Multi-Pluss II AC outputs question

Anyone else had a proper head-scratch moment reading the Victron Multiplus II manual before install?

Just going through mine ahead of wiring up the boat and noticed the two AC outputs behave quite differently — AC Out 1 stays live regardless (pass-through from shore power or inverting from the batteries), whereas AC Out 2 only gets power when there's an AC input present, essentially dropping out the moment you go off-grid.

For a UK setup this actually matters quite a bit depending on what you're running. I'm planning to put my critical 240V loads — fridge, a few sockets — on AC Out 1 so they keep ticking over on battery when I'm away from a marina. AC Out 2 seems ideal for "luxury" loads you'd only want available on hookup anyway, like an immersion heater or a battery charger for power tools, so you're not accidentally hammering your Fogstar lithium bank trying to heat a tank of water at anchor.

Couple of questions for anyone who's done this already:

• Have you found the AC Out 2 dropout causes any issues with smart devices that get confused when power disappears?
• Is there a way to configure AC Out 2 behaviour through VE.Config or do you just have to live with it?

Seems like Victron have been quite deliberate about this design but the manual is about as clear as a muddy estuary on the why of it all. Would be good to hear how others have split their loads across the two outputs — especially anyone running a similar liveaboard or off-grid cabin setup here in the UK.

@BC_Boats AC Out 2 drops dead the moment your batteries give up the ghost — brilliant if you want your kettle to mysteriously stop working mid-brew but your bilge pump to carry on regardless.

Yeah, @BC_Boats, had exactly that moment myself last spring! To add to what @WheresMeWires87 is getting at — AC Out 1 is your "always on" output, powered whether you're on shore power, inverting from batteries, or charging. Really useful for anything safety-critical like bilge pump controllers or navigation electronics on a boat install.

AC Out 2 is the clever one though — you can actually configure it to switch on/off based on battery state of charge thresholds via VE.Configure, not just drop out on low battery. So you could have non-essential loads like a water heater only kick in when your bank is sufficiently topped up. Proper useful for solar setups where you want to prioritise charging before running heavy loads. Worth spending an hour with VEConfigure3 before you finalise your wiring plan — saves a lot of head-scratching later!

Yeah so AC Out 1 is your "always on" output — it'll pass shore power through AND invert from batteries. AC Out 2 is load-shedding territory, cuts when you're running on batteries only.

Practical upshot for my motorhome setup: non-essentials (second socket ring, water heater) go on Out 2. Fridge, CPAP, anything you actually need stays on Out 1.

Worth knowing you can tweak the threshold in VictronConnect — so AC Out 2 doesn't just drop dead at 0%, you can set it to shed load at say 50% SOC instead. Gives you a bit of warning rather than your kettle just dying mid-brew.

@Derek1977 probably knows the exact parameter name off the top of his head — it's somewhere in the inverter settings, "AC Out 2 control" or similar. Check the CCGX/Cerbo config if you've got one.

Worth adding to what @OffGridMax laid out — in practice, AC Out 2 is brilliant for intentional load shedding. On my setup I've got the washing machine and immersion heater on Out 2, so they automatically drop off when I go off-grid or the batteries dip below my configured threshold. No manual intervention needed.

You can tweak that threshold in VictronConnect (or VEConfigure if you're going deeper), so it's not just binary shore/battery — you can have Out 2 cut at, say, 50% SOC to protect your bank.

For a boat install especially, that kind of automatic load management is worth its weight. Just make sure your critical navigation electronics and bilge pump circuit are firmly on Out 1.