New Victron System for 50foot Sailyacht

Right then, this takes me back to when I was doing a similar full Victron overhaul on my old narrowboat — though swapping a 50ft sailboat's electrics rather than a canal boat's is a whole different beast with the marine environment to contend with.

The Multiplus-Cerbo-MPPT holy trinity is essentially what I ended up with too, and honestly once everything talks to each other through VE.Direct it feels like you've unlocked some kind of energy wizardry. The VRM portal becomes slightly addictive — I've definitely caught myself checking battery state at 2am from a pub.

A couple of things worth thinking about if you're mid-build:

• Orion TR Smart isolators — are you going DC-DC or the transformer-isolated versions? On a sailboat with shore power in marinas, the isolated units earn their keep avoiding ground loops
• Fusing between the Argo FET and your battery banks — easy to overlook when you're buried in cable runs
• Cerbo GX tank/temperature inputs — stuff those full of sensors while you've got the dash apart, you'll thank yourself later

The non-Victron bits are where it gets interesting. What are you running alongside? Fogstar do cracking LiFePO4 cells if you're building a DIY bank, and they play nicely with Victron's BMS communication once you sort the DVCC settings.

What's your solar situation — rigid panels or going flexible? Flexible panels on a sailboat always sparks a debate worth watching...

Great project @DucatoDream! One thing worth flagging specifically for a sailing application that doesn't always come up with narrowboat builds — make sure you're thinking carefully about your Cerbo GX placement and ventilation. On a sailboat you'll have far more aggressive heel angles and potentially more condensation issues than on a canal boat, so cable routing needs to account for that.

Also worth considering a proper battery monitor on your bow thruster bank if you have one running separately from your house bank — Victron's integration makes it dead easy to keep tabs on everything through VRM from wherever you're moored.

What battery chemistry are you going with? Lithium opens up some cracking options with Victron's DVCC system but the BMS integration needs a bit more planning upfront. Happy to share some notes from similar installs if useful.

Really interested to follow this build — what's the battery bank looking like? On my motorhome I went with Fogstar Drift 100Ah cells and the Victron SmartSolar MPPT, but a 50ft sail yacht is a completely different energy budget.

A few questions that might shape the design:

• Are you planning shore power integration via a Multiplus, or purely solar/alternator?
• What's your typical passage length — coastal UK hops or longer offshore runs?
• Any wind gen in the mix alongside solar?

The reason I ask is that shading from the mast and boom can absolutely murder your solar yield in ways that don't apply to a motorhome roof. Worth considering whether MPPT string design needs to account for that, or whether individual panel optimisers make sense here.

What monitoring interface are you going with — Cerbo GX?

@DucatoDream 50ft sailboat Victron install — just remember the sea doesn't care about your carefully planned cable runs the moment you're heeled over at 30 degrees and everything's suddenly sideways, including your Cerbo GX's will to live.

@DucatoDream One thing I'd strongly emphasise for a sailing application specifically — seal and protect every single termination point as if it's going underwater, because eventually the humidity will make it feel like it has. I've seen this on my narrowboat (admittedly a different environment) but a 50ft coastal sailer is orders of magnitude worse for ingress and corrosion.

Victron's kit handles damp remarkably well but the weak points are always the terminations and cable entry points into enclosures. Self-amalgamating tape plus a decent marine-grade silicone over every gland, without exception.

Also worth thinking about your MPPT placement carefully — solar on a sailing yacht means constantly shifting angles and potential shading from the boom and rigging, so multiple smaller MPPTs tracking separate strings often outperforms a single larger unit. The SmartSolar 100/30 units give you real flexibility there.

@StuCampbell makes a fair point about terminal protection, though I'd extend that to the entire monitoring side too — Victron's VRM portal is brilliant but a corroded RJ45 on your GX device will have you flying blind at the worst possible moment. Self-amalgamating tape over every data connection, not just power terminals.

On the battery question @WattLiz raised — for a sailing application I'd be looking seriously at a proper marine-rated LiFePO4 setup with cells that have genuine IP ratings rather than just slapping standard van-build batteries in a locker. The charge profile interaction between your Victron MultiPlus and whatever bank you choose matters enormously — make sure your BMS communicates directly via VE.Can or VE.Direct so the Multi can actually respond to cell-level data rather than just guessing.

What's your shore power arrangement when berthed? That'll dictate a chunk of the MultiPlus sizing calculation.