49 Sunpreme 340W Solar Panels + Inverters $3,499

Blimey, that's a chunky lot of panels for the price — 49 units at 340W gives you a theoretical 16.66kWp array, which on paper sounds like the stuff of dreams for a tiny house setup like mine.

A few things I'd want to dig into before parting with any cash though:

• Sunpreme used bifacial glass-glass technology, which is genuinely interesting (better longevity, no EVA delamination issues), but the company went under a few years back. Replacement warranty claims are going to be... optimistic, let's say.
• Are these new old stock, pulls from a commercial installation, or something in between? Condition and degradation history matter enormously here.
• 49 is an awkward number. You're almost certainly going to have one odd panel out when designing strings for a Victron MPPT or similar — worth modelling your string configurations before committing.
• What inverters are actually included? That detail's doing a lot of heavy lifting in that listing title.

The per-watt price could be attractive depending on condition, but I've seen similar bulk lots on eBay UK where the transport costs and import duties quietly ate the savings alive.

Anyone here had hands-on experience with Sunpreme panels long-term? Curious whether the glass-glass construction has held up as well in practice as it does in theory. Could be genuinely useful for a ground-mount build where bifacial gain is actually achievable.

@Titch a few things worth flagging before you get too excited:

The dollar sign is a red flag — this forum is UK-focused and that pricing screams US listing. Import duties, VAT, and shipping 49 panels transatlantically will absolutely obliterate that bargain price point.

Sunpreme were a bifacial panel manufacturer that went into administration several years back. If these are new-old-stock, warranty is essentially worthless and cell degradation may already be significant.

16.66kWp also needs serious infrastructure — you're looking at a substantial MPPT setup (multiple Victron SmartSolar 150/100 units minimum), proper DNO notification under G99, and potentially planning permission depending on your installation type.

For a tiny house, that capacity is frankly overkill unless you're selling to the grid, which as a private dwelling complicates things considerably.

What's your actual daily consumption figure? That's the number that should drive panel quantity, not the other way round.

@DevonDweller raises a fair point about the dollar sign, but I'm more concerned about the practicalities even if the deal were legit.

16.66kWp sounds glorious until you realise you need somewhere to actually put 49 panels. That's roughly the roof area of a small aircraft hangar 😅

From my narrowboat adventures I've learned the hard way that headline wattage and real-world output are very different beasts — what's the claimed efficiency rating on these Sunpremes? And more importantly, what inverters are bundled in? "Inverters" (plural, unspecified) could mean anything from a pair of decent Victron units to some mystery-brand boxes that'll give up the ghost first cold snap.

Has anyone managed to find a datasheet for the actual panels? That'd tell us a lot more than the listing does.

@Titch worth noting that even if this deal were UK-legit, 49 panels is an awkward number — most string inverter configs want clean multiples. You'd likely be leaving one panel orphaned or running a mismatched string, which hammers your overall yield.

From my own boat install (Victron MPPT 100/50 paired with Renogy panels), I learned the hard way that panel count and string design need planning from the start, not as an afterthought.

At 340W each you're also looking at serious roof real estate — roughly 195m² assuming standard panel dimensions. That's way beyond a typical tiny house footprint. Where's it all actually going?

@LakelandNomad that's a really useful point about string configs — hadn't thought about that. Even if you went with something like a Victron MultiPlus setup, how would you handle the odd number practically? Would you just leave one panel out and run 48, or is there a smarter way to wire it?

Also — 16.66kWp sounds massive but what's the realistic yield in the UK vs theoretical peak? I've got a much smaller array on my garden office and the gap between what the specs suggest and what I actually see on cloudy days is pretty eye-opening. Wondering if anyone's run the numbers on what this size system would genuinely produce annually at, say, a typical southern England location.