Why does stepping on a panel create microcracks?
Even if the glass does not break, microcracks form in the roughly 170 micron thick silicon cell underneath. The damage is not visible to the eye, but it is detected by electroluminescence imaging. In field measurements the power loss can be around 0.55% for a light crack and up to 9% in older modules with severe cracks, and this damage is generally outside warranty coverage.
The critical point is what the certification covers. The IEC 61215 mechanical load test is for distributed load: 5400 Pa snow load on the front face, 2400 Pa wind load on the back face. A footprint, on the other hand, is a point load; a distributed load certification does not cover point load.
- The cell thickness is about 170 microns; it cracks under point pressure while the glass stays intact.
- The crack is not visible to the eye; electroluminescence imaging is required to detect it.
- The power loss does not appear immediately but grows over time with thermal cycles: about 0.55% for a light crack in a modern multi-busbar design, and up to 9% after four months for a severe crack in older 4-busbar modules.
- Manufacturer warranties exclude damage caused by stepping on the panel and by physical impact.
For this reason, when choosing a cleaning method, solutions that do not require a person to climb onto the panel are preferred. The ROBEG ELS-03 works on the panel array with a wheeled chassis structure that distributes its load as it advances.
The full story: Our Services