I have 12x 445w panels. I have been running them in series/parallel (6x2) connected to grid tie inverter (Growatt 6kW Grid-Tie Inverter | MIN 6000TL-X). They are facing south at 28 degrees tilt which is the "ideal" fixed angle for my location.
I have been unhappy with my production since I hooked them up. I have peaked at 3500w at any one time. With a theoretical limit of 5340 that's only 65% effeciency. I have been running that for a few months. I bought a MPPT meter to test each panel to see if I had a bad one but it was cheap Chinese and released all it's stored smoke instantly when hooked to a single panel. Since the meter didn't work out I decided to try and test using my inverter. I only hooked up one of the series (6 panels) and got 2300w. I then switched to the other series and got 2250w. So why would I lose 1000w when putting in parallel. No shading.
So I decided to do another test and hook them all in series but I can only use 11 panels because of VOC. When I hooked all 12 and measured with the fluke I got 498v so I took a panel out (11 now) and voltage went down to 450ish. The inverter maxes at 500v and I didn't want to risk it if there is a soar flare on a cold day and blow the inverter. Now that I'm using 11 panels in series I am getting 4000w. That's 81% efficiency. Producing more power with one less panel.
All that to ask, why would parallel lose so much power. Can I somehow get that last panel back in so I'm not wasting it. The inverter has a second MPPT input but it would cost too much for more wire for the 445w I would gain.
Second, I have 3 other 6x2 strings on the roof hooked to off-grid. Am I potentially losing that much wattage from them as well? They don't have as high of an input voltage so I'd have to lose 2 panels per inverter to put them in series so I don't think I would gain anything. I typically get up to 3800w from those strings.
If I did put them in series by removing 2 panels per inverter then I would have 6 panels on the roof and one removed from grid tie that are now unused and maybe put them on a second grid tie? They are located all over so lots of wire to use that way. Not sure I'd ever get a return on my investment.
Last question. If the grid tie inverter has 2 inputs, are they 100% independent and won't effect each other. I ask because when I teste each series of 6 panels alone I got 2300w which is 86% efficiency. I would have to run another set of wires but maybe that is the best solution as long as it makes financial sense. I don't want "2 mppt inputs" to just act as a combiner box and gain me nothing.
Thanks!
I have been unhappy with my production since I hooked them up. I have peaked at 3500w at any one time. With a theoretical limit of 5340 that's only 65% effeciency. I have been running that for a few months. I bought a MPPT meter to test each panel to see if I had a bad one but it was cheap Chinese and released all it's stored smoke instantly when hooked to a single panel. Since the meter didn't work out I decided to try and test using my inverter. I only hooked up one of the series (6 panels) and got 2300w. I then switched to the other series and got 2250w. So why would I lose 1000w when putting in parallel. No shading.
So I decided to do another test and hook them all in series but I can only use 11 panels because of VOC. When I hooked all 12 and measured with the fluke I got 498v so I took a panel out (11 now) and voltage went down to 450ish. The inverter maxes at 500v and I didn't want to risk it if there is a soar flare on a cold day and blow the inverter. Now that I'm using 11 panels in series I am getting 4000w. That's 81% efficiency. Producing more power with one less panel.
All that to ask, why would parallel lose so much power. Can I somehow get that last panel back in so I'm not wasting it. The inverter has a second MPPT input but it would cost too much for more wire for the 445w I would gain.
Second, I have 3 other 6x2 strings on the roof hooked to off-grid. Am I potentially losing that much wattage from them as well? They don't have as high of an input voltage so I'd have to lose 2 panels per inverter to put them in series so I don't think I would gain anything. I typically get up to 3800w from those strings.
If I did put them in series by removing 2 panels per inverter then I would have 6 panels on the roof and one removed from grid tie that are now unused and maybe put them on a second grid tie? They are located all over so lots of wire to use that way. Not sure I'd ever get a return on my investment.
Last question. If the grid tie inverter has 2 inputs, are they 100% independent and won't effect each other. I ask because when I teste each series of 6 panels alone I got 2300w which is 86% efficiency. I would have to run another set of wires but maybe that is the best solution as long as it makes financial sense. I don't want "2 mppt inputs" to just act as a combiner box and gain me nothing.
Thanks!