Anyone else running MPPT on a shaded partial array — what are you actually getting?

Fitted a Victron SmartSolar 100/30 in the van last month alongside two 200W panels wired in series. One panel gets shade from the roof vent for a chunk of the morning and the output tanks hard — talking 40–50% loss on what I'd expect.

Read all the stuff about wiring in parallel instead to reduce shade impact, but then I lose the voltage headroom that makes the MPPT actually earn its keep. Bit of a catch-22. Anyone tried optimisers like the Tigo or SolarEdge kit on a small van setup? Feels like overkill but I'm open to it.

Also curious whether the Victron's built-in MPPT algorithm is even doing its job properly in patchy conditions — mine seems to just hunt around and settle on a rubbish operating point rather than finding the real peak. Might be a config thing but not sure where to start.

@LuckySkipper welcome to the forum — good to see someone actually sharing real-world numbers rather than just spec sheet fantasies.

What you're describing is classic series-string behaviour. When one panel is shaded, the shaded cells become the bottleneck for the entire string. Your 100/30 can only work with what it's given.

A few things worth trying:

• Rewire to parallel if your VOC allows it — shading one panel then only hurts that panel's contribution
• Check whether your panels have bypass diodes — most modern ones do, but they vary in quality
• The Victron app will show your daily yield history; post a screenshot if you want people to dig into the numbers properly

Running a similar setup on the boat — shading from the canopy was killing my morning harvest until I sorted the wiring. Night and day difference.

Hey @LuckySkipper, yeah this is a classic series wiring headache — one shaded panel drags the whole string down hard. Worth considering rewiring to parallel if your panel voltages are low enough to stay within the controller's input range, as parallel configurations handle partial shading much better since each panel operates more independently. The Victron app should give you a decent picture of what's happening — check your absorption/bulk times and the daily yield graphs to see exactly when the drop is occurring. Some people also swear by adding bypass diodes, though decent panels should already have them built into the junction box. What's your actual Voc per panel? That'll determine whether parallel is even a viable option with the 100/30. Would help narrow things down.

@LuckySkipper I ran into exactly this with my garden office setup — two panels in series and a pergola beam was clipping one of them from about 8am to 10:30am. Losses were brutal, far worse than the shaded percentage would suggest.

Switched to parallel wiring and the difference was night and day. Individual panel MPPT isn't really an option at that budget, but parallel at least means the shaded panel only loses its own output rather than throttling the whole string.

Worth also checking whether your Victron app shows the MPPT hunting — mine was constantly cycling through voltage sweeps trying to find the real peak. That constant hunting was actually burning efficiency even outside the shaded window.

If rewiring isn't straightforward, Tigo optimisers are worth a look — fitted a pair on my static caravan array and recovered a decent chunk of those morning losses.

@LuckySkipper worth checking whether your Victron is actually re-sweeping for a new MPP during that shaded period — the SmartSolar does periodic sweeps but the default interval might mean it's sat on a suboptimal point for longer than it needs to. You can tweak that behaviour via the VictronConnect app. Also, have a look at the history data in the app over a few days — it'll show you your peak power and absorption patterns clearly enough that you can actually see where it's losing the plot each morning. Might help you quantify what you're genuinely losing versus what's just unavoidable given the geometry. If the vent shade is predictable and consistent, you could also look at whether repositioning one panel changes anything practically.