What's that diode in a solar panel for?

[John1397]

Solar panels come with a diode like in diagram A what does this accomplish as I always hook them up like in diagram B

 

[rbelli1]

The diode in diagram A is useful when you have multiple panels and one is covered by clouds. This allows current to keep flowing in that case. For a single panel it is not required. It doesn't hurt to be there except for extremely small panels when working in the micro-amp range.

The diode in diagram B is only useful if there is a chance that the powered device may produce a current. You don't really want to feed current through you solar panel. If that condition is not possible it is best to leave it out.

BoB

 

[gleem]

The diode in diagram B is only useful if there is a chance that the powered device may produce a current. You don't really want to feed current through you solar panel. If that condition is not possible it is best to leave it out.

This condition exists at night when the batteries connected to the solar panels have a voltage that can cause the panels to drain the battery through the panels. So unless you disconnect your battery at night you need a "blocking diode".in series with the panel.

 

[rbelli1]

So unless you disconnect your battery at night

Or have no battery.

BoB

 

[berkeman]

The diode in diagram A is useful when you have multiple panels and one is covered by clouds.

And in that case, the ground symbol goes away, and the diagram shows multiple panels.