Last March, I installed a rooftop solar panel system. It consists of eight 170W panels and a single 200W panel connected in a 3P3S configuration as shown in the first attachment. I had purchased the 200W panel first, but for the space I have to install on top of a cargo trailer, the dimensions of the 170W panel made much more sense, so I ordered 8 of those. Since I already owned the 200W panel, I figured I would include it in the system even though I knew it would suffer slightly from mismatched current flow.
So my first question: is there any serious cause for concern with this setup?
Fast forward to today. Over the summer I noticed a severe drop in power produced by this system. Back in April-June I was getting 5-6kWh on a good sunny day, but now in August I only get 1-2kWh in a day. I contacted the manufacturer (Alrska) customer support, and they had me measure the Isc and Voc for each panel. These measurements were taken on a sunny day around 11am with panels lying flat on the roof.
Panel 1: 22.15V 6.0A
Panel 2: 22.15V 5.4A
Panel 3: 26.1V 2.6A (200W panel)
Panel 4: 21.7V 6.5A
Panel 5: 21.7V 5.6A
Panel 6: 21.6V 5.4A
Panel 7: 21.4V 1.8A
Panel 8: 21.4V 5.8A
Panel 9: 21.2V 2.0A
Clearly Panels 3, 7, and 9 have very poor performance! I repeated these measurements at 4pm and saw the same three panels with significantly lower Isc than the other six. It seems to me that these panels have been damaged prematurely after only 5 months or are defective.
I explained the situation to the customer service rep and provided them with the above measurements. They claimed that, because I connected a 200W panel in parallel with 170W panels, this could cause damage to the panels and therefore they would not agree to any warranty claim. A screenshot of their explanation is attached.
Is there any merit to the company's explanation?
To me it seems incredibly fishy, and goes against everything I have read on DIY solar and other sources about connected mismatched panels. Yes, it is not a good thing to mismatch because you lose some of the wattage, but has anyone ever heard of this significantly damaging a panel like this? I feel like they came up with a bull%$^# explanation so they don't have to honor their warranty on what seems to me a defective product. I'm regretting opting for the "cheap" and unproven manufacturer since it's starting to look like I'm stuck with a bunch of bad panels.
So my first question: is there any serious cause for concern with this setup?
Fast forward to today. Over the summer I noticed a severe drop in power produced by this system. Back in April-June I was getting 5-6kWh on a good sunny day, but now in August I only get 1-2kWh in a day. I contacted the manufacturer (Alrska) customer support, and they had me measure the Isc and Voc for each panel. These measurements were taken on a sunny day around 11am with panels lying flat on the roof.
Panel 1: 22.15V 6.0A
Panel 2: 22.15V 5.4A
Panel 3: 26.1V 2.6A (200W panel)
Panel 4: 21.7V 6.5A
Panel 5: 21.7V 5.6A
Panel 6: 21.6V 5.4A
Panel 7: 21.4V 1.8A
Panel 8: 21.4V 5.8A
Panel 9: 21.2V 2.0A
Clearly Panels 3, 7, and 9 have very poor performance! I repeated these measurements at 4pm and saw the same three panels with significantly lower Isc than the other six. It seems to me that these panels have been damaged prematurely after only 5 months or are defective.
I explained the situation to the customer service rep and provided them with the above measurements. They claimed that, because I connected a 200W panel in parallel with 170W panels, this could cause damage to the panels and therefore they would not agree to any warranty claim. A screenshot of their explanation is attached.
Is there any merit to the company's explanation?
To me it seems incredibly fishy, and goes against everything I have read on DIY solar and other sources about connected mismatched panels. Yes, it is not a good thing to mismatch because you lose some of the wattage, but has anyone ever heard of this significantly damaging a panel like this? I feel like they came up with a bull%$^# explanation so they don't have to honor their warranty on what seems to me a defective product. I'm regretting opting for the "cheap" and unproven manufacturer since it's starting to look like I'm stuck with a bunch of bad panels.
