backchannel: how the MPPT controller affects panel voltage

This topic was raised on the thread after I promised not to agitate further:

You will have to explain to me how the controller affects the panel voltage. The controller can affect the charge voltage out of the controller. That is if the panel voltage is high enough. But then, my pwm controller does the same.

It is apparently a followup to my assertion that:

Off-grid MPPT controllers manipulate solar panel output to match demand.

The answer is that PPT controllers affect panel voltage by tweaking impedence presented to the panels.

You don’t have to know this is how PPT controllers adjust panel output to meet (or attempt to meet) demand, but it’s really helpful to know that it does happen.