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

[evanevery]

to date porsche has not identified any steps or procedures that will avoid this problem...

I'm curious if ANYBODY has had this problem who is simply plugging their car in and using the default charging profile.

IOW: Has anyone who is NOT using any of the software "magic" had this issue?

I'm not using any software, any added profiles, any timers, any magic at all. I expect I'm in the minority here, but I've not had any issues (knock on wood). There was speculation early on that this problem was specifically related to manipulating the charging profile while the car was charging (Remotely or via a Scheduled Timer).

Sponsored

 

[Dave T]

to date porsche has not identified any steps or procedures that will avoid this problem - and from conversations with porsche service they have tacidly acknowleged there is an issue - and apparently porsche germany is investigating issues and may have a solution in a future update.

attributing the fact that you haven’t seen the rare and non-reproducible issue due proceedures followed is like claiming you’re safe from elephants cause one hasn’t attacked you yet.

this is a frustrating but rare problem.

there is no excuse for this to occur the vehicle has ample opportunity and normally ample power to provide to the 12V system - I look forward to future updates from porsche that will further reduce the fequency of this issue

in the mean time I have my 12V booster in the trunk of my Taycan.

You can open the trunk if the car has no 12v power?

 

[daveo4EV]

you can by folding down the seats once you are inside the vehicle.

 

[Vim Schrotnock]

to date porsche has not identified any steps or procedures that will avoid this problem - and from conversations with porsche service they have tacidly acknowleged there is an issue - and apparently porsche germany is investigating issues and may have a solution in a future update.

attributing the fact that you haven’t seen the rare and non-reproducible issue due proceedures followed is like claiming you’re safe from elephants cause one hasn’t attacked you yet.

this is a frustrating but rare problem.

there is no excuse for this to occur the vehicle has ample opportunity and normally ample power to provide to the 12V system - I look forward to future updates from porsche that will further reduce the fequency of this issue

in the mean time I have my 12V booster in the trunk of my Taycan.

I've asked my tech to do the following:

1. turn car on and leave key in car with all accessories functioning (heated seats, wheel, climate, radio etc.) and wait until car automatically turns 'off'. Then turn car back on again with all the same conditions and wait at least 15 minutes, or until car turns 'off' automatically for the second time. Then drive car to AC charging station and charge with my 'home' profile (7am timer, 85% charge).

This is my best bet as to how to reproduce this issue. Both times I had this issue, I did the above (I was sitting in the car on the phone). I've sat in the car a number of times and it's turned 'off' automatically, but I've driven it after that, not just turned back on and continued in 'Park'.

 

[drjhyatt]

Just add me to the list; found my Taycan 4S dead in the garage hooked up to the Porsche Mobile charger. I have been having difficulties with the Porsche connect app with profiles and timers. Shut the iphone app down yesterday and set the direct charge box in the car per instructions from Porsche support. Plugged into charger at home and the green charge light went on immediately, this morning no lights, no car, cannot unplug. Letting my wife deal with having the car towed to dealer.

 

[KensingtonPark]

Just add me to the list; found my Taycan 4S dead in the garage hooked up to the Porsche Mobile charger. I have been having difficulties with the Porsche connect app with profiles and timers. Shut the iphone app down yesterday and set the direct charge box in the car per instructions from Porsche support. Plugged into charger at home and the green charge light went on immediately, this morning no lights, no car, cannot unplug. Letting my wife deal with having the car towed to dealer.

Was the car locked? Your tale is very surprising to me if it was locked.

 

[drjhyatt]

Was the car locked? Your tale is very surprising to me if it was locked.

Not locked.

 

[Reg]

Just add me to the list; found my Taycan 4S dead in the garage hooked up to the Porsche Mobile charger.

I wonder how many people have had this issue with non-Porsche mobile chargers.

Sorry to hear about your problems.

 

[daveo4EV]

according to my information the type of EVSE does not matter, but it’s supposed to be less frequent with Porsche Mobile Connect Charger

of course we lack an overview of total numbers.

 

[Vim Schrotnock]

according to my information the type of EVSE does not matter, but it’s supposed to be less frequent with Porsche Mobile Connect Charger

of course we lack an overview of total numbers.

I have the Porsche mobile charger and the charger and the in-home wiring have been checked twice. No problems identified. The problem is clearly in the car. Could be hardware (battery), could be software. My bet is on the software.

 

[daveo4EV]

I’d lay big money on software - or indirectly hardware in that the hardware may not be up to the task of being shutdown for low power mode - but I’d be super surprised if it’s hardware related…

there is some backchannel communication between the vehicle to the PMCC (you can see the lights change color if charge it charging or waiting to charger) - this feedback is NOT part of the J-1772 specification - so we know porsche is doing some things behyond the strict spec - I would not be surprised if the vehicle has a software problem where it can get confused if it’s not talking to a Porsche charger

but this problem is not caused by different EVSE’s - but the EVSE and their behaviors may expose bugs in the Porsche vehicle software.

 

[Miwa]

I don't think the "doing something different waiting for the car" is unique to the PMCC and the Taycan. My ChargePoint definitely makes different sounds of relays closing depending on if the wife's Bolt starts charging when plugged in, or if it's waiting to start charging later. I hear the relays clunk after a bit if the car is waiting. Imagine the PMCC is doing something similar and has graphical feedback also.

 

[Dave T]

Clearly the problem is related to some kind of phantom drain on the 12v battery. But another issue is that it clearly doesn't keep the 12v battery charged using the car's main battery bank, which is baffling. You've got a bazillion kwh battery sitting there, and it may even be connected to AC power. Yet the 12v battery dies. Perhaps it only charges the 12v battery when the car is being driven, like an ICE car? Very odd.

 

[daveo4EV]

no it’s more than that- teh light are either white, not charging, blue delay’d charging, and green charging - green done charging - the 1772 protcol only has a start/stop - it does not have ‘delay’d charging” as an option - and yet the PMCC lights turn blue - not a state supported by 1772 protocol

the PMCC also definately states it’s trying to establish communication with the vehicle as on screen status...

it’s also does not show blue lights when my Bolt is delay’ing hte charge, but does when the Taycan is delaying the charge...

Porsche has definately “expanded” the 1772 protocol and they have bi-directional communication between a Taycan and the PMCC - I’m not suggesting this is malicous and it’s probably techincally creative, and the 1772 protocol sucks and needs some expansion....

however it’s not hard to imagine a software bug in the Porsche Vehicle 1772 protocol handlers potentially having a bug when it’s plugged into a non-porsche charger causing the software to have a timeout or error condition that leaves it “awake” and sucking 12V battery because of it’s inability to say speak my Gen2 Tesla chargers in 1772 mode…

the PMCC clearly demonstrates states with LED’s and on screen messages not possible with a strict 1772 implementation

I also doubt Porsche did a lot of testing with non Porsche EVSE’s - and that assertion is bourn out by the infrequent nature of this problem and so far to date that hte problem always occurs while the vehicle is actually plugged in to a charger…

my bet (which we’ll never know) is that some error condition in charging communication leaves some thread/process “awake” and keeps the main computer awake running off the 12V battery until the 12V battery gets too low…

 

[Scandinavian]

however it’s not hard to imagine a software bug in the Porsche Vehicle 1772 protocol handlers potentially having a bug when it’s plugged into a non-porsche charger causing the software to have a timeout or error condition that leaves it “awake” and sucking 12V battery because of it’s inability to say speak my Gen2 Tesla chargers in 1772 mode…

I think both of the last two reports came from owners with the Porsche charger. So it does not really matter what happens With third party EVSE.

Sponsored