Small Scale Offgrid Solar PV: Installation Manual
This side of the building faces south (white arrow); deviation around 25ᵒ .
However, it‟s more important that there‟s no object in front of the Panel that could affect its
performance with shading, such as buildings, trees or topography.
The shade of an object depends on its height, general shape and position in relation to the Panel;
so it‟s difficult to predict without a calculation using the exact measurements. But if there‟s a
possibility that the shade could affect the Panel‟s performance (if the object is higher than the
Panel), it‟s better that it is positioned elsewhere. If it‟s necessary to choose, it‟s better for the
panel faces west or east, if it would be affected by shading facing south.
2.1 Optimal Inclination for the Solar Panel
Appendix 2 has more information on this. However, the inclination of the Panel is usually
determined by the roof pitch.
The optimum angle to generate maximum solar gain is a function of latitude, but also the use and
efficiency of the solar system over the course of the year
Latitude in Guatemala is 14º (37' 15" N)
Optimal tilt for summer use = angle of latitude – 20º 5º For a water pump for example
Optimal tilt for winter use = angle of latitude + 20º 35º. For example, an offgrid solar
system with year-round demand, including winter
Optimum tilt for maximum total generation during the year is equal to angle of latitude 15º.
For a grid connected installation, for example.
3. Fixing the Solar Panel to the Roof
Always take great care on the roof to avoid accidents. Remember that the rain makes a
galvanized metal roof very slippery. You should use boards to spread your weight over the roof
sheets. Only step where there is an interior beam below (indicated by a line of screws.)
8