Is this panel a problem?

[J.P.M.]

Please be careful to not read more into the data than what is there. SolarEdge doesn't report the power produced by each panel instantaneously, it relies on random timing that can lead to differences of 10-20 min from one panel to the next. During the mid-morning and afternoon, this difference in timing can make it appear like one panel is over or under producing, but really, it is just reporting power at a slightly different time of day when more or less irradiance was present.

During the middle of the day, irradiance rate of change is lowest, and panel power should more or less converge. However, the middle of the day is when performance variation due to temperature differences is likely to be most visible.

Looking at daily or weekly totals can offer insight into performance too. Below is the energy produced in my system from the last week... none of the days was truly clear, there were morning clouds to varying degrees as is typical this time of year. In this view, I have a low of 81.33 kWh to a high of 88.45 kWh over the week, a difference of around 8%. However, I know that the panel that got 88 kWh is out on the end of the roof, gets great airflow, and doesn't even have an optimizer underneath of it to generate heat or impede airflow since I wired the string in a way that tried to minimize the overall physical length of the circuit (the panel next to it, 1.2.13, has two optimizers under it). I also have QC data from the pallet that would lead me to expect some performances differences from one panel to the next, but haven't bothered to correlate the panel serial numbers to the actual installed location.

To some extent, there might also be calibration differences in the optimizers. If you add up the optimizer energy, it never equals the energy reported by the inverter, or the energy I measure with a revenue grade meter on the inverter's output. Some of that is related to the inverter efficiency, but there isn't much reason to believe that the accuracy of the optimizers is better than a couple percent.

Again, the OP's system could be perfectly healthy, and even if one panel out of 10 truly is under-performing by 4%, the net impact on the system is only 0.4%... unless it gets worse, the cost of messing with it is probably greater than the value of any additional energy to be generated. production.JPG

FWIW, after measuring all the panel temps for my system well over 100 times as described previously, and finding what I generally expected in terms of leading edge temps. being lower than the rest, a 10 C. temp. difference highest to lowest temp. on a 4 X 4 landscape array with most of adjacent panel temp. change happening at the array leading edges, was not at all uncommon. Wind, of course was always a facto, and the pattern of temp. change seemed general similar to the output pattern you show, at least in a qualitative sense. Because I have a string inverter, I have no per panel information other than temp. estimates I took w/an IR thermometer measured from the back of the panels.

[AzRoute66]

One of your questions was "I haven't asked the installers to take a look at it yet, should I?". I would say, "Why not?" Should be free, and they might know why it is the runt of the litter.

[Heataholic]

If you scroll through the day does it get close to the others at times?
It is fairly close and pv modules are generally rated with some variance in production capability.
it could also be a but of dirt in that module as well.

We got some decent rain this weekend so I doubt it is a dirt issue, the system has only been up a couple of months to begin with, but I am obviously a novice so I can't guarantee that statement. I picked those 4 spots to show it is pretty consistently lower all day than its neighbors. The other panels on the other strings all seem to even out pretty well over the course of the day except that one, there is 39 panels on the roof total.

As for the layout I will upload the plans. There is a valley on both sides of the bottom row but the panels aren't very close to it and the issue is all day as opposed to just the morning when there might be shade from the one side. It also doesn't appear to cause a similar problem to the other panel on the opposite side.

Someone asked why I hadn't asked the installer yet and to that all I can say is being around homes for the last decade and talking to hundreds of contractors about various issues I've learned that sometimes they will bull**** their way out of fixing something. Today alone the customer service rep from the builder on this house told me the doors warping and sticking and them not being painted on the top and bottom are completely unrelated. They will fix the doors but they don't have to paint the doors, which is complete bull****. Posting the question here I get impartial opinions from a decent number of seemingly experts who have nothing to gain or lose by doing so. Simply put I an fairly confident I can trust the advice given here whereas the installer might lie to me just to get me to leave them alone.

