12v outputs for factory fitted aux battery

[jacobk]

I have a 2016 Multivan (TDI, 204, 4motion, DSG, Highline, Dynaudio) with a factory fitted battery under the driver seat. The car has a aux heater, electrical sliding doors (both sides), electrical driver seat.

I'm trying to figure out if the 12V socket in the trunk and next to the backseat of the car is connected to this battery. I've found: Скачивание файла -vw-t6-fitting-locations-eng.pdf and the fuse card under the seat looks like the one on page 36. From my amateur perspective it seems that there's multiple v12 sockets connected to it. But they are labeled "12 V socket 2 -u18-" etc. And I cannot find a corresponding chart specifying where these sockets are.

My question is if anybody know if I can tell with certainty from the spec alone which battery these sockets are connected to? If not, how would I test, with a multimeter or similar, which battery a given socket is drawing power from?

 

[Deaky]

It’s very likely to be one of the 15a fuses in your first photo. Plug something in to it then pull the fuses one by one to find which it is

 

[mmi]

My question is if anybody know if I can tell with certainty from the spec alone which battery these sockets are connected to?

All sockets except the lower one in the dash are wired to the aux battery. In the wiring diagram No. 85.

how would I test, with a multimeter or similar, which battery a given socket is drawing power from?

Probably the most simple way is to measure voltages at starter and aux battery, then compare voltages at the sockets. To make voltage difference larger between the batteries turn on e,g. headlights and/or just IGNition on (do not start engine).

 

[jacobk]

It’s very likely to be one of the 15a fuses in your first photo. Plug something in to it then pull the fuses one by one to find which it is

Thanks. That's a great and simple suggestion!

 

[jacobk]

All sockets except the lower one in the dash are wired to the aux battery. In the wiring diagran No. 85.


Probably the most simple way is to measure voltages at starter and aux battery, then compare voltages at the sockets. To make voltage difference larger between the batteries turn on e,g. headlights and/or just IGNition on (do not start engine).

Thanks! I cannot find diagram No. 85. Is that in the file I linked or some other wiring diagram?

I will try the "pull fuses method" first. But I understand the suggested method. Good to know if I want to do further investigations

 

[mmi]

Thanks! I cannot find diagram No. 85. Is that in the file I linked or some other wiring diagram?

Not sure about the link, but yes - on that site somewhere.
Or e.g here

 

[n10n]

One more: I see you have CTEK -style quick connector for charging your 2nd battery. With ignition off, connect the charger and see it charges. Then measure the voltage at sockets - if you see > 13V you're seeing the charge voltage and hence the socket is fed through aux battery

 

[jacobk]

One more: I see you have CTEK -style quick connector for charging your 2nd battery. With ignition off, connect the charger and see it charges. Then measure the voltage at sockets - if you see > 13V you're seeing the charge voltage and hence the socket is fed through aux battery

Oh, didnt know. Is that the blue/black cable with black/orange connector? I don’t think I have anything I can connect to it. Will google ctek

Speaking of charging, for factory fitted batteries like this. If thats a charger-connection. Is it possible to charge battery while having devices connected to the 12v sockets with power still supplied to them?

E.g. If I want to run a small fridge of that battery but connect/charge the battery to external power over night.

Also, I tried the fuse-method and most v12 sockets are indeed connected to this battery. Thanks for the help!

 

[n10n]

Oh, didnt know. Is that the blue/black cable with black/orange connector?

To my untrained eye looks more like red/black cable. But yeah, the free connector dangling about, looking like in photo below taken from MXS 10 product page. It's not a factory thing so someone has added it.

MXS 10 UK

56-818

www.ctek.com

Speaking of charging, for factory fitted batteries like this. If thats a charger-connection. Is it possible to charge battery while having devices connected to the 12v sockets with power still supplied to them?

Sure, I do it all the time with charging either from solar panel or a charger while having fridge etc connected. It's no different to situation when you are running the engine and using the sockets - then the charging is just provided by alternator rather than an external charger.