Pioneer of Daytime EL Inspection

EL Inspection — Now in Daylight
An “X-ray” for every PV module

Q: Can EL really be done in daylight?

Yes. With SWIR imaging and differential algorithms, readable EL images are captured in daylight (0–1200 W/m²) — no need to wait for night.

Q: Do modules need to be shut down?

Operating-condition EL images modules while they generate power, with no output impact. An offline biased mode is also available per project.

Q: Should I buy equipment or a service?

Either. Buy the daytime EL system for long-term frequent needs, or choose our pay-per-project inspection service for one-off needs.

UAV-borne short-wave infrared imaging works day or night and supports operating-condition EL, delivering image-grade evidence across the plant lifecycle.

View Real EL Images Book Inspection / Get a Plan

Why Longsafe Daytime EL

We moved EL inspection from night to daylight — more efficient and safer.

☀️

24/7 operation

Inspect by day or night — no waiting for darkness, doubling the working window and cutting night high-altitude risk.

⚡

Operating-condition EL

Imaging while modules generate power — no shutdown, no output loss, reflecting real operating state.

🚁

Fast UAV coverage

For large bases and distributed sites — about 1000–1500 modules/day, ≤5s per module.

🔬

SWIR pixel-level imaging

InGaAs sensor clearly identifies hidden cracks, micro-cracks, broken gridlines, cold solder, PID, poor sintering and breakage.

Covering the key inspection scenarios

From grid-connection acceptance to O&M, from ground plants to rooftops.

🏜️

Ground-mount plants

Pre-grid installation checks and O&M health inspection for large ground/mountain/plateau plants — daytime work keeps the schedule on track.

🏭

C&I rooftops

Operating-condition EL inspection for rooftop distributed modules — no shutdown, fast defect screening.

🏢

Testing institutions

Daytime/night EL comparison data and large-batch module testing as a capability extension for third-party labs.

Same module: daytime EL vs night EL

Field test on a 28-module rooftop string — EL images of the same modules captured in daytime operating mode and standard night mode, so daytime results can be read directly against the night baseline.

Pair 1 · Cracks & defect cluster · Daytime EL — **Pair 1 · Cracks & defect cluster**A clear crack extension and defect cluster in the upper-left region — identical defect shape and position in both daytime and night images.

Pair 1 · Cracks & defect cluster · Night EL — **Pair 1 · Cracks & defect cluster**A clear crack extension and defect cluster in the upper-left region — identical defect shape and position in both daytime and night images.

Pair 2 · Defect band reading · Daytime EL — **Pair 2 · Defect band reading**The horizontal defect band in the middle is clearly readable under both conditions, with identical defect localization.

Pair 2 · Defect band reading · Night EL — **Pair 2 · Defect band reading**The horizontal defect band in the middle is clearly readable under both conditions, with identical defect localization.

Pair 3 · Bright/dark cells · Daytime EL — **Pair 3 · Bright/dark cells**Metastable bright/dark-cell comparison — more pronounced at night, while the processed daytime image still reads the same features.

Pair 3 · Bright/dark cells · Night EL — **Pair 3 · Bright/dark cells**Metastable bright/dark-cell comparison — more pronounced at night, while the processed daytime image still reads the same features.

Samples are direct imaging output of the GK-8000 system, unretouched. Measured in this comparison: day/night image SNR ≥ 20 dB, registration error < 1 px, identical defect localization. Acquisition and defect reading follow IEC TS 60904-13:2018.

On real project sites

From C&I rooftops to mountain ground-mount plants, drone-based daytime EL is already at work on these projects — field shots and real daytime EL imaging samples.

Drone daytime EL · C&I rooftopDistributed rooftop plant in Shenyang — the drone skims the module array, imaging each panel under daytime operating conditions.

Daytime EL imaging sample · module defectsA module EL image captured under daytime operating conditions — a distinct defect cluster is visible at lower left, the direct imaging output of drone daytime EL.

On-site rooftop operationCrew operating the drone and terminal on the roof, streaming EL imagery in real time.

Rooftop module EL inspectionC&I rooftop in Suizhou — daytime screening for micro-cracks and virtual solder on live modules.

Large rooftop arrayContinuous C&I rooftop PV covered efficiently in a single daytime EL pass.

Mountain ground-mount plantHillside PV project in the Philippines — pre-grid installation EL on sloped arrays.

Incoming module samplingOn an overseas site, batch sampling EL to verify incoming module quality.

Field photos carry capture time and anti-tamper watermarks; the EL sample is the device's direct imaging output — all verifiably real. Some site details are anonymized to protect client privacy.

Let the imaging speak

Workflow aligned with IEC TS 60904-13:2018 — quantifiable, traceable, archivable data.

24h

Day & Night

1000–1500

modules/day throughput

0–1200

W/m² ambient light range

IEC 60904-13

workflow aligned to the standard

FAQ

Can EL really be done in daylight?

Yes. With SWIR imaging and differential algorithms, readable EL images are captured in daylight (0–1200 W/m²) — no need to wait for night.

Do modules need to be shut down?