12V Battery Dies after 2-3 Days being Parked

[HungryEyes77]

My MY20 Taycan 4S with performance battery had a dead 12V battery after our spring break trip this year.
Had to call Porsche Mobility for a jump start (I paid for a 2-year Extended Warranty).

Then, most recently, I had a 4-day weekend away, so I made sure my HV battery was charged to 80% and left the car plugged into the Porsche Mobile Connect while I was away. Came back, and again, the 12V battery is dead, and I had to call for a boost.

The car is scheduled for service in a couple of days, and the dealer asked if I had a dashcam, which I do. It's the FitcamX.
They told me that it's the dashcam that is the likely source of the 12V drain.

Question is:
1. I've had the Dashcam installed since 2021 and have never had issues leaving my car for more than 2 weeks and coming back to a car that is pretty at the same SoC before my trip and a 12V that's still showing about 13.5V.

2. Is the 12V covered by extended warranty? The dealer couldn't (or didn't) want to give me an answer over the phone.

3. Anyone else have similar issues with an installed FitcamX?

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[figure1a]

Usually, batteries are not covered by extended warranty because of aging. The newly dead battery symptom could be a sign of the age of the battery not taking a full charge anymore. But, these 12V batteries are lithium and are supposed to go 10+ years with no issues. So maybe you can argue that with the Porsche warranty.

 

[daveo4EV]

My MY20 Taycan 4S with performance battery had a dead 12V battery after our spring break trip this year.
Had to call Porsche Mobility for a jump start (I paid for a 2-year Extended Warranty).

Then, most recently, I had a 4-day weekend away, so I made sure my HV battery was charged to 80% and left the car plugged into the Porsche Mobile Connect while I was away. Came back, and again, the 12V battery is dead, and I had to call for a boost.

The car is scheduled for service in a couple of days, and the dealer asked if I had a dashcam, which I do. It's the FitcamX.
They told me that it's the dashcam that is the likely source of the 12V drain.

Question is:
1. I've had the Dashcam installed since 2021 and have never had issues leaving my car for more than 2 weeks and coming back to a car that is pretty at the same SoC before my trip and a 12V that's still showing about 13.5V.

2. Is the 12V covered by extended warranty? The dealer couldn't (or didn't) want to give me an answer over the phone.

3. Anyone else have similar issues with an installed FitcamX?

any vampire drain will deplete the 12V battery very quickly - there is not much capacity since they don't need to do much …

12V battery is typically not covered by warranty any more than brakes are - it's considered a "consumable"…

the dash cam is likely root cause here - but also the 12V battery may just be at end of life and not holding a lot of juice any more

good luck.

 

[SergeyIndy]

12V battery capacity should be measurable. I am not sure about these Lithium kind, but the old school Macan 12V was measured to be at 50% after 8 years and was due to be replaced for a small fortune as they need to be registered to the car. My 2020 Cayenne (6 years old) has the Lithium kind and I do not remember dealer measuring it but it did not come up as due for replacement.

Therefore, for the OP, something else may be wrong as HV battery has to cycle in intervals to top up 12V.

 

[gtm]

My MY20 Taycan 4S with performance battery had a dead 12V battery after our spring break trip this year.
Had to call Porsche Mobility for a jump start (I paid for a 2-year Extended Warranty).

Then, most recently, I had a 4-day weekend away, so I made sure my HV battery was charged to 80% and left the car plugged into the Porsche Mobile Connect while I was away. Came back, and again, the 12V battery is dead, and I had to call for a boost.

The car is scheduled for service in a couple of days, and the dealer asked if I had a dashcam, which I do. It's the FitcamX.
They told me that it's the dashcam that is the likely source of the 12V drain.

Question is:
1. I've had the Dashcam installed since 2021 and have never had issues leaving my car for more than 2 weeks and coming back to a car that is pretty at the same SoC before my trip and a 12V that's still showing about 13.5V.

2. Is the 12V covered by extended warranty? The dealer couldn't (or didn't) want to give me an answer over the phone.

3. Anyone else have similar issues with an installed FitcamX?

I've had a FitcamX installed almost since day 1. Never a problem leaving the car for as long as 6 weeks. But I have the power wired into the rain sensor which is switched on and off with the "ignition". I believe you can hardwire the FitcamX to the fuse panel to enable a parking/sentry mode. It should be off unless an impact is registered. Powered by the rain sensor? It's not the FitcamX. Hardwired then maybe it's the culprit. Dealer can do a draw test and determine how much, if any, current is flowing with the car shut down. The other question is why the 12V battery wasn't topped off as the voltage dropped below the threshold voltage.

