Anyone else running Victron MPPT alongside cheap panels — what's your actual real-world harvest?

Picked up four 200W Renogy monos off eBay (£60 the lot, one had a cracked corner but tests fine) and wired them 2S2P into a Victron SmartSolar 100/30 on the boat. Nominal 800W array, 24V LiFePO4 bank — Fogstar cells, 200Ah.

On a decent sunny day in late April I'm seeing maybe 380–420Wh by early afternoon, which feels low. Victron app shows absorption kicking in around 11am most days, so I'm wondering if the bank is just full by then and I'm not actually missing harvest — but I'm also not fully trusting my own reasoning here.

Has anyone done a proper comparison between budget panels and, say, Jakiper or SunSynk-spec panels on the same controller? Curious whether the cracked cell is dragging the whole string down or if 400Wh on a spring day is just about right for a shaded mooring situation.

@RKE_Builds that 2S2P config on a narrowboat — are you running them flat on the roof or tilted at all? I've been agonising over this for my own boat setup and I suspect the "lay flat and forget it" approach loses a shocking amount in winter.

Also, genuinely curious — does the SmartSolar 100/30 ever get close to that 30A limit in peak summer, or is the "800W nominal" figure just aspirational marketing fiction that dissolves the moment a cloud looks at you funny?

I'm trying to work out whether a Victron controller is worth the premium for an emergency backup / narrowboat setup or whether I'm just paying for the Bluetooth smugness. Current evidence suggests: probably the Bluetooth smugness.

Hey @RKE_Builds nice score on those panels! I'm running a similar setup on my static cabin — four 180W monos into a SmartSolar 100/30 on a 24V LiFePO4 bank.

Honest real-world numbers: on a decent UK summer day I'm seeing 550-650Wh actual harvest, maybe touching 700Wh if conditions align properly. Winter's grim obviously, 150-200Wh on a clear day is about what you'd expect.

The Victron MPPT side of things is genuinely excellent — load-matched tracking is spot on and the VictronConnect data logging makes spotting problems dead easy. The cheap panels are the limiting factor really, mine show quite a spread in Voc between strings which costs you a bit of efficiency in 2S2P.

Worth checking your cracked panel's Voc periodically — delamination can creep in around damage and performance drops off gradually without being obvious. 👍

@RKE_Builds interested to know what you're actually seeing in kWh terms on a decent summer day vs a grey October day — that gap is what I'm trying to plan around for my garden office build.

I've got a Victron SmartSolar 100/20 on order and debating whether to go 2S2P like you or just 4S with higher-voltage cheaper panels. The 100/20 input limit is the constraint I keep bumping into.

One thing I haven't seen discussed — does the cracked-corner panel show any meaningful output drop compared to the others? I've seen some dodgy deals on Facebook Marketplace with similar "tests fine" claims and I'm always a bit sceptical about long-term delamination risk, especially in the UK wet.

@RKE_Builds my garden office Fogstar-banked setup pulls about 60–70% of rated wattage on a proper July scorcher and roughly "enough to boil a kettle and cry" in October — the Victron SmartSolar earns its keep by squeezing every last photon out of what little Yorkshire decides to offer.

@RKE_Builds nice panel score. Running a similar Victron 100/30 on the narrowboat with 400W of mixed mono panels — nothing as tidy as your 2S2P but it works.

What I've noticed is the Victron's absorption algorithm does the heavy lifting when the panels are mediocre. On a proper bright June day I'm seeing around 1.6–1.8kWh into my 200Ah LiFePO4 bank. November? Sometimes barely 0.3kWh if we're moored under trees and the clouds are doing their worst.

The cracked panel thing is worth watching — I had a similar one that tested fine for months then started dropping output noticeably once damp got into the laminate over winter. Worth logging it in the VictronConnect app so you've got a baseline to compare against later.

The 24V bank will help you squeeze more from the controller at lower irradiance too.

Solid find on those Renogys, @RKE_Builds. On my van build with a 100/30 and 400W of mono I'm typically seeing 1.8–2.2kWh on a decent June/July day with good positioning, dropping to maybe 400–600Wh on a proper grey November day. The Victron's MPPT tracking is genuinely impressive even in low light — it'll still squeeze something useful out of overcast conditions where a cheaper PWM controller basically gives up.

One thing worth checking with your 2S2P config on a boat: keep an eye on any partial shading across one string, as it'll drag the other down more than you'd expect. The SmartSolar app history graphs are brilliant for spotting exactly when and why you're losing harvest. What orientation are your panels sitting at?