mppt vs pwm

jrnymn7 wrote:
12thgenusa,

"300 watts is more than 245 watts. At 13.5 v output it means 4 amps difference"
This was directed to JiminDenver's comment that he only sees a few more amps out of a pair of 150s compared to a 245.

Four 250w/24v panels = 1000w.

Six 160w/12v panels = 960w

1000w - 960w = 40w.

40w / 13.5v = ~3a

At 13.5v that's only a 3a difference, and yet a 960w/12v/series array produces 12 amps less than the 1000w/24v/parallel array. So where did the extra 9 amps go? That's a 20% loss.
Where is your documentation for the 20% difference?

The comparison being discussed is 12v series (44v) vs. 24v parallel (36v), using mppt. The Rogue comparison is between 12v parallel (17v) vs. 24v parallel (36v). So while the Rogue publication may actually show mppt works a little better with 12v panels, at low amperages, it does not address the issue at hand.

This comment intended to address the notion that higher voltage input to lower voltage output is much more inefficient than low voltage input to low voltage output. It is slightly less efficient, but minimally so. The actual documentation shows that 24-v panels to 24-v system is most efficient, 12-v panels to 12-v system is second best and 24-v panels to 12-v system comes in third. However, there is only slight difference between the last two.

"Panels in series has nothing to do with it"

Real world observations seem to indicate that 12v panels wired in series, coupled with an mppt controller, will produce less output than a single 24v panel of equal wattage.
Again, show me real world documentation of this, not "I know a guy . . ." anecdotal stories.
The controller does not know series or parallel. It only sees voltage and current.