If I don’t drive the car for six months, will the 12V battery run out of power?

[Gino]

I also have a wifi outlet which I planned to use if the 12V battery charge data was not being properly maintained but have not needed to use it since the 12V battery never goes below 13.3v.
Now I’m not sure if it matters for people living in very hot or very cold environments but in Southern California where the temperature in my garage is somewhere between 50 degrees to 80 degrees F max and is very dry so no leakage current drain due to humidity. Before I began using my 120V charger and kept the main battery at 60% just to be safely above 50% before going away for 2-4 weeks I saw not even a 1% drop in SOC over a month of sitting.
I was told by my dealer if I have everything off in the car, my key fobs out of range or in faraday cage pouches and you don’t open the Porsche app to check on the vehicle too often then I should have no draw down on the main battery or the 12v battery.
This I confirmed over 6 months of monitoring the 12V battery (13.5v) which did fluctuate a little between 13.2v to 13.5v and my main battery never dropped more than 1% over 4 weeks.
The only time I did see a drop of 1-2% was when I first got my Taycan CPO and it had timers active to cool down or heat up the cabin for the morning commute which the previous owner had set.
Once I deleted all timers for preconditioning the interior temp in the mornings my main battery SOC became rock solid.
Unfortunately Porsche does not make it clear exactly how the 12V battery is maintained. There is something else going on for those who have had their 12v batteries die in as few as 9 days.
I would put an inline meter to measure leakage current from the battery to ground. It should be zero when the car is asleep. If it’s not then you have to find what is draining the battery. If it’s not something you left on or left plugged in then it is something in the car’s electrical system which is burning down the battery over time.
Just one LED on a 5v USB cigarette lighter adapter can burn down a 12V battery in 7-10 days. The cheaper the USB adapter the less efficient it is and will drain your battery faster.

Sponsored

 

[Gino]

If you don’t drive the car for 6 months disconnect the negative wire from the battery. Else you have very good chances of having to purchase an expensive Lithium battery once you come back.

conversion to AGM works very well and is very much prefered!

I was thinking that switching to an AGM battery once my lithium ion battery needs to be replaced but you need to confirm the charging circuitry & profile is ok to charge an AGM battery. It could cause damage to the AGM battery if it gets overcharged and could jeopardize its lifetime if undercharged.
Does anyone know the exact voltage the charger on the Taycan uses to keep the 12V battery fully charged? I’m inclined to think it is 13.5V since I have never recorded any voltage over the 6 months I monitored the 12v battery which was above 13.5V.
I know my AGM batteries in my RV charge at 14.1V and I’m pretty sure you can’t charge Li-ion batteries at 14.1V since you would risk overcharging.

 

[tophamn]

If the 12 volt does die, learn how to use your emergency key...

I'd suggest if possible, such as in a locked garage, to leave the hood popped so if you need to 'jump' the 12V it's easily accessible.

 

[Gino]

If you don’t drive the car for 6 months disconnect the negative wire from the battery. Else you have very good chances of having to purchase an expensive Lithium battery once you come back.

conversion to AGM works very well and is very much prefered!

Battery Type	Charging Voltage	Float Voltage	Notes
Li-Ion (3S)	12.6V-12.8V (4.2V/cell)	N/A	No float; charger should cut off
LiFePO	14.2V-14.6V	N/A	Use BMS protection
AGM	14.4V-14.7V	13.2V-13.8V	Avoid overcharging, use smart charger

 

[Gino]

Better explained, that’s why AGM chargers damages lithium batteries.
At the same time though, if the lithium batteries requires less voltage, replacing the battery with an AGM, will result in the car sending the same lower voltage to recharge it and I’m not sure it can work properly..

Yes, I also read if you just switch to an AGM battery it is likely going to make the SOC measurements of the high voltage battery inaccurate.
Sounds like a risk I’m not likely to take until after my extended warranty ends in 2030.
By that time I should know how long the Lithium ion 13.5V batteries actually last.
I won’t feel so bad paying $1500 if it lasts 10+ years which is possible since my Taycan always charges in my garage and the 13.5V battery is consistently maintained between 13.2V to 13.5V for the last 20 months.

