Taycan 12v battery issue

[AKM]

I own a 2021 Porsche Taycan 4S which has about 4000 miles on the odometer due to the fact that I spend my winters in Florida and
also drive it minimally in the summer.Upon my return from Florida about 5 weeks ago the battery was totally dead and had to be towed to the dealer.A couple of days later the dealer determined that the 12v battery (lithium) was totally dead and had had to be replaced
at a cost of over $2000. In addition the car needed a battery maintainer costing more $'s. PS Porsche advises to leave the charger unplugged if you go for any long trip. On the other hand my previous EV, Tesla 4S required the charger to stay plugged in.
From what I can deduce from this situation Porsche should have installed a battery maintainer from the outset so that the battery did
not completely breakdown.The 12V battery is not under warranty so this is a significant cost to the owner. Moreover, it has been 5 weeks since the car went in to the shop as Porsche has been unable to obtain the battery from Germany. Wonder if the newer Taycans have a built in battery maintainer or have addressed this problem in some other way.Feel that this should have been done under recall by Porsche as from what I understand other owners have a similar problem!!
Comments?

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[Shaf]

I’ve not done a lot of research but I think the owners manual suggests the car plugged in and that a maintainer be put on the 12 volt battery. CTEK has one available on Amazon for about $113. I just bought one before I leave for about 6 weeks. Read the owners manual rather than rely on the dealer. Sorry for your trouble.

 

[jasperp]

Why can't the car maintain the 12V by itself. Using the main battery or the main power supply ?
Sounds like a design fault.

 

[Vercingetorix]

https://www.taycanforum.com/forum/t...battery-issues-and-a-potential-solution.4603/

 

[FlyingPoint]

I was surprised when the OP indicated that a 12v battery is not covered by warranty. I have had 12v batteries replaced under warranty in other Porsches. As I researched the issue, the warranty will not cover battery failure due to the storage of vehicle. They don't make a distinction between batteries, so I guess it could be either or.

Not withstanding what the Owner's Manual says to do when storing a car, here is what page 6 of the Taycan Warranty books announces:

• If you do not plan to drive your Taycan regularly, or plan not to drive it for several weeks, it is recommended that the vehicle be left plugged into the home charger when not using it. This enables the vehicle to maintain a charge level that helps maintain Battery performance over time.

 

[MartyMeatball]

Your 12V battery is fine. It has internal battery management and shuts down if the charge is too low.

The dealer sold you something you didn't need. All you need to do is "jumpstart" the car. Pop the frunk and attach some jumper cables to the 12V posts. Turn the car on and it will proceed to charge the 12V battery from the traction battery.

There is a software update to address the 12V battery dying during storage.

 

[XLR82XS]

There are plenty of posts on the Audi etron forum about drivers leaving their car plugged into the L2 charger for long lengths of time and returning to find a dead 12V battery. The 12V battery is only charged from the HV battery while the car is running. When a charger is plugged into the car certain electronics are activated which eventually runs down the 12V battery. Usually a low power jump to the 12V battery will restore the car to service.

Not true according to Porsche. See post #5 as well.

 

[Eric]

I own a 2021 Porsche Taycan 4S which has about 4000 miles on the odometer due to the fact that I spend my winters in Florida and
also drive it minimally in the summer.Upon my return from Florida about 5 weeks ago the battery was totally dead and had to be towed to the dealer.A couple of days later the dealer determined that the 12v battery (lithium) was totally dead and had had to be replaced
at a cost of over $2000. In addition the car needed a battery maintainer costing more $'s. PS Porsche advises to leave the charger unplugged if you go for any long trip. On the other hand my previous EV, Tesla 4S required the charger to stay plugged in.
From what I can deduce from this situation Porsche should have installed a battery maintainer from the outset so that the battery did
not completely breakdown.The 12V battery is not under warranty so this is a significant cost to the owner. Moreover, it has been 5 weeks since the car went in to the shop as Porsche has been unable to obtain the battery from Germany. Wonder if the newer Taycans have a built in battery maintainer or have addressed this problem in some other way.Feel that this should have been done under recall by Porsche as from what I understand other owners have a similar problem!!
Comments?

The battery should be under warranty see no reason why it would not.I travel a lot and also have a 4S 21 with 15 k miles on it .I left the car in May for two months charged to 90% and when i came back the SOC was still 90% and the battery 12.4 Volts

 

[Dr Monty]

I was surprised when the OP indicated that a 12v battery is not covered by warranty. I have had 12v batteries replaced under warranty in other Porsches. As I researched the issue, the warranty will not cover battery failure due to the storage of vehicle. They don't make a distinction between batteries, so I guess it could be either or.

Not withstanding what the Owner's Manual says to do when storing a car, here is what page 6 of the Taycan Warranty books announces:

• If you do not plan to drive your Taycan regularly, or plan not to drive it for several weeks, it is recommended that the vehicle be left plugged into the home charger when not using it. This enables the vehicle to maintain a charge level that helps maintain Battery performance over time.

Well, I wish I had known this info (assuming it is correct for my MY2021 4S CT.). I had the most recent SW update in July (or August?). However after not driving the car for three weeks (and after just two days selling my other car - a totally reliable MB E-Class All-Terrain) I found my Taycan to be totally inert. Had to use the emergency mechanical key to open the car, but it is dead as a stone.

So, then tried to get the “frunk” / bonnet to open, (to charge the 12V battery) which is accomplished by hooking a battery charger to a connection in the Fuse box area on the drives side. Murphy’s Law applied however, and that didn’t work.

Now waiting for Porsche Assistance to come and try their hand at it.

Hopefully when it goes in for its next pending Recall - brake warning system malfunction / Firmware/ SW. update I hope it will get the prophesied SW fix for the 12V battery discharge issue.

Fortunately my car is in a garage, but since I can’t even close the door (window doesn’t roll down that little bit to fit) this could be No fun if it was outside in the currently pouring rain.

Really disappointing. To think that yesterday I went to the Porsche Experience Center and had fun with. Boxster GTS 4.0. A much better experience than an inert 21st Century super car.

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