Is my solar Underproducing ? Can someone help?

[Peter2021]

Hi I have a system off 22 panels each 395W and it was designed to produce 8.75KW .
Picture attached ( original Plan Design)

and the peak I get from Enphase controller is about 6-6.2KW in perfect conditions all panels exposed to sun. (Picture attached- production)

I am not sure if I understand correctly but should my system be close (Peek Power) around 7.5-8.7KW ?
6.2KW seems low like 30% production loss in its original design...

Am I right or wrong.. please help me to understand real time production performance.

Controller updates every 15Min but I get about 60% of a day of full roof exposure and peek number seems low...
I tried to check with the installer but he beats me around the bushes about monthly production that I suppose oxide what they estimated.

But I get the feeling I should be getting more if Peek performance was close to original design.

Please advise.

thanks
Peter.

 

[Bluedog225]

Hi Peter-welcome. It would be helpful to know your location (generally) and temperature.

 

[Bud Martin]

Do you have the graph that shows what is being produced through out the day?

 

[OzSolar]

I am not sure if I understand correctly but should my system be close (Peek Power) around 7.5-8.7KW ?
6.2KW seems low like 30% production loss in its original design...

Am I right or wrong.. please help me to understand real time production performance

New system? Give it 12 months and see how close your actual annual KWH is to your predicted KWH.

Research NOCT vs STC.

I suspect you'll find that things are humming along just fine.

 

[Peter2021]

Hello and thank you for replies

I am located in East Coast NY (Long Island)
I attached todays production picture but I am not looking toward daily or weekly or monthly production, just checking if my system is underproducing when it reports peek 6.2KW when it was design to be 8.75KW as seen in above picture..

it feels like my peek should be 8KW not 6KW? am I wrong?

 

[GLC]

My best production has been 15 percent less that panel ratings on best days, best sun angle and best temp.

 

[OzSolar]

22 x 395 x .8 = ~7KW is the best you'll ever see at NOCT.

You're well within the realm of reason. My ~16kW spend most of the day at 10kW or less and never gets past 12KW. All perfectly normal and it's meeting the KWH predictions which is all that matters.

it feels like my peek should be 8KW not 6KW? am I wrong?

Not wrong, rather uninformed. A properly designed system will only see it's peak a for a few hours on a few days of the year.

 

[ncsolarelectric]

Hello and thank you for replies

I am located in East Coast NY (Long Island)
I attached todays production picture but I am not looking toward daily or weekly or monthly production, just checking if my system is underproducing when it reports peek 6.2KW when it was design to be 8.75KW as seen in above picture..

it feels like my peek should be 8KW not 6KW? am I wrong?


View attachment 95687

The panel ratings are funny things. The way to calculate the actual efficiency depends on the Inverter output Maximum rating, not the DC rating. You're quoting 8.75kW "DC", at the solar panels. The IQ7Plus microinverters output 290W "maximum continuous AC output power" per inverter. You have 22 inverters. So 22 x 290 = 6.38kW "AC", which is what your Peak Power is reporting. It reports AC, the system size is DC. The system is never 100% efficient when converting DC to AC! The panels aren't even 100% efficient when comparing their optimal STC values with the real-world NOCT values. Your system is working perfectly!

 

[Bud Martin]

So you have 22 395W panels = 8.69KW
So lets be generous and assume 90% efficiency (instead of 80%), 8.69KW * .90 = 7.821KW.
5 hours is the typical solar production per day, 7.821KW * 5 = 39.105KWh per day (we are not factoring other system loss for simple calculation), you are producing 38.30KWh already and the day is not over yet per your graph, I would say your system is doing well.

 

[Bluedog225]

And conditions not exactly perfect. Just sayin.

