Microinverter confusion.. Doesn't make sense.

[scrambler]

The only thing I know that gets your panels to provide 110% of the STC is what is called Cloud Edge effects.

On sunny days with clouds when the sun passes through the edge of the cloud you get some refraction that can increase the amount of sun reaching the panel.
That will create a production burst that can exceed the nominal rating of the panel, but it is brief so it does not affects the global day production in a significant way

[solardreamer]

I am also skeptical of YouTube videos as most of the people don't have any real knowledge of what they are talking about.
With that said, we do know that junction efficiency increase when temperatures go down. I would doubt that 25C is the optimal temperature but more likely the one that they could get away with without getting ridiculed.
I see a few YouTube videos making this claim, some of them seem credible others I have no idea. A quick search and I did find a few articles discussing the cooling effects on PV panels. It seems to line up with the claims.
https://www.researchgate.net/figure/...fig2_259169728

Sure cooler temperature at the same irradiance means higher PV power but in the real world those conditions don't meaningfully exist. As for the paper's focus on water cooling, it's is a common idea but I am not aware of a practical and economical water cooling solution for rooftop solar where the total cost of ownership is lower than the incremental PV production value from water cooling.

[robbyg]

I'm in Michigan and have some 400w QCells going and they push 350 to 380 quite frequently for hours on end.. During the cold spring, seeing 390 and 400 isn't unusual. To think that the microinverter would be clipping at 320 is just kind of ridiculous.

I'm not sure how I feel about a company advertising a configuration that wastes so much power. Almost as if they're trying to drum up sales for a product that isn't a proper match for the panel.

I have seen this in a few of my hobbies. The company in question is lagging behind in technology so they create a spin to make their product seem to still be better than the newer products on the market. I suspect that making a Micro Inverter that can do 400 Watts reliably is a serious challenge. Compound that with the testing time needed and the rate at which Panel wattage's go up annually and your pretty much better off shooting for 550 Watts and praying your product is still relevant by time it hits the market. .

[robbyg]

Not sure what the YouTubers did but if they get above STC from a real world system then it's certainly notable especially if it's financially worthwhile to have larger inverters in such cases. However, I am skeptical as YouTube also has lots of "free energy" videos.

I am also skeptical of YouTube videos as most of the people don't have any real knowledge of what they are talking about.
With that said, we do know that junction efficiency increase when temperatures go down. I would doubt that 25C is the optimal temperature but more likely the one that they could get away with without getting ridiculed.
I see a few YouTube videos making this claim, some of them seem credible others I have no idea. A quick search and I did find a few articles discussing the cooling effects on PV panels. It seems to line up with the claims.
https://www.researchgate.net/figure/...fig2_259169728

[J.P.M.]

Not sure what the YouTubers did but if they get above STC from a real world system then it's certainly notable especially if it's financially worthwhile to have larger inverters in such cases. However, I am skeptical as YouTube also has lots of "free energy" videos.

U-tube == The new idiot's bible.

[solardreamer]

That is true as a general rule but there are some videos on YouTube of people in cold sunny areas getting 110% or more of the STC from their panels.
It's still ridiculous even in warmer areas to hookup a 430W Panel to a 320W Micro Inverter. You can see clipping happening all throughout the peak sun hours. Normally this would not be an issue as there are some benefits during off peak solar hours but the cost of high quality brand name 430 or 440W panels like LG makes it an even worst pairing IMHO.

Not sure what the YouTubers did but if they get above STC from a real world system then it's certainly notable especially if it's financially worthwhile to have larger inverters in such cases. However, I am skeptical as YouTube also has lots of "free energy" videos.

[peakbagger]

They usually write a whitepaper explaining that clipping is good

I also see my panels putting out more than rating on my 10 year old panels in very cold weather with snow on the ground.

[Murby]

That is true as a general rule but there are some videos on YouTube of people in cold sunny areas getting 110% or more of the STC from their panels.
It's still ridiculous even in warmer areas to hookup a 430W Panel to a 320W Micro Inverter. You can see clipping happening all throughout the peak sun hours. Normally this would not be an issue as there are some benefits during off peak solar hours but the cost of high quality brand name 430 or 440W panels like LG makes it an even worst pairing IMHO.

I'm in Michigan and have some 400w QCells going and they push 350 to 380 quite frequently for hours on end.. During the cold spring, seeing 390 and 400 isn't unusual. To think that the microinverter would be clipping at 320 is just kind of ridiculous.

I'm not sure how I feel about a company advertising a configuration that wastes so much power. Almost as if they're trying to drum up sales for a product that isn't a proper match for the panel.

[robbyg]

That seems typical based on the STC spec of panels. Panel to inverter power ratio range can go up to 1.50. You never get 100% from a 430 watt STC spec panel in the real world because the spec is done under ideal lab conditions (e.g. temp, etc.) and there is DC/AC conversion loss plus degradation due to aging. Panels usually have a separate PTC spec that is lower and based on more realistic conditions.

That is true as a general rule but there are some videos on YouTube of people in cold sunny areas getting 110% or more of the STC from their panels.
It's still ridiculous even in warmer areas to hookup a 430W Panel to a 320W Micro Inverter. You can see clipping happening all throughout the peak sun hours. Normally this would not be an issue as there are some benefits during off peak solar hours but the cost of high quality brand name 430 or 440W panels like LG makes it an even worst pairing IMHO.

[solardreamer]

I'm looking at the Enphase IQ7X specs that say the microinverter is good for panels between 320W to 460W+ but they have a maximum AC output of only 320 watts? Huh?

That makes no sense unless you're using them above Canada or the Antarctic. So you hook up a 430 watt panel and its going to be clipping all day long???

Am I reading this right? Who would do such a thing?

That seems typical based on the STC spec of panels. Panel to inverter power ratio range can go up to 1.50. You never get 100% from a 430 watt STC spec panel in the real world because the spec is done under ideal lab conditions (e.g. temp, etc.) and there is DC/AC conversion loss plus degradation due to aging. Panels usually have a separate PTC spec that is lower and based on more realistic conditions.

[Murby]

I'm looking at the Enphase IQ7X specs that say the microinverter is good for panels between 320W to 460W+ but they have a maximum AC output of only 320 watts? Huh?

That makes no sense unless you're using them above Canada or the Antarctic. So you hook up a 430 watt panel and its going to be clipping all day long???

Am I reading this right? Who would do such a thing?