 

[HungryEyes77]

I've had a FitcamX installed almost since day 1. Never a problem leaving the car for as long as 6 weeks. But I have the power wired into the rain sensor which is switched on and off with the "ignition". I believe you can hardwire the FitcamX to the fuse panel to enable a parking/sentry mode. It should be off unless an impact is registered. Powered by the rain sensor? It's not the FitcamX. Hardwired then maybe it's the culprit. Dealer can do a draw test and determine how much, if any, current is flowing with the car shut down. The other question is why the 12V battery wasn't topped off as the voltage dropped below the threshold voltage.

My FitcamX is also wired via rain sensor but it runs 24hrs. Not sure how because I know it didn’t do that at first but it started doing that at some point without any changes to wiring. I don’t know the exact point because I don’t often check the videos unless there’s an incident that necessitates it.

Also weird is that when the car is plugged in, the HV Battery doesn’t top up the 12V like the service bulletin suggests.

I guess I’ll remove the Fitcamx and see what the dealer discovers.

 

[gtm]

My FitcamX is also wired via rain sensor but it runs 24hrs. Not sure how because I know it didn’t do that at first but it started doing that at some point without any changes to wiring. I don’t know the exact point because I don’t often check the videos unless there’s an incident that necessitates it.

Also weird is that when the car is plugged in, the HV Battery doesn’t top up the 12V like the service bulletin suggests.

I guess I’ll remove the Fitcamx and see what the dealer discovers.

The FitcamX can't magically start to draw current on a circuit that is supposed to shut off when you turn the car off. Are you seeing video recordings that show 24 hour activity? I don't think there is any software change that could switch that circuit to being alive all the time. Any accident repairs? Blaming the dashcam is the easy way out for the dealership. Even if the FitcamX is on the HV battery should be able to cope for a "4-day weekend away".

 

[HungryEyes77]

The FitcamX can't magically start to draw current on a circuit that is supposed to shut off when you turn the car off. Are you seeing video recordings that show 24 hour activity? I don't think there is any software change that could switch that circuit to being alive all the time. Any accident repairs? Blaming the dashcam is the easy way out for the dealership. Even if the FitcamX is on the HV battery should be able to cope for a "4-day weekend away".

Yes, at some point I noticed that my camera captured recordings in the middle of the night or at times I know I've left the car locked for long periods of time.

No change in wiring since I installed it, connected to the rain sensor.

There's been software updates and other recalls applied but never has the dealer previously mentioned touching the wiring to the rain sensor; and I would think I'd get a call from them before they would even touch an aftermarket item.

 

[ct14garage]

Your LiFePo4 12V battery is fucked... replace it with an AGM one.

We do this to all our customers, cheap, reliable, it's the best option really. The Taycan Gateway is ready to accept any AGM or even Gel battery with a very simple coding. Porsche used the LiFePo4 crap just to look good I guess.

Don't bother with it, they're super expense and the company that makes that battery A123System went bankrupt lmfao

AGM is the way to go

 

[rtemsamani]

Your LiFePo4 12V battery is fucked... replace it with an AGM one.

We do this to all our customers, cheap, reliable, it's the best option really. The Taycan Gateway is ready to accept any AGM or even Gel battery with a very simple coding. Porsche used the LiFePo4 crap just to look good I guess.

Don't bother with it, they're super expense and the company that makes that battery A123System went bankrupt lmfao

AGM is the way to go

That sounds better todo… is the so called simple coding todo by yourself with piwis?

 

[TaYcanAficionado]

Your LiFePo4 12V battery is fucked... replace it with an AGM one.

We do this to all our customers, cheap, reliable, it's the best option really. The Taycan Gateway is ready to accept any AGM or even Gel battery with a very simple coding. Porsche used the LiFePo4 crap just to look good I guess.

