12v MPPT and 24v MPPT vs 24v PWM Test
Got a chance to try out comparing amps to the battery using MPPT vs PWM on a 24v battery bank and comparing those with the usual MPPT on 12v with my 230w panel. The bank is four 6s, so it was easy ...
Forum Discussion
Salvo says it must be measurement error or bad equipment or whatever, anytime the results don't agree with what he thinks they should be. Getting real tired of that. Sorry.
If anybody thinks my numbers are wrong, post your own! Not hard.
Yes the MPPT OUTPUT watts is divided by the battery voltage to get your "amps to the battery" The lower the battery voltage the more amps you get from the same watts. That is why MPPT salesmen always talk about how great MPPT is on a nearly dead battery :) they also like to do their examples on an ice flow at the North Pole so panel temps will be low.
STC is panel temp of 25C. Panel is about 20C or so higher than ambient. So to have 25C panel it has to be freezing out!!! At normal camping ambient of 16C, my panel is already 44C, and at 25C ambient (80F folks--not a real heat wave) panel is 51C. The panel loses 10% of its wattage between 25C and 50C--look it up!)
Meanwhile PWM uses panel amps, which actually rise a little with higher temps, so PWM is not affected by the panel getting hot. That is what I have seen, and it is not because I can't measure things properly or because my equipment is sub-par. Get over it!!! :(
If anybody thinks my numbers are wrong, post your own! Not hard.
Yes the MPPT OUTPUT watts is divided by the battery voltage to get your "amps to the battery" The lower the battery voltage the more amps you get from the same watts. That is why MPPT salesmen always talk about how great MPPT is on a nearly dead battery :) they also like to do their examples on an ice flow at the North Pole so panel temps will be low.
STC is panel temp of 25C. Panel is about 20C or so higher than ambient. So to have 25C panel it has to be freezing out!!! At normal camping ambient of 16C, my panel is already 44C, and at 25C ambient (80F folks--not a real heat wave) panel is 51C. The panel loses 10% of its wattage between 25C and 50C--look it up!)
Meanwhile PWM uses panel amps, which actually rise a little with higher temps, so PWM is not affected by the panel getting hot. That is what I have seen, and it is not because I can't measure things properly or because my equipment is sub-par. Get over it!!! :(
