[CONFIRMED&DANGEROUS] 9J1.2 LETS YOU DRIVE WITH POOR ISOLATION AS WELL

[ct14garage]

Been complaining for years that 9J1.1 Taycan allows you to drive and charge normally even when the situation inside the battery is egregious with very poor isolation and modules nearing dead short.

Today I can confirm this issue persists in 9J1.2..... A customer slid his car to our shop after he was driving in the expressway after he heard a loud bang accompanied by an immediate red Electrical System Fault and burnt plastic smell inside the car. He really thought his Taycan was gonna go up in flames!

We opened the battery and found that coolant leaked inside the battery which eventually caused a full short circuit (luckily this did not develop into a thermal runaway event and thus fire).

Later through pressurizing the coolant inlet and coolant outlet of the battery we found a minor leak, yet the inside of the battery was completely waterlogged which means the leak would have been going on for a while before the much coolant eventually made it into the battery. Customer never got any warning, not even a yellow one until it popped.

Last photo is how much coolant we recovered out of the battery.

PS: This is now confirmed to be an inherent issue with every Taycan from Gen 1 to Gen 2 whereby whenever isolation is poor in the battery (be it due to water/coolant inside the battery or due to failing modules the BMS will ignore it and will allow you to continue driving as normal)

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[chun]

At the end of the day it's a BMS software issue. I wonder why they didn't fix it yet.
There's no way at this point they are un-aware of it.

I wonder if some complaints to NTHSA/EU equivalent would make them take some action towards fixing this

 

[rim23]

At the end of the day it's a BMS software issue. I wonder why they didn't fix it yet.
There's no way at this point they are un-aware of it.

I wonder if some complaints to NTHSA/EU equivalent would make them take some action towards fixing this

Unless they believe the likelihood of such a case is very low and there are barely any cars that have this problem.

though, even 1 such a car already deserves a proper investigation and solution to the problem. It’s not a yet another rattle problem

 

[Murph7355]

I wonder why they don't have leak detection tape in the battery housing... Given how sensitive electricity and water are.

Do you know how/where the leak came from?

 

[D00notD00d]

Not that there shouldn’t be safety prevention, but is this a result of flood damage?
If I remember correctly, Porsche claims the battery compartment is only water resistant, not waterproof. That may be their escape.

 

[ct14garage]

I wonder why they don't have leak detection tape in the battery housing... Given how sensitive electricity and water are.

Not that there shouldn’t be safety prevention, but is this a result of flood damage?
If I remember correctly, Porsche claims the battery compartment is only water resistant, not waterproof. That may be their escape.

This is coolant and not flood water. That water escaped the battery's coolant system through a ruptured coolant passage and made its way into the modules. In this case the water DID NOT come from outside!!!

 

[prj]

Not that there shouldn’t be safety prevention, but is this a result of flood damage?
If I remember correctly, Porsche claims the battery compartment is only water resistant, not waterproof. That may be their escape.

It does not matter if it was coolant or something else. The car should immediately shut down if there is an isolation fault. Continuing to function is very dangerous and can result in a fire or injury/death if someone gets zapped with 800V.

 

[anonymouse]

Counting down until we see this post cloned all over the internet with no context by EV haters, extrapolated into "all Taycans will catch fire"
10,9, 8...

 

[prj]

Counting down until we see this post cloned all over the internet with no context by EV haters, extrapolated into "all Taycans will catch fire"
10,9, 8...

Good, maybe then Porsche does something about it.

 

[Dee]

It does not matter if it was coolant or something else. The car should immediately shut down if there is an isolation fault. Continuing to function is very dangerous and can result in a fire or injury/death if someone gets zapped with 800V.

Rain water or fresh water have low conductivity (1-50 µS/cm) so an actual short circuit or detecting it would take much longer than ingress of traditional coolant which is 3.000 µS/cm to 5.000 µS/cm.

With the growth of the number of EV's nowadays there should be a more suitable coolant, especially while it's cooling electrical components....
The automotive industry haven't thought of that yet cuz these are still very rare occasions.

 

[Dee]

I don't understand why there was no coolant leakage detection warning as Cris is talking about a significant loss of coolant.
Any comment to that @ct14garage ?

 

[prj]

Rain water or fresh water have low conductivity (1-50 µS/cm) so an actual short circuit or detecting it would take much longer than ingress of traditional coolant which is 3.000 µS/cm to 5.000 µS/cm.

With the growth of the number of EV's nowadays there should be a more suitable coolant, especially while it's cooling electrical components....
The automotive industry haven't thought of that yet cuz these are still very rare occasions.

No it does not take long. The BMS can measure the isolation very precisely.
They just choose to ignore the readings.

All the Chinese cars instantly trip a fault when isolation is degraded.

However, with the Taycan we have situations where the car is driving fine without errors, yet when you plug in a DC charger THAT already detects an isolation fault and does not let you charge.

 

[ct14garage]

I don't understand why there was no coolant leakage detection warning as Cris is talking about a significant loss of coolant.
Any comment to that @ct14garage ?

This is how much coolant we recovered from the battery. While it may seem like a lot it hadn't yet reached the threshold at which the sensor in the coolant tank triggers.

Short circuit in the battery came before low coolant warning

 

[Dee]

No it does not take long. The BMS can measure the isolation very precisely.
They just choose to ignore the readings.

Yes it does.
If there's no or minor change in isolation value (due to low conductivity) there will be no detection.
I know what you mean by ignoring the readings but there's a difference this time.

Low conductivity = no change in isolation value (within the envelope that is).
Higher conductivity = significant change in isolation value (but ignored by the BMS to a certain extent).

 

[prj]

Yes it does.
If there's no or minor change in isolation value (due to low conductivity) there will be no detection.
I know what you mean by ignoring the readings but there's a difference this time.

Low conductivity = no change in isolation value (within the envelope that is).
Higher conductivity = significant change in isolation value (but ignored by the BMS to a certain extent).

When the battery compartment is flooded with water there is a large enough change in isolation value that it can be detected.
Certainly it is visible on an isolation tester... The water is not pristinely clean.

When a DC charger is showing an isolation fault and the car has no warning at all, then 100% the BMS is not operating safely, not sure what there is to discuss here.

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