Topping up 12V during long period off the road

[anonymouse]

We will be away for six weeks and although the vehicle will be plugged into power, I understand the 12V is likely to die because (unlike Tesla) it doesn’t charge from the main battery when parked. We don’t have trickle chargers etc available as recommended by Porsche and others.

Does it charge fairly quickly when main power is turned on? I was wondering whether we should have our son go and sit in the car for 15 mins half way through our trip, with the power on - would that top up the 12v or just drain it further?

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[800v]

From what I understand, having your son turn on the car fully is already enough -- it can't hurt to wait a bit while it's on to charge up the 12V battery (15 min should be enough) but the Taycan will already charge up the 12V battery from the HV battery automatically while it's off. The problem is that it does that at most 8 times when the car is off. However, when you turn on the car you get a fresh 8 times again
At least, that is how we think it works: see my post here.

Also, if you are unable to have someone turn on the car, I know that you can use the Posche app to remotely pre-heat the car for 30min or so to to recharge the 12V battery. see my post here. I believe that pre-heat also "turns on" the car and gives you a fresh 8 times but I have not been able to verify this.

Finally, as a final measure, I would leave the hood open (unlocked) when leaving. If the 12V battery would drain it is then easy to attach a charger to recharge it. If the hood is closed you need to do all these tricks to open the hood first ..

 

[Tooney]

https://www.taycanforum.com/forum/t...rging-and-towing-questions.19457/#post-299912

 

[Gino]

We will be away for six weeks and although the vehicle will be plugged into power, I understand the 12V is likely to die because (unlike Tesla) it doesn’t charge from the main battery when parked. We don’t have trickle chargers etc available as recommended by Porsche and others.

Does it charge fairly quickly when main power is turned on? I was wondering whether we should have our son go and sit in the car for 15 mins half way through our trip, with the power on - would that top up the 12v or just drain it further?

Now I'm confused again. I was told that as long as your main battery is at 50% or greater the 12v battery is maintained by the main battery. I have had my Taycan sit for as long as 2-3 weeks where the main battery charge level did not change at all during that period.
I was also told not to use the My Porsche app too often checking on the car's status because this "wakes up" the car and drains the 12v battery.
I have not seen any evidence of this over 2-3 weeks so I'm wondering if it is as simple as they said that the 12v battery is always maintained by the main battery as long as it has at least 50% SOC.
Evidently this was outlined in a Porsche Service Bulletin but I haven't seen it.

 

[The Kraken]

I laft my car with 65% charge on the main battery and was away for 3 weeks and the car's 12v battery simply died. The AA had to come and manually open the car, remove some panels in floor well and fiddle about to be able to get a charger onto it. The main battery still had 63% charge on it. Recovery chap said it was a design fault and he's called out at least once a wek to sort out this problem.

 

[anonymouse]

Another bit of dumb “copy how ICE cars work“ design it seems.
in the end I’ve gone for turning on climate remotely for an hour a couple of times during my absence and we will see whether that makes things better or worse; one theory is that this will power the car up and recharge the 12V from the main battery.

 

[anonymouse]

Just in case others are interested: the result of leaving the car off the road for six weeks with one top up mid way through (by running a cycle of climate conditioning after 3 weeks) was a success. Car all fine in return, no flat 12V.

I wasn’t able to run preconditioning a second time remotely because the car disappeared from the network (as usual, thanks Porsche for your crappy software design). Also to my surprise, a car parked with 60% set as profile and daily timer, seems to have magically charged to 85% or above. More software weirdnesses.

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