Module Low Irradiance Performance

[Rapha123]

I have a module with very low "low irradiance" losses for a site in the UK when using the .pan file from PVsyst which has been provided by the module manufacturer. I also have additional information on the Rseries and Rshunt values as well as efficiency values from the manufacturer at different irradiance levels. However the shunt resistance profile appears almost linear rather than exponential. Is it safe to consider inputting the measured values for Rseries and Rshunt or just rely on inputting the low irradiance efficiency profile to accurately predict the output of the module?

Thanks,

Raph

[JamesP]

I'm finding the same sort of thing with a normal exponential shunt resistance profile. I'd like to know more about how the irradiance and temperature losses are calculated.

James.

[André Mermoud]

The determination of these parameters is really not easy, and cannot be evaluated directly from usual standard certifications.

Please have a look on the FAQ What explains the difference of Yieldsa between different modules

For the PVsyst database I use to filter the values proposed by the manufacturers, when they seem too optimistic by respect to what I know about the model, and usually I ask independent assessment.

Now if you use the PAN files directly from the manufacturer, there is no control of course.

[JamesP]

Thanks a lot André that's really helpful.