It works! Manual MPPT controller v2.0
Well this $10 shipped DC-DC buck converter lets me find the maximum power point from one solar panel as it charges a battery.
The panel output in morning light varied from 39 watts at the panel voltage up to just over 44 watts at just under 16 V from the panel at 85 degrees outside. The single control on the device is supposed to vary the output voltage, but the battery far overpowers its ability to do that so instead it pulls down the voltage on the panels at the input as you try to increase the output voltage.
It is silly, impractical, and even at the max power point it may yet be less efficient than panel direct or PWM. But it DOES let me determine real world max power point of one of my Unisolars under various conditions as I had hoped, and I can use it to see if eventually investing in a real MPPT controller is worthwhile for me with my actual setup, because I can measure the real performance differences under real world conditions.
I know it's not supposed to work, but it does.
Woot!
Jim
The panel output in morning light varied from 39 watts at the panel voltage up to just over 44 watts at just under 16 V from the panel at 85 degrees outside. The single control on the device is supposed to vary the output voltage, but the battery far overpowers its ability to do that so instead it pulls down the voltage on the panels at the input as you try to increase the output voltage.
It is silly, impractical, and even at the max power point it may yet be less efficient than panel direct or PWM. But it DOES let me determine real world max power point of one of my Unisolars under various conditions as I had hoped, and I can use it to see if eventually investing in a real MPPT controller is worthwhile for me with my actual setup, because I can measure the real performance differences under real world conditions.
I know it's not supposed to work, but it does.
Woot!
Jim
