NABCEP PV Associate cheat sheet

Solar Panel Cleaning and System Maintenance

• Soiling reduces yield; typical losses range from 1–5% in temperate areas and can exceed 20% in dusty or agricultural regions.

• Cleaning frequency depends on local soiling rate, rainfall, tilt angle, and module orientation; monitor production data to schedule cleaning.

• Use deionized or low-mineral water and soft brushes; avoid abrasive pads, high-pressure spray, and harsh detergents that damage coatings.

• Clean during early morning or late afternoon when modules are cool; thermal shock from cold water on hot glass can crack modules.

• Inspect for hot spots, cracked glass, snail trails, delamination, and loose connectors during each maintenance visit.

• Thermal imaging and I-V curve tracing identify underperforming strings and modules; compare against expected performance.

• Torque check on mounting hardware, connector mating, and grounding bonds should follow manufacturer maintenance intervals.

• Vegetation management and snow removal protect production; avoid walking on modules and use proper fall protection on roofs.