Differences In Panels

[ButchDeal]

I will probably try swapping panels around to see if it makes a difference. As to heat, I can't see how there would be anything in that specific area to cause more heat. The panels are over the living room and a master bedroom which have high ceilings. If anything, I would have expected the western facing panels to show some heat effects as they are over the kitchen, a water heater and a non air-conditioned garage.

Granted 5.5 kw is not a lot but it will add up. While the utility power cost is not that much to replace the loss, $3.00 per watt for install is to be considered too.

I have looked into getting an infra-red camera to see if it is actually a heating issue. However, I could just about replace the panels for the cost of a good FLIR camera or to have a heat survey done.

I guess I'll continue to watch it for a while... Thanks for the insight and suggestions!

The heat differences are unlikely to be something in the house but the ability for the modules to ventilate on outside outside as we have already mentioned it is clear that the ones on the end are higher producing because of better ventilation.

[SunEagle]

Ah. I found the reason that post by DrLumen went unapproved. It has the word -ictchen that starts with a K. That will trigger any post to get unapproved. Long story but there was a lot of spam that contained that word so it became a no no to say.

[littleharbor]

Ah , we remember the k, i t c h e n spammers. Haven't heard from them lately.

[DrLumen]

The heat differences are unlikely to be something in the house but the ability for the modules to ventilate on outside outside as we have already mentioned it is clear that the ones on the end are higher producing because of better ventilation.

Maybe coupled with 'unlucky' panels but to do a quick calc, 10% @ .38 temp coefficient would mean a 53 degree (F) temperature difference. Maybe, but that seems a bit improbable.

Thanks for the info SunEagle. I will refrain from using the K word.

[ButchDeal]

Maybe coupled with 'unlucky' panels but to do a quick calc, 10% @ .38 temp coefficient would mean a 53 degree (F) temperature difference. Maybe, but that seems a bit improbable.

Thanks for the info SunEagle. I will refrain from using the K word.

as I stated the head difference is NOT related to something inside the house unless you have a fire in one of the rooms.

also coupled with the -0,+5% difference in PV modules, the 2% accuracy of the measuring equipment, etc

have you look through the playback of several days to looks for patterns?
have you looked at the charts for other differences.

[cebury]

Maybe coupled with 'unlucky' panels but to do a quick calc, 10% @ .38 temp coefficient would mean a 53 degree (F) temperature difference. Maybe, but that seems a bit improbable.

Thanks for the info SunEagle. I will refrain from using the K word.

Nobody is saying everything is 100% so drop it. There will be a confluence of factors, listed in this thread. Which is the largest? You may not know until you move the panels around, find another solution, or never. If you want to keep troubleshooting without roof work, Butch and I have made suggestions how you can use the Solaredge monitoring tool to troubleshoot further.

If you feel 5kwh per 6 weeks adds up to real money, I would respectfully ask how much is your time worth or stress? Or to pay the installer to swap panels (they apparently wont do it for free if it is not a problem in their eyes?), or how much is it worth to risk injury to do the roof work yourself? If you can do it, more power to you.

But I think we are talking less than 40kwh @ .20 per kwh tops annual avg, $8 bucks a year tops?

If you need some help doing charts to monitor that panels Power output over time, not just energy, let me know. Thats how I found my intermittent problem when one panel seemed a bit lower than the others, before it got bad enough to create a large enough energy disparity... similar to your situation but unlikely the same cause.

[DrLumen]

Nobody is saying everything is 100% so drop it. There will be a confluence of factors, listed in this thread. Which is the largest? You may not know until you move the panels around, find another solution, or never. If you want to keep troubleshooting without roof work, Butch and I have made suggestions how you can use the Solaredge monitoring tool to troubleshoot further.

If you feel 5kwh per 6 weeks adds up to real money, I would respectfully ask how much is your time worth or stress? Or to pay the installer to swap panels (they apparently wont do it for free if it is not a problem in their eyes?), or how much is it worth to risk injury to do the roof work yourself? If you can do it, more power to you.

But I think we are talking less than 40kwh @ .20 per kwh tops annual avg, $8 bucks a year tops?

If you need some help doing charts to monitor that panels Power output over time, not just energy, let me know. Thats how I found my intermittent problem when one panel seemed a bit lower than the others, before it got bad enough to create a large enough energy disparity... similar to your situation but unlikely the same cause.

Thanks for the offer but I have been over the playback, the charts, exports of the data and correlations to temp, humidity, optimizer voltage, planetary alignments, pet sacrifices...

I think you are mistaking my continued posts as inflexibility whereas I'm just stating what I have been over, my thought process and details concerning my particular install - not necessarily as a demand or belief something must be done or that my 10% loss is going to be the end of the world. This was started more out of curiosity than as some type of effort to try and beat down anyone's theories.

As I said before, thanks for the ideas and suggestions.

[cebury]

Thanks for explaining your intentions, it does come across a little as inflexibility, hard to tell. I hope you find a cause and this isnt "normal", just for the sake of learning another potential rare fringe circumstance and making search efforrs payoff.

Attached is mine for todays performance.
image_9841.jpg

This is the physical/logical layout of my South facing 7.28kw array with 260watt CS panels, Energy at about 7pm sun still out. The 1.1.1 and 1.2.14 panels get brief shadows this time of year. The rest of the array is unshaded. You will notice half the array, from 1.1.8 and 1.2.7 to the right (really the opposite, to the West IRL) is over my attic which is hotter than the left half of panels over my garage which doesnt have an attic. All that condutive and radiant heat through the roof deck must affect that airflow and heat dissipation under that half of panels. There are no roof vents under any panels.

So comparing 1.2.5 with another similar placed unshaded panel 1.2.6 approx. (yesterdays show 0.1kwh diff) .1kwh x 42 days would be 4.2kwh over 6 weeks. Ditto between a couple other panels.

Good luck to you.

[DrLumen]

When looking at the voltages for my problem children and those surrounding them, I noticed another oddity. #22 is almost always the first one to wake in the morning and the last to shutdown. In a very small time window in the morning and evening and very cloudy conditions, the under-performing ones (13 & 22) actually perform a very small amount better (like 1%) than the rest. With that, is it possible the panel manufacturers can tune the performance of panels to certain light conditions? Perhaps, this 'undocumented feature' would be a cause for them to accumulate more heat and/or skewing the temperature co-efficient to be out of spec?

Just wondering as I could see how these might be a little better for more northern climates but not so good for Texas and vice versa. Perhaps they vary the mix depending on where they are going?

I know, probably over thinking it again...

[sdold]

I know, probably over thinking it again...

Yep. In a few weeks you'll become bored with watching the numbers and will forget all about it, just like I did.

[Rawas1939]

thanks a lot guys... i'm a newbie in solar panels and that's why i am here. thanks for making it clear. also, if i would have some questions for you, can i ask them? it's just the thing that i have health issues and nearly all my time goes onto https://pharmacyreviews.md as i have to search for my needs. but would like to learn more so i would appreciate some of your help. thanks and thanks for exampling the difference i couldn't understand.