My First PWM Solar Run
Well, I guess you could say I lost my solar charging virginity... finally. :)
Two 140w 12v Poly panels, in parallel, manual tracking, Isc 8.15a (x2), Voc 22.4, 50' (one way) of 6awg cable to Solar30 pwm (set to 14.4Vabs), 4' of 2awg to four 6v GC2 (430Ah).
Bank at 12.53 ocv, 81% soc, -82Ah's.
Conditions were cloud free, except for the odd small, very thin passer by, and about 70-75F ambient, throughout test.
1:10pm:
Isc of 9a each, 19.79 Voc, no idea of panel temps.
I made up adapters to go from panels' mc4's to mini welding connectors, so all V readings begin just after those adapters. So not sure how much loss thru the adapters, themselves. Flipped the switch... calculated about 7% V loss, adapters to cc, at about 18a... 13.47v input, 13.29v output, so 98.5% efficiency thru controller. Cabinet temp was about 80F using a wall thermometer.
2:15pm:
16a (controller), 16.8a (Trimetric), passed thru @ 14.31v adapters, 13.51v input, 13.33v output, and 13.25v at bank...
- adapters to input; 94.4% eff.
- thru controller; 98.6% eff.
- controller to bank; 99.4% eff.
- overall, adapters to bank; 92.5% eff.
2:45pm: 16.4a (controller), 17.2a (Trimetric), Vbatt ?
3:45pm: 16a (controller), Vbatt 13.4v
4:30pm: 16.1a ("), Vbatt 13.53v, 90% soc, -43Ah's.
* 5:05pm: 15.2a ("), Vbatt 13.54v, 60 degree tilt, pointed...
... switched to flat position, laying east to west, amps dropped to 9a @ 13.44v, so a 41% loss compared to tracked.
5:40pm: (tracked) 15.2a @ 13.87v
6:35pm: 13.2a @13.93v, 95% soc, -22Ah's.
7:05pm: (light clouds), 75 degree tilt, pointed, 0a @ 13.35v.
Harvest;
+80Ah's per Solar30, +63Ah's per Trimetric, set to 85% eff.
Observations/Conclusions;
- Need +2v at adapters above ocv to do 16(+)a bulk, and a minimum of +1v at adapters to overcome Vbatt + R at finishing amps.
- Need to do more tracked vs. flat comparisons, throughout next charge. And I found even the smallest of adjustments could make a measurable difference.
- Need to figure out a way to know loss thru adapters?
- Shading only one cell brought the entire array's amps down considerably. Shading an entire row, either way, had the same result as shading a single cell.
- The occasional Isc check showed Isc in excess of 10a, at times, so these panels can really put out, even at mild ambient temps.
Two 140w 12v Poly panels, in parallel, manual tracking, Isc 8.15a (x2), Voc 22.4, 50' (one way) of 6awg cable to Solar30 pwm (set to 14.4Vabs), 4' of 2awg to four 6v GC2 (430Ah).
Bank at 12.53 ocv, 81% soc, -82Ah's.
Conditions were cloud free, except for the odd small, very thin passer by, and about 70-75F ambient, throughout test.
1:10pm:
Isc of 9a each, 19.79 Voc, no idea of panel temps.
I made up adapters to go from panels' mc4's to mini welding connectors, so all V readings begin just after those adapters. So not sure how much loss thru the adapters, themselves. Flipped the switch... calculated about 7% V loss, adapters to cc, at about 18a... 13.47v input, 13.29v output, so 98.5% efficiency thru controller. Cabinet temp was about 80F using a wall thermometer.
2:15pm:
16a (controller), 16.8a (Trimetric), passed thru @ 14.31v adapters, 13.51v input, 13.33v output, and 13.25v at bank...
- adapters to input; 94.4% eff.
- thru controller; 98.6% eff.
- controller to bank; 99.4% eff.
- overall, adapters to bank; 92.5% eff.
2:45pm: 16.4a (controller), 17.2a (Trimetric), Vbatt ?
3:45pm: 16a (controller), Vbatt 13.4v
4:30pm: 16.1a ("), Vbatt 13.53v, 90% soc, -43Ah's.
* 5:05pm: 15.2a ("), Vbatt 13.54v, 60 degree tilt, pointed...
... switched to flat position, laying east to west, amps dropped to 9a @ 13.44v, so a 41% loss compared to tracked.
5:40pm: (tracked) 15.2a @ 13.87v
6:35pm: 13.2a @13.93v, 95% soc, -22Ah's.
7:05pm: (light clouds), 75 degree tilt, pointed, 0a @ 13.35v.
Harvest;
+80Ah's per Solar30, +63Ah's per Trimetric, set to 85% eff.
Observations/Conclusions;
- Need +2v at adapters above ocv to do 16(+)a bulk, and a minimum of +1v at adapters to overcome Vbatt + R at finishing amps.
- Need to do more tracked vs. flat comparisons, throughout next charge. And I found even the smallest of adjustments could make a measurable difference.
- Need to figure out a way to know loss thru adapters?
- Shading only one cell brought the entire array's amps down considerably. Shading an entire row, either way, had the same result as shading a single cell.
- The occasional Isc check showed Isc in excess of 10a, at times, so these panels can really put out, even at mild ambient temps.
