MultiPlus ? 48/20000/250-100 oder MP2

Been going back and forth on this one for my shepherd's hut build and thought I'd throw it open for discussion.

Looking at the MultiPlus 48/5000 versus the MultiPlus-II — the AC Out 2 functionality is what's really swaying me toward the MP2 if I'm honest. The switchable relay output that cuts AC Out 2 when you drop below a set SOC is genuinely useful when you're trying to protect a smaller battery bank from getting hammered overnight.

For context, my static caravan uses an older MultiPlus and I've managed fine, but the hut is going to be more sensitive — I want to be able to shed non-essential loads automatically (water heater, that sort of thing) without babysitting the system manually.

Few things I'm still not 100% clear on:

• Is the AC Out 2 relay on the standard MultiPlus actually software-controllable via VE.Configure / VEConfigure 3, or is it purely SOC-triggered?
• Does the MP2's implementation give you more granular control through Venus OS / a Cerbo GX?
• For a smallish off-grid setup (probably 10-15kWh Fogstar lithium), is the MP2 overkill or genuinely worth the premium?

I've seen a few threads on the Victron Community forum touching on this but mostly European installs — wondering if anyone here running UK-based off-grid setups has actually compared the two in practice.

What are people running? And has anyone found the AC Out 2 switching to be a genuine game-changer for load management?

Reply by SolarTom:

@BoatMick great project! For a shepherd's hut the MP-II is worth the premium in my opinion, mainly because of the built-in grid code support — handy if you ever want to connect to a DNO supply down the line, even temporarily. The AC Out 2 feature you're hinting at is genuinely useful for non-essential loads like an immersion heater or an EV charger that you'd want automatically shed when on battery only.

One thing worth considering for a hut specifically is physical size — the 5000VA MP-II is noticeably chunkier than the original MultiPlus, so measure your installation space carefully.

What's your battery setup looking like? That might influence which direction makes more sense practically speaking.

Has anyone actually used the AC Out 2 to shed non-critical loads automatically when the battery drops below a set SOC? That's the bit I keep coming back to for my narrowboat setup — being able to drop the water heater or a secondary circuit without any manual intervention seems genuinely useful when you're on a rural mooring with no hookup for days.

@BoatMick for a shepherd's hut specifically, what's your expected peak draw? If you're not running anything particularly hungry simultaneously, do you actually need that AC Out 2 functionality in practice, or is it more of a "nice to have" that justifies the price difference on paper?

Curious what the real-world programming looks like via VE.Configure — is it straightforward or does it need a lot of fiddling to get the thresholds right?

@BoatMick done exactly this on my boat — AC Out 2 running the washing machine and a small immersion heater, both drop off automatically when the batteries get grumpy below around 50% SOC. Set it up through VEConfigure in about twenty minutes once you've stopped swearing at the interface.

@AGM_Pro yes, works brilliantly in practice. The relay logic is dead simple once you understand it's just a configurable threshold — SOC, voltage, or even a custom assistant. I've got mine set on voltage rather than SOC because my battery monitor has the accuracy of a broken compass on a rough day.

For a shepherd's hut the AC Out 2 is genuinely transformative — stick your kettle and electric shower on Out 1, everything "nice to have" on Out 2, and let the MP-II sort itself out. Fogstar cells won't complain either.

@AGM_Pro yes, I've had AC Out 2 doing exactly that on my shepherd's hut for two winters now. Set mine to disconnect at 40% SOC via VEConfigure — kettle and electric blanket on that circuit. What surprised me was how educational it became; you really start noticing your consumption patterns when the kettle suddenly stops working on a grey November morning.

The MP-II talks beautifully with my Victron MPPT and Cerbo GX, so the whole thing behaves like one organism rather than separate bits arguing with each other. That integration alone justified the cost difference for me over the standard MultiPlus.

@JohnDixon's immersion heater trick on a boat is clever — I'd considered something similar for my domestic hot water circuit when there's surplus generation.