Smidge204 said:
You've demonstrated that MPPT is used to reduce voltage at te top of battery charging cycles, but at the same time current is increased - that is not reducing power.
You still misunderstand how it works. When the battery gets fully charged, the voltage across the PV array is *increased* so that the current from the array decreases. Since you were at the maximum power point during bulk charging, any increase in voltage reduces the power from the array. By moving off the MPPT point, you are deoptimizing the production of the panel. The panel will now heat up more than if you had taken maximum power from it. As you can easily see from the curves, just moving the voltage up 10% or so will allow you to reduce the current (and therefore the power) all the way to zero. With this small range of voltage movement you can regulate at any power level from zero to the full power of the array.
Let's put it yet another way: Assuming you have an array that is 20% efficient, you will achieve this only at the maximum power point. As you increase the voltage gradually toward the open circuit voltage, you gradually decrease the efficiency of the panel toward zero. The array can be operated at any efficiency between 0% and 20% to meet the needs of the load. That is precisely how a MPPT controller operates as it moves from bulk charging to absorption.