12V drain on leaving car standing.

[tylerdurden]

my 1y old car has been recovered twice due to the 12V issue.
My suspicion is the 12V has a fault.
Porsche have not found a fault and have not changed it.

I am about to go away for 2w and will leave it standing at home, charges at 85% with the power cable removed.

I now have the voltage readout set in the info part of the central display. It usually reads 14V.


If I leave the care for 2w am I right in thinking there should be not drop in voltage readout when I come back to the car in 2weeks? Would a drop indicate a fault battery issue?

Thanks for your thoughts

Sponsored

 

[eddieterry]

To be safe maybe attach a 12 Volt CTEC lithium maintainer - See:
https://www.taycanforum.com/forum/threads/trickle-charger-battery-tender-for-2024-taycan-gts.23265/

 

[EVBHP]

Same issue here. Now at my dealers who tell me they have not replaced the 12v but have received some info from Germany and some "wiring changes" should sort it. I'm sceptical.

 

[tylerdurden]

I don't want to attach CTEK. Im trying to develop an evidence base to confirm my suspicion that there is a faulty 12V battery or wiring loom.

 

[eddieterry]

The problem is that it seems by reports to be intermittent without any known reason - probably software related.

 

[W1NGE]

my 1y old car has been recovered twice due to the 12V issue.
My suspicion is the 12V has a fault.
Porsche have not found a fault and have not changed it.

I am about to go away for 2w and will leave it standing at home, charges at 85% with the power cable removed.

I now have the voltage readout set in the info part of the central display. It usually reads 14V.


If I leave the care for 2w am I right in thinking there should be not drop in voltage readout when I come back to the car in 2weeks? Would a drop indicate a fault battery issue?

Thanks for your thoughts

14v - and not 13.6v? [Macan EV reads 15v which is weird but...]

Leaving connected is an option too

Follow the guidance and if still an issue then Porsche should step up.

 

[chun]

14v - and not 13.6v? [Macan EV reads 15v which is weird but...]

Leaving connected is an option too

Follow the guidance and if still an issue then Porsche should step up.

Mine will also show 14v right when the car starts, even 14.2; but it goes down to 13.6 as soon as I engage drive / reverse.

Likely just a miss-read as power cycles thrrough the battery on booting up

 

[eddieterry]

Yes the large battery starts charging the small one straight away with up to 14.2 volts showing and then drops once it is charged, obviously the longer that takes the lower the 12 Volt was.

 

[f1eng]

Yes the large battery starts charging the small one straight away with up to 14.2 volts showing and then drops once it is charged, obviously the longer that takes the lower the 12 Volt was.

I set off on my first long trip this year yesterday, 4 ½ hours driving and the 12V display was showing over 14 V all the way with 14.1V at the end plus a message saying you can't use the PCM when the battery is low at a stop after 3 hours to charge the main battery.
It has only once shown less than 14V briefly once since the failure over Christmas and that was at the end of a 2 mile drive so surprising.

I am absolutely sure there is a fault, I suspect the battery itself since my car was one of the ones in storage for months due to shortage of 12V batteries and maybe they rushed QC or had a new unknown supplier.

 

[kurand]

just had porsche assistance/aa power may taycan up from dead in the garage after just 4 days idle. it was plugged into the my home evse, but still the 12v battery died. not sure how to keep this thing alive. think i’ll start leaving the frunk open so i can at least easily reactivate the 12v battery.

 

[f1eng]

just had porsche assistance/aa power may taycan up from dead in the garage after just 4 days idle. it was plugged into the my home evse, but still the 12v battery died. not sure how to keep this thing alive. think i’ll start leaving the frunk open so i can at least easily reactivate the 12v battery.

I had thought about doing the same but it has only happened to me once so far but it is wrong and Porsche need to find a fix.

 

[eddieterry]

I still think a lithium CTEK battery charge once a week when weather is cold stops any worry.

 

[f1eng]

I still think a lithium CTEK battery charge once a week when weather is cold stops any worry.

I would agree for the period up until Porsche diagnose the fault and fix it.
Otherwise carefully monitoring the fault and its symptoms may be helpful with the diagnosis.

 

[anonymouse]

After mine died with just 9 days in the (UK ie not real) cold, I have had a Porsche specialist wire a Ctek connecter below the wipers so I can plug in a battery conditioner. All ok so far, but I completely agree that there is something fishy going on with the number of 12V failures over the last six weeks, and Porsche need to investigate.

I didn't book my car in to the dealer because there was a 2 month wait for loan cars and they are a couple of hours drive away - but I will prompt them to see if any wider solutions are becoming evident. On another forum one user says their dealer is aware of a problem but he provides no more detail than that.

Plus I'm very cranky that for such an expensive car I had to go out and buy a battery conditioner.

 

[eddieterry]

After mine died with just 9 days in the (UK ie not real) cold, I have had a Porsche specialist wire a Ctek connecter below the wipers so I can plug in a battery conditioner. All ok so far, but I completely agree that there is something fishy going on with the number of 12V failures over the last six weeks, and Porsche need to investigate.

I didn't book my car in to the dealer because there was a 2 month wait for loan cars and they are a couple of hours drive away - but I will prompt them to see if any wider solutions are becoming evident. On another forum one user says their dealer is aware of a problem but he provides no more detail than that.

Plus I'm very cranky that for such an expensive car I had to go out and buy a battery conditioner.

Have you got a photo of how they connected as at the moment I am using crocodile clips as can’t see quite where I could permanently fit the positive terminal to.

Sponsored