Blocking Diodes For Solar Panels In Parallel

Mainly we use two kinds of diodes for effective solar panels bypass and blocking diodes.

Blocking diodes for solar panels in parallel. There are two functions a diode can perform in 12volt solar systems either as a blocking diode or as a bypass diode. It allows the current to flow from the panel to the battery but blocks the flow in opposite direction. Now let s consider what happens if one of the panels in the above diagram is shaded. Blocking diodes are usually included in the construction of solar panels so further blocking diodes are not required.

This would prevent current flowing from one parallel string into a lower current string possibly due to shading and therefore helps minimize mismatch losses in parallel connected arrays. If your panels are a grouping of other panels then you won t need a diode. Difference between bypass and blocking diodes source. To prevent this from happening a blocking diode is installed.

It is always installed in series with the solar panel. There is a possibility of the current flowing from the battery to the solar panel thereby discharging the battery overnight. Blocking diodes are used to prevent your batteries from discharging backwards through your solar panels at night. This is a real problem at night because we could lose all the power we gained during the day.

When a solar panel is shaded the output current reduces dramatically and when it s dark it actually absorbs current. Also we should consider bypass diodes in this. Not only will that panel not be producing any significant power but it will also have a high resistance blocking the flow of power produced by the unshaded panel. Again current flows from high to low voltage so during a sunny day the voltage of a solar panel will be higher than the voltage of a deep cycle battery and the current will naturally flow from the panel to the battery.

Blocking diodes will be of benefit in any system using solar panels to charge a battery. A solar panel it a grouping of cells in a series parallel configuration of one form or another typically inside a housing. Store bought panels will typically have a protection diode already in place. This is to prevent current flow from branches in high sunlight feeding current into those in shadow.

I recall reading somewhere that one should also install a blocking diode for each parallel string. I was told recently that panels in parallel should have blocking diodes in each branch.