Solar panel discharge diode

[Wunja]

I recently had to repair the connection on my 10w solar panel (one of the connection tabs had corroded to nothing leaving just enough on the back of the panel to solder a new wire to).

Whilst I was doing this I realised that the diode that prevents the battery discharging at night was soldered across the connections I.E. in parallel with the panel and not as I expected in series.

How does that work? I'm sure it does work as the battery hasn't gone flat!

 

[Rigger Mortice]

I would also expect it to be in series.
There is some doubt as to whether a diode really is needed though. If the power lost due to the voltage drop of the diode is greater than the losses at night then it serves no useful purpose.

Last season I took the diode out during the long days/short nights of summer. It was difficult to see if it made much/any difference but it certainly was not worse than having it in place. If anything, I got the impression that I got more out of the panel than normal.

 

[VicS]

Sounds like a bypass diode. But you'd only use them with panels or parts of panels in series to maintain performance when one panel or part panel is in shade.

A blocking diode will be in series.

 

[VicS]

Bump

Surely someone has some more to add ??

 

[ghostlymoron]

What was the make of the panel. Maybe contact manufacturer for specs/wiring diagram. Agree that blocking diodes should be in series or they will not work.