 

[Chiu]

If you don’t drive the car for 6 months disconnect the negative wire from the battery. Else you have very good chances of having to purchase an expensive Lithium battery once you come back.

conversion to AGM works very well and is very much prefered!

Thank you. If the negative terminal is disconnected for an extended period, will any components or settings be lost?

 

[SteveDC]

I'd suggest if possible, such as in a locked garage, to leave the hood popped so if you need to 'jump' the 12V it's easily accessible.

There’s a recent post on that point. You use a piece of wood to push down the locking mechanism on the hood, fooling the car into thinking the trunk is closed. Then gently lower the hood. This allow you to get to the battery without having to go the procedure of manually unlocking the driver’s door, then supplying an electrical source, so as to permit you to use your key to pop open the trunk, to get at the battery! This is a cumbersome procedure., just like with the 911, probably to make it tough on thieves. A dealer is supposed to have suggested this faux locking work around. As these various posts show, there is a lack of consensus on the best way to deal with 12 volt. That’s my story, and I’m sticking to it. ?

 

[TAYC4S]

You don't need a trickle charger. If the main battery is charged and your s/w is up to date, you can leave it alone. I had my car in the garage for over 3 months and never touched it. It had automatically gone into some kind of hibernating mode and woke up perfectly fine. The only other thing to bear in mind is keeping your car keys a good distance away from the car so that they are not trying to sync all the time...

 

[Dee]

You don't need a trickle charger. If the main battery is charged and your s/w is up to date, you can leave it alone. I had my car in the garage for over 3 months and never touched it. It had automatically gone into some kind of hibernating mode and woke up perfectly fine. The only other thing to bear in mind is keeping your car keys a good distance away from the car so that they are not trying to sync all the time...

Absolutely true BUT...
There are cars that are up-to-date and still die.
Just test if it'll hold for three/four weeks and if it does, it'll be fine the next coming months.
People that have experienced problems should go for the preconditioning/week and/or use a trickle charger.

 

[Tooney]

"If I don’t drive the car for six months, will the 12V battery run out of power?"
Another Taycan situation for Inspector Dirty Harry Callahan:
'You've gotta ask yourself one question: "Do I feel lucky?" Well, do ya, punk?'

 

[Emokeff88]

I'd like to ask if anyone has experience leaving their Taycan parked for up to 6 months without use.
I’ll be on an overseas assignment in the U.S. for a while (about 6 months), and before I leave, I plan to charge the high-voltage battery to at least 85%.

What I’d like to ask is:
Will the 12V auxiliary battery gradually lose charge due to the extended period of non-use?
I recall that after a certain software update, the main battery can charge the 12V battery. Sometimes, I even see the 12V battery voltage on the dashboard reading over 13.5V.

Do I need to manually charge the 12V battery?

I deployed to Japan for 6 months, car sat the whole time plugged in and turned on with no issues like it was the next day. The car only topped off the battery a handful of times and hardly lost any charge.

 

[Chiu]

I deployed to Japan for 6 months, car sat the whole time plugged in and turned on with no issues like it was the next day. The car only topped off the battery a handful of times and hardly lost any charge.

So you just plugged in the charging cable, locked the car, and left—and six months later, everything was as if nothing had happened?
Was your charging profile set to 50% or higher?

 

[TAYC4S]

So you just plugged in the charging cable, locked the car, and left—and six months later, everything was as if nothing had happened?
Was your charging profile set to 50% or higher?

Yep - but I only had it plugged in just in case I needed to remotely force a charge on the car - I did not need to as there was hardly no battery discharge in the period. By the way, this was over Winter in the UK as well!

 

[Emokeff88]

I made a post about long term storage results from my deployment.

https://www.taycanforum.com/forum/threads/6-month-deployment-storage-results.21847/#post-340708

 

[Watchesandburgers]

Porsche has issued two TSBs about storing Taycans:
For Taycans delivered to owners: https://static.nhtsa.gov/odi/tsbs/2022/MC-10209809-0001.pdf
For new Taycans not yet delivered: https://static.nhtsa.gov/odi/tsbs/2022/MC-10209808-0001.pdf

^-- THIS --^

Sponsored