Unsure about the correct wiring

Been through this exact headache last year when I moved my boat over to LiFePO4 with a full Victron setup — SmartSolar MPPT, MultiPlus, Cerbo GX, the lot.

Honestly the wiring diagrams Victron provide are decent, but they assume a fairly clean textbook install. Real-world stuff on a boat (or a van, I'd imagine) gets messy fast — fuse placement, busbar sizing, where exactly the battery shunt goes relative to everything else.

Few things I learned the hard way:

• Shunt placement is critical — it needs to be the only path between negative busbar and battery negative, otherwise your SOC readings will be garbage
• Cable sizing is where people cut corners — don't. Especially with LiFePO4 which can dump current fast
• Fuse as close to the positive terminal as physically possible — I've seen people put this 600mm down the cable which defeats the point entirely

The Victron wiring unlimited guide is worth downloading if you haven't already. Not perfect but it covers most common configurations.

What specific part of the wiring are you uncertain about? There's a big difference between "I don't know where the MPPT connects" versus "I'm not sure how to integrate shore power." Both valid but very different conversations.

Also — are you fitting a BMS with external control, or relying on the battery's built-in BMS to handle everything? That changes the design quite a bit, particularly around the charge disconnect behaviour.

Anyone else on here done a full Victron van build recently? Curious whether the ESS assistant setup is worth the complexity for a mobile system.

@ExBrickie Glad you mentioned this because the Victron diagrams can look deceptively simple until you're actually staring at a pile of cable and wondering which earth goes where!

One thing that really helped me was downloading the specific wiring unlimited guide from Victron's website — it goes into far more detail than the quick-start sheets. Also, their VictronConnect app shows you a live system overview once everything's connected, which is brilliant for spotting if something's gone wrong before you commission it properly.

What particular bit of the wiring are you unsure about? The MultiPlus AC connections, the battery cabling, or the VE.Bus/VE.Direct comms cables to the Cerbo? They're all quite different beasts and worth tackling separately rather than all at once. Happy to help if you can share a bit more detail about where you're stuck. 😊

@ExBrickie my static caravan Victron setup had me staring at those diagrams like they were ancient hieroglyphics — turns out the actual wiring is 40% guesswork, 40% YouTube rabbit holes, and 20% eventually phoning a Victron dealer who sighs heavily before helping you.

@ExBrickie worth being precise here — Victron's diagrams are actually split across multiple documents depending on your exact config. The MultiPlus wiring guide, the MPPT guide, and the Cerbo GX manual all need reading together, not in isolation.

For my cabin setup I found the Victron Wiring Unlimited PDF far more useful than the individual product sheets. Covers busbar sizing, fusing placement, cable runs — the stuff the quick-start guides gloss over.

Also, what's your battery comms setup? If you're running a proper BMS with VE.Can or VE.Bus, the wiring topology changes slightly. Don't assume the generic diagram applies without checking whether you've got a managed or unmanaged battery situation.

@PeakExplorer that's a really good point about the split documentation — caught me out badly when I was wiring up my shepherd's hut last spring. I had the SmartSolar PDF open, the MultiPlus one open, and the Cerbo GX guide, and they weren't quite consistent with each other on the battery sense wiring.

What actually saved me was the Victron community forum — someone had done a hand-drawn consolidated diagram for exactly my combination of kit. Worth searching there before you pull your hair out.

Also @ExBrickie — did you use a Lynx Distributor for your busbar setup on the boat? I went with a basic busbar from Amazon which I now slightly regret. Wondering if the Lynx would've made the whole thing cleaner to follow later.