Here is a list of things to consider when installing solar panels for your home. This information has been gathered over the years and are some of the thing’s installers do not tell you about, or simply do not know themselves. How many panels do I need? That will depend on the size of your system. Say you have a 5KW system, you would need a total solar panel wattage more or less equivalent to your system size. As example, if you use 275W panels, consider 18 of them rather than 12. 275x12=3300W & 275x18=4950W. This is a best scenario case, as your panels would need to follow the sun throughout the day and be at the perfect angle to the sun. This is not the case for household installations. Hence you can bargain on maybe 80% of the above values at best. The effect of Shadows? Even if a panel is only partially shaded, it’s output could be reduced by up to 90%. Now consider that you have 6 panels set up as a group (connected together). As example 275Wx6panels=1650W. Should only 1 of the 6 panels be partially shaded, the total output will be reduced to 1650Wx10%=165W. This is because each panel is not operating independently but is rather operating as a group. The effect of Clouds? Panels do charge even if it is cloudy, albeit at a much lower output than normal. This is another reason why you should consider more rather than less panels. The effect of direction in which panels are facing? In SA if panels are facing in a fixed direction, the best direction would be north. Consider that the pitch of your roof may not be at the ideal angle facing the sun, thus making the panels less effective. Panels on the roof or on stands? Panels of roofs can be considered. The advantage is that they will be more theft proof there. The main consideration will be the effect of shadows and in which direction your roof is facing as previously explained. It is not easy to clean the panels on the roof. Panels on stands could be placed so that they are less effected by shadows, if you have the space available. They can usually be tilted at a better angle to the sun than those mounted on roofs. If you have time, you could also face them east in the mornings, north midday, and west in afternoons. The effect of summer and winter? You will get more power output from your panels in summer as the sun-hours are longer, although heat will reduce its efficiency downwards. Power consumption is also generally higher in summer due to irrigation and cooling needs amongst others. Winter days are shorter, meaning less output from panels, but irrigation and cooling needs are also less. If there are trees on the northern side of your house it may affect the sun getting to the panels in winter, or only getting to the panels much later than you expected. Setting up panels in groups? This is where careful planning needs to be done. Should you want to install panels on your roof, determine whether your roof is facing north-south or east-west. If you have a north-facing roof, you will be good to go.
On an east-west facing roof consider the following. It would be a bad idea to group (connect) all the panels on the east and western sides together as one group. The reason being that early morning the eastern panels will get most the sun, while the western panels get less sun. The total output of this group of panels will be determined by the panels on the western side in the mornings. The reverse will happen in the afternoons.
It will be far better to connect the panels into 2 separate groups. This will ensure maximum output from your panels throughout the day. Until next time.
Deur: Johan Swart.
