MultiRS 6000 minimum voltage

Got a bit of a head-scratcher with my MultiRS 6000 setup at the cabin and wondering if anyone's hit the same wall.

Running an east/west split across my static caravan roof — panels face opposite directions obviously, so I've wired them into the two separate MPPT inputs on the Multi RS rather than lumping them together like some sort of solar smoothie. Makes sense in theory, mornings on one input, afternoons on the other, everyone's happy.

Here's where it gets murky though: what's the actual minimum array voltage each input needs to wake up and start doing something useful? The Victron docs are a bit vague and I've had a couple of grey mornings where I'd swear at least one string should be producing something, but the VRM is showing nowt until well into the day.

Specifically:

• Is there a minimum start voltage before the MPPT on each input kicks in?
• Does it differ between the two inputs, or are they treated identically?
• Anyone noticed weird behaviour when one input is producing and the other's essentially dead — does the whole unit throw a wobble?

My Fogstar lithium bank is sitting at a healthy state of charge so it's not a low-battery cutoff thing. Just feels like I'm losing a chunk of early morning generation on the east-facing string and I can't work out if that's the hardware being fussy or just the British weather doing its thing (almost certainly the latter, let's be honest).

Any MultiRS veterans who've actually mapped this out properly, I'd love to know what voltages you're seeing on each input before they come alive.

@DailyWanderer the MultiRS is fussy about minimum array voltage — needs to see at least 38V before it'll even attempt to track, and that's at the low end. With an E/W split you're likely getting one string lagging badly in the mornings and the inverter just sitting there waiting.

What's your string voltage on each side? If you've got mismatched VOC between the two orientations it can cause the MPPT to hunt around rather than lock on properly.

On my narrowboat I ran a similar split layout (not MultiRS, Victron Quattro + separate SmartSolar) specifically to avoid this — kept the strings independent so each could optimise without dragging the other down. Might be worth considering if your wiring allows it.

Post your Victron Connect screenshots if you can — the history tab will show whether it's actually reaching bulk or just flicking in and out.

@DorsetSolar has the 38V floor covered, so I'll add some texture from my own east/west experience.

The sneaky gotcha with that split orientation is that both MPP trackers need to hit minimum voltage simultaneously before the unit wakes up properly. On grey mornings I've watched my setup faff about for ages because the east array climbed above threshold while the west was still lagging — the inverter just sat there sulking.

Worth checking your string voltage at the controller inputs rather than panel spec sheet figures. Real-world cold-soak voltage can actually help here — panels run cooler, Voc climbs — but heavily overcast conditions are where east/west splits really expose that minimum voltage sensitivity.

What's your string configuration on each tracker? Series vs parallel will dramatically affect whether you're comfortably above 38V when things are gloomy.

Worth adding — the temperature derating can catch you off guard on cold mornings too. Voc climbs as panels cool down overnight, so double-check your string calc doesn't push you over the MultiRS input ceiling (145V I think?) when it's a crisp winter morning.

On the east/west split itself, I ran something similar across my cabin roof before I understood the shading interaction properly. The two strings effectively drag each other down through the day if they're wired together rather than feeding separate MPPTs. The MultiRS has two independent trackers — make sure you're actually using both separately, not combining the strings into one.

Might sound obvious but I definitely bodged that initially 😅

Had this exact issue at my cabin last winter. The east/west split sounds great on paper but in practice you can end up with both MPPTs in a kind of limbo at dawn/dusk — neither string hitting threshold properly.

What sorted it for me was checking the minimum Vmp under worst-case conditions (hot summer afternoon, panels thermally derated) rather than just STC figures. Easy to be 5-6V lower than you'd expect.

Also worth logging via VRM for a week or two — the dropouts show up clearly in the graphs and you can see exactly when and why it's losing lock. Saved me a lot of guesswork.