY22 TS CT (production date nov 2021) and is stated as WRS0....however, these LG batteries come out of the same factory and other cars do have WRS6 or other numbers.

Does WRS0 warrant that nothing will happen to this battery?...while essentially all can be flawed! I do not understand this WRS0 (all should be fine approach).

Besides: asking for a friend
How can one go from WRS0 to WRS6 to help it a bit! My friend wants a brand new J1.2 Turbo S battery badly and tune it thereafter!!
Once again, asking for a friend.

WRS0/WRS1 is a different kind of failure to ARB6/ARB7 even if the symptoms are very similar

WRS0/WRS1 = Mostly cells randomly dropping voltage (which comes together with isolation faults which causes what Ive shown in the video). This is however much easier to detect and mostly not dangerous because the moment the cell drops voltage the BMS notices the voltage imbalance and shuts the battery down with the red light of death.

ARB6/ARB7 = Isolation faults which not necessarily are accompanied by voltage drop. The module could hold perfect voltage in balance with all the others and still be fully shorted.
This is why AI diagnosis is necessary for this type.

 

[Rik_CT4s]

WRS0/WRS1 is a different kind of failure to ARB6/ARB7 even if the symptoms are very similar

WRS0/WRS1 = Mostly cells randomly dropping voltage (which comes together with isolation faults which causes what Ive shown in the video). This is however much easier to detect and mostly not dangerous because the moment the cell drops voltage the BMS notices the voltage imbalance and shuts the battery down with the red light of death.

ARB6/ARB7 = Isolation faults which not necessarily are accompanied by voltage drop. The module could hold perfect voltage in balance with all the others and still be fully shorted.
This is why AI diagnosis is necessary for this type.

Sorry one more question. Is there a chance under WRS0/WRS1 that also a battery change may happen...or only with ARB6/7....or is there no severity difference between all these campaigns?
Cheers and thank you.

 

[ct14garage]

Is there a chance under WRS0/WRS1 that also a battery change may happen

The battery will be replaced (or at the very least repaired) once it fails. Irrespective of the cause of the failure. Be it WRS0 or ARB6 or something else. They can't refuse to fix a failed battery (unless accident damage ofc).

 

[Tooney]

ARB6/ARB7 = Isolation faults which not necessarily are accompanied by voltage drop. The module could hold perfect voltage in balance with all the others and still be fully shorted.
This is why AI diagnosis is necessary for this type.

In your post about your battery status app, you wrote:

tCAN-Pro will show you all battery information as well as a visualization of all the modules, their polarity, and their voltage. The app will automatically flag faulty modules (using Porsche's criteria of voltage difference between cells at resting state we identify failed / likely to fail modules).​

​

In the case of modules having OK voltage balances but are fully shorted-out, what would be measured by Porsche software to detect such short-outs in individual modules?

 

[ct14garage]

In the case of modules having OK voltage balances but are fully shorted-out, what would be measured by software to detect such short-outs in individual modules?

If the ARB6 affected modules have started showing their symptoms through deteriorating isolation even if they remain within balance the app will detect this through the isolation measurement.

Even though it may not accurately find out the specific affected module, this is because we don't have any data from the BMS which allows us to individually measure modules isolation so we can only use a combination of data to estimate the bad ones...

If the ARB6 affected module is still in perfect condition, good balance, good isolation. There is a way to predict whether it will have an issue in the future.. But it really requires AI processing.

When I heard through a Porsche dealer tech friend of mine that LG has an AI powered app that through a VAL finds out exactly which modules are gonna fail in the future, I found it hard to believe!....
But a while later when I got my hands on the said LG app while reverse engineering it I found why it's necessary to use an AI model.

This is because what LG does is go through the cells voltages under load (ie while driving, charging etc). Doing that on each of the 396 cells over a span of at least 10 minutes on their load requires MASSIVE data processing that can be done only really with an AI model.


A reverse engineered version of this is coming to tCAN-Pro very soon! But it will not be free, obviously, this is due to the fact that AI processing cannot be run on a $40 VPS whatever.. no it requires to be run in specialized AWS instances with massive computing power that cost $$$$...

So to sum up:

tCAN-PRO CURRENTLY CAN:

* Identify failed modules affected by WRS0/WRS1 (or otherwise balance issues)
* Identify failed modules affected by ARB6/ARB7 (or otherwise isolation problems)

tCAN-PRO IN THE FUTURE WILL:
* Predict modules that will fail in the future in ARB6 affected cars (enterprise functionality really)

 

[zionong319]

Being a Taycan ownder, thank you so much for sharing. Ordered the cable on Amazon. Will check it out soon.