 

[Peter2021]

Thank you all
Yes I never expected to be 100% but about 30% loss seemed a lot but now I am a little more satisfied with the provided knowledge. I have no experience and solar knowledge. I did some research online and it seems to be a bit off... I did take into consideration DC -> AC conversion and some loss there..
Also installer installed inverters right under each panel and they converting to AC when they reach Enphase IO controller that reports the numbers in pictures.
So seeing 6K peek ( and I know its at a specific point not all day ) seemed a little off. Perhaps Design shows 8.75KW DC and not AC and thous my confusion.

Anyway thanks for clearing it up and I feel better that its working within its design parameters...

I am new at this so I would like to learn as much as possible since we get access to these beautiful production numbers and not knowing about it forums are great places to ask about these details.

 

[Bud Martin]

"Perhaps Design shows 8.75KW DC and not AC and thous my confusion."
That is 8.75KWh, not the same as KW, you have 8.69KW of solar panels (22 panels * 395W = 8.69KW).

kW vs. kWh: What's the Difference? | Direct Energy Regulated Services

Learn the key difference between a kilowatt (kW) and a kilowatt-hour (kWh) and what they mean on your energy bill.

www.directenergyregulatedservices.com

 

[Peter2021]

yes I meant 8.69 kW not kWh

but I am happy otherwise.... I wonder if others can cheap in some of other solar Planed designs and they peek and daily production in New York area for some comparison.


thanks all

 

[schmism]

My best production has been 15 percent less that panel ratings on best days, best sun angle and best temp.

Makes me feel good about my real world numbers. Today I peaked at -10% panel rateing however it was cool and sunny. ~15% is normal and can nudge up to 20% in hot summer.

 

[Peter2021]

Schmism
what is your system design? what is your kW system?

 

[Prefersdirt]

My ~16kW spend most of the day at 10kW or less and never gets past 12KW. All perfectly normal and it's meeting the KWH predictions which is all that matters.

Perfect statement for me as I am debating between a 12K or a 16K setup. Going to go larger!

 

[Hedges]

Hi I have a system off 22 panels each 395W and it was designed to produce 8.75KW .

and the peak I get from Enphase controller is about 6-6.2KW in perfect conditions all panels exposed to sun. (Picture attached- production)

Are the Enphase IQ7PLUS-72-2 (240) inverters 290VA?

https://www.solarelectricsupply.com/enphase-iq7plus-72-2-us-microinverter-72-cell-240va

"

Solar Panel Compatibility

235 W - 440 W +

Maximum continuous output power

290 VA

"

22 x 290 = 6380W

If so, expect 6380W peak, with a curve that clips flat at the top rather than rounded like OzSolar shows.

 

[BillG]

would an upgrade to IQ8’s with higher 380va max output increase production all other variables being equal?

 

[ncsolarelectric]

would an upgrade to IQ8’s with higher 380va max output increase production all other variables being equal?

Yes, it would. However, how significant that is to the bottom line depends on your utility rates. It will only capture that little extra that the panels put out at the peak of the day, and do nothing more than what you have now for the rest of the day. Also, in the winter you typically do not max out the system. So mostly they only help capture that extra energy in the summer, middle of the day. The IQ8A inverters are more expensive, and you can't return the ones you have, it would drastically increase your ROI payback to change at this time.

 

[Peter2021]

Are the Enphase IQ7PLUS-72-2 (240) inverters 290VA?

https://www.solarelectricsupply.com/enphase-iq7plus-72-2-us-microinverter-72-cell-240va

"

Solar Panel Compatibility

235 W - 440 W +

Maximum continuous output power

290 VA

"

22 x 290 = 6380W

If so, expect 6380W peak, with a curve that clips flat at the top rather than rounded like OzSolar shows.

No, I upgraded to IQ8Plus so I can use new backup technology like Sunlight Backup I know Plan shows old style which was not compatible with new backup systems.

System builder | Enphase

enphase.com

idea is great and saves money on expensive battery installations.. (this is what I expected from solar system for year but no one is doing it ) utilizing sun while the grid is down... . finally here
I missed it my panels are 395 W rated.