mppt vs pwm

smkettner wrote:

jrnymn7 wrote:
Salvo,

Are you saying, because of its buck converter, if a small enough load is applied, during abs or float, the MPPT controller does not need to kick into full blown mppt mode, because the bucker itself can handle the increased demand? But if the load is too much for the bucker to handle, then it will kick back into full blown mppt mode?

Controller is just trying to hold the set voltage.
Controller will switch back and forth between MPPT and PWM as needed to hold the voltage.
Not really a big deal.

Same as your vehicle using cruise control downshifts as needed to make power to go up a hill.
Vehicle is just trying to hold the set speed.

Unless I'm mistaken, Jim has seen his amperage rise and fall, without the controller switching between pwm and mppt. This indicates there is available power for the controller to use, without having to switch to mppt. That seems to be the mystery to be solved. It must have something to do with the buck converter.

Like with your analogy, on a not so steep hill, engine revs/power may indeed increase, but it can maintain speed without actually shifting gears.

In float, I can see the load just using the surplus current; Isc minus float current; but with a large enough load, at some point more current is required... above and beyond Isc. Jim sees currents above Isc while the controller is still in pwm mode. So the controller is apparently getting extra power from the array, without utilizing its 'maximum power' tracking ability.