Solar question
I am working through the solar deal hopping to have something in place for the spring. Right now I am looking at 200 to 250 watts worth of panels that I can expand in the future. Just so I understa...
Forum Discussion
BFL13 wrote:
So to answer the question of overcast day MPPT vs PWM for chance to equalize, my answer is MPPT or PWM has nothing to do with it.
I tend to agree
BFL13 wrote:
And BTW the "urban myth" about MPPT doing something in low light vs PWM has not been seen by me with both running at the same time when I had both set-ups. In fact for most of the summer the MPPT has under-performed PWM due to higher panel temperature lowering panel voltage so get fewer amps with MPPT than would with PWM.
I don't agree. What is happening is that the input voltage is too low for summer time use. If the system is 33 volts the opposite may be true. In fact the higher the input voltage for MPPT the better, for hot weather use. There will be as a result slightly greater losses at the MPPT controller (98% down to 95%).
BFL13 wrote:
Even if there were a slight MPPT advantage on overcast days it is too small to matter in daily AH compared with daily usage. Anyway from April to October around here it sure can't be seen. Maybe if you did solar in winter, but then solar is hurting then no matter which set-up you have.
I agree for a 24 volt MPPT vs a 12 volt PWM. I don't agree with a higher voltage MPPT (say 100 volts).
No one is going to attempt to equalize in poor solar conditions.
Solar in winter is going to need every bit of advantage possible, including tilting panels, or if there is snow cover a vertical (90 degrees) installation to get a "bounce" off the white surface.
