Rogue MPPT, 490W and charging mysteries
Now that we were finally all in one place - me, Rogue 3048 and my rig - it was time to have some fun. 1)Battery: old starter, tested beyond dead, plates above the water. No wonder, 8 months in Mex...
Forum Discussion
Yes, one AGM was not performing properly - the one that didn't go below 1.5A, and later was subjected to the load test, which test results puzzled me. The load test puzzle has been resolved TAD - now I know that SOC pre-charge was 60%, not 75%. Still, 2 issues remained unresolved: looong forced ABS being unable to drop the current below 1.5, and during the load test after that looong charging the V dropped to 12.45 immediately. I charged this battery again, it did reach ABS=1A this time, before the 4-hour timer had expired (don't remember exactly when, but it did).
2 other AGMs charged in parallel reached ABS 2A without problem. BUT during their charging there occurred the aforesaid weird issue with shading of one of panels. MPPT was 18A, then one panel shaded another by ~10%, MPPT dropped to 3A (can't say how abruptly, I've been on the roof trying to locate the studs, studfinders DON'T see wooden studs under3/8" plywood, this is a separate story). Lifted the panel out of shade, it jumped into ABS 12A, lowered the panel back into shade, still ABS 12A. 2 panels in parallel, 3 diodes per panel: 245W
Somebody installed panels in series from and with AM solar, and I recall he said/quoted that panels with 3 or more diodes work better in parallel. I don't want to open this can of worms in this thread - shading of parallel VS series VS number of diodes. Amps dropping from 12 to 3 with mere 10% shade on ONE panel, alright, maybe, but then it goes into ABS 12A and REMAINS at 12A when shaded again. Marc says MPPT is slow - but MPPT drop from 12 A to 3A with enough sun to generate 12A is weird. And keeping 12A in shade again is weird. This looks like a "freeze" of software that you see in computers sometimes - rebooting (abruptly changing the light conditions in my case) brings things back to normal. In this case the firmware update might help. Will see if this happens again.
Marc,
I probably didn't read the manual well, since tried to tune-up VTRIM at different temps - which is of course difficult. Multimeter error by 0.1V to the lower side... maybe... It's a good multimeter, not $10. Tomorrow will borrow 2 other meters from 2 neighbors and see what happens.
Full Mosey -
here is the link to Rogue manual in case if you haven't found yet: http://www.roguepowertech.com/documents/MPT3048Rev2-Manual.pdf
2 other AGMs charged in parallel reached ABS 2A without problem. BUT during their charging there occurred the aforesaid weird issue with shading of one of panels. MPPT was 18A, then one panel shaded another by ~10%, MPPT dropped to 3A (can't say how abruptly, I've been on the roof trying to locate the studs, studfinders DON'T see wooden studs under3/8" plywood, this is a separate story). Lifted the panel out of shade, it jumped into ABS 12A, lowered the panel back into shade, still ABS 12A. 2 panels in parallel, 3 diodes per panel: 245W
Somebody installed panels in series from and with AM solar, and I recall he said/quoted that panels with 3 or more diodes work better in parallel. I don't want to open this can of worms in this thread - shading of parallel VS series VS number of diodes. Amps dropping from 12 to 3 with mere 10% shade on ONE panel, alright, maybe, but then it goes into ABS 12A and REMAINS at 12A when shaded again. Marc says MPPT is slow - but MPPT drop from 12 A to 3A with enough sun to generate 12A is weird. And keeping 12A in shade again is weird. This looks like a "freeze" of software that you see in computers sometimes - rebooting (abruptly changing the light conditions in my case) brings things back to normal. In this case the firmware update might help. Will see if this happens again.
Marc,
I probably didn't read the manual well, since tried to tune-up VTRIM at different temps - which is of course difficult. Multimeter error by 0.1V to the lower side... maybe... It's a good multimeter, not $10. Tomorrow will borrow 2 other meters from 2 neighbors and see what happens.
Full Mosey -
here is the link to Rogue manual in case if you haven't found yet: http://www.roguepowertech.com/documents/MPT3048Rev2-Manual.pdf