Seems like as of right now I can let it be but I should keep an eye on it in case it gets worse. If that assessment is wrong then I misunderstood and please correct me so I can have the installer take a look.

Thanks for the great responses.

[littleharbor]

I have hung hundreds of doors in my day and will say, IMO, it is imperative to seal the top and bottom of all wooden doors. The top and bottom of the stiles are end grain which is like a wick when it comes to moisture/water absorption. The least problem you will have is the door swelling and sticking, followed by paint peeling. warping and eventually rot. Some of the doors I have hung, (from scratch, BTW) will have labels clearly stating "All 6 sides of this door must be sealed" You are right and the BSing contractor is wrong.
Excuse the interruption. I had to throw that in. Back to the topic at hand.

[ButchDeal]

Seems like as of right now I can let it be but I should keep an eye on it in case it gets worse. If that assessment is wrong then I misunderstood and please correct me so I can have the installer take a look.

You didn't give the location of the site. in much of the US that module will have a shadow from the ridge line but should be clear by your first image
I would think that it being tucked into a valley like it is with a roof line extending under it would reduce circulation of cooling air under the module a bit. In fact the opposite module in a similar situation shows a slight reduction in performance as well: 1.2.7.
1.2.7 does better than 1.2.10 though most likely due to increased circulation since there is no module above it and increase in diffuse light.

Most of the simulations we use do not model air circulation and cooling but it is clear that 1.2.10 gets less diffuse light because of its proximity to the valley with extended roof below it.

[Heataholic]

You didn't give the location of the site. in much of the US that module will have a shadow from the ridge line but should be clear by your first image
I would think that it being tucked into a valley like it is with a roof line extending under it would reduce circulation of cooling air under the module a bit. In fact the opposite module in a similar situation shows a slight reduction in performance as well: 1.2.7.
1.2.7 does better than 1.2.10 though most likely due to increased circulation since there is no module above it and increase in diffuse light.

Most of the simulations we use do not model air circulation and cooling but it is clear that 1.2.10 gets less diffuse light because of its proximity to the valley with extended roof below it.

Sorry it is in the large upside down diamond in the top middle of that last uploaded image. The bottom portion of that diamond that is flat left to right overhangs nothing/the roof on the sides. I will take a picture of it tomorrow when the sun comes out. There is no visible shading on the room after about 8 am maybe earlier, the roof isn't very steep since we don't get snow out here. It isn't really tucked into the valley but I will get a picture of it tomorrow to show it better. Here is the year to date on the string.

[sensij]

So it underperforms the average panel in that group by 3.5%. I think there are reasons to believe that location would run warmer than the panels nearby, and agree the best course of action would be to just let it go, but keep an eye on it. Dealing with panel mismatch like this (thermal, manufacturing variation from one panel to the next, etc) is where the SolarEdge system does its best work, even if it doesn't add up to much.

Just to put this in perspective, you are looking at a loss of <10 kWh over two months. Even if you could get that location to produce equally with the others in that row, that only increases your revenue by about $10 / year, less than $1 / mo difference in your electric bill.

[ButchDeal]

Sorry it is in the large upside down diamond in the top middle of that last uploaded image. The bottom portion of that diamond that is flat left to right overhangs nothing/the roof on the sides. I will take a picture of it tomorrow when the sun comes out. There is no visible shading on the room after about 8 am maybe earlier, the roof isn't very steep since we don't get snow out here. It isn't really tucked into the valley but I will get a picture of it tomorrow to show it better. Here is the year to date on the string.

YEs that is the location I was talking about. you can see from the design that the roof of the diamond section overhangs the roof to the right of it. This overhang and the valley will prevent some air flow. Roof_Layout_pdf__1_page_.jpg

It is also listed as a 5:12 pitch roof.

[J.P.M.]

That looks like a temp. difference to me with some small shading effect. Same as others, I'd keep an eye on it, but for the amount of loss involved, and the possible reasons for it, as well as the idea that any annual deficit may be within published output tolerances as others have also noted, it may be something you'll need to live with.