When PV modules arrive on-site, the first step is to verify the integrity of the shipment. Start by cross-checking the delivery note against the purchase order to confirm the quantity, model, and specifications match what was agreed upon. If there’s a mismatch, document it immediately with photos and notify the supplier. Open the packaging carefully—avoid using sharp tools that could scratch the glass surface. Look for visible damage to the cardboard, pallets, or foam inserts. Broken packaging doesn’t always mean damaged modules, but it’s a red flag that warrants closer inspection.
Next, perform a physical inspection of randomly selected modules. Remove at least 5-10% of the units from different pallets for a thorough check. Examine the glass for cracks, chips, or scratches longer than 10mm—these can compromise long-term performance. Check the aluminum frames for dents or twists using a straightedge tool. Even minor warping (more than 2mm deviation over 1m length) can cause installation issues or stress fractures. Peel back the junction box cover gently to ensure seals are intact and cables aren’t pinched or frayed.
Electrical validation is critical. Use a calibrated IV curve tracer to test sample modules under standard test conditions (STC: 25°C cell temperature, 1000W/m² irradiance). Compare the measured Voc (open-circuit voltage), Isc (short-circuit current), Vmp (voltage at maximum power), and Imp (current at maximum power) against the manufacturer’s datasheet. Allow a tolerance of ±3% for power output—anything beyond that requires investigation. Don’t skip this step even if the modules “look” fine; latent defects like microcracks or faulty bypass diodes won’t be visible to the naked eye.
Check the labeling on both the module and shipping documents. Each unit should have a legible serial number, model code, and certification marks (IEC 61215, IEC 61730 for safety). Verify the date codes to ensure you didn’t receive old stock that’s been warehoused for years. Look for anti-reflective coating uniformity by tilting the module under bright light—patchy coatings indicate production flaws.
Don’t overlook documentation. The delivery must include a complete set of factory test reports, warranty certificates, and a PV module handling guide. Cross-reference the batch number on the modules with the test reports. If the reports show lower-than-claimed efficiencies, you have grounds for rejection.
For crystalline silicon modules, use an electroluminescence (EL) tester on sampled units if possible. This specialized equipment reveals hidden defects like microcracks, broken cells, or soldering issues that standard inspections miss. While not all installers have EL testers, it’s becoming a best practice for large-scale projects.
Finally, store the modules properly if they won’t be installed immediately. Keep them in their original packaging, stacked vertically (not flat) on stable pallets. Avoid outdoor storage—UV exposure degrades unpackaged modules, and temperature fluctuations can cause condensation. If outdoor storage is unavoidable, cover the stacks with breathable tarps and elevate them at least 150mm above ground to prevent water ingress.
Remember to photograph every step of the inspection process—timestamped images serve as crucial evidence if disputes arise later. By methodically checking these aspects, you’ll catch 95% of potential issues before installation, saving costly rework or warranty claims down the line.