HERE IS MY BATTERY SITUATION.

[lcarron]

Based on CT14 software and Car Scanner I have a voltage differential of 0.1 volt on 6 to 10 modules. I had it 3 times out of 10 measurements. Not very good, I know. This is a 2022 4s CT with 50K and a SOH of 80%, and I received the Arb6/Arb7 letter last year. The diagnostic software was installed over the air four weeks ago, and I did not receive any notification of any kind and the issues mentioned above were there before the software installation.

Also, when the SOC is below 40% I’m losing 5-6 percent at night, but strangely enough, the cell voltage is identical before and after the percentage drop, so this is not a balancing issue. If I’m running a couple of launches, the differential is up to .2 volt on those 10 modules. They are definitely weaker.

I know what you are going to say. Bring the car to the dealer.

What other information/diagnostics can you give me based on the symptoms above?

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[Johann55]

Strange you get no warnings on dash. Could you share screenshots with more details from both apps: individual cell voltages, cell SOC graph, etc?

 

[Dee]

Strange you get no warnings on dash. Could you share screenshots with more details from both apps: individual cell voltages, cell SOC graph, etc?

You can use the search button on this forum.
It's pretty easy.
https://www.taycanforum.com/forum/t...diagnosis-for-the-community.27701/post-415218

 

[lcarron]

Strange you get no warnings on dash. Could you share screenshots with more details from both apps: individual cell voltages, cell SOC graph, etc?

In the graph below you can see 10 dips and you can calculate the difference between min and max and you multiply it by 6. It will give you a estimate of each module differential. I know it is a bit quick and dirty but I also downloaded in excel each cell individually and conclude the same thing.

 

[dropdead]

Sadly i don't think that this will warrant any action on the side of Porsche from what i've seen. They will just tell you that this is "normal" and to be expected. As long as your overall SoH doesn't drop significantly they will send you home.

 

[Johann55]

How about fluctuations in individual cell SOC values? Do all cells have equal SOC, with so high voltage variations?

 

[lcarron]

Very interesting question, I never thought about it.
The culprit modules (10 of them) do have one percent less than the rest.

 

[lcarron]

How about fluctuations in individual cell SOC values? Do all cells have equal SOC, with so high voltage variations?

Actually, I spent some time to check it. 10 modules are at 19-20 % SOC and the 23 other ones are at 24 %. Then yes there is a big SOC discrepancy between modules.

 

[tbinmd]

just do the rebalance procedure. Had the same issue on my wife 22 CT4 and it fixed the battery, This was back in June, battery is still fine. Procedure is easy to do, just takes time.

 

[lcarron]

I did it and did not fix the issue. SOC still dropping when below 40%!

 

[BjörnfromHamburg]

Wouldn't exactly that fact (drainage over night) be a valid reason to get Porsche engaged?

 

[lcarron]

Wouldn't exactly that fact (drainage over night) be a valid reason to get Porsche engaged?

The first response from Porsche USA or GMBH was that it is normal behavior due to battery aging. They only checked the logs but did not perform any tests. I pushed back, telling them that an aging battery has less capacity, but it should not lose 6% on 10 modules overnight for no reason. My SOH is 82% at 50Kmiles. It is going to be fun.

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