Variation in output of individual panel question

[dcchapman7]

Quick question, how much variation in output should there be between two panels right next to each other if the temp, sun exposure and all other factors are the same? Just had a new system installed and started on Wednesday, good production, just notice one panel in a group that consistently produces about .11 - .16 kWh less than those around it, inspected and there is no shading, bird droppings or excessive dust/dirt on it... In the screenshot below it is the panel that shows output 1.97...

[ButchDeal]

Login to the web site and view in through the day. What power is it producing at any instant compared to the others?

[sensij]

Login to the web site and view in through the day. What power is it producing at any instant compared to the others?

Instanteous output is hard to trust since reporting time between panels can vary 10 min or more. If the OP has report access, looking at the voltage and current curves for that panel compared to a neighbor could be revealing.

[dcchapman7]

So there is a difference - when I look at the playback option of output in every 15 minute increments - in the morning - from 8:45 - 10:30 the output of this single panel looks to be quite a bit less than it's neighboring panels (screen shot below) - then after 10:30 it seems to catch up and be fairly close the rest of the day...so probably not a problem, likely shading I wasn't aware of... I realized that when you just click panel layout on the monitoring portal it is just showing cumulative production for the day, so will have to climb up there and check if that panel is getting shaded at that time... thanks for the feedback.

[ButchDeal]

So there is a difference - when I look at the playback option of output in every 15 minute increments - in the morning - from 8:45 - 10:30 the output of this single panel looks to be quite a bit less than it's neighboring panels (screen shot below) - then after 10:30 it seems to catch up and be fairly close the rest of the day...so probably not a problem, likely shading I wasn't aware of... I realized that when you just click panel layout on the monitoring portal it is just showing cumulative production for the day, so will have to climb up there and check if that panel is getting shaded at that time... thanks for the feedback.

Usually in the playback you can see shadows from early or late that were not considered. If the modules even out with the rest at any time it usually isn't an equipment issue.

[ButchDeal]

Instanteous output is hard to trust since reporting time between panels can vary 10 min or more. If the OP has report access, looking at the voltage and current curves for that panel compared to a neighbor could be revealing.

I always start with the playback and look for shadows in early or late that homeowners didn't consider. Find times when the equipment are the same and you can usually be assured there isn't a problem.

[dcchapman7]

All right, haven't posted on this thread for a long time, but have been continuing to monitor performance of my PV system the last few months - noticed over the last couple weeks that one panel in the system seems to be under producing compared to neighboring panels, no shading from vents or chimney or trees or anything else that I can tell watching over the course of the day... I inspected the panel from the roof and there is no debris, bird droppings or dirt caked on it... wondering if any of you could take a look at my monitoring portal with solar edge (saw a previous post that detailed how to make the portal viewable to the public) - here is the link: https://monitoringpublic.solaredge.c...20Solar%20Edge - the panel in question is panel 1.0.23 in screen shot from the portal below - I should mention that prior to the last 2 weeks this panel was performing very close to neighboring panels and then all of the sudden the drop in performance... any feedback is appreciated. Thanks.

[max2k]

All right, haven't posted on this thread for a long time, but have been continuing to monitor performance of my PV system the last few months - noticed over the last couple weeks that one panel in the system seems to be under producing compared to neighboring panels, no shading from vents or chimney or trees or anything else that I can tell watching over the course of the day... I inspected the panel from the roof and there is no debris, bird droppings or dirt caked on it... wondering if any of you could take a look at my monitoring portal with solar edge (saw a previous post that detailed how to make the portal viewable to the public) - here is the link: https://monitoringpublic.solaredge.c...20Solar%20Edge - the panel in question is panel 1.0.23 in screen shot from the portal below - I should mention that prior to the last 2 weeks this panel was performing very close to neighboring panels and then all of the sudden the drop in performance... any feedback is appreciated. Thanks.

looks like 1/3 of its cells are gone

[sensij]

looks like 1/3 of its cells are gone

If 1/3rd of the cell is being bypassed, it should be clear in the voltage data. dcchapman7 , are you familiar with the "charts" section of the portal?

[ButchDeal]

All right, haven't posted on this thread for a long time, but have been continuing to monitor performance of my PV system the last few months - noticed over the last couple weeks that one panel in the system seems to be under producing compared to neighboring panels, no shading from vents or chimney or trees or anything else that I can tell watching over the course of the day... I inspected the panel from the roof and there is no debris, bird droppings or dirt caked on it... wondering if any of you could take a look at my monitoring portal with solar edge (saw a previous post that detailed how to make the portal viewable to the public) - here is the link: https://monitoringpublic.solaredge.c...20Solar%20Edge - the panel in question is panel 1.0.23 in screen shot from the portal below - I should mention that prior to the last 2 weeks this panel was performing very close to neighboring panels and then all of the sudden the drop in performance... any feedback is appreciated. Thanks.

In the public view we do not have full access to the reports just the layout and dashboard.
take a look at 10:15 am yesterday output though...
Your installer was lazy in setting up the monitoring portal. These modules can not all be in a single string as it indicates, and it doesn't look like they are all facing south from the time lapse.

[dcchapman7]

Thanks for the replies, where is the charts section and what exactly should I be looking for in it about voltage compared to neighboring panels? Happy to post screenshots of what I find...

[ButchDeal]

Thanks for the replies, where is the charts section and what exactly should I be looking for in it about voltage compared to neighboring panels? Happy to post screenshots of what I find...

You should see it if your installer gave you owner access. (note not the admin section though) highlighted in red:

Dashboard.jpg

[dcchapman7]

No, do not see owner access... thoughts on next steps if any?... ask installer to review portal info?... expect them to come and test the panel in some way?

[dcchapman7]

No, do not see owner access... thoughts on next steps if any?... ask installer to review portal info?... expect them to come and test the panel in some way?

[sensij]

No, do not see owner access... thoughts on next steps if any?... ask installer to review portal info?... expect them to come and test the panel in some way?

Totally depends on the installer. Some will look at the same data you've shown here, conclude they have no risk of failing to meet some contractual system level performance guarantee, and just move on. Others will dig deeper, in ways we've suggested here. Doesn't hurt to ask, but if the contract doesn't require this level of support, it is hard to know what to expect.