Once again...the battery...

[Vim Schrotnock]

I 'rebalanced' my battery Friday, and got the 'red code of death' on Saturday morning. The OBD data is attached. As a welcome relief, the car does not show any codes now, so hopefully I'll be able to drive it to the dealer this afternoon. A couple points on the OBD data. At full charge, the replaced modules are showing a lower voltage than any others. This has never happened. Perhaps as a result, the SOH has dropped from 94% to 90%, which again is completely opposite of what I've experienced. All prior balancing have increased the SOH. The 4% is low, but I've done this before in rebalancing and never had a problem.

I'll be heading to the dealer, and will report back.

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[Caraholic]

Sorry to hear. Are you by chance also part of the latest battery recall.

 

[d00d]

How are you rebalancing, charging to 100% and letting the BMC do its thing?

 

[Tooney]

At the low SoC, it appears the replaced cells have a higher voltage than all the other cells.
Any idea why that is so? Is that typical at low SoC when you have rebalanced before?

 

[j.w.s]

I 'rebalanced' my battery Friday, and got the 'red code of death' on Saturday morning. The OBD data is attached. As a welcome relief, the car does not show any codes now, so hopefully I'll be able to drive it to the dealer this afternoon. A couple points on the OBD data. At full charge, the replaced modules are showing a lower voltage than any others. This has never happened. Perhaps as a result, the SOH has dropped from 94% to 90%, which again is completely opposite of what I've experienced. All prior balancing have increased the SOH. The 4% is low, but I've done this before in rebalancing and never had a problem.

I'll be heading to the dealer, and will report back.

I do not have inside knowledge about the Porsche battery management system specifically. But I do build lithium batteries, and in doing so commonly start out with not-quite-balanced battery packs, and I have a technique that may apply to the Taycan.

The Battery Management System (BMS) has a "balancer" function to bring each of the cells in a pack to the same voltage. It does this by drawing current from the highest voltage cell and stuffing it into the lowest voltage cell until they are all at the same voltage. But there are limits to this process:
1) It only starts when the battery is fairly full but not entirely full. Balancing generally DOES NOT happen at low states of charge. The exact start voltage is a configuration item, but balancing might start at 80% or 90% charge and it might or might not end before the pack is at 100%.
2) The amount of current that the balancer can draw from a battery is typically VERY limited. It works nicely to keep a well balanced pack fully balanced, but the current is likely too low to bring a not well balanced pack into proper balance under typical conditions.

Because of the above, balancing your pack might best be done by:
1) Draining the car to say 70%
2) Charging up to 95-100% at a VERY low rate so that you give the balancer plenty of time to work. As in charge at 1KW or even less, not your typical 9.6KW to 19KW.
3) Repeating a few times if the voltages don't fully converge.

The above said, your pack is only ~0.01 voltage off of balance, which I doubt would itself cause any type of error to be thrown, much less one with "death" in its nickname. I would guess that your problems are worse than just a slightly off balance battery pack.

 

[Vim Schrotnock]

Thanks for the input, very interesting and much appreciated. I did have the chance to speak with one of the 11 certified Porche battery technicians in the country when my battery went bad due to a faulty module. I’ve been following the rebalancing procedure that he recommended for the battery which was to drain to 10 to 15% and let it sit overnight then to recharge With my home charger to 100%

I agree with you I think it’s definitely something more than rebalancing, and I have indicated that I will require a new battery pack at this point. Hopefully that’s not too much for Porche to grant me given the 3+ months the car has been in the shop because of electrical issues over the 3+ years I’ve had it. We’ll see and I’ll keep everyone posted.

 

[Vim Schrotnock]

At the low SoC, it appears the replaced cells have a higher voltage than all the other cells.
Any idea why that is so? Is that typical at low SoC when you have rebalanced before?

Yes, the replaced modules have always had a higher voltage than the other cells. The difference in voltage is maximum when the battery charge is at its minimum and there are very slight bumps in voltage for the two modules at the maximum battery charge. Looking at the latest maximum battery charge, you can see the two modules are now slightly lower and this has never happened since I got the modules replaced, so something is definitely wrong.

How are you rebalancing, charging to 100% and letting the BMC do its thing?

see my answer to a subsequent poster. I’ve been rebalancing using the procedure outlined to me by the Porche certified battery technician.

 

[Vim Schrotnock]

Sorry to hear. Are you by chance also part of the latest battery recall.

Checking the battery recall, my Vin does not come up. We’ll see.

 

[WasserGKuehlt]

Thanks for the input, very interesting and much appreciated. I did have the chance to speak with one of the 11 certified Porche battery technicians in the country when my battery went bad due to a faulty module. I’ve been following the rebalancing procedure that he recommended for the battery which was to drain to 10 to 15% and let it sit overnight then to recharge With my home charger to 100%

I agree with you I think it’s definitely something more than rebalancing, and I have indicated that I will require a new battery pack at this point. Hopefully that’s not too much for Porche to grant me given the 3+ months the car has been in the shop because of electrical issues over the 3+ years I’ve had it. We’ll see and I’ll keep everyone posted.

It’s obviously extremely suspicious that the same modules (index-/placement-wise) are having issues. Hopefully they’ll take this opportunity to do a deep dive into the failure mode, and replace your battery. Let us know if you end up getting a gen 2 (battery). ??

 

[T4S]

I 'rebalanced' my battery Friday, and got the 'red code of death' on Saturday morning. The OBD data is attached. As a welcome relief, the car does not show any codes now, so hopefully I'll be able to drive it to the dealer this afternoon. A couple points on the OBD data. At full charge, the replaced modules are showing a lower voltage than any others. This has never happened. Perhaps as a result, the SOH has dropped from 94% to 90%, which again is completely opposite of what I've experienced. All prior balancing have increased the SOH. The 4% is low, but I've done this before in rebalancing and never had a problem.

I'll be heading to the dealer, and will report back.

I recently got my car back after a month of being in service to replace my HV battery modules. After seeing your post, I took a look at the voltage data from my HV battery pack and the results are below. Granted, this is at 95% charge after I finished charging to 100%, but the imbalance looks similar to yours. Can you guess how many modules I got replaced?

I haven't received any Electrical System Errors, but this has me a bit concerned and I only had the car back for less than a week. However, I will run the battery down to 10-15%, take the data, and recharge back up to 100% to hopefully rebalance the battery.

Let us know how it goes with your car!

 

[BMonte13]

Is rebalancing something that is mentioned in the manual or maintenance schedule?

 

[electricsidecar]

Added this to the red circle of death tracker: https://github.com/ElectricSidecar/Porsche-Taycan/issues/15.

 

[Scandinavian]

I 'rebalanced' my battery Friday, and got the 'red code of death' on Saturday morning. The OBD data is attached. As a welcome relief, the car does not show any codes now, so hopefully I'll be able to drive it to the dealer this afternoon. A couple points on the OBD data. At full charge, the replaced modules are showing a lower voltage than any others. This has never happened. Perhaps as a result, the SOH has dropped from 94% to 90%, which again is completely opposite of what I've experienced. All prior balancing have increased the SOH. The 4% is low, but I've done this before in rebalancing and never had a problem.

Your reading of the battery pack voltage show exactly the same patern as mine did after the repair. I had very good SoH data directly after the repair, but it soon settled to about 90 %. And I did not get any increase in SoH when rebalabcing at all.

You have me very concerned now and look forward to hearing your solution!

Luckily I am on a long roadtrip now but NOT with the Taycan. That is at Porsche to find the leak of Rainwater. I can not believe all the faults the Taycan has shown. Luckily enough all under warranty so no costs apart from missing out driving with the thing.

 

[andb]

Seems like replacing only few modules of a faulty battery is not solving the problem and may be more expensive for Porsche if repaired battery dies again. New pack may be better since there's many years left for warranty claims.

 

[Vim Schrotnock]

Checking the battery recall, my Vin does not come up. We’ll see.

Just checked again, and I am part of the April 19 battery recall. My SA has noted this, and I'm waiting for them to respond. I'm especially concerned with the following statement on the recall notice:

THE REMEDY IS NOT AVAILABLE AT THIS TIME

What the heck does this mean? Have I lost the ability to drive my car until "THE REMEDY" becomes available? Why wouldn't they just replace my battery pack? Anyone have any insights?

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