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Supplemental panels facing east/west
#1
All my 15+kW of panels face south, tilted at an reasonable angle.  Total daily output is excellent, however, depending on the season, there is maybe 1 hour after sunrise and 1 hour before sunset when the sun is too shallow and at the wrong direction for my panels to produce any appreciable power, thus my batteries have to step in.
I'm thinking that I could extend my non-batteries hours by 1~2 hours if I were able to better catch the rays during sunrise/sunset.
My idea is to install 500W of panels facing southeast, and another 500W of panels facing southwest, both at a nearly vertical angle. They would both get their own GTI inputs.

What do you think?  Has anyone tried something like this?
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#2
If you can face them south, this is far far better.

When the sun is low in the sky the light has to travel through a lot more atmosphere so you don't get as much energy landing on the panels in the first place, plus as the season changes the position of sunset/sunrise also moves.

If you can move the existing panels (ground mount and not a roof) angle half to face slightly east and half to face slightly west. This would reduce the mid-day peak while adding energy in the shoulder periods before and after high noon (plus a bit more late and early in the day)
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If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#3
I have 3 directions.. But not for extending the solar hours but due to limitations of roof.

You get more kWh south most likely than the others so you should beware of that you dont get as much at those angles but you could potentially have some more power during longer hours during the day even when batery is full.

I can see that my curve extends earlier in morning and later in the evening but it does not overall give more produced kWh....
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#4
I have an splayed array so I can catch some morning sun and some late afternoon sun. It seems to work quite well - If I have the use for the power (I'm at home and can charge my car) I can get 8-9kWh in a good UK summer day from 2.4kW peak of panels
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#5
My panels are south at 25deg angle - and from what I've read, doing east and/or west is done if you don't have other choices but south is the most efficient for Northern Hemisphere.

Can you change the angle? For example this site suggests https://www.solarpaneltilt.com/ 55deg in winter would be better for my latitude.
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#6
For reference, my panels are almost directly east and west facing at about 10 degrees (laid flat on the roof) so during winter the absolute worst case. Sunny days are actually near on the worst because when it is cloudy there is a lot more light / energy being reflected down... blue sky with no direct sunlight is effectively looking into space which effecitvely is a giant energy vaccume out of the planet. With 8kW of solar I can get about 4kWh on a sunny day mid winter
If you can't quantify how much they cost, it's a deal, I'll buy 5 of them for 3 lumps of rocking horse ......
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#7
(09-03-2019, 07:46 PM)completelycharged Wrote: With 8kW of solar I can get about 4kWh on a sunny day mid winter

I have 7kw facing south at 25deg (Southern Oregon - 42deg N lattitude).  Absolute max was 46.8 on Jun 20th - typical is 40kwh in summer.   My winter max is 20kwh (about 50% of summer max) but its so cloudy my average 12.
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#8
(09-03-2019, 12:35 PM)completelycharged Wrote: When the sun is low in the sky the light has to travel through a lot more atmosphere so you don't get as much energy landing on the panels in the first place, plus as the season changes the position of sunset/sunrise also moves.

If you can move the existing panels (ground mount and not a roof) angle half to face slightly east and half to face slightly west. This would reduce the mid-day peak while adding energy in the shoulder periods before and after high noon (plus a bit more late and early in the day)

I've been playing around with this tool to see the sunrise/sunset directions throughout the year.   Quite surprised to see the summer directions: nearly NORTH-east and NORTH-west (I live in 38deg N).
https://www.suncalc.org

So I think I will add "wings" to my existing south-facing array.  Just not sure about the direction and tilt angle.  Probably SE-ish and WE-ish, at maybe 60deg (very steep).
Does anyone have a tool that can calculate (ideally display a graph) the expected hourly production given the geographical location, panel tilt angle, and direction?  Ideally specify multiple arrays, and simulate the combined output?


All interesting stuff everyone.  Yes, south is the "ideal" direction, but my aim is not to maximize daily energy output, but to extend the time the panels produce usable amount of power.  And conversely reduce the time my batteries have to pitch in.
Modular PowerShelf using 3D printed packs.  30kWh and growing.
https://secondlifestorage.com/t-AJW22-s-...PowerShelf
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#9
I’ve done what you’re saying in Brisbane Aus (so best facing North rather than South).
We’re export limited to 5kW so not much use facing more panels North so have added so East and West panels to avoid importing as much early and late in the day.
Ours are microinverters direct to AC but the same principal.
On a pure output per panel level they’re not very good performers, it does help to reduce our import though, on that basis I’m happy with it.



Yes that’s a lot of power usage, charging our EV direct from solar...
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#10
(09-04-2019, 04:21 AM)Jon Wrote: [...] so have added so East and West panels to avoid importing as much early and late in the day. [...]

Do you have a before-after comparison graph?  Or a rough estimate how many hours the upgrade extended your non-import time?
Modular PowerShelf using 3D printed packs.  30kWh and growing.
https://secondlifestorage.com/t-AJW22-s-...PowerShelf
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