When I did my self build it used 16mm welding cable from the engine battery to the two leisure battery’s for decent charging and the same cable from the batteries to electric bus bars, worked a treat.
Although this forum is not made up of members doing there first VW conversion, many members have decades of experience and knowledge to share. I believe a combined effort of members here could build a moho from scratch including engine, transmission and chassisNot to argue, but ask a professional, most of what you read on a moho forum will be hearsay.
Admin knows his stuff
I think you may have posted up a wiring diagram from Peter as well? That diagram is a good resource for folk to look at as well.I linked my two 125ah lbs and my 125ah vb together, I took advise from Peter, (Listerdiesel) he knocked me up a 25mm2 cable and sent a fuse, 25a i think, it worked fine til I sold the van.
I think the diagram was posted on Motorhomebuilder in fact and from memory was by Peter although not identified directly as such (the description of the creator being a great help to many would certainly match the description of Peter).I don't think I ever did a diagram nor Peter, it was just connecting 3 batteries together in reality so just + to+ & - to-, but fusing was mega important as it is in any wiring, one thing I always to without fail is to have a fuse next to each battery regardless if it is linking two batteries in the same place double failsafe, fuse sizing has always confused me, all I recall is fuse the cable not what it is powering in a 12/24v system.
Qor you....Yes, that is a possibility, but I would say that unless there is a chance that the wires between the batteries would shortened to the metal mass, a single fuse between the batteries and the cable will suffice.
(By the way, being an electrical engineer, I think I know a little about this subject).