Moisture as stress factor for PV-modules

The humidity is considered as an important degradation factor for PV-modules. The famous Damp/Heat test within the type approval testing according to IEC 61215 should take the moisture impact into account. We carried out damp/heat tests at different temperatures with different commercial crystalline Silicon PV-modules of the same basic design but with different materials and from different manufacturers. Taking the differences of time to failure and activation energies into account for service life models showed that adopted accelerated life tests would require very different stress levels according to the module properties.