Anyone else running a Victron MultiPlus in a shepherd's hut without grid hookup — what's your idle draw reality?

Picked up a MultiPlus-II 12/3000 for the hut last spring, and the spec sheet says ~11W idle draw. In practice I'm clocking closer to 18–20W on the clamp meter, which over a long winter night adds up to an unwanted 200Wh+ just keeping the thing ticking over.

Running it alongside a Fogstar Drift 200Ah LiFePO4 bank, so the capacity is there, but I've got a single 200W Renogy panel on the roof that's doing its best in a Scottish November (spoiler: it's not enough to compensate).

I've played with the search mode / PowerAssist settings in VictronConnect, and dropping into search mode helped, but the hut has a small fridge that causes enough micro-surges to make search mode more trouble than it's worth — basically plays a little percussion solo every 15 minutes.

Anyone found a sensible threshold setting, or just accepted the idle tax and thrown another panel at the problem?

Has anyone actually verified whether that gap closes when you dial down the UPS/search mode settings in VE.Config? I've been curious about this for my van build — wondering if the PowerAssist feature being enabled adds to idle overhead even when there's no load demanding it.

Also worth checking — is your low battery cut-off voltage set conservatively? I read somewhere that the MultiPlus works slightly harder monitoring thresholds when it's hovering near trigger points.

What firmware version are you on? There were apparently some efficiency tweaks in recent releases but I've not seen hard data comparing before/after idle draw on the 12/3000 specifically.

Running a smaller Phoenix 12/1200 myself currently, so my numbers won't be comparable, but genuinely trying to understand this before I potentially upsize.

Hey @SaltyTrekker, yeah that 11W figure is very much a "best case in a lab" number in my experience. Mine settled around 16–17W once properly warmed up, but ambient temperature plays a bigger role than people expect — cold winters in particular push it higher as the unit works harder internally.

Worth checking your AC input/output wiring too; any loose connections or undersized cable can introduce resistive losses that show up on a clamp meter and get mistakenly attributed to the unit itself.

@PaddyGibson raises a fair point about VE.Config — I'd also look at whether PowerAssist is enabled unnecessarily, as that keeps additional circuitry active even at idle. If you're genuinely off-grid with no shore power coming in, disabling it made a noticeable difference on mine.

TracyRobinson | Posts: 847 | Location: Shropshire

@SaltyTrekker that gap between spec and reality is pretty typical in my experience — Victron's idle figures are measured under fairly controlled lab conditions, often without the full BMS comms overhead and any connected loads on the AC output side.

Worth checking whether your ESS assistant is loaded if you've configured any grid-tie features — that alone can nudge idle consumption up noticeably even without a grid connection present.

Also, is your battery temperature sitting low overnight? The internal fan cycling on thermals can account for a watt or two that people don't always attribute to the inverter itself.

@PaddyGibson raises a fair point about search mode — though on a shepherd's hut with a fridge running, you might find the constant reconnection cycling actually costs you more than just leaving it in normal mode.

Mine idles at about 19W too — turns out the MultiPlus is basically a small electric heater that occasionally charges batteries as a side project.