orienting solar panels south??

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orienting solar panels south??

Postby australsolarier » Thu Sep 14, 2017 11:55 am

i was just looking at one of those two dimensional charts that shows solar efficiency of different orientations and tilts.
so we have 30 degrees tilt to north 100% optimum
and amazingly 30 degrees tilt to south still has 60 to 70% of the optimum harvest.
that doesn't sound too bad, particularly if you are short of space.
so i decided to try this out, will take a few months maybe.
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Re: orienting solar panels south??

Postby Gordon-Loomberah » Thu Sep 14, 2017 12:07 pm

It really depends on your latitude. For much of the populated areas of Australia it wont be too bad in summer, but there could be pretty abysmal output in winter. In far southern regions the sun may never hit the front of the panels!
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Re: orienting solar panels south??

Postby Warpspeed » Thu Sep 14, 2017 12:21 pm

Even in Melbourne, the sun rises and sets well south of due east/west for quite a few months of the year.

If you are located north of Capricorn, in mid summer the sun will be directly overhead at mid day, so south will work just as well as north !

And on those dreadful grey dismal days when there is no visible sun, just a diffuse miserable grey twilight, any direction will work. Pointing straight up is probably best, but as long as it can see some sky it will work pretty much the same in any direction.

So if every other available roof surface are already covered with solar panels, there is still something to be gained from south facing panels, especially if they are pointing pretty well upwards.
Last edited by Warpspeed on Thu Sep 14, 2017 12:30 pm, edited 1 time in total.
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Re: orienting solar panels south??

Postby australsolarier » Thu Sep 14, 2017 12:29 pm

yes in strong overcast, 0 degree tilt works the best. quite a few of my arrays are flat, well, 8 degrees west, for that particular reason. they work just as well like 30 degree tilt towards north in the summer. and yes in the winter in full sun they are not as effective compared to higher tilts towards north.
but then, in overcast weather that is when you need most anyway.
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Re: orienting solar panels south??

Postby Warpspeed » Thu Sep 14, 2017 1:00 pm

I have pretty much the same thing here. The almost flat north facing panels work best in mid summer and in mid winter when there is total cloud cover. The more elevated north facing panels are much better in a clear blue sky.

Flat mounted panels pointing almost straight up work much better than I expected, and if/when I add more panels later on, that is what I will add. The main aim of that will be better performance in total cloud.

A also have an east west virtual tracker. The combination of panels facing in four very different directions seems to make for a very good combination.
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Re: orienting solar panels south??

Postby australsolarier » Thu Sep 14, 2017 1:17 pm

yes there is something to be said for different orientations. like not putting all your eggs into the same nest. it also saves you in solar chargers or at least stretches the solar charger's capacity.
and it is very satisfactory to see the east facing array providing all your needs and starting to charge the battery into the bargain at 7.00 in the morning.
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Re: orienting solar panels south??

Postby australsolarier » Sat Sep 23, 2017 9:33 am

In far southern regions the sun may never hit the front of the panels! (gordon's quote)

gordon, you are only partly right. yes at noon at high latitudes the sun might not reach the front of the panels. however, i am sure you know, the orb of the sun is much larger, though lower, than in more equatorial areas. so in the mornings and evenings they will get direct sun.
even here, sydney latitude, in summer mornings the sun shines on the back of my north oriented, tilt 30 degrees panels.
i ordered 6 panels. they will be installed one array 30 degrees tilt south orientation, the second array 15 degrees. they will have their own midnite classic for the time being. i intend to report back once they are installed and i have some data.
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Re: orienting solar panels south??

Postby Gordon-Loomberah » Sat Sep 23, 2017 11:44 am

australsolarier wrote:gordon, you are only partly right.


I was only talking about far S Aust in winter...
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Re: orienting solar panels south??

Postby australsolarier » Thu Oct 05, 2017 1:52 pm

ok,
being a person of doing rather than just talking about,
i installed two arrays oriented to the south. one array is tilted 32 degrees, the other 20 degrees.

the 32 degrees array has been running for a few days. and data taken. i used 250w poly panels, 3 in series. they have their own midnite classic solar charger. setting that midnite classic to take precedence (raising the float V 3 decimals) on a sunny day the array makes 1.8kw. the peak on those panels oriented into the sun are about 650w, the peak with south orientation is 256w at the moment (close enough to the equinox).

the 20 degree tilt array was delayed, because? guess what? , the courier smashed one of the panels. 4 others they only damaged the frame.
that 20 degree array was installed today, just ready for a peak measurement. 392w. as expected better than the 32 degrees tilt array.
i will post more data as it comes.
was thinking about a 45 degree south, but i suppose the might be a bit a waste of resources.
the south tilt arrays i installed behind the north tilt arrays. this area gets fairly shaded in the winter anyway.
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Re: orienting solar panels south??

Postby australsolarier » Thu Oct 05, 2017 2:00 pm

i might add here,
the production curve is flatter then north oriented, almost like a tracked curve.
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