Why Do I Need Blocking Diodes For Solar Panels

If you have two 175 watt panels each at 42 volts you will need two 8 amp 45 volt diodes.

Why do i need blocking diodes for solar panels.

Not only will that panel not be producing any significant power but it will also have a high resistance blocking the flow of. Nowadays most solar power systems have a charge controller between the solar panel and the battery and this charge controller prevents this backflow of electricity eliminating the need for a blocking diode. If you have multiple parallel strings of solar panels that get shaded at different times a blocking diode in series will help prevent the power from the sunny string being forced back up through the shaded string. This is where a solar panel blocking diodes is used.

The diode is able to stop this backwards flow and ensures that the energy collected is safely stored. Blocking diodes are usually included in the construction of solar panels so further blocking diodes are not required. This is common on sailboats with a solar panel on both the port and the starboard sides. Watch our video below to learn more.

The energy flow is now reversed and escapes out through the solar panel. Blocking diode in a solar panel is used to prevent the batteries from draining or discharging back through the pv cells inside the solar panel as they acts as load in night or in case of fully covered sky by clouds etc. Now let s consider what happens if one of the panels in the above diagram is shaded. There may be however some instances when a blocking diode can still be helpful.