A normal photo of a full array showing an IR image in the inset box. Performance is as expected in this case.

Example of a full solar cell hot spot in a monocrystalline silicon module. In this case the increase in temperature may or may not indicate an unsafe condition. It does however, indicate less than ideal output

In this case, a substring of the module in the center of the image has a shorted sub-string. The shorted string is placed in short circuit, resulting in the non-uniform heating expected in that condition.

An image of a Module in short circuit current imaged from behind. The variation in heating is expected in this test condition.

Identifying Defects
An image of a module in with a number of defects. The substring in the center of the module is dark, indicating a short in that portion of the circuit. The highly illuminated busbars in the lower left corner indicate a resistance problem in the dark portions, and current crowding in the light portions.

Identifying PID
The trend in array wiring configurations is to move to higher and higher voltages. These higher voltages, combined with the use of bipolar and non-isolated inverter topologies have uncovered a fail mechanism presently not evaluated by required UL/IEC tests. Solar cells inside the impacted modules become increasingly shunted over time. Cell shunting first leads to noticeable power loss under low light conditions but continues to worsen until power production is impacted throughout the day. This failure mechanism has been referred to as Potential Induced Degradation (PID) and can result in 25% to 50% of an array affected, with the impact on each module as large as a 50% loss.

Highlighting Cracked Solar Cells
The module imaged was damaged in transportation. It has a total of 10 cracked cells. Its power production is identical to module with no cracked solar cells at the beginning of its life. It is not predicted to perform as well over time.

Working in the combiner box
Results from String-level testing often reveal field wiring errors.

Identifying subtle differences in big populations
Module-level IV testing finds degradation mechanisms impacting all modules and can identify subtle differences in big populations.

The obvious and the not-so-obvious
Knowing what to look for when inspecting panels often helps find the problems quickly.

Weather
Often with damage that occurs from the elements, it’s abundantly clear upon visual inspection why the system isn’t performing.

Improper manufacturing
Issues like the one show here was found initially with IR, but required visual inspection to identify it as a workmanship issue.

CORE Energy Works uses the latest technology to assess damage, discover defects, monitor degradation and employ preventative maintenance practices that keep your PV assets in top working order.

Contact CORE Energy Works for field or laboratory performance testing of photovoltaic products.