16 panels East or 8 panels east 8 panels west split

[The Launderer]

Also, I suspect that an East/West split will not need such a large inverter, since the panels will never all be in direct, straight-facing sun at the same time.

While 4kWp East-facing (or West-facing) would probably need a near-4kW inverter, I suspect that a split system with 2kWp East and 2kWp West would only need a (less expensive)3kW inverter.

Proposed Fronius 3.6 in one string for all panels facing east. Will probably go with twin tracker Power One 3.6 if decide to go with split system. Would the sun in mid summer at its highest not be more or less shining on both arrays equally and 3kW a liitle undersized? The Power One is a little cheaper than the Fronius so additional costs of cabling and isolators would be covered.

 

[wstevew]

If it helps at midday (before bst) the arrays are almost equal in output but the west slightly higher due to being a tad cooler.


I would say power one seem to be the installers first choice inverter.

Although I do like the sma with its sunny beam and relay and other developments in the pipeline.

 

[FB.]

Proposed Fronius 3.6 in one string for all panels facing east. Will probably go with twin tracker Power One 3.6 if decide to go with split system. Would the sun in mid summer at its highest not be more or less shining on both arrays equally and 3kW a liitle undersized? The Power One is a little cheaper than the Fronius so additional costs of cabling and isolators would be covered.

The panels only get close to peak output when the sun is straight in front of them and high enough in the sky to compliment the pitch of the roof.
If the sun isn't straight at the panels, some light is lost through reflection, or because it has to travel through a greater thickness of glass as the angle of incidence flattens (that's why WW2 German tanks had quite shallow sloped armour; to increase the chances of deflection and "virtually" increase the thickness).

At peak summer sun, it will be 60 degrees high in the sky, and 90 degrees off to the side of an East or West facing panel, with the roof slope of 35 degrees also slightly tilting the panels away from the sun.

A quick "back of an envelope" calculation suggests that the panels will only be at three-quarters capacity, due to the angle of incidence of the light.

If the panels were South-facing, that 60-degree-high sun, plus a 30-degree roof slope, would make for 99% efficiency as the sun would be shining almost perfectly at the panels.




Here's a re-post from when I gave some approximations for the performance of my SE-facing, 40-degree, 3.75kWp system (3.6 inverter), in ideal conditions:

"....On a nice day, power generation typically looks like this (in recent weeks, before the clocks changed!):
7am: 0.5kW
8am: 1kW
9am: 2kW
10am: 3kW
11am: 3kW
12noon: 2.5Kw
1pm: 2kW
2pm: 1.5kW
3pm: 1kW
4pm: 0.5kW
5pm: 0.25kW
6pm: 0.1kW....."

Those generation stats would probably be 20% higher in summer.



/

 

[FB.]

This link will give an interesting read about armour plate, but also give an idea of light reflection/deflection/angle of incidence on solar panels.

Sloped armour - Wikipedia, the free encyclopedia

If sloped armour is harder for anti-tank rounds to punch through, then it is also more difficult for light rays to pass through tilted glass.

 

[wstevew]

Peak sun for me is 62 degrees high
current is around 45 degrees high

If my peak generation is 2.5 currently then it is 65% of capacity

So I should see a maximum peak of around 2.88kwh when the sun is 62 degrees high?

Or would it be slightly higher as the pitch is only 22.5 degrees

 

[FB.]

-

I also put up this chart relating peak generation time with the facing of the panels: