Light Soaking

[jamesparkSF]

Is the light soaking factor introduced to the nameplate rating of the PV module or after the binning process (or module quality loss) is factored in?

For example, if we say that we have a 160W nameplate module, and a quality loss of -0.8% (reflecting positive binning), assuming a 2% light soaking gain, does that 2% get factored into the 160W OR factored in after the -0.8% quality gain on top of the 160W nameplate of the module?

[André Mermoud]

The light soaking appears after some time of operation (otherwise it would be included in the STC performance).

So that these 2 different "loss" contribution are independent. Therefore they are cumulative.

If you assume +0.8% of "Module quality loss" for positive sorting, and +2% of Light soaking, the global gain after some months of operation will be +2.8%.

[jamesparkSF]

As for the duration of time for the light soaking gain to stabilize, is there a way to manually specify the time or amount of irradiance needed to stabilize this effect? Please see highlighted portion in the attached image.

[André Mermoud]

In PVsyst, we consider the light soaking effect as a temporary effect.

The "pre-light soaking" period is sufficient short for neglecting it in the annual yield. Nothing is foreseen for taking this initial loss into account.