Picked up a used 200W panel off Facebook Marketplace — worth it or a gamble?

Done this twice now and both times it's paid off, so I'd say worth it if you do a bit of due diligence before handing over cash.

Main things I check:

• Visual inspection first — microcracks are the killer. Look for any discolouration, delamination, or dark spots on the cells
• Check the junction box — dodgy connections or signs of heat damage are a red flag
• Ask for the brand — even a rough idea helps. Generic no-name panels can be fine, but Renogy, Victron, or similar at least gives you something to Google

If you've got a multimeter, measure open-circuit voltage in decent daylight. A 200W panel should give you somewhere around 20-22V OCV. Anything wildly off and walk away.

Mine came from a static caravan that got re-roofed — previous owner had no use for it. Paid £40, tested fine, been running on my shepherd's hut for two seasons without issue.

The real gamble is panels that've been on a roof for 10+ years with no provenance. Output degrades roughly 0.5% per year, so an older panel will underperform — just factor that into what you're willing to pay.

Honestly, Facebook Marketplace is one of the best ways to stretch a tight off-grid budget. Just don't skip the checks.

Anyone else picked up second-hand panels recently? Curious what people are finding out there price-wise at the moment — seems to vary massively by region.

@BirchLover good shout on the visual stuff. One thing I'd add — bring a clamp meter if you can. Do a quick Isc test right there in the seller's driveway (assuming it's not overcast). You're not going to get rated current in UK conditions but you'll quickly spot if a panel is producing significantly below what you'd expect. Had one that looked immaculate but was barely pushing half its rated short-circuit current on a bright day — walked away.

Also worth checking the junction box at the back. Lifting the lid if they'll let you — corrosion or dodgy solder joints in there are a nightmare to fix properly later.

For 200W panels specifically, £40-60 seems to be the sweet spot on Marketplace right now. Above that I'd start questioning whether a reconditioned one from somewhere like Bimble Solar makes more sense.

@BirchLover bought three second-hand panels off Facebook over the past couple of years for the cabin build — two were brilliant, one was a £40 lesson in trusting dodgy blokes in vans.

The thing nobody mentions: ask why they're selling. Genuine answers sound like "upgraded to a bigger array" or "sold the motorhome." Vague answers like "just don't need it anymore" with no story behind it — that's when I start poking harder.

Also worth knowing the panel's age if you can. Older panels degrade roughly 0.5% per year output, so a 10-year-old 200W panel is realistically running closer to 190W. Not a dealbreaker, but factor it into your negotiating.

@JA_Solar's clamp meter suggestion is solid — I'd add, do the test in full sun around midday, not "yeah it was a bit cloudy but the numbers looked alright."

@MountainHermit that 2-out-of-3 success rate is roughly what I've been told to expect anecdotally, which honestly isn't bad if the price reflects the risk.

Quick question for the thread — does anyone know if there's a way to check for delamination without specialist kit? I've seen some panels where the EVA layer looks slightly yellowed or bubbly and I wasn't sure if that's cosmetic or if it actually tanks the output significantly.

Also wondering whether it's worth buying a cheap solar charge controller just to do a basic load test on-site before purchasing, rather than taking the seller's word for it. Would a basic Renogy one give you enough data to make a judgement call, or do you really need proper IV curve tracing equipment?

@NotAnElectrician that 2/3 ratio does seem about right from what I've seen too, but I reckon the odds improve a lot depending on where the panel came from originally.

Panels pulled from motorhome or caravan roofs tend to fare better in my experience — they're often only a few years old and haven't been fixed at a dodgy angle or left completely unmonitored. Garden/static installs are more of a lottery.

Quick question for the thread — has anyone actually used a thermal imaging app (or a proper FLIR camera) to check for hotspots on a used panel before buying? I've seen it mentioned on a few forums but never tried it myself. Wondering if it's genuinely useful or overkill for a £40–60 panel purchase?