Solar panels contain a number of solar cells. Each silicon cell produces approximately 0.6 volts. The example panel below has 60 cells connected in series giving an output of 36 volts.
They are connected in three groups of 20. Each group has a by-pass diode fitted which will by-pass that group of cells if ANY one of the cells is not producing a voltage. ie if any cell is in shade.
Click on a cell(s) to see the effect on output voltage if that cell is shaded.
= Cell in Sun
= Cell in SHADE Just one Cell in its group in shade will render that 20 cell group inoperative.
One or more cells in a group if shaded will effectively shut down that group of 20 cells. ie a loss of 12 Volts, 1/3 the Panel maximum output.