Anyone else finding their MPPT struggling to keep up on partial shade days?

I've got a 400W array on the van roof (2x 200W Renogy panels in series) feeding into a Victron SmartSolar 100/30, and I've noticed that on patchy cloud days the controller seems to take ages to re-find the MPP after each shadow passes. We're talking 30-40 seconds sometimes before it settles back to a decent charging current. On a full overcast day it's actually fine — steady if low output — but these in-and-out cloud days in Cornwall are genuinely costing me a fair bit of harvested energy over the course of a day.

I've had a poke around in VictronConnect and I'm currently running the default "Optimised (with BatteryLife)" algorithm on a 200Ah LiFePO4 bank. I've seen some chat elsewhere about switching to Fixed Voltage or tweaking the absorption settings, but honestly I'm a bit wary of fiddling blind. The Victron documentation isn't exactly a page-turner.

Has anyone found a particular algorithm setting or wiring tweak that noticeably improves MPPT tracking speed in these conditions? I'm also wondering whether putting the panels in parallel rather than series might behave differently under partial shade — lower voltage, higher current. Curious what others have experienced, especially if you're running similar kit in areas with equally unpredictable skies.

@CornishSolar mate, your panels in series on a partially shaded day is basically asking one dodgy cloud to kneecap your entire array — parallel wiring or an optimizer on each panel sorts it sharpish, learned that the hard way on my static caravan setup when a rogue chimney shadow turned my 600W array into an expensive paperweight. 🌥️

@CornishSolar @VanKen is right about the series issue, but to add a bit more context - when panels are wired in series, one shaded panel drags down the entire string's current. The MPPT then has to hunt for the new maximum power point, which takes time, and on patchy days with clouds rolling through every few minutes it's constantly chasing its tail.

If your van roof layout allows it, switching to parallel would make a noticeable difference - each panel operates more independently so partial shading only affects that one panel's contribution rather than nuking the whole array.

Worth also checking your Victron app to see the actual tracking behaviour - the SmartSolar logs are quite detailed. Sometimes the "scanning" behaviour you're seeing is normal MPPT hunting rather than anything broken. What voltage are you seeing during those patchy periods?