SunPower has said that its E20/327 solar modules have passed potential induced degradation (PID) testing at PV Evolution Labs.

The company said that its modules achieved less than a 0.2% power loss during the PID tests. PV Evolution Labs PID test includes a 600 hour damp heat conditioning, as defined in international testing standards, and maximum rated voltage stress.

SunPower noted that during the testing period, visual inspections, flash testing and high-resolution electroluminescence images are taken to accurately evaluate and monitor the panel's durability. After 100 hours of testing, a panel must demonstrate less than five percent power loss and less than 10 percent after 600 hours to pass the test.

However, the company claimed, without providing further details that only 50% of all modules tested successfully passed the program's criteria.

"This third-party testing program confirms that SunPower solar panels are virtually PID free in any grounding configuration and offer extreme resistance to degradation, with the results surpassing the nearest conventional panel," said Tom Werner, SunPower president and CEO. "As a solar technology leader, we are committed to providing our customers with third-party validation, assuring them that they are buying the most reliable panels on the market today."

SunPower also claimed that of the 50% of modules that failed PID testing, power losses ranged from 18% - 87%. The company did not provide further details to support the claims.

