12 Volt Battery

[Nesting]

I have a Taycan 2022, and it says in the user manual, that the 12V battery is connected and charged by the main car battery, even when the car is turned off. Unless the car battery gets at very low charge.

So maybe there indeed was a bug somewhere, but you should not need to connect your 12V battery to an outside source as long as you keep your car charged properly.

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[Dee]

I've had my Taycan for about three months. A month ago I 'lost' the 12v battery and needed to get the car jump started. This week I brought my car in for the WNA5 software update. When I picked up my car, I spoke with the service advisor and we discussed the problem I had with the 12v battery. He said that as part of the WNA5 update there was a software change which should prevent the car, in some cases, from continuing to use 12v power immediately after a charging session. It turns out that when I lost the 12v battery, it was three days after I had charged to 85% but then parked without using the car. So maybe my car was affected by this 'bug'.

Lets hope the WNA5 update has fixed the 12v problem permanently.

I'm in other groups as well and we haven't seen any 12V-issues lately so that's a pretty good sign imho.

 

[MartyMeatball]

Welp, add me to the dead 12V club. Went to use the car yesterday and it was dead. Fortunately my jumper cables were just long enough to reach from my other car and I was able to wake it up.

 

[raharris]

Welp, add me to the dead 12V club. Went to use the car yesterday and it was dead. Fortunately my jumper cables were just long enough to reach from my other car and I was able to wake it up.

What model year?

 

[daveo4EV]

These are the facts I have learned about the 12-volt battery:

1. The 12-volt battery is lithium-ion.
2. It does not interface with the larger battery that drives the car; in other words, the larger battery does not charge the 12-volt battery under any circumstances.
3. The 12-volt battery loses 1 1/2 percent of its charge each day the car is not driven.
4. If you store your Taycan for more than two weeks, you should attach a battery tender to the 12-volt battery.
5. The battery tender must be for a lithium-ion battery. Porsche and other brands sell battery tenders that service both regular and lithium-ion batteries. There is a switch on the tenders that you select for the type of battery you want to be charged.
6. The battery tender should be connected directly to your 12-volt battery, which is located in the front trunk. Do not connect the battery tender via the cigarette lighter; it will not work efficiently or at all.
7. The Porsche brand battery tender for lithium-ion batteries is expensive. You could purchase a tender for less money on Amazon: NOCO Genius 10 Battery Maintainer.

as @Dee has noted these facts are 100% wrong - there is in fact a DC/DC charger in the Taycan (and other EV's) where the big battery will charge the "little" battery

so much wrong with this post - it's hard to know where to start.

 

[CygnusX-1]

These are the facts I have learned about the 12-volt battery:

1. The 12-volt battery is lithium-ion.
2. It does not interface with the larger battery that drives the car; in other words, the larger battery does not charge the 12-volt battery under any circumstances.
3. The 12-volt battery loses 1 1/2 percent of its charge each day the car is not driven.
4. If you store your Taycan for more than two weeks, you should attach a battery tender to the 12-volt battery.
5. The battery tender must be for a lithium-ion battery. Porsche and other brands sell battery tenders that service both regular and lithium-ion batteries. There is a switch on the tenders that you select for the type of battery you want to be charged.
6. The battery tender should be connected directly to your 12-volt battery, which is located in the front trunk. Do not connect the battery tender via the cigarette lighter; it will not work efficiently or at all.
7. The Porsche brand battery tender for lithium-ion batteries is expensive. You could purchase a tender for less money on Amazon: NOCO Genius 10 Battery Maintainer.

If any of this was true it would be a black mark on Porsche’s engineering. I’ve owned a Model S for 9 years and have never used a “battery tender”. I’ve never used jumper cables (in fact, was told by Tesla NEVER to use jumpers) and I’ve never had the 12V die on me. I have replaced it, one time, as part of regular maintenance.

Reading stuff like this makes me wonder how many of the “issues” people report about their Taycans are just a function of user error or ignorance.

 

[MartyMeatball]

What model year?

2021

 

[raharris]

as @Dee has noted these facts are 100% wrong - there is in fact a DC/DC charger in the Taycan (and other EV's) where the big battery will charge the "little" battery

so much wrong with this post - it's hard to know where to start.

Under what circumstances does the main battery charge the 12v? If it was when it dropped below a certain level, should never see a flat 12v battery? Or is that a consequence of an earlier bug? Or does the vehicle have to be on and/or moving to top up the 12v?

