Non standard roof/optimizers

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

Comments

  • Screwdriva
    Screwdriva Posts: 1,125
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    Yes. This was shared in your previous thread, #2. SolarEdge is an excellent choice of inverter/ optimizer for shading and multiple strings.
    -  10 x 400w LG + 6 x 550W SHARP BiFacial Panels + SE 3680 HD Wave Inverter + SE Optimizers. SE London.
    -  Triple aspect. (22% ENE/ 33% SSE/ 45% WSW)
    -  Viessmann 200-W on Advanced Weather Comp. (the most efficient gas boiler sold)
  • 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
    ispookie666 Posts: 1,175
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    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. 
    “Don't raise your voice, improve your argument." - Desmond Tutu

    System 1 - 14 x 250W SunModule SW + Enphase ME215 microinverters (July 2015)
    System 2 - 20 x 330W Jinko Panels + Enphase IQ7+ microinverters (Jan 2022) + Givenergy AC Coupled inverter + 2 * 8.2KWh Battery (May 2022) + Mitsubishi 7.1 KW and 2* Daikin 2.5 KW A2A Heat Pump
  • Raxiel
    Raxiel Posts: 1,398
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    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.
    3.6 kW PV in the Midlands - 9x Sharp 400W black panels - 6x facing SE and 3x facing SW, Solaredge Optimisers and Inverter. 400W Derril Water (one day). Octopus Flux
  • Exiled_Tyke
    Exiled_Tyke Posts: 1,182
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    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.  
    Install 28th Nov 15, 3.3kW, (11x300LG), SolarEdge, SW. W Yorks.
    Install 2: Sept 19, 600W SSE
    Solax 6.3kWh battery
  • Thanks for the advice all
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