Shade effect on series panels.
Pictured below is the shading on 2 of 6 series-connected panels: And this is what the controller says: So, 57.2 x 5.6 = 320w (IN) Normal (full sun) should be about 84 x 7.5 = 630w,...
Forum Discussion
red31 wrote:BFL13 wrote:
The amps is what it is, so the controller must fiddle with R to change V. R being a "load".
Yes, one can make an IV curve with a bunch of resistors and light.
Isc is max resistance, Voc is zero resistance, various values in between define the iv curve. Mppt imposes a resistance/load and makes constant adjustments to find/keep mppt, via computer control.
PWM in abs pulses panel current and no current, panel current is at batt V and no current is at Voc. 50% duty cycle would be 50% @ 14.6v and 50% @ ~20v (Voc). 14.6+20 / 2 = ~ 17v. With more OFF time (Voc) the average V goes up. I believe mine does this at 60hrz.
Thanks for the clarification that in PWM it is the current that goes on and off, to make the voltage whatever, and that it is between Voc and batt V. So it passes through batt V to the panel same as any PWM controller.
Makes it interesting when batt v can be 12 and panel 24 instead of 12-12, but why not? Harder with a 24v panel to keep the average above Vmp with 12v batt though.
