I-V prototype rates 58.1% of retired modules for reuse

According to Second Life Solar, the Rapid-Triage prototype, developed by CSIRO Energy and tested by the company, can assess a module’s electrical and mechanical condition in less than 60 seconds, at a cost of a few Australian dollars per module. The new study found that 58.1% of the analyzed modules met its performance criteria for possible second-life use.

The team, including scientists from the Australian National University and CSIRO Energy, tested 3,749 modules during 18 testing days between December 2024 and June 2025. The panels came from more than 100 manufacturers and had rated outputs ranging from 160 W to 370 W. They had been removed for end-of-life replacement, system upgrades, weather damage or building works—not all for the same underlying reason.

The screening works in two passes. First, the system acts as a quality-control filter, rejecting unusual current-voltage, or I-V, curves that can signal mismatched sections, abnormal diode behavior or early current collapse. Modules that pass then receive a quantitative health assessment based on measures including fill factor, series resistance, shunt resistance and estimated power degradation. The study rejected modules with a fill factor below 60% or estimated degradation above 25%.

For modules that passed the I-V screen, the median estimated residual useful life was around 12 years. That gives recyclers and reuse businesses a faster way to identify panels worth testing further instead of sending every retired module down the same path. The scale matters: the researchers compared performance-based screening with electroluminescence, or EL, imaging across 3,679 modules with matching EL data, rather than relying on a small sample.

And so, concretely, a high-performing panel is not automatically safe to reinstall. Around 14% of modules that passed the combined I-V and EL screening failed wet-leakage insulation-resistance testing, a check for electrical insulation integrity. The researchers therefore present automated I-V screening as a scalable performance filter, not a replacement for additional safety testing; faulty insulation can create electrical risks and trigger an inverter’s ground-fault protection.