My plan is to switch between the 30 degree and 15 degree struts as the seasons change.
Are there struts available that are designed for this biannual procedure?
Not really. The renusol struts swop out easy enough so with a bit of creativity and an extra set of hands we should be good.
What improvement in power can one expect by positioning the panels at right angle to the sun??
Play around here to estimate differences in azimuth and tilt.
Or a quick one to illustrate what is the best angle for where one is ⌠Solar Angle Calculator | Solar Panel Angle Calculator
The power reduces by the cosine of the angle of incidence of the sun so flat panels in winter are a no no.
I would just angle then around 30 degrees though and get the best winter production. The longer days in summer will anyway compensate.
Yes, this is my thinking as wellâŚ
I presume the angle that is quoted is not the elevation angle (wrt the horizontal) but the other one that shall remain namelessâŚ
If you want to use the elevation angle (rather than the angle of incidence), simply use sine instead of cosine. Fairly simple to remember since cos(0) = 1, that is to say if the sun hits it straight on (0 degrees/radians off a line perpendicular to the module), you get 100%.
It also means that being a little bit off (since the top of a sine/cosine wave is fairly flat) doesnât make a big difference, but once you are more than a little bit off the effect becomes dramatic. For example, you can be 25° off and still get 90% of the power, but more than that, and it slips pretty quickly.
The sunâs azimuth rises and falls +/- 23.5 degrees between the seasons about the mean. The mean is the equinox azimuth, which will be your geographical latitude.
Flatter panels outperform ideally sloped panels on overcast days.
A minimum slope of 5 degrees is said to be needed for the rain to clean the panels.
In practical terms, fancy brackets are expensive and require maintenance, so it is more aesthetically pleasing, cheaper and less labour to use the existing roof pitch (providing it exceeds 5 degrees) and add extra panels.
In terms of the Summer/Winter debate:
I am in KZN, so a summer rainfall area. In Winter, obviously, there is a shorter day, but on the flip-side, it is a very reliable day, cold and basically, a blue sky is guaranteed.
Summer is a longer day, and can be a more productive day, but I can go through several consecutive days of overcast weather. This is when I am happier about having those sub-optimum flatter panels, but more of them. I can get by.
It is my opinion that optimally angled and sloped panels tick the box in theory, but a greater number of sub-optimally positioned panels fit my personal needs better. I have around 24kWp of panels, the best production I have ever seen is 18kWp, with 16kWp typical in Summer and 12kWp in Winter.
A productive day in Summer is around 95kWh, but if the unproductive days are factored in the average is about 65kWh. 65kWh is incidentally what I get in Winter, but I can rely on it every day, so the Winter average and Summer average is about the same.
On a very overcast day, ( in Summer) I can count on about 1.5kWp throughout most of the day.
Why would they represent the angle as an angle between the panel and a 90° angle to horizontal? Everybody else talks about slope as the angle from horizontal. Or is it just me?
Iâm also getting ready to get solar in Cape Town with a flat roof. I have 2x panels for solar water heating installed at an angle. I had assumed a angled install for the solar PV panels would be needed, but some are going flat.
I heard the suggestion is to set the angle for winter, but in Cape Town winters are a bit more cloudy?
Itâs preferable to mount your panels at an angle. The sun is never vertically overhead in CT so you can have any angle between the summer and winter optimum angle but not horizontal.
Before Jaco installed my latest system and I was playing around with two 100watt panels and a 12v inverter, I managed to get my hands on quite a few 12v heavy duty linear actuators, with around 150mm travel. The idea back then was to make an adjustable panel mount, to cater for all seasons.
Do yourself a favour and check the improvement in performance by adjusting the panels manually. I think this is a bit of a pipe dreamâŚ
I monitored the kW from my panels as the sun lowered in the west and was surprised to find little change for hours until the sun was a lot lower⌠
Yup. Have a look at a cosine plot sometime. +/- 35° before you go below 0.8 (20% efficiency loss). That is a 70° range with little efficiency loss. But outside of that range, efficiency drops very quickly.
Resurrecting an old but very informative thread, apologies guys but this is perfect place for my query and I need some guidance.
My panels are on a flat roof but slightly angled North.
I have my eye on a 3rd 5Kw battery. Our consumption needs will not really change, but I WANT a slightly bigger buffer.
So then comes the NEED. To charge the bigger bank (I barely now make it during winter to get it full, but I do manage)
So I have space for 4 more panels and it will be a relative easy install I can do myself. So I want to go as big as I can. I have 550W panels in mind and will also put them on a 3rd MPPT.
So my question.
Do I do 2 strings in serie which I then parallel which would give me a theoretical 22 amps extra?
Or do I parallel all 4 giving me roughly 44 amps?
How important is that extra 50V for the MPPT to work its magic? Letâs say Iâm looking at a 150 | 45 (doubt I would get away with the 150 | 35 which would result in the clipping mentioned above)
In my laymanâs mind - an amp is an amp and the more of them you have, the better.
What would you do to make the panels and MPPT earn its keep?
Volts x amps and amps x volts is same ole same âŚ
The deets come in on the volts. The better one to focus on.
The higher the volts the less voltage drop over the length of the cable to the MPPT, the better the MPPT preforms.
And MPPTs like volts more. (in non-tech terms)
EDIT: Geez ⌠that is in some serious non-tech terms. 
Bottom line: Get as close to the 150v as you can, keeping in mind the Temp Coeff and lowest temps.
My cables from panels to MPPT will be less than 15 meters and I have thick cables. Not too worried about that.
I need to understand why 22 amps with 100 Volts is better than 44 amps with 50 Volts. I have never been able to understand this and nobody has been able to explain it to me.
But donât get too technical please. 
With what I have in mind, I cannot get to 150V in any event. 100 will be the closest.