More MPPT Confusion and Question
Still trying to understand my MPPT set-up and what would be the effect of changing things a bit. My 230w (30.0 Vmp x 7.7 Imp) poly panel has a Vmp of 30.0v with a measurement tolerance of +/- 3% S...
Forum Discussion
The solar controller may be sub-par but it does better in the Spring and Fall than in Summer. My amps to the battery seasonally change with panel temperatures. ( IR gun pointing up under the panel) The panel is the thing that loses power with high temps, not the controller. So I believe the controller is not the culprit as such.
It is the way the amps are created from the power with an MPPT controller that is the problem, compared with getting Isc with PWM
Another possible is in that Tracer owner's manual it has graphs of controller efficiency vs array wattage, where efficiency falls off into the lower 90s from mid-90s as you get up in wattage toward the controller's max rating.
With my 230w panel and the controller rated for 250w, that puts me at the lower end of controller efficiency, which would account for a few more of my missing watts at the output, Spring or Summer.
The best output watts I have seen in the Spring is about 205-210w of the rated 230w- goes with about 15.5 amps. In Summer I mostly see 180w or so with about 13.5 amps.
EDIT: 27w/13.5v = 2 amps. So do the above figures make sense?
207-180 = 27 and 15.5-13.5 = 2. Ta da!
And where 10% of panel power is lost at 50C, and 10% of 230w is 23w = 1.7 amps
With my PWM and same array wattage it would be 14.5 amps every time despite the change in panel temperature. (based on actual results with 200w and 210w scaled to 230w)
This is all with ambient around 16C for the "good" results and only 25C for the "bad" results, so I would not like to be trying my MPPT set-up at 35C ambient like down there gets. :(
I have no comparable figures to compare with mine where Brand X is using a different controller in the same conditions.
Salvo's direct plot above with his 135w comes out the same as I got with my 130w and PWM so that is a cross-check on that.
It is the way the amps are created from the power with an MPPT controller that is the problem, compared with getting Isc with PWM
Another possible is in that Tracer owner's manual it has graphs of controller efficiency vs array wattage, where efficiency falls off into the lower 90s from mid-90s as you get up in wattage toward the controller's max rating.
With my 230w panel and the controller rated for 250w, that puts me at the lower end of controller efficiency, which would account for a few more of my missing watts at the output, Spring or Summer.
The best output watts I have seen in the Spring is about 205-210w of the rated 230w- goes with about 15.5 amps. In Summer I mostly see 180w or so with about 13.5 amps.
EDIT: 27w/13.5v = 2 amps. So do the above figures make sense?
207-180 = 27 and 15.5-13.5 = 2. Ta da!
And where 10% of panel power is lost at 50C, and 10% of 230w is 23w = 1.7 amps
With my PWM and same array wattage it would be 14.5 amps every time despite the change in panel temperature. (based on actual results with 200w and 210w scaled to 230w)
This is all with ambient around 16C for the "good" results and only 25C for the "bad" results, so I would not like to be trying my MPPT set-up at 35C ambient like down there gets. :(
I have no comparable figures to compare with mine where Brand X is using a different controller in the same conditions.
Salvo's direct plot above with his 135w comes out the same as I got with my 130w and PWM so that is a cross-check on that.
