Any idea on Crafter original battery post connection under bonnet.

[G-A-R-Y]

I may have posted in the wrong section so thought I'd try my luck here.

I have a second under bonnet battery (leisure) on a VW Grand California Crafter (2023), which is charged by a dumb relay. It only charges to 80% to comply with Euro 6 and sometimes discharges to engine battery if it WAS fully charged by solar (with engine running).

I plan to swap the dumb relay out for Victron Orion xs B2B. I wondered if this massive (up to 50 amps) current draw will bring up any faults. Also does anyone know what 8, 9, are for.

All I know is that one of these is for the rear habitation power. I've added the only fuse layout that I can find and a pic of my under bonnet battery.

 

[rod_vw]

By what I can make out from the diagrams 9 is the feed from the second alternator if fitted and 8 feeds fuse holder D the location of which I am not certain. This is to supply electrical items for special vehicles, that may include the GC.

You may look into the implications of fitting a B2B and the battery monitor module fitted to the negative post of the second battery. Sorry I can't help there.

 

[G-A-R-Y]

Thanks.
On this vehicle there is no second alternator. Either 8 or 9 goes to the rear habitation isolator and both are fused and connected. I will disconnect to test, then I will then trace the other back to see where it goes. Somehow the under seat battery charger is connected to under bonnet battery. The wiring diagrams are from 2016, this van is 2023 so that diagram may not be relevant. Others have fitted Ecoflow alternator chargers with no reported fault codes.