How can remotely force my Taycan 4S 2020 to charge the 12V battery?

[exilen94]

How can remotely force my Taycan 4S 2020 to charge the 12V battery?

Does the battery charge if you just turn on the car with the power button and let it idle for 5 minutes without driving? Like just press on button then off?

car is parked in underground parking which sometime can have unstable Internet connection

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[Genau]

@prj has written extensively about how the HV battery charges the 12V battery. Take a look at some of his posts:

https://www.taycanforum.com/forum/search/368380/?q=12v+battery&c[users]=prj&o=relevance​

 

[Dee]

You don't need to.
The car takes care of that itself.

 

[M3Taycan]

I was cleaning out the Taycan yesterday in preparation to drop it off for the 20K service today. I did not start the car, so it was running on the 12V accessory battery. After about ~20 minutes, I received a message on the center display along the bottom in text (I forgot to capture a photo) indicating that the car needed to be started so the HV battery could charge the 12V battery, which was being depleted. Once I started the car by pressing the button on the dash, the 12V battery voltage initially showed 13.1V. It then increased to 14.2V and stayed there for a few minutes before the text message cleared. A few minutes later, the 12V battery was showing 13.5V, which is its normal voltage level.

Today, the 12V battery was again at 13.5V, with no issues. The car was garaged at approximately 65°F.

Takeaway: If you do not start your Taycan and leave the frunk, doors, and display for the trunk/frunk on, and the trunk open, then you’re running off the 12V battery (in accessory mode). You may deplete the 12V battery. This is similar to the behavior of any ICE car.

However, the Taycan HV battery will charge a 12V battery when it detects depletion, when the vehicle is parked, and doors/funk/trunk are closed, as well as when operational. @prj link https://www.taycanforum.com/forum/search/368380/?q=12v+battery&c[users]=prj&o=relevance provides the answers.

 

[Mikegrr]

Mine died when I left the car 5 months. People tell me that’s not possible, but it happened. The car was charging when the 12 volt died. It supposed to charge the 12 volt but it didn’t. 2021 model.

 

[69Mach390]

Mine died when I left the car 5 months. People tell me that’s not possible, but it happened. The car was charging when the 12 volt died. It supposed to charge the 12 volt but it didn’t. 2021 model.

Now that the car is 5 years old, are you sure the 12v didn’t just go bad?

Or was it fine when you charged it again?

 

[Mikegrr]

This was after I had the car 2 years. Should last longer than 5 years anyway

 

[Dee]

Mine died when I left the car 5 months. People tell me that’s not possible, but it happened. The car was charging when the 12 volt died. It supposed to charge the 12 volt but it didn’t. 2021 model.

Haha, 5 months!
That doesn't say anything.
Did it die in the first week or after 4 months?
Big difference.
If it died in the first week, it's a software bug or you're not updated.
If it died after 4 months that's a pretty good score imho.

Next time, if you're not using it for 5 months, get the 12V out and put it on a trickle charger.
That's common practice on all cars.

 

[Dee]

Now that the car is 5 years old, are you sure the 12v didn’t just go bad?

These 12V li-ion batteries last very long cuz they're not stressed like a 12V battery of an ICE (high amps due to starter motor).

 

[M3Taycan]

Hi @prj Would you please comment on this page from the Taycan user manual (page 148)?
Is what happened to @Mikegrr, or is his case special?

1. All doors, covers, the hood, and the trunk should be closed.
   • Question: @Mikegrr was your doors, trunk, and funk closed and locked?
2. Deactivate operational readiness.
   • Question: What does that mean? Does the key fob need to be disabled or placed in a Faraday bag to prevent communication with the car? However, the Porsche key fob stops communicating once stationary for some time.
3. Connect the HV battery to the power grid for trickle charging.
   • Question: I am not sure you can trickle charge indefinitely. Once the AC charge reaches 80%, it stops. My ChargePoint stops the session but remains active, although no energy is being provided. Will an AC home charger automatically start a new charging cycle to charge back to 80% without user intervention? I never experienced it, so I am not sure.
4. Is this 6-week interval real? @Mikegrr car lay up: 5 months ~= 21 weeks; 21/6 = 3.5 intervals would be required.
   
   
   
   
   
   
   
   
   
   
   
   
   
   

 

[prj]

Am aware of the section in the original J1.1 manual, but not sure how applicable it is to the Taycan with the latest updates.

The reason I say this is because the most recent TSB for J1.1 that is out is different and does not mention any trickle chargers as well.

P.S.

So Porsche recommends just connecting the HVB to the charger and that is supposedly enough to "trickle charge" it. I didn't do that and had no issues, and I know the car periodically wakes up by itself due to stuff updating on Porsche Connect in the My Porsche app.

 

[M3Taycan]

Am aware of the section in the original J1.1 manual, but not sure how applicable it is to the Taycan with the latest updates.

As I've written before, I've left my car for almost 2 months not plugged in and had zero issues.

The reason I say this is because this section is nowhere to be found in the J1.2 manual online and the most recent TSB for J1.1 that is out is different and does not mention any trickle chargers as well.

LATEST UPDATES -- OK.

Thank You!

 

[prj]

LATEST UPDATES -- OK.

Thank You!

I edited the post a little bit with latest info, I did locate the relevant portion in the J1.2 manual.
I think the way it is worded is also somewhat confusing. The TSB is not much clearer.

https://static.nhtsa.gov/odi/tsbs/2022/MC-10209809-0001.pdf

They even say themselves:

What I gather from it, is that if it is parked for longer than 8 weeks, and not connected to the AC charger, then you might need to charge the 12V battery separately.

I didn't quite hit the 8 weeks on mine, was 7 or so.
But most issues here seem to be not from leaving it for a long time, rather people have 12V malfunctions after less than a week, which indicates a different cause.

Either way - the way the TSB is worded indicates that you should not have any issues with the 12V battery for a minimum of 8 weeks even if you don't connect anything at all. So those with 12V battery issues should first ask the question:
Has the car been unused for 8 weeks or more?

If the answer is "no", then something is faulty.

 

[Mikegrr]

My cars on a trickle charger now. Don’t want to take a chance. I also leave the frunk open in case something happens.

 

[M3Taycan]

My cars on a trickle charger now. Don’t want to take a chance. I also leave the frunk open in case something happens.

Trickle-charging the 12V battery is a preventive measure when your vehicle is parked and turned off for 21 weeks or more. Yep, good idea to leave your frunk open. You are probably using CTEK 56 -926 Lithium US.

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