12V Battery Dead

[Desert05]

4S delivered Aug 7,2020. On 11/29 vehicle had been on home charger(ChargePoint HomeFlex 50)car charged to 85% but completely DEAD. Called Porsche Roadside after I had used "key" to manually open door....had to follow the procedure to open frunk and then jump start the 12V and was able to back out of garage. Then loaded on to flatbed to dealer.

I shared posts from this Forum regarding 12V with the Service Advisor and was told that they did not apply to my VIN. Further, told by Service Advisor that 12V was recharged and did not need replacement. However, the cause for the 12V failure was that the Porsche Connect App on my phone needs to be shutdown or it keeps communicating with the PCM continuing to wake the car up and thus draining the 12V.

Has anyone else been told this ? It's hard to believe this...

Sponsored

 

[MN_taycan]

Has anyone else been told this ? It's hard to believe this...

After mine died (and I went through the same jump/porsche RSA flatbed to dealer /talk with service advisor process you did) they said I didn't need any updates either (delivery in late July -so similar vintage as yours). I also had the sales guy I bought from screenshot the dealer view of my VIN and my updates, were in fact, clear.

The night mine died I was deleting profiles from my app during the charging timer window. So I surmised it was this weird "app setting changes during charging = dead car" issue others have highlighted/mentioned and your SA alluded to. I haven't messed with charge settings on the phone app during charging since, and I haven't had the issue since (happened in September). Many other posters have highlighted the oddity of having a very large power source available (traction battery...) that should be able to keep the 12V system happy.

Personally I do understand the need for a degree of separation software-wise between traction and 12V from a fire risk standpoint, but I still do not understand why app communication leads to a 12V fault.

 

[Desert05]

After mine died (and I went through the same jump/porsche RSA flatbed to dealer /talk with service advisor process you did) they said I didn't need any updates either (delivery in late July -so similar vintage as yours). I also had the sales guy I bought from screenshot the dealer view of my VIN and my updates, were in fact, clear.

The night mine died I was deleting profiles from my app during the charging timer window. So I surmised it was this weird "app setting changes during charging = dead car" issue others have highlighted/mentioned and your SA alluded to. I haven't messed with charge settings on the phone app during charging since, and I haven't had the issue since (happened in September). Many other posters have highlighted the oddity of having a very large power source available (traction battery...) that should be able to keep the 12V system happy.

Personally I do understand the need for a degree of separation software-wise between traction and 12V from a fire risk standpoint, but I still do not understand why app communication leads to a 12V fault.

 

[Desert05]

Found Dead again this morning after charging to 85%.... had to pull emergency release which is now snapped to release charger...will jump start again tomorrow and flatbed to dealer....(hope its not getting to be like my VIN 23 Fisker which I dumped for a 45% loss after winning the NY
Lemon Law case...but got $0 as Fisker went bankrupt)......

Hopefully the dealer has another trained Taycan Tech who will not give me the same malarkey of closing out of the Porsche Connect App...which I have religiously.... done since getting the car back. Can't wait to hear the explanation this time.

 

[daveo4EV]

Hopefully the dealer has another trained Taycan Tech who will not give me the same malarkey of closing out of the Porsche Connect App...which I have religiously.... done since getting the car back. Can't wait to hear the explanation this time.

it's a software but that currently has NO particular set of steps that you can or can not do to cause of avoid it - until Porsche fixes the underlying software (no published schedule to date) this problem will remain and can strike at any time.

 

[KensingtonPark]

Found Dead again this morning after charging to 85%.... had to pull emergency release which is now snapped to release charger...will jump start again tomorrow and flatbed to dealer....(hope its not getting to be like my VIN 23 Fisker which I dumped for a 45% loss after winning the NY
Lemon Law case...but got $0 as Fisker went bankrupt)......

Hopefully the dealer has another trained Taycan Tech who will not give me the same malarkey of closing out of the Porsche Connect App...which I have religiously.... done since getting the car back. Can't wait to hear the explanation this time.

Out of curiosity, were the doors to your car itself locked when this happened? This is so consistent with my other electric plugin vehicles in their early years...

 

[Desert05]

Out of curiosity, were the doors to your car itself locked when this happened? This is so consistent with my other electric plugin vehicles in their early years...

This time door wasn't locked.

 

[Gubbjaevel]

If you have this from time to time - have you tried another charger?
Early on (March) there was an issue with a specific charger (Defa I believe) what in some way activated (constantly) the 12V system - thus discharging it.

 

[chrisk]

it's a software but that currently has NO particular set of steps that you can or can not do to cause of avoid it - until Porsche fixes the underlying software (no published schedule to date) this problem will remain and can strike at any time.

This post is just my speculation after reading carefully every thread about the 12v battery drain problem and my own experience in both hardware and software systems. Without access to the actual code it is hard to know for sure.

