Electric Sailboat with Full Victron Setup 48 & 12v system

Saw a post doing the rounds about someone fitting a full Victron 48/12v dual-bus setup into a 38ft sailboat with electric propulsion — looked absolutely rammed in that engine bay. Got me thinking.

I run a similar split-voltage setup in my shepherd's hut (48v Victron Multiplus-II for the inverter side, 12v bus for lighting and 12v loads via an Orion-Tr). Works a treat on land where space isn't really a constraint, but I keep wondering how you'd manage the thermal side of things in a marine environment. Condensation alone would make me nervous.

Few things I'm curious about if anyone's done this on a boat — or even in a tight mobile install:

• Cable routing — how are you keeping 48v and 12v separated without it becoming spaghetti?
• BMS comms — are you running CAN bus back to the Cerbo, or just VE.Direct from each battery?
• Fusing strategy — particularly where the Orion-Tr DC-DC sits in the chain

My hut install isn't pretty either if I'm honest. Fogstar Drift 48v battery, Cerbo GX, and about four more connectors than I'd planned when I started. It always "keeps getting more crowded" as someone wisely put it.

Anyone running Victron kit in a genuinely wet/marine environment? Curious whether IP ratings on the kit actually hold up or whether it's more about enclosure design.

Boats are just caravans that try to kill you with corrosion instead of damp — same Victron MultiPlus-II headaches, just saltier.

The 48V bus for propulsion makes sense but watch your DC-DC converter sizing between the two buses; people chronically underspec the Orion-TR Smart thinking the 12V loads are "just lighting" then wonder why their bilge pump browns out mid-drama. Also, marine environment absolutely murders unsealed battery terminals — if they've gone Fogstar or similar lithium without proper IP-rated enclosures in that engine bay, they'll be crying into their compass within two seasons. Victron's CERBO GX with the tank/temperature monitoring makes sense on a boat at least, unlike my static van where I just know it's cold and miserable.

@Rob1963 ha, fair point on the corrosion front — makes my motorhome installation look positively straightforward.

Genuinely curious about the 48v propulsion side of this though. Has anyone here actually run a dual-bus setup like this in a moving vehicle (land or water)? I've been thinking about whether a 48v backbone would ever make sense in a larger motorhome build, stepping down to 12v for the habitation stuff via a DC-DC converter.

The Victron Orion-XS looks promising for that kind of 48→12v conversion — anyone used one in anger?

Main thing holding me back is the battery cost at 48v. Fogstar do some decent 48v lithium options now but it's still a significant jump from my current 12v setup. Wondering if the efficiency gains actually stack up in real-world use rather than on paper.

@Rob1963 nailed it, though I'd say boats try harder — at least a caravan doesn't sink when the bilge pump relay corrodes through at 2am.

Done a fair bit of emergency backup planning for my own setup and the number of failure modes on a marine 48v system would keep a paranoid engineer awake for years. Salt air

@AZY_Marine the bilge pump point is no joke — on the narrowboat I had a Victron BMV-712 throw a low voltage alarm at 2am because a corroded connection had been slowly dragging the 12v bus down for weeks. Completely silent failure until it wasn't.

The 48v propulsion side on a sailboat is a different beast though. Running dual buses means your DC-DC converter becomes absolutely critical — if that fails you're not just uncomfortable, you're potentially without navigation lights or VHF.

On the static caravan the stakes are obviously lower but the damp-related connection issues are genuinely similar. Dielectric grease everywhere, proper marine-grade terminals even when it feels overkill. Victron kit is solid but it can't save you from a corroded Anderson connector hiding inside a cable run.