A crude explanation is that solar panels are basically a Constant Current source. They have a maximum Voltage when open circuit, and a maximum Current when sho

A crude explanation is that solar panels are basically a Constant Current source. They have a maximum Voltage when open circuit, and a maximum Current when shorted. And the maximum power point is somewhere between those two extremes. Exactly where depends on various conditions, like the strength of the sunlight (clouding, etc).