EL is an “X-ray” for modules

How daytime EL works

Traditional EL must wait for darkness, constrained by schedule, weather and safety. The GK-8000 uses short-wave infrared (InGaAs) imaging with lock-in differential algorithms to capture readable EL images in daylight (0–1200 W/m²) — moving a night-only task into the day, with a longer working window, higher efficiency and lower night high-altitude risk.

What is operating-condition EL

Conventional offline night EL requires shutting down modules and applying external bias. Operating-condition EL images modules while they are energized and generating power — no shutdown, no output impact — reflecting the true operating state, something offline night EL cannot do.

Why EL is a “complement”, not a replacement

When power data and infrared thermal results conflict, you often need a method that directly sees the internal structure to settle it:

• Infrared thermal tells you “where it is hot”, but whether it is a crack, cold solder or shading needs further judgment;
• IV curves tell you “overall electrical performance”, but not which module or location is at fault;
• EL imaging directly shows internal cracks and broken gridlines — like an X-ray — settling disputes and forming a closed-loop diagnosis.

Used together, the three provide more complete and credible diagnosis.

Aligned with international standards

EL image acquisition, image-quality evaluation and defect interpretation follow IEC TS 60904-13:2018; operating-condition EL is a field method Longsafe developed for in-service modules, and its specific test conditions differ from conventional forward-bias EL. On-site work references IEA-PVPS Task 13 environmental and safety guidance, with report structure mapping to the standard clauses for archiving and grid-connection evidence.