Do All Solar Panels Have Blocking Diodes

This is a real problem at night because we could lose all the power we gained during the day.

Do all solar panels have blocking diodes.

If your panels are a grouping of other panels then you won t need a diode. 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. When you use a controller a solar panel blocking diode is not necessary. If you have two 175 watt panels each at 42 volts you will need two 8 amp 45 volt diodes.

As a result in the days before charge controllers people would put a blocking diode in series between the battery and the solar panel only allowing power to go into the battery. Again current flows from high to low voltage. Blocking diodes will be of benefit in any system using solar panels to charge a battery. Blocking diodes are used to prevent your batteries from discharging backward through your solar panels at night.

So during a sunny day the voltage of a solar panel will be higher than the voltage of a deep cycle battery so current will naturally flow from the panel to the battery. A solar panel it a grouping of cells in a series parallel configuration of one form or another typically inside a housing. One last point do not confuse a blocking diode with a bypass diode. A solar panel array has more than one branch or strings connected in parallel consisting of solar panels bypass diodes and blocking diodes.

This way your existing equipment batteries and you newly purchased 12v solar panel charger will be protected and give you a long reliable working life. 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. There are two functions a diode can perform in 12volt solar systems either as a blocking diode or as a bypass diode. Store bought panels will typically have a protection diode already in place.

You will find out about bypass diodes in detail below this heading. The diode needs to have a voltage and amperage rating above that of the panel. When a solar panel is shaded the output current reduces dramatically and when it s dark it actually absorbs current.