Lowest OCV An MPPT Is "Worth It"?
There has to be some experience here on this forum to share. When I look at the MPPT manufacturer's data specs, the incredo-hyperbole gives me diarrhea.
Forum Discussion
Hi,
I chose to go with 33 volts in a series/parallel configuration. At the time the panels cost about the same as an MPPT charge controller, so MPPT was the way to go. The choice allowed me to use the #10 prewire from the factory and have low transmission losses.
Now, with cheap panels, if there is room on the roof a pwm offers a slightly better "bang for the buck". Why only slightly better? Because 17 volt panels are generally more expensive per watt than higher voltage ones.
I do regularly see 17 amps from 256 watts of panels. In winter I've seen 15.4 volts and that has sometimes caused the inverter to shut down from over voltage.
My only mistake was maxing out the charge controller. That means any upgrade in wattage will require a new controller.
I chose to go with 33 volts in a series/parallel configuration. At the time the panels cost about the same as an MPPT charge controller, so MPPT was the way to go. The choice allowed me to use the #10 prewire from the factory and have low transmission losses.
Now, with cheap panels, if there is room on the roof a pwm offers a slightly better "bang for the buck". Why only slightly better? Because 17 volt panels are generally more expensive per watt than higher voltage ones.
I do regularly see 17 amps from 256 watts of panels. In winter I've seen 15.4 volts and that has sometimes caused the inverter to shut down from over voltage.
My only mistake was maxing out the charge controller. That means any upgrade in wattage will require a new controller.
