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EEVblog 1386 - 295W Inverter vs 370W Solar Panel - WTF

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EEVblog:
Why do Dave's new 370W LG solar panels use lower rated 295W Enphase microinverters?
What gives?
Inverter clipping, solar panel overrating, DC/AC ratio, solar irradiance, and microinverter underrating explained.
And a look at data from Dave's old 3kW system to predict how many days a year the new 5kW system will clip.

EEVblog:
Follow-up:

FrankT:
I have a similar system in Melbourne.  12 panels, 335W Neon2, 270W peak Enphase S270s.  I wondered what effect clipping would have, so I made display showing the generated power vs consumed, $, and predicted solar and predicted clipping.  The attachment shows a good day, 8 Jan 2021.  The solid red line is the predicted power; the dotted orange line is the predicted clipped value.  My calculations don't take into account ambient light (that was too hard), which is why there is a large error in the morning and evening (5 panels get more morning sun, 7 get more afternoon sun).

Clipping starts mid-September and stops mid-March.

WizardTim:
Have you made your PV data publicly available anywhere to download as a CSV? I’ve looked at what you’ve put up on ‘pvoutput.org’ and from what I understand I can’t download historic CSV data only the owner can? I ask because I have some MATLAB and R scripts I wrote awhile ago for Energy Queensland to visualise half hourly consumption and PV generation trends and I’m interested to see exactly how much those microinverters would have clipped your generation.

EEVblog:

--- Quote from: FrankT on April 13, 2021, 08:38:33 am ---I have a similar system in Melbourne.  12 panels, 335W Neon2, 270W peak Enphase S270s.  I wondered what effect clipping would have, so I made display showing the generated power vs consumed, $, and predicted solar and predicted clipping.  The attachment shows a good day, 8 Jan 2021.  The solid red line is the predicted power; the dotted orange line is the predicted clipped value.  My calculations don't take into account ambient light (that was too hard), which is why there is a large error in the morning and evening (5 panels get more morning sun, 7 get more afternoon sun).

Clipping starts mid-September and stops mid-March.

--- End quote ---

Interesting, thanks.
Will need a full year to really analyse mine.

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