Backsheets

[AE-NMidlands]

(not baksheesh, for those currently in Turkey!)
I am being offered these https://www.renugen.co.uk/trina-vertex- ... backsheet/
which have a white back-sheet.
It had never occurred to me that panels have back-sheets... why white?
And has anybody got experience of Trina panels?

(I specifically asked them to quote for polycrystalline panels as I know I can over-size the system and it will lower cost and mean less curtailment in summer... why quote for these monoctrystalline ones instead?)
A

[Stinsy]

The ones with black backsheets look "blacker". They are known as "all black". Basically the bits between the cells are black. I've heard if oyu live in a conservation area you need to have a black backsheet.

[nowty]

(I specifically asked them to quote for polycrystalline panels as I know I can over-size the system and it will lower cost and mean less curtailment in summer... why quote for these monoctrystalline ones instead?)
A

Your statement makes no sense to me whatsoever unless you have some strange aversion to monocrystalline panels.

EDIT - I think you mean the poly ones would be cheaper ?

[AE-NMidlands]

(I specifically asked them to quote for polycrystalline panels as I know I can over-size the system and it will lower cost and mean less curtailment in summer... why quote for these monocrystalline ones instead?)
A

Your statement makes no sense to me whatsoever unless you have some strange aversion to monocrystalline panels.
EDIT - I think you mean the poly ones would be cheaper ?

Yes, I thought that polycrystalline panels were cheaper, performed less well per unit area at peak output but were "better" (meaning delivered a higher proportion of their peak output?) in diffused light conditions (overcast.)
Given that I can fit far more panels on my roof than I can export the power from (or soak up in battery re-charging or water-heating) I thought a higher output panel might not be cost-effective, because we wouldn't be able to make any sensible use of a significant proportion of the power for a lot of the year.
Why pay for top-performing panels if there is nowhere for the electrons to go?
A

[smegal]

(I specifically asked them to quote for polycrystalline panels as I know I can over-size the system and it will lower cost and mean less curtailment in summer... why quote for these monocrystalline ones instead?)
A

Your statement makes no sense to me whatsoever unless you have some strange aversion to monocrystalline panels.
EDIT - I think you mean the poly ones would be cheaper ?

Yes, I thought that polycrystalline panels were cheaper, performed less well per unit area at peak output but were "better" (meaning delivered a higher proportion of their peak output?) in diffused light conditions (overcast.)
Given that I can fit far more panels on my roof than I can export the power from (or soak up in battery re-charging or water-heating) I thought a higher output panel might not be cost-effective, because we wouldn't be able to make any sensible use of a significant proportion of the power for a lot of the year.
Why pay for top-performing panels if there is nowhere for the electrons to go?
A

The supplier that I use (tradesparky) don't offer many poly panels. I think they are becoming obsolete. Back in the day, you paid a premium for mono panels, that doesn't seem to be the case any more.

I'm also not sure about the performance. I thought mono performed better in all situations.

[nowty]

There was some evidence in the early days about Poly panels being slightly more efficient in diffused light but if there is any advantage its so minute and is wiped out by general Monocrystalline performance in direct light. Remember direct light in winter is pretty weak so Mono would still win.

As to backsheets and all that, the all black ones are slightly less efficient due to running hotter with all the extra black colour on the frame and on the front / backsheet. Trina panels have been around for as long as I can remember so should be a good brand.

At the end of the day a cheaper larger array will still win over an expensive smaller array.