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Studies on East/West vs South facing panel in North America?

RememberTheMagic

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Sep 26, 2021
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So assuming for sake of argument your only option was to put panels on a 3-degree roof pitched East-West where the east pitch is 10’ off the ground, sloping westward to 9 foot (almost flat roof); also knowing that in this area southern-facing panels get good light from 10 am-4 pm before the trees start shading in the summer and 11 am-3 pm in the winter.

The question is this…. Am I going to lose 35% or more putting these panels on an east-west roof pitch laying almost flat (or slightly facing westward), or will the difference between this and southern facing panels will be more like 10% ?
 
You could use PVWatts to simulate those two scenerios. PvWatts requires input about location that can affect results. Shading is another issue that requires someone to go on your roof with a device to plot the output. PVWatts could tell you how much production would occur in the late afternoons to test your assumption.
 
You could use PVWatts to simulate those two scenerios. PvWatts requires input about location that can affect results. Shading is another issue that requires someone to go on your roof with a device to plot the output. PVWatts could tell you how much production would occur in the late afternoons to test your assumption.
Is that an APP or website?
 
 
Due south is 180 degrees true, not magnetic. You will have to look up magnetic deviation for your location. Try Google maps for your address.
 
Is this drawing still accurate I’m assuming it’s only 4° off from 180
 

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Yes, you will be loosing a substantial amount of output leaving them flat. Just because you have a flat roof, doesn't mean your panels have to also be flat. The roof of my workshop has only about a 5degree slant, so I built a triangular frame out of unistruts to hold my panels at the correct angle for my latitude.

BTW, to anchor the frame on my steel roof, I first mounted 4' long unistruts directly on the roofing, four struts perpendicular to the array frame, utilizing standard gasketed roofing screws drilled down into the framing. I then positioned 2.5" bolts sticking straight up out of the roofing unistruts. I then bolted the array frame to those bolts projecting upwards.
 
Where and when did you get it? Does that offset confirm what you get as true south for your location?
Declination gradually changes over time. For my area in California, the graph suggests ~15 degrees East, though for the US Geological Survey, their official number as of 2020 was 12.5 degrees East.

I have a very nice Silva compass that is declination adjustable, but realisticly, that level of precision is really only necesary if you are surveying legal property boundries. For my own system, I just went out at night and identified the North Star, and laid down a 20' length of pipe orient true North.
 
What about temperatures with respect to safety on full cell solar panels?
I see the advantage of half cells as more paths, hence less resistance, less heat, but which would that be an issue in areas where max temperature is 36 degrees(in extreme cases)?
 
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