Don't bother with it, they're super expense and the company that makes that battery A123System went bankrupt lmfao

AGM is the way to go

haven't had any battery problems so far, but your post has made me happy, as having to spend $3,000 or more for a 12v battery replacement is just stupid. So please allow my question: assuming that you decide to replace the lifepo4 battery with an AGM one once the lifepo4 dies, what specification should the AGM battery be? I am mainly asking because, as far as I know, the taycan lifepo4 battery has its own BMS (one of the reasons why it's so expensive) and, further, the charging parameters for a lifepo4 battery should be different than an AGM battery.

Thanks for your insight.

 

[ct14garage]

That sounds better todo… is the so called simple coding todo by yourself with piwis?

With PIWIS or the conversion kits usually come with an OBD dongle that you can plug

Furthermroe my app tCAN-Pro will some come with this coding feature

https://www.taycanforum.com/forum/t...an-battery-diagnosis-for-the-community.27701/

 

[ct14garage]

haven't had any battery problems so far, but your post has made me happy, as having to spend $3,000 or more for a 12v battery replacement is just stupid. So please allow my question: assuming that you decide to replace the lifepo4 battery with an AGM one once the lifepo4 dies, what specification should the AGM battery be? I am mainly asking because, as far as I know, the taycan lifepo4 battery has its own BMS (one of the reasons why it's so expensive) and, further, the charging parameters for a lifepo4 battery should be different than an AGM battery.

Thanks for your insight.

You need a conversion kit with a negative wire and voltage sensing kit so the car can correctly read the voltage.

Battery should be LN0 40Ah AGM

 

[Gino]

I've had a FitcamX installed almost since day 1. Never a problem leaving the car for as long as 6 weeks. But I have the power wired into the rain sensor which is switched on and off with the "ignition". I believe you can hardwire the FitcamX to the fuse panel to enable a parking/sentry mode. It should be off unless an impact is registered. Powered by the rain sensor? It's not the FitcamX. Hardwired then maybe it's the culprit. Dealer can do a draw test and determine how much, if any, current is flowing with the car shut down. The other question is why the 12V battery wasn't topped off as the voltage dropped below the threshold voltage.

I think there is something else going on here. I’ve been told my 2021 HV battery will keep the 12V battery topped off as long as the HV SOC is above 50%.
There should be no reason for the 12V battery to die unless the battery itself has gone bad which is part of the 4 year “bumper to bumper” warranty and I think is also covered under the extended ”bumper to bumper” Porsche warranty. It seems odd the lithium ion battery would die so quickly after only 5 years which makes me suspicious that the HV battery is not properly maintaining the 12V battery.
The only other thing I could imagine is that between 2020 & early 2024 when I was told there was a software update which allowed the HV battery to maintain the 12V battery charge when SOC was above 50%.
I’m not sure how the 12V battery was being charged/maintained in 2020 up to the time they updated the software in early 2024. The drain from the FitCam may have exacerbated the problem but I am not convinced it is the root cause of the failure unless you allowed your car to constantly sit at less than 50% SOC since you bought it.
Good luck!

 

[HungryEyes77]

I think there is something else going on here. I’ve been told my 2021 HV battery will keep the 12V battery topped off as long as the HV SOC is above 50%.
There should be no reason for the 12V battery to die unless the battery itself has gone bad which is part of the 4 year “bumper to bumper” warranty and I think is also covered under the extended ”bumper to bumper” Porsche warranty. It seems odd the lithium ion battery would die so quickly after only 5 years which makes me suspicious that the HV battery is not properly maintaining the 12V battery.
The only other thing I could imagine is that between 2020 & early 2024 when I was told there was a software update which allowed the HV battery to maintain the 12V battery charge when SOC was above 50%.
I’m not sure how the 12V battery was being charged/maintained in 2020 up to the time they updated the software in early 2024. The drain from the FitCam may have exacerbated the problem but I am not convinced it is the root cause of the failure unless you allowed your car to constantly sit at less than 50% SOC since you bought it.
Good luck!

Thank you. I'll pass this on to the service advisor today. They did confirm that the extended Porsche warranty is an extension of the original warranty.

The HV battery is definitely not maintaining the charge on the 12V. Before my last trip, I made sure SoC was 80% and I left the L2 charger plugged in. Hopefully once diagnosed, I'll get a replaced 12V battery too.

On a side note: In Canada, I'm told we don't have the service action for the recall on the HV battery yet; but since I won't need the car for a couple weeks I told them to do a range test to escalate the issue. They've done this for another MY2020 with success that ended up needing a couple of modules replaced.

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