Non standard roof/optimizers

cheesesarnie

Hi all.
In the final stages of solar quotes. 
Our roof has an annoying layout. As per the image we're looking at distributing panels across the 4 aspects south/east/west.

I assumed the S/W and S/E would each have their own string, job done. The prospective installers believe optimisers are required because 'all the panels in a string need to be facing in the same direction'?

Does that seem right? I can't see the point of them really as there's no shading.

Thanks

Screwdriva

Yes. This was shared in your previous thread, #2. SolarEdge is an excellent choice of inverter/ optimizer for shading and multiple strings.

cheesesarnie

Thanks. Yes agree solaredge & installers have quoted for that it's just during on site survey this weekend there was a bit of a debate (installer vs installer office) whether it was infact necessary where there's no discernable shading.
Potentially installer didn't realise 3 aspects caused a need for them.
With only 3 panels in the final spec actually on south aspects I suppose I need to run the numbers to see whether leaving out those panels (and reducing to 2 simple strings / removing the need for solaredge cost) is the best ROI.
Cheers

ispookie666

cheesesarnie said:

Thanks. Yes agree solaredge & installers have quoted for that it's just during on site survey this weekend there was a bit of a debate (installer vs installer office) whether it was infact necessary where there's no discernable shading.
Potentially installer didn't realise 3 aspects caused a need for them.
With only 3 panels in the final spec actually on south aspects I suppose I need to run the numbers to see whether leaving out those panels (and reducing to 2 simple strings / removing the need for solaredge cost) is the best ROI.
Cheers

I would say, get the maximum number of panels you can afford on the roof. It will be prohibitive to put them up later. 

Raxiel

They might not be in 'shade' but different panels on different aspects will have different levels of illumination at any given time of day, so it makes sense for them to either be different strings or one string with optimisers, otherwise the whole string is dragged down by the least optimal.

I don't know if multiple un-optimised strings are more or less expensive than adding optimisers to one, but the quote I ultimately accepted was the latter and came in much cheaper than the quotes for the former, although other factors relating to the companies themselves were probably more of an impact.

Exiled_Tyke

As @Raxiel points out, it's not just shading which will produce differing levels of production from the panels. Different aspects will cause this. And in my case my west facing system has two roofs at different pitches which also means I need optimisers.    There can be no doubt that your set up needs optimisers here.  

cheesesarnie

Thanks for the advice all