Influence of partial shading and angle of incidence:

Through the series of solar cells, the power output of the solar module greatly changed when sections or individual cells of the module are shaded. The weakest illuminated solar cell is crucial for the power output of the module!

Typically, 36 to 40 individual solar cells are connected in series and together they form the solar module. By this series connection - such as a chain - adds up the voltage of the individual cells of each approximately 0.5 volts to the voltage that is required for loading a battery.

To generate the optimal power output areas for the modules should be shaded as seldom as possible. Etc. In any case, never mount a modules below railing, handrail, antenna mounts, ropes... .

The following diagrams illustrate the correlations:

Power supply at partial shading

“Shading-resistant” panels


Terms like “shading resist” are appearing more and more frequently in advertising. With these modules, for example, narrower cells attempt to reduce the effect of shading by connecting strings in parallel within a module. As shown in the graphic, the advantages usually come at the cost of disadvantages in other shading situations.

Influence of the angle of incidence:

To get the best performance from solar modules, the sun should always fall at the right angle to the modules and incident on all cells of a module at the same angle.

Of course you could come up with any possible mechanisms that allows to orientate the module after the sun - in practice, this effort you will do very often. The module will be mounted on flat surfaces. Sure you have a power loss but but that's practical.

The modules should not be bended too much, so that all cells of the module are equally illuminated by the sun. When bending a module around the large boom the solar module can not generate power.