12V drain on leaving car standing.

[SteveDC]

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 think you need to use a trickle charger designed for lithium batteries. CTEK makes one. The HV battery will recharge the 12 volt only a certain number of times, I think 6 times, and the HV battery must be at or above 50% SOC throughout. It sounds like there may be a problem with your 12 volt. My MY 21 4S regularly goes for 10 days/2 weeks without a problem, but I keep the HV above 50% SOC.

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[ThaJamez]

I had the 12V battery empty issue this morning after car being idle for +-10 days. Some cold nights (-2 to -4 degrees Celcius)

I went for a drive today a noticed some strange behaviour. The navigation couldn’t find dc chargers, internet radio not working, warnings about charger port…

After resetting PCM these issues seem to be solved. But when testing at a fast DC charger I got warnings about the 12 V battery almost being empty. Also the car shutdown every time after 2-3 minutes.

In this topic I read the following
You need the Lithium version of the CTEK to work with the Taycan 12 V.

I have a battery charger that I’ve used in the past for my BMW, is that suited to (try to) charge the 12 V Taycan battery?

Manual says
This device is a primary switched battery charger with pulsed maintenance charging. The battery charger is suitable for charging the following rechargeable 6 V or 12 V lead batteries with electrolyte solution or gel and rechargeable AGM batteries:

Is AGM = Lithium ?

 

[simcity]

I went for a drive today a noticed some strange behaviour. The navigation couldn’t find dc chargers, internet radio not working, warnings about charger port…

After resetting PCM these issues seem to be solved. But when testing at a fast DC charger I got warnings about the 12 V battery almost being empty. Also the car shutdown every time after 2-3 minutes.

In this topic I read the following
You need the Lithium version of the CTEK to work with the Taycan 12 V.

I have a battery charger that I’ve used in the past for my BMW, is that suited to (try to) charge the 12 V Taycan battery?

Manual says
This device is a primary switched battery charger with pulsed maintenance charging. The battery charger is suitable for charging the following rechargeable 6 V or 12 V lead batteries with electrolyte solution or gel and rechargeable AGM batteries:

Is AGM = Lithium ?

No AGM is a lead-acid chemistry. Absorbed Glass Matt. Leak free basically.

You need a lithium specific charger for medium to long term maintenance charging…

Like this CTEK below. Porsche also do a branded version which does both lead-acid and Lithium batteries.
https://www.ctek.com/uk/battery-chargers-12v-24v/vehicle-type/motorcycle/lithium-xs-uk

 

[kurand]

Porsche needs to understand that they have a problem with the 12V battery in the J1.1 Taycan. If your car is afflicted with this problem, is still under warrantee and you have sufficient time, then please call Porsche Assisnace to resolve the problem. That way, Porsche should get the message…

 

[asiviero]

I think you need to use a trickle charger designed for lithium batteries. CTEK makes one. The HV battery will recharge the 12 volt only a certain number of times, I think 6 times, and the HV battery must be at or above 50% SOC throughout. It sounds like there may be a problem with your 12 volt. My MY 21 4S regularly goes for 10 days/2 weeks without a problem, but I keep the HV above 50% SOC.

After reading other posts also other users experience on reddit, I came to conclusion that a trickle charger can mess up the 12V monitoring of the Taycan.
for example: https://static.nhtsa.gov/odi/tsbs/2023/MC-10233963-0001.pdf

the 12V battery is supposed to be charged at every power-on cycle of the car and keeping the charge between 13.4 and 14.5. if this doesn't happen it need to be fixed by the Dealer with a correct diagnosis.

ALSO don't mess too much with those 2 finger manual reset, because it could be the car is doing some OTA of some car unit and you may brick or causing malfunctions. just power it off, leave it close, log off from the app. all the units will reset themself after 15-60min.

Porsche as far as I know is very bad on communicating those updates, but they happen more frequently then we think.

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