Installers that fit larger output panels (650w, 700w)

Well getting 4.1kwp instead of 2.4kwp is the reason. If I'm going to fork out a min of 8k or more on an install, I'd like to get the most I can on the roof space I have. There's lot of houses in this country like mine.

I was also told that optimisers will do the job in combining all 6 panels on the one string, no differently to how a chimney shading etc would cause some panels to perform worse than others. Those 650w panels have a peak output of 92% of the 700w panel peak. So that is supposed to be where optimisers would work fine. Worst case, it could be done as 3x700 and 3x650 on two strings with each of the strings generating the adequate min voltage for the inverter inputs.

On the size, I get the argument but surely this is solvable in this day and age. Below I put the mockups of the panels alongside a typical 410w panel. That to be seems to be quite solvable for logistics.

DC999, it's semi-detached, south-facing. The north side has got three velux windows for the attic extension. There's no east or west roof. I do have a rear extension that is East-West but its heavily shaded bewteen 11-1pm and also has 4 velux windows to its name and just not worth the effort.

And the very thing you mentioned on string size was why I was recommended to put all panels on the one string with optimisers. The guideline was that if the weaker panel + 25% matches or exceeds the stronger one, the optimisers will do a good job.

Links to both panels above

I was quoted €9500 for a 2.4kwp install, no battery. All I'd get back in grant would be €1900. So €7600 in total. That was a ridiculous price obviously and I backed away.

If I could pay 8k for 4kwp. I'd get €2400 grant back, bringing it to €5600. That would be workable in my mind as something that would recover cost in about 6 years. I would not need a battery to start. I'd be happy to use what I can and get FIT for the rest. Adding a battery later on would be the preference.

That apex edge you see there is the end of the roof slate. So the grey section is the gully and then apex. So its got the space.

As for smaller panel sizes, I tried all kinds of variations and the 4x700 and 2x650 are still the best option thus far. You can see the 350w setup I tried earlier based on the panels suggested by Big Lar.

There was one config I did with 410w narrow panels and they did really well if you went a bit creative on the left "50cm" edge but again... you have to find an installer that will source such panels.

So its going to boil down to it being an installers market doing what they want and screw the customer. It should be called the "Photovoltaic Tiger"

I knew they were bifacial but understood the 700w specs to be for the front side and the additional performance rated on the light leakage into the underside.

Even from the specs, they show this going to 875W best case.

Am I correct on this?

That said, the 650w is definitely not bifacial and then should be taken as a 6x650 = 3900kwp

I will likely have to wait this out unless I do manage to find a smaller installer that is flexible.

But I think also, half this issue is that the uptake of solar is still very low despite the demand on installers. If it picks up, these kinds of low yield 2.4kwp installs will not fly any longer, especially when there are so many.of these semi-D roofs that can't take 14 panels.

That's the hope :)

Unless this is part of the claim of being N-type instead of P-type. The 700w panel is also shingled and they claim that also performs better.

I wasn't specifically seeking these panels or brand as such. It was more a case of finding a variety of capacities and sizes and these two met the target of reaching 4kp on the space I have.