 

[D00notD00d]

@ct14garage In the cases like this which you see, is there any sign of moisture/water Ingres? Obviously regardless of that, the BMS should incorporate logic to detect this fault.

I wonder what if anything the new Battery Monitoring software will do to detect this? Once this is installed it will be interesting to compare.
As there is no official importer, does Thailand get OTA updates or is this just workshop only for your location?

 

[D00notD00d]

I do hope so but I think LG is at fault here.
Porsche should demand new, safer cells and a proper BMS for their customers cuz this is going wrong sooner or later.
I think Porsche's good name is at stake here although LG should get the blame.

My understanding is that the BMS is Porsche’s own and is produced in house.
As manufacturer they’re accountable for the BMS software and overall product safety.

https://newsroom.porsche.com/en/202...od-mode-battery-management-systems-32389.html

 

[ct14garage]

@ct14garage In the cases like this which you see, is there any sign of moisture/water Ingres? Obviously regardless of that, the BMS should incorporate logic to detect this fault.

I wonder what if anything the new Battery Monitoring software will do to detect this? Once this is installed it will be interesting to compare.
As there is no official importer, does Thailand get OTA updates or is this just workshop only for your location?

The BMS already has anything it needs in place to detect this. As it can accurately read the isolation. In the video we read the isolation from the BMS both with PIWIS and tCAN-Pro from the BMS. In both softwares it shows as terrible.

But the BMS doesnt care about this and it does nothing about it. Just allows you to continue driving.

The solution is as easy as

if (isoBattPlus < 100 || isoBattMinus < 100) {
openBatteryContactor();
}

Or perhaps to avoid false readings and cars from getting stranded

#define ISO_THRESHOLD 100
#define MAX_CONSECUTIVE 3

// Dummy function to simulate contactor opening
void openBatteryContactor() {
    printf("Battery contactor opened!\n");
}

// Main logic to call each cycle
void checkIsolation(int isoBattPlus, int isoBattMinus) {
    static int consecutiveLowCount = 0;

    if (isoBattPlus < ISO_THRESHOLD || isoBattMinus < ISO_THRESHOLD) {
        consecutiveLowCount++;
        if (consecutiveLowCount >= MAX_CONSECUTIVE) {
            openBatteryContactor();
            consecutiveLowCount = 0; // Reset after opening
        }
    } else {
        consecutiveLowCount = 0; // Reset if condition not met
    }
}

Not much more than these few lines of code are needed to make this safer!

 

[hifi239]

...Out of every 10 VINs 8 are flagged for ARB6

Wait, aren't all J1.1 Taycans flagged for ARB6 or ARB7? Where the only difference is whether the Porsche can access the car OTA?

 

[ct14garage]

Wait, aren't all J1.1 Taycans flagged for ARB6 or ARB7? Where the only difference is whether the Porsche can access the car OTA?

Nope, some Taycans arent flagged for ARB6 nor ARB7. But it’s the minority!

 

[chun]

Nope, some Taycans arent flagged for ARB6 nor ARB7. But it’s the minority!

Is there any common thread between the un-flagged ones? Not sure how much you can see in Porsche's system.

For example multiple people from Belgium have stated that they don't have any recall. I would suspect that Belgian Taycan's aren't special, and are omitted due to some regulations or something.

 

[JackSparrow]

Here’s a weird thought.
Could the live frame backfeed the contactors given enough voltage potential and prevent them from opening, even if the BMS was coded “correctly”.
One reason it may be something like this, is many owners reported the red screen preventing the vehicle from operating.
This is pure speculation on my part.

 

[ct14garage]

Here’s a weird thought.
Could the live frame backfeed the contactors given enough voltage potential and prevent them from opening, even if the BMS was coded “correctly”.
One reason it may be something like this, is many owners reported the red screen preventing the vehicle from operating.
This is pure speculation on my part.

Unlikely, because I've seen several car where the leak was so severe that the DCDC picked it up and requested safety shutdown. Then the contactor did open.

Also in this cases I can see with PIWIS that the BMS does not request safety shutdown even though it displays the red lamp due to isolation.

----

Those red light cars you've seen it's probably due to voltage delta that exceeds 0.3V and that immediately opens the contactor in any case.

Isolation is not the only thing that can go wrong in a battery. Porsche's BMS acts very quickly on voltage delta issues but not so much isolation

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