Dingo 20 20 solar controller

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That theory of the solar panel current traveling through an internal route in the panel is the first i have evr heard of that idea.
Can you explain the intricacies of such an event please? I would like to understand that phenomenon.

Quote "Now this current starts to flow within the solar panel itself.
Yep, that's right if you interrupt the external current path of a solar panel (cell), the sun induced photo current will take the internal route instead."

Now that's a new concept. The general wisdom is that if nothing is drawn from the panel there is no current flow within the panel.

So you guys really wanna know....ok here goes AFAIK.

As you're probably aware of, a PV cell is made up of a semi conductive p and n region resembling a diode.

An electric field of variable intensity exists where these two regions come together (called the depletion zone).
This field acts as a charge separator.

Incoming light creates extra charge carriers on both sides of the depletion zone.
A buildup of charge carriers weakens the field.

Provided there's an external current path the charge buildup is moderate, leaving the field intact.
Charge diffusion through the depletion zone remains small.

What happens in open circuit?
There is no external current path, charge on both sides of the depletion zone keeps building until the diode becomes forward biased.
At a voltage of about 0.6V the cell basically short circuits itself.
That's why a 36 cell solar panel has an open circuit voltage of 36*0.6V=21.6V (temp dependent).

I'm not an expert though, just knowing enough that I know I don't know everything about this :)
Like drift current caused by minority carrier recombination.
In open circuit, the field becomes weak enough for the resulting diffusion current to balance the opposing drift current so that the net current is zero - you asked!


Cheers