Multi RS Solar and solar panel incompability

Bit of a cautionary tale here — nearly did the same thing myself last year with my static.

Picked up some cheap panels from a clearance sale, got excited about the price and nearly just wired them straight into my Victron Multi RS Solar without checking the specs properly. Mate stopped me just in time.

The Multi RS is fussy about input. People forget it's not just about wattage — you've got to check:

• Voc (open circuit voltage) — needs to stay within the inverter's PV input range
• Vmp — your operating voltage has to suit the MPPT tracker range
• String configuration — get this wrong and you're either under-performing or risking the hardware

My setup ended up being two separate strings on the dual tracker, which sorted it, but only after I actually sat down with the datasheet rather than just eyeballing it.

Anyone else running the Multi RS Solar? Curious what panels people are pairing with it. I've seen a few threads suggesting Longi and JA Solar panels work well but never seen anyone confirm it for the dual tracker specifically.

Also — did Victron's compatibility tool actually help anyone or is it as vague as I found it? Felt like I was guessing half the time.

Don't rush panel purchases just because something's on discount. Learned that the hard way, almost.

Done exactly this with my shepherd's hut build 😬

Spent ages spec-ing out the Multi RS Solar then nearly bought a job lot of panels without checking the Voc properly. The Multi RS has that higher MPPT input range which is great but it'll absolutely fry itself if you exceed the max input voltage — especially on a cold morning when Voc spikes.

Worth everyone bookmarking Victron's compatibility tool before buying any panels. Also check the temperature coefficient — panels behave very differently at -10°C vs the spec sheet conditions.

@ZFS_OffGrid what panels were you looking at originally? Sometimes the cheaper Renogy ones are actually fine once you run the numbers properly, it's the random clearance stuff with dodgy datasheets that catches people out.

@Fiona1974 mate, the Multi RS Solar's Voc limit will humble you faster than a low bridge on the Oxford Canal 🚢

@Fiona1974 it's an easy trap to fall into — you spend weeks obsessing over the inverter spec sheet and then gloss over the array voltage limits like they're small print on a car insurance renewal.

With the Multi RS Solar the maximum PV voltage is 680V and you absolutely need to account for Voc at low temperatures, not STC ratings. Cold winter morning in the UK, your panels will spike well above what they'll show on a datasheet at 25°C.

Run everything through Victron's MPPT calculator before you commit to a string config. Saved me a headache on my cabin setup last year when I realised my proposed 4S arrangement would've been pushing it uncomfortably close to the limit by February.

Cheap panels aren't inherently the problem — not reading the spec sheet properly is.

Hey @Fiona1974 — glad you caught it before wiring anything up! The thing that catches a lot of people out with the Multi RS Solar specifically is that the Voc limit isn't just a warm-weather figure. You need to be calculating your worst-case cold morning voltage, because on a proper frosty January day those panels will push significantly higher than their rated Voc. I'd recommend running the numbers through Victron's MPPT calculator rather than just eyeballing it — it accounts for temperature coefficients properly. Also worth double-checking your string configuration, because sometimes you can rearrange series/parallel to bring everything within spec without needing to ditch the panels entirely. Might save you having to return them if you haven't already!

Yep, @MaxReid95 is right to flag that — and it's worth mentioning that the Voc changes with temperature too. Those clearance panels are often older stock or from less reputable manufacturers, and the spec sheets can be... optimistic, shall we say. Always worth derate-checking your actual Voc at your coldest expected ambient temperature, not just the standard test conditions figure. A crisp winter morning can push Voc up noticeably above what you'd see at 25°C STC. Victron's own wiring unlimited documentation covers this well if you haven't already had a look, @Fiona1974. Basically add a decent safety margin on top of your calculated cold-weather Voc before you even think about committing to a string configuration. Saved me a nasty surprise on my setup last February! 🌡️