Vegetation / shading
Shadows from vegetation or structures falling across modules. An operational finding rather than a module fault — but persistent shading costs real energy and can create genuine cell damage over time.
Thermal signature
Warm bands or patches whose shape follows the shadow edge rather than cell or substring geometry — grass lines along the bottom of rows, tree silhouettes, pole shadows. The pattern shifts with sun position between flights, and the paired RGB frame shows the vegetation directly.
Typical ΔT
Varies with shadow density and duration — commonly 5–20 °C where shaded cells force their substrings into bypass (typical industry interpretation aligned with IEC TS 62446-3).
What causes it
- Grass or weeds grown above the bottom edge of low-tilt rows
- Trees or windbreaks encroaching on outer rows
- Fixed structures — poles, fences, inverter stations — casting recurring shadows
- Inter-row shading from layout or seasonal sun angles
Power impact
Shading losses are non-linear: one shaded cell can knock its whole substring into bypass, so a strip of grass along a row's lower edge can cost far more than the shaded area suggests. Chronic shading also cycles bypass diodes and heats mismatch cells, accelerating wear.
Recommended action
Fix: next maintenance window
Schedule vegetation management at the next maintenance window: mow or trim the flagged areas, review the mowing cycle against growth rates, and reassess any fixed-structure shading in the site layout. Re-inspect to confirm the losses clear.
Frequently asked questions
Grass only shades the bottom few centimetres — does it really matter?
Yes, disproportionately. Cells are wired in series, so shading the bottom row of cells can collapse the output of every substring it touches — on landscape-mounted modules a few centimetres of grass can cost a third or more of the module. This is one of the cheapest losses on a site to fix.
Can shading permanently damage modules?
Chronic shading can. The same cells get driven toward reverse bias every day, their bypass diodes conduct for hours at a time, and both accumulate stress. Sites with long-standing vegetation shading often develop real cell and diode faults in exactly those locations.
Related anomalies
Suspect vegetation / shading on your site?
Fly the site, upload the thermal frames, and get every module graded against this taxonomy — severity-ranked, with flagged imagery and per-module locations. Quote your site size in seconds.
ΔT figures and abnormality classes on this page describe the typical industry interpretation aligned with IEC TS 62446-3 — indicative engineering guidance, not normative text from the specification. Temperature differentials are only meaningful when captured at ≥600 W/m² irradiance (per the TS) and verified on site before repair work.