Solar panel physical hot spot (production drop)

Use only checks that match the exact appliance or system and its official guide.

1. Check 1

   Review the monitoring history for the same panel, microinverter, or string and compare it with neighboring equipment over matching daylight periods, noting cloud cover, snow, shade, and recent storms.

   Expected result: One panel or string shows a persistent new drop while neighbors track expected output, or the entire array drops together during the same weather or inverter event.

   Next step: Save the monitoring alerts and production graph, then use the ground inspection and professional testing path for a localized issue. Do not label a module defective from one cloudy-day reading.

   Why this matters

   Why: A localized persistent change makes a module, connector, or string issue more likely. A whole-array change makes irradiance, snow, inverter availability, or another shared system condition more likely than one physical hot spot.

2. Check 2

   From the ground or an approved safe viewpoint, visually scan the affected module and nearby modules for cracked glass, discoloration, bubbling, delamination, a warped or detached frame, unusual staining, or loose-looking cable routing.

   Expected result: A defect or physical displacement is visible, or the modules appear intact from the available viewpoint.

   Next step: Photograph the condition from a safe location and arrange a qualified PV inspection. Never walk, climb, or lean on modules to see an inaccessible area.

   Why this matters

   Why: Visible damage can explain both a localized production loss and abnormal heating and should be evaluated before the system is returned to normal operation. A clean appearance does not rule out cell, bypass-diode, junction-box, or connector damage.

3. Check 3

   Check from ground level whether new shade, snow, ice, leaves, or other debris covers part of the affected panel or changes the light pattern across a row; do not scrape, shovel, or spray the modules.

   Expected result: The production drop appears only while the obstruction or shade is present and begins to recover after natural clearing, or the panel remains affected with an unobstructed view.

   Next step: Allow ordinary snow or ice to clear safely, document recurring shade, and compare production again under similar sunlight. Have a professional handle any removal or roof access that is not clearly safe and manufacturer-approved.

   Why this matters

   Why: A reversible environmental obstruction is more likely when output follows the changing light pattern. Persistent underperformance after unobstructed sunlight keeps physical module or electrical faults in consideration.

4. Check 4

   Ask a qualified PV technician to perform an infrared scan and the electrical tests appropriate for the system, using the module layout and monitoring history to target the affected area.

   Expected result: The scan shows a localized module, junction-box, connector, or cable hot spot, or no repeatable abnormal heating is found.

   Next step: Keep the technician's report and module location with the system records. Follow the professional's safe shutdown and repair recommendation rather than opening energized equipment or swapping parts experimentally.

   Why this matters

   Why: Repeatable localized heating supports a physical or electrical fault that requires diagnosis; a normal scan shifts attention toward temporary shade, soiling, monitoring, inverter, or other non-hot-spot causes. Imaging must be interpreted by a trained professional.

5. Check 5

   After a severe weather event, have the system owner or qualified inspector check accessible ground-level views for broken glass, detached frames, displaced racking, damaged cable routing, and production changes before the array is returned to normal operation.

   Expected result: Storm-related damage or a new production drop is present, or no visible damage and no new localized change is found.

   Next step: Keep people away from damaged or overhead components and arrange a trained inspection. If damage is confirmed, follow the qualified professional's isolation and repair plan before re-energizing the system.

   Why this matters

   Why: Wind, hail, snow, ice, and water entry can damage modules, racking, wiring, or enclosures even when a crack is not obvious. An unchanged system makes storm damage less likely but does not replace electrical testing after a serious event.