Anyone else running a Victron MultiPlus on a static van? Struggling to size it correctly

Been trying to work out the right MultiPlus spec for my static caravan setup. Currently running a 48V system with 400Ah of Fogstar Drift lithium, fed by 800W of solar on the roof. Most of the time it's fine, but I keep second-guessing myself on whether the 1600VA unit is enough or if I should've gone for the 3000VA.

The issue is the kettle. It's a 2.2kW kettle and I've read the MultiPlus 1600 can handle brief peaks beyond its rating, but I'm not 100% sure how long it'll tolerate it before it starts throttling or throwing faults. Has anyone actually tested this in practice rather than just going on the spec sheet?

Also wondering about the shore power side — I've got a 16A hookup available on site. Is it worth configuring the PowerAssist feature to blend shore and battery when the kettle kicks in, or is that more hassle than it's worth for a static setup?

Hey @YorkshireCamper, what appliances are you planning to run? That's really the key question before settling on a MultiPlus size.

With 800W of solar and 400Ah of Fogstar Drift, you've got a decent foundation. The MultiPlus comes in 1600W, 3000W and 5000W variants mainly - the 3000W is the sweet spot for most static van setups in my experience.

One thing worth considering is surge capacity rather than continuous draw - kettles, washing machines and fridges all spike hard on startup. The MultiPlus handles surge well but you want headroom.

Also worth mentioning - are you grid-tied at all or purely off-grid? If you've got a hook-up point occasionally, the MultiPlus charger functionality becomes really useful and might influence which spec makes sense for your situation.

What's your peak daily consumption looking like roughly?

@YorkshireCamper the classic "how long is a piece of wire" question of the off-grid world 😄

Seriously though — add up your peak loads, not your average loads. That kettle, that microwave, that hair dryer your partner "definitely won't be using" — they all hit at the same time somehow.

On a

@YorkshireCamper worth looking at your peak/surge loads not just running watts — that's what caught me out initially. My kettle and microwave together briefly pulled nearly 3kW on startup even though steady-state draw was lower.

Also, are you planning to use the MultiPlus for grid/shore power passthrough at any point? That changes the equation quite a bit on a static van versus a purely off-grid mobile setup.

With 800W solar and 400Ah Fogstar, what's your typical daily consumption like? The MultiPlus 2000 vs 3000 decision probably hinges on whether you're ever running two heavy loads simultaneously.

@YorkshireCamper ran into exactly this sizing puzzle on my narrowboat before I started using the same kit for emergency backup and EV charging at the mooring.

One thing nobody's mentioned yet — the MultiPlus has a transfer switch built in, so if you've got any shore power hookup at the static van site, that affects your sizing decision too. The 2000VA handles most domestic loads comfortably, but the moment you're thinking about an electric shower or induction hob, you're looking at the 3000VA minimum.

What really sorted my thinking was using Victron's online sizing tool — plug in your appliances, it spits out a sensible recommendation. Saved me from either over-specifying (expensive) or under-specifying (frustrating).

What's the single biggest load you're expecting to run? That one appliance usually dictates the whole decision.