Hi, I'd like to install a second (leisure) battery to use during a 4 week camping tour this summer.

I see there's a factory option for this which located a battery in the rear left boot but that option is not fitted in my car which is a 2017 L&K estate. I've ordered a battery-to-battery charger which is compatible with smart alternators but it needs an 'enable' signal from the car to tell it when the engine is running and power is available.

A bit of searching suggests the BCM likely has an output for this purpose, enabled in vcds by "MAS01490-ENG142037-Energy management-Zweitbatterie".

I searched the wiring diagrams on fixmycarinfo.com hoping to identify the connector and pin but couldn't see any mention of the second battery option.

Has anyone done this or can suggest how to identify whether the signal should be available ?

People doing this on VW T6 vans who found the second battery wiring in Erwin and used it for this purpose :

https://forums.ross-tech.com/index.php?threads/23023/

Thanks.

Good luck, hope you find the way to do it.

I only can link you the diagram of how a second battery sits in the SIII.

I however have no idea how is in reality.

https://www.lllparts.co.uk/catalogs/skoda/CZ/SUP/851/9/915/915010

7 hours ago, leolito said:

Good luck, hope you find the way to do it.

I only can link you the diagram of how a second battery sits in the SIII.

I however have no idea how is in reality.

https://www.lllparts.co.uk/catalogs/skoda/CZ/SUP/851/9/915/915010

Yes I saw that and I've put mine in the same place after removing the (huge) subwoofer. I 3D printed a tray for the battery and secured it from both sides with a ratchet straps and it's solid. I couldn't find any signal which becomes live only when the engine is running so I've defaulted to a terminal 15 connection in the fusebox so on with ignition. Just need to never leave the ignition on. It seems to work ok.