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12V battery: convert to a cheap alternative?

Vercingetorix

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I have for some time been thinking of installing one of these CTEK cables on the 12 volt battery. And then hide the plug somewhere accessible without requiring to open the bonnet. However I have earlier not done so, since Porsche could void the warranty due non approved accessories ??

After the latest episode I will however ask Porsche to install this cable. Lets see what the response will be. It is far to complicated to open the bonnet otherwise.

What do you think?
I would install Optimate..
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eddieterry

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Although I have used the CTEC Lithium charger to top up when I get the 12 Volt low message I don’t leave it connected to maintain as Porsche have warned me that the use of the CTEC on the Taycan 12 Volt is not supported as the following maximum values must never be exceeded: Max. charging voltage: 14.8V (even in the event of a fault with battery disconnected; no voltage peaks permitted). Max. charging current: 90A and that CTEC chargers are listed for all their models except Taycan.

They use 90A Deutronic chargers which have the ability to control current levels and are available online. For example: https://www.deutronic.com/ but for me the price is a bit too high.

I am hoping that the visit for the 12 Volt Switch firmware and software update next week will sort it.
 

ecko04

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I have for some time been thinking of installing one of these CTEK cables on the 12 volt battery. And then hide the plug somewhere accessible without requiring to open the bonnet. However I have earlier not done so, since Porsche could void the warranty due non approved accessories ??

After the latest episode I will however ask Porsche to install this cable. Lets see what the response will be. It is far to complicated to open the bonnet otherwise.

What do you think?
Porsche Taycan 12V battery: convert to a cheap alternative? IMG_8623
Sounds like this is what you’re talking about. About a month ago I ran a NOCO lead from the battery behind the ACC/NV grille that pops off.
 

ecko04

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I would install Optimate..
I could be mistaken, but I don’t think Optimate makes one that can charge to the nominal voltage of the LFP in the Taycan. Last I checked Optimate’s LFP charges to around 12.8V nominal while the LFP in the Taycan and programmed to the gateway looks for a ~13.5V nominal.

I like something like the NOCO that can kick that LFP up to 14.6V.
 

Vercingetorix

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I could be mistaken, but I don’t think Optimate makes one that can charge to the nominal voltage of the LFP in the Taycan. Last I checked Optimate’s LFP charges to around 12.8V nominal while the LFP in the Taycan and programmed to the gateway looks for a ~13.5V nominal.

I like something like the NOCO that can kick that LFP up to 14.6V.
Porsche Taycan 12V battery: convert to a cheap alternative? IMG_8863
 


Scandinavian

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Sorry, it was late after a long trouble some day.

I wasn’t planning to use a charger for this, only the boost function of either the lithium charger or a separate booster, to activate the relay.

I could use the same principle if a lithium booster has a cable that could be in place permanently.

Like @ecko04 showed!
 


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I am hoping that the visit for the 12 Volt Switch firmware and software update next week will sort it.
Would you know the Porsche service reference for this update? I am having my car in for service in a weeks time and want to be sure they perform this, if available here.
Thanks
 
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Warranty void. For the battery anyway.
To my understanding, the Porsche warranty doesn't cover the 12V battery anyway.

But then again, connecting a foreign power supply to your Taycans electronics isn't a good idea anyway.
The car itself should take care of that.
If not, it's Porsche's problem.
 

eddieterry

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Not sure of Porsche service reference - they just said it was a new 12 Volt Switch firmware or software (can’t remember which) that has recently come out and should address my problem.
 

jdzions

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Sigh. The moral of the story for me: when I park my2025 Taycan in winter, expecting not to drive it for a month or more, I need to pop the frunk before putting the cover on. That way, if the 12v BMS decides to turn catatonic, I have a place I can easily attach my 12v jumpstart pack (with its "override" button that just puts 12v on the clamps without trying to talk to the battery).

Once I get enough room in the garage that I can park the Taycan next to the '84 911 Cabriolet that got first dibs, it'll be a lot easier to start it once a week to prevent the issue.

Just got off the phone with my dealer contact who said "yeah, your 12v battery is probably dead, call Porsche Roadside Assistance for a tow to the dealership and they'll get it handled."
 

prj

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Sigh. The moral of the story for me: when I park my2025 Taycan in winter, expecting not to drive it for a month or more, I need to pop the frunk before putting the cover on. That way, if the 12v BMS decides to turn catatonic, I have a place I can easily attach my 12v jumpstart pack (with its "override" button that just puts 12v on the clamps without trying to talk to the battery).

Once I get enough room in the garage that I can park the Taycan next to the '84 911 Cabriolet that got first dibs, it'll be a lot easier to start it once a week to prevent the issue.

Just got off the phone with my dealer contact who said "yeah, your 12v battery is probably dead, call Porsche Roadside Assistance for a tow to the dealership and they'll get it handled."
Get the recall done, it addresses the problem.
 

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Get the recall done, it addresses the problem.
You sound very confident about the recall for the 12 V battery solving the issue.

Do you have any further information to share about how this now works?

I have the recall done and would like the confidence to not needing the frunk open, due to several occassions of calling Porsche Assistance for this issue At airports
 

prj

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You sound very confident about the recall for the 12 V battery solving the issue.

Do you have any further information to share about how this now works?

I have the recall done and would like the confidence to not needing the frunk open, due to several occassions of calling Porsche Assistance for this issue At airports
Most people never had any problems, as the TSB says:

Due to a software error of the battery sensor of the
12-volt vehicle electrical system battery, it is possible
that the battery data of the affected vehicles is calcu-
lated incorrectly.
"it is possible" - well I guess on some cars it is possible, on others not - why, we will probably never know what exactly they messed up there.

But "it was possible" on enough cars that we had a lot of people here on the forum who had problems. While others (including myself) never had a single issue.

For you the only way to find out is to try it ;)
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