220V socket in the trunk

[Frankie]

I have a 220V outlet in the trunk. My question is where the car gets its 220v power from. From the 12V battery or the 100kWh high-voltage battery?
I can imagine that if it draws power from the 12V battery, the car battery would be so discharged that it might not start.
And if it uses the 12V battery, how long can you draw, say, 100 watts from the car?

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[PrudentOcean]

My understanding is that the car uses the 12V battery to power the outlet in the cargo area.

Having said that, the car will top off the 12V battery using the HV battery as needed. Also, you cannot keep the outlet powered for more than 30 minutes when operational readiness is not established, and even that needs to be enabled on the PCM before you exit the vehicle -- it's the same checkbox that allows the air conditioning to continue to operate.

 

[Frankie]

I plugged a 20-watt LED work light into the outlet a few times, and after 30 minutes, the power went off. I then immediately pressed the power button to the left of the steering wheel, and I had power again for 30 minutes. And then I did that again. But the question is how many times you can repeat this. I don't want the car to stop starting due to low battery voltage.
But if, as you wrote, the high-voltage battery is charging the 12V, that's fine, of course.

 

[pm4s]

I will try my best to calculate this (more knowledgeable folk can chime in).

Typical Resting AGM battery: 12.7V
Typical Dead AGM battery: 11.8V
(12.7 + 11.8) / 2 = 12.2V (50% life)
If battery drops to 12V you will start to have problems so to be safe I will calculate to 50% = 12.2V

12V x 68Ah (Macan battery capacity) = 816 Wh x 50% = 408 Wh, we consider 350-400 Wh for safety
Your load is 25-30W after inverter losses (12V step up to 230V)
350 Wh / 28 W = ~12 hours which means 24 x 30min sessions
So my answer is, personally I would feel safe doing this 24 times.

Remember every time you press the Start button you close the conductors for the HV battery, boot up all the ECUs, engage relays, start screens, AC, lights, whatnot which all drains the 12V battery.

The only thing that would work for you is the HV battery topping up the 12V but with no mention of this anywhere in the manual I did not take this into consideration.

As someone who had a flat battery due to a fault there were only 3 ways I could charge it:
- driving the car
- charging the car (HV battery)
- 12V battery trickle charger (obvious)

My suggestion would be to measure the 12V voltage with a multimeter and also check it on the screen to see if it is consistent, do not let it drop under 12.2V.

 

[daveo4EV]

I plugged a 20-watt LED work light into the outlet a few times, and after 30 minutes, the power went off. I then immediately pressed the power button to the left of the steering wheel, and I had power again for 30 minutes. And then I did that again. But the question is how many times you can repeat this. I don't want the car to stop starting due to low battery voltage.
But if, as you wrote, the high-voltage battery is charging the 12V, that's fine, of course.

it’s expected that the big battery charges the 12v battery until the big battery is “too low” - as long as there are no bugs in Porsche’s battery mgmt software you can run the the AC power outlet for quite some time! and the car will have plenty of power to wake up for normal operation

 

[Frankie]

@pm4s : Great calculation! Thanks!

 

[jwatte]

Yes, the trunk socket is powered by 12V (I considered tapping into it when I installed my underglow.)

What's worse, it only allows about 120 Watts, which isn't enough for charging modern workstation- or gaming-class laptops. I was quite disappointed when I found this out -- a typical "old system OEM" solution rather than a modern integrated systems solution we'd expect from a new EV platform.

I would probably not option this on a new order.

 

[sm06]

I also wish I did not option the trunk/boot charging receptacle. I have found it does not allow me to use a cooler, kettle, or laptop charger. Really nothing else I would plug in there.

 

[pm4s]

That's the unfortunate Porsche world we live in, crap specs for 3 times the price just to get the badge.
For the price of a "well" specced Macan I could buy 3 EV3s and those come with V2L 230V x 16A = 3680W = 3.68kW. They also have V2H & V2G.
Macan offers as an optional extra (obviously) a measly 150W 230V socket from a petrol Seat (not kidding or maybe a Skoda which ever parts bin they raided) and has no idea what V2L/V2H/V2G even means.
The worst part is since you are already raiding the bin why don't you give us USB-C connector on the rear view mirror housing from Skoda (great for dashcam) or OTA updates/ability to purchase upgrades from VW store?
I'm not asking for 4 sockets of 9.6kW like a Ford F-150 Lightning has but ever the bare minimum seems like too much to ask for Porsche.
This is an SUV and Utility is seriously lacking, don't get me started on the cramped rear seats, I've sat in the back of the Nissan that was half the size of the Macan but had twice the space in the rear but no sloping roof (which is important in an SUV!).

 

[jwatte]

If I needed the back seats, I would have gotten the Escalade

 

[Degenatron]

My understanding is that the car uses the 12V battery to power the outlet in the cargo area.

Having said that, the car will top off the 12V battery using the HV battery as needed. Also, you cannot keep the outlet powered for more than 30 minutes when operational readiness is not established, and even that needs to be enabled on the PCM before you exit the vehicle -- it's the same checkbox that allows the air conditioning to continue to operate.

Just to add to this I noticed the behaviour of the 12V charging logic while wiring up a dashcam:

After operational readiness is turned off, 12V remains powered at 14.4V, so the HV battery is still charging the 12V battery. After 30 mins this turns off and drops to whatever the 12V battery voltage is.

So if the 220V socket has power then the 12V battery is being charged by the HV battery. Therefore using the 220V will not drain the 12V, you will only drain the HV battery indirectly.

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