Anyone else running a Victron MPPT alongside cheap Ali panels — what are your real-world figures?

Picked up four 200W panels off a bloke on Facebook Marketplace for £60 the lot — no-name Chinese stuff, probably came off a static caravan. Wired them up as two pairs in series/parallel giving me a nominal 48V array into my Victron SmartSolar 100/30. Running into a 200Ah 12V lithium bank.

On a half-decent October day I'm seeing around 18–22A at peak, which works out to roughly 220–260W. Given the panels are supposedly 800W total I know that's not spectacular, but they're also shaded by the roofline until about 10am so I'm losing the morning entirely. Clear summer days I've hit 28A a couple of times.

The Victron app is brilliant for logging — I can see absorption kicking in around 14.2V and the daily totals have been sitting between 0.8 and 1.4kWh depending on cloud cover. For a £60 punt on secondhand panels I'm not complaining, but I'm genuinely curious whether the cheap panels are underperforming beyond what the shade explains, or whether these figures are about right for this time of year in the North West.

Has anyone done a proper comparison between budget panels and decent tier-1 kit like Longi or JA Solar on the same controller? Would love to know if upgrading the panels would make a meaningful real-world difference or whether I'm chasing marginal gains.

@RetiredChef26 classic Facebook Marketplace score tbh. Running two no-name 200W panels I grabbed similar way into a Victron SmartSolar 100/30 on my van build. Rated figures are basically fiction — I see maybe 75-80% of spec on a decent day. Mid-July, south-facing, panels clean = roughly 280W peak from a theoretical 400W array. Factor in UK cloud cover and you're lucky to average that across a week.

The Victron side of things is solid though — MPPT algorithm genuinely squeezes what's there. Worth checking your actual Voc before wiring, some of these surplus caravan panels are degraded more than you'd expect. Had one pulling noticeably less than its pair which was skewing the whole string.

What charge controller you running them into?

Running four of the Renogy 200W panels on my narrowboat into a Victron SmartSolar 100/30 — those are at least branded, but still budget end. Real-world peak I see is about 78–82% of rated output on a decent summer day, which matches what you'd expect accounting for cell temp, wiring losses and the usual British "sunny with haze" nonsense.

The Victron MPPT honestly does a solid job squeezing what's there — the BlueSolar app data shows it hunting the actual MPP pretty aggressively even when cloud cover is patchy.

Worth checking your Voc doesn't spike too high on cold mornings with that series config — two 200W panels in series could push close to controller limits depending on specs. What's the open-circuit voltage on those panels?

Hey @RetiredChef26, great score on those panels! I'm running a similar setup — four unbranded 200W panels (bought new from Ali direct, about £40 each) into a Victron SmartSolar 100/20.

Honest real-world figures: on a decent clear summer day I'll see maybe 340-360W peak rather than the theoretical 400W, but that's pretty normal with no-name panels — the rated wattage is always optimistic. Winter days are obviously grim, but even overcast I'm pulling 40-60W which keeps my leisure battery ticking over nicely.

The Victron's Bluetooth monitoring is brilliant for spotting any dodgy behaviour from budget panels. Worth keeping an eye on the VictronConnect app — if one string is consistently underperforming it can indicate a duff panel or a dodgy connection.

What voltage are you running your battery bank at? That'll affect how you want those panels configured.