Anyone actually running a full 12v setup on nothing but cheap eBay panels? What's the real-world verdict?

So I've been putting together a budget van build and I'm genuinely curious whether anyone's managed a proper functional 12v system using those no-name 100W panels you see all over eBay for £35-45 each. I've got two of them wired in parallel feeding into a basic PWM controller (a Epever Tracer 1210A, nothing fancy) and into a 100Ah leisure battery. On paper it should be fine, but I'm getting some scratchy numbers.

The panels are supposedly 100W each but on a decent sunny day I'm seeing maybe 140W peak combined rather than the 200W I'd expect. That's a 30% shortfall which feels like a lot, even accounting for real-world conditions. I've re-checked my wiring and connections, and everything looks tidy. I'm wondering if the cells themselves are just significantly underrated from the factory, or whether my PWM controller is the culprit throttling things.

Has anyone actually tested cheap panels with a proper clamp meter or compared them side-by-side against a branded panel like a Renogy or Rich Solar? I'd love to know if upgrading to an MPPT controller would claw back meaningful wattage, or if the panels themselves are just genuinely poor quality and that's where the loss is happening.

@SarahFrost been running a couple of those no-name 100W panels on the boat for a couple of seasons now. Honestly? Not bad for the money.

Main things I noticed:

• Actual output tends to be 80-85W peak, not the advertised 100W
• Degraded a bit faster than my Renogy panels did
• Connectors are often ropey — worth replacing the MC4s straight away

That said, if you're on a tight budget they'll absolutely run a basic 12v system. Just buy one more than you think you need to compensate for the lower real-world output.

Wouldn't put them on a permanent install, but for a van build where you might upgrade later anyway, makes sense to start cheap and learn what your actual consumption is before spending serious money.

@LizHunt replied:

@SarahFrost I've got four of those cheapies on my narrowboat and they've held up better than I expected, though I did get caught out early on with wildly optimistic watt ratings. My honest tip - assume you're getting maybe 70-75% of the advertised output in real UK conditions and plan around that. You won't be disappointed then.

The bigger issue I found wasn't the panels themselves but the dodgy MC4 connectors they sometimes come with. Replaced those pretty sharpish after one started arcing. Grab quality connectors separately and you'll be much better off.

Curious what @FellLover found over those couple of seasons - did output degrade noticeably year on year? Mine are only 18 months old so I'm still watching that closely.

@TracyGrant replied:

@SarahFrost I ran two of those exact panels on my camper for about 18 months before upgrading. Honest verdict - they work, but expect maybe 70-80W actual output rather than the rated 100W. That's fine if you account for it in your calculations upfront rather than assuming full spec.

Biggest tip I'd give: spend what you save on the panels on decent connectors and proper MC4 crimping. Had one panel that was perfectly functional but had a dodgy factory connector that caused no end of grief until I redid it myself.

Also worth buying one more panel than you think you need to compensate for the lower real-world output. At those prices it still works out cheaper than branded gear. @FellLover and @LizHunt's experiences seem to mirror mine - they're genuinely usable kit if you go in with realistic expectations.

Running a similar budget setup in my van — two no-name 100W panels wired in parallel feeding a Victron MPPT. The panels themselves have been fine honestly, but that's where I'd say spend the money you save: a decent charge controller makes a massive difference to how much you actually extract from cheap panels.

The real gotcha with eBay panels isn't usually lifespan, it's the stated wattage being optimistic. I'd mentally rate mine at about 80W each and plan accordingly. On a decent summer day parked at a good angle I'm seeing roughly what I'd expect from that.

@TracyGrant curious what you upgraded to — was it worth the extra outlay or do you wish you'd just added a third cheap panel?

@SarahFrost three of those eBay specials on my cabin roof for two years now — the real gotcha nobody mentions is that "100W" is apparently a suggestion rather than a guarantee, so I grabbed a cheap clamp meter and discovered my "300W array" is actually delivering about 210W peak on a good day 😅 still charges my Fogstar batteries fine though, just budget for about 70% of whatever the sticker claims and you'll not be disappointed.

@Curly63 replied:

@SarahFrost Worth mentioning something nobody's touched on yet — check the actual Voc and Isc figures on those cheap panels before you commit to a charge controller. I bought four of them last summer and two were wildly different to the spec sheet, which played havoc with my MPPT sizing calculations. Not a dealbreaker, but get a basic multimeter on them straight away when they arrive. Also, framing quality is often the real weak point rather than the cells themselves — mine had poorly sealed junction boxes and one let moisture in over winter. A bead of silicone round the box costs nothing and could save you a lot of grief. Overall though? Genuinely decent value if you go in with realistic expectations. 👍

@Jonno88 replied:

@SarahFrost I've got four of those cheap panels on my shed roof, been going about 18 months. Honestly the output figures are optimistic — I reckon they're genuinely 75-80W rather than 100W in real conditions. That said, at £40 a pop you're still getting decent watts-per-pound compared to branded kit. Main thing I'd add to what @Curly63 is saying about the specs — the junction boxes on the cheap ones are properly flimsy. Two of mine had dodgy MC4 connections out of the box. Worth checking continuity before you roof them permanently, saves a right headache later.