Don Breaks His Taycan - The Saga of the 12v Battery

[wmras]

Me too...

I think most of the "gravity" of the observations and analysis brings us to the orbit of a PCM (or other electronics) which isn't shutting down after it has been woken up to change charging parameters (remotely or via a timer)...

I'll place actual money on that...

$0.02

Have been trying for months to get the 12v battery to discharge - multiple Porsche Connect operations, different departure methods, different charging methods, controls in different modes, etc. All to see if a trickle charger through the OBDI port will bring it back to life. No joy! A big disappointment for someone with a reputation of being able to break anything!

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[Chuck J]

Have been trying for months to get the 12v battery to discharge - multiple Porsche Connect operations, different departure methods, different charging methods, controls in different modes, etc. All to see if a trickle charger through the OBDI port will bring it back to life. No joy! A big disappointment for someone with a reputation of being able to break anything!

Perhaps your relay is not broken.

Chuck J

 

[chrisk]

Have been trying for months to get the 12v battery to discharge - multiple Porsche Connect operations, different departure methods, different charging methods, controls in different modes, etc. All to see if a trickle charger through the OBDI port will bring it back to life. No joy! A big disappointment for someone with a reputation of being able to break anything!

How about leaving a device like a dashcam on and connected to the cigarette socket?

 

[evanevery]

How about leaving a device like a dashcam on and connected to the cigarette socket?

Here we go again...

(Much of this has already been discussed in depth if you want to read this very thread in its entirety... There are also other threads...)

 

[NaiM5]

In a general google search for “dead 12v electric car,” seems like every manufacturer is plagued with some derivative of this issue. I have to say, I do like Hyundai’s answer with an emergency 12V battery connect switch [to the propulsion battery].

The fact that every EV brand including Tesla, Nissan, and VW has 12V issues leads me to believe that the 12V battery in electric cars simply don‘t carry enough mAH juice. So why don‘t we just install a bigger battery?

Let’s ditch the small motorcycle 12V or the light weight Li-on battery in our Taycan and put back in a massive group 31 12V Ni-mh battery from like a Ford F-150.“ Seriously, do we really care about the added weight of a group 31 battery? Do we feel any cooler with a Li-on battery in our Porsche? I’d pack a 12V 1985 SEL560 Mercedes clunker 12V battery in my Taycan if it addresses the embarrassment of having to jump a $200k Porsche.

In my book, the only car that justifies a small, light weight 12V battery is a GT3/GT2 RS.

 

[chrisk]

So why don‘t we just install a bigger battery?

Let’s ditch the small motorcycle 12V or the light weight Li-on battery in our Taycan and put back in a massive group 31 12V Ni-mh battery from like a Ford F-150.

The smaller battery probably takes less power to charge while driving which might be important given there is no alternator.
Btw I also like Hyundai's self-jump capability.

 

[NaiM5]

The smaller battery probably takes less power to charge while driving which might be important given there is no alternator.
Btw I also like Hyundai's self-jump capability.

Right, that makes sense as a Li-on battery charges much faster than a Ni-mh battery. And logic suggests that neither the speed, weight, nor capacity of the 12V would matter if the plug-in charger for the traction battery would also charge the 12V aux battery at the same time, but for some strange reason EVERY electric vehicle manufacturer has designed the 12V battery to charge only when the car is on and running. Why? I’m not an electrical engineer, but seems like a solve able problem.

What am I missing here?

*Sounds like an opportunity to solve a problem and make serious $$$ if someone can figure this out.

 

[louv]

Size doesn’t matter.

 

[Skier]

Size doesn’t matter.

For many things...

 

[evanevery]

Size doesn’t matter.

I agree... (and also appreciate the humor).

Its not the size of the battery. You don't see it having a hard time trying to keep up with the demand. (You can watch this in the "Info" window on the console).

Its fully fine until all of a sudden it isn't.

The solution to this problem isn't installing a needlessly larger and heavier battery. Its identifying where that unexpected demand is coming from and fixing it.

 

[Chuck J]

Software or hardware relay issue is my guess.

Chuck J

 

[BlueShoes]

Software or hardware relay issue is my guess.

Chuck J

This. When mine crapped out it was plugged in but did not charge. The logs on the PMCC don't show the charge at all so it didn't even get going to the point to register - the next day it's completely dead. Given there are instances where being plugged in was not even remotely involved, that makes me think there is something on the car that not only kept the system from sleeping but also prevented it from charging.

 

[daveo4EV]

once the 12V dies there is no computer left running to wake the vehicle up to "charge" - the car really is a brick once it's dead.

 

[BlueShoes]

once the 12V dies there is no computer left running to wake the vehicle up to "charge" - the car really is a brick once it's dead.

That would mean my 12v was dead when I pulled in and parked b/c I don't charge on a timer. And maybe that's the case.... but I pulled in and plugged in like normal but the PMCC never saw it.

 

[chrisk]

That would mean my 12v was dead when I pulled in and parked b/c I don't charge on a timer. And maybe that's the case.... but I pulled in and plugged in like normal but the PMCC never saw it.

Your case sounds more like the car trying and trying to establish a connection to PMCC but failing for some reason. That kept the computer on until the battery died. I believe this issue was supposed to be addressed by the OBC reprogramming campaign. I personally do not use timers and I wait to see the green light coming on every time I plug in the charger.

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