Are solar panels right for me?

Shading

If even a small section of a panel is shaded by the branch of a tree or telephone pole then there will be a large reduction in power output from the panel. This is because a PV solar panel is typically made up of three substrings of cells connected with one another.

The output of the whole panel is limited to the output passing through the weakest cell. If one cell (typically out of 60 cells in a module) is shaded, it will affect the power output of the whole panel.

In addition to a loss of power output, shading can have much more serious effects on photovoltaic solar panels – shading can cause hot spot damage to cells in which a shaded cell or cells overheat and potentially burn out.

However, each substring is usually protected by a bypass diode, which protects the cell against the formation of hotspots. They can also be effective in mitigating shading losses by “bypassing” the affected substring of cells, allowing the other substrings to perform at full power.

If there is a lot of shading on the roof, it might be beneficial to add optimisers to the panel array to mitigate the shading losses. These optimiser allow each individual module to operate separately from the other modules.