My understanding was that during charging, there was a relay that disconnected the main battery from most of the circuits during charging and that is the noises we here as charging commences. But that is based on “YouTube wisdom” and on a different EV

 

[JimBob]

The 12v battery is automatically charged by the HV battery. This from Porsche

The Porsche Taycan is equipped with a 12-volt Lithium-Ion battery which is automatically charged and maintained by the High-Voltage (HV) traction battery and battery electronics.

Provided of course the system is operating properly.

 

[Kinney]

Received my Taycan 6 weeks ago. today had to call out Porsche assistance as I could not open my car the remote would not open the doors. The roadside assistance found that my 12 volt battery was flat as I had not used the car in 10/14 days. He got it going again and said that I need to use the car every 3 days or so to keep it charged. or buy a trickle charger to keep the battery positive. my question why haven't Porsche provided a convertor from the main car battery to provide a trickle charge to the 12 volt battery.

You will read many opinions about maintaining the charge of the 12V battery. I offer mine: After much research and after confirming that the large drive battery does not tend the 12V battery when the car is turned off, I purchased a trickle charger for the 12V battery and connect it to the car if it sits for more than a week. (My car sits unused for weeks at a time.) The car does not have to be driven every three days or so to maintain the charge of the 12V battery. It will maintain its charge for a much longer time.
The trickle charger is easy to connect in the frunk - - one clamp to the positive post of the battery; one clamp to a negative post that is located to the left of the battery. Do not use a clamp on the negative post of the battery. Also, make certain that you purchase a tender that is designed for 12 V lithium-ion batteries.

 

[ciaranob]

You will read many opinions about maintaining the charge of the 12V battery. I offer mine: After much research and after confirming that the large drive battery does not tend the 12V battery when the car is turned off, I purchased a trickle charger for the 12V battery and connect it to the car if it sits for more than a week. (My car sits unused for weeks at a time.) The car does not have to be driven every three days or so to maintain the charge of the 12V battery. It will maintain its charge for a much longer time.
The trickle charger is easy to connect in the frunk - - one clamp to the positive post of the battery; one clamp to a negative post that is located to the left of the battery. Do not use a clamp on the negative post of the battery. Also, make certain that you purchase a tender that is designed for 12 V lithium-ion batteries.

Quoting 'facts' and now 'opinions' without any source or verifiable reference is never a good base to start from - back up your statements with Porsche documentation and you'll get far more positive responses.

@daveo4EV

In that car manual reference to 12v battery potentially having issues in the case of the main HV battery having a very "low SoC', do we know what are the actual numbers? It seems weird they do not state what 'low' means in this case (I'd assume below 5% but thats just a total guess!?)

 

[Jayyvr890]

It's software problem that causes overconsumption of the 12V battery when car is off. You should take the car into the dealer to have the electronic and drive module software updates done.

No 12V battery will drain just after a few weeks. I have a 10 year old Mini (4 year old 12V) and I can leave the car parked for 2 months with no issue lol.

 

[IrwinJ]

I asked about this in another thread (I started) and haven't received the specific answer I'm looking for.

It's one thing to leave the car for 2 weeks, but at the end of October I'll be leaving my Taycan in my western NC unheated garage for 6 months, so:

first question: in this situation should I attach a trickle charger (designed for a lithium battery) to my 12 volt battery?

second question: if I leave the main battery charged at say 85% will it survive the 6 months without draining itself?

 

[ciaranob]

I asked about this in another thread (I started) and haven't received the specific answer I'm looking for.

It's one thing to leave the car for 2 weeks, but at the end of October I'll be leaving my Taycan in my western NC unheated garage for 6 months, so:

first question: in this situation should I attach a trickle charger (designed for a lithium battery) to my 12 volt battery?

second question: if I leave the main battery charged at say 85% will it survive the 6 months without draining itself?

Q1 - No - and do not ping your car more than once or twice a month whilst away as activating PCM remotely uses the 12V battery.

Q2 - Yes.

and a) inflate tires to recommended psi in GTK app and b) re-confirm all with dealership !

 

[IrwinJ]

and a) inflate tires to recommended psi in GTK app and b) re-confirm all with dealership !

definitely - I know that from storing my SL 550 every year for the last 7 years!

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