12v battery drain issue during charging. Just my speculation
I suspect the 12v drain bug is due to one of the following reasons
1) the timer core implementation might be very naive. A naive implementation would wake the car up every minute (or so) to check if it is time to start charging. Sometimes the timers code is implemented in the Operating System and the engineers who wrote the charger module might not realize that they use a naive function that drains the car. I have seen this many times in early mobile apps.
2) there is some kind of error when establishing a connection with the charger. The car keeps retrying fruitlessly and drains the 12v battery.

12v battery drain workaround (?)
To minimize the chance of a dead 12v battery I do not use a timer or min charge (aka charging profile). I always use direct charge and I make sure the green light starts blinking. I also try to charge during the day so I can unplug when I want to stop charging.

12v battery drain due to Porsche Mobile App
I have also uninstalled the Porsche app from my phone because it runs in the background and sometimes it connected to my car without being open (like random notifications for the a/c). Every time the app connects to the car it also drains the 12v battery. This looks like another case where the engineers who wrote the mobile/server app did not talk to the engineers who build the actual car and they have not made a good design on how often the car should communicate with the app.

 

[KensingtonPark]

This time door wasn't locked.

So the battery died a different time when the doors were locked?

 

[Desert05]

So the battery died a different time when the doors were locked?

So the battery died a different time when the doors were locked?

First time last week....this week it wasn't locked.

 

[PanameraFrank]

Delete the Porsche Connect app completely and don't use a charging profile. I can almost guarantee that'll solve the problem.

It might seem like you're missing out but honestly the app is so terrible it's easier not to use it.

(To be clear, the app & 12V problem is a major fuckup by Porsche. They should have just removed the functionality altogether until they fixed it. Sorry for everyone that has to deal with it.)

 

[Alemany]

I am an experienced software engineer and this remind me of bugs that college students or fresh college grads make.

I suspect the 12v drain bug is due to one of the following reasons
1) the timer core implementation might bevery naive. A naive implementation would wake the car up every minute to check if it is time to start charging. Sometimes the timers code is implemented in the Operating System and the engineers who wrote the charger module might not realize that they use a naive function that drains the car. I have seen this many times in early mobile apps.
2) there is some kind of error when establishing a connection with the charger. The car keeps retrying fruitlessly and drains the 12v battery.

Again this is just my speculation after reading carefully every thread about the 12v battery problem and my own experience in both hardware and software systems.

To workaround my speculated issues I do not use a timer or min charge. I always use direct charge and I make sure the green light starts blinking. I also try to charge during the day so I can unplug when I want to stop charging.

I have also uninstalled the porsche app from my phone because it run in the background and sometimes it connected to my car without being open (like random notifications for the a/c)

I am a twice Tesla owner with a 2021 Taycan Turbo S on its way. This blows my mind. This is not rocket science and is a majorly irritating issue to those who have it. More so because there is no reason why this should happen in the first place and it doesn't happen with other brands, Tesla for example, which I leave plugged in days at a time (forget to unplug it sometimes after is fully charged and not in use), and which I use the app continuously. I understand major design flaws, all cars have them when they first launch (Tesla did, in spades!). But this issue? So easy to fix? (a logic to stop checking if battery low, an alert if battery is low, a recharge from main battery system if needed, etc. etc,). I just don't understand.

 

[KensingtonPark]

I am a twice Tesla owner with a 2021 Taycan Turbo S on its way. This blows my mind. This is not rocket science and is a majorly irritating issue to those who have it. More so because there is no reason why this should happen in the first place and it doesn't happen with other brands, Tesla for example, which I leave plugged in days at a time (forget to unplug it sometimes after is fully charged and not in use), and which I use the app continuously. I understand major design flaws, all cars have them when they first launch (Tesla did, in spades!). But this issue? So easy to fix? (a logic to stop checking if battery low, an alert if battery is low, a recharge from main battery system if needed, etc. etc,). I just don't understand.

I don't know when you had your Tesla, but during the time that I owned a Model S, I frequented the Tesla Motors Club Forum as regularly as I do this one now. It is like deja vu: Multiple reports of dead 12v batteries. Same happened when I owned a Volvo XC90 T8 plugin hybrid. I myself also experienced a dead 12v battery with both of these cars. The only difference (so far) for me is that I have not yet had it happen to my Taycan. But the discussions are strikingly familiar.

This is why I asked about the door locking, as that was what ultimately started me on a good path with both cars and (so far) seems to be potentially helping now with my Taycan.

 

[daveo4EV]

the first place and it doesn't happen with other brands, Tesla for example

this is 100% incorrect - my Tesla(s) which I've owned since 2013 have had similar problems with 12V issues in spades

I agree this is a screw up by Porsche - but please let's not pretend Tesla is actually any better in this space...I'm a huge Tesla fan (owned 5 Teslas - never more than 2 at once) - and love the cars and what they've done for EV's - but they are far from immune to 12V issues - and right now all the 2017/2018 Model 3's are having big problems with 12V batteries - just read the forums…

Porsche needs to fix this, but Tesla is no better - that's a fact.

Sponsored