Damaged solar panels rarely announce themselves. Cell cracks are usually invisible, and IEA PVPS Task 13 notes that in many cases a crack can't be detected even by a power measurement right after it happens - only an electroluminescence or lock-in thermography image reveals it. The most thorough review of field degradation modes (Jordan et al., 2017) ranks hotspots as the top concern in systems installed in the previous 10 years, followed by internal circuit discoloration, with encapsulant discoloration the most common mode in older systems. Catch problems early and you protect your warranty and roof. For how panels age normally versus abnormal damage, see our guide on old solar panels.
Three patterns are worth knowing by sight: dark hotspot rectangles or burn marks through the glass, snail-trail discoloration along cell cracks, and bubbles or clouding from delamination. Some damage never comes from weather at all. IEA PVPS Task 13 documents cell cracks from modules falling over or an insufficiently rigid pallet pressing on the lowest module in transit, and glass breakage from screws tightened too far. A panel can arrive or be mounted already damaged.
What Are the Most Common Types of Solar Panel Damage?
Crystalline silicon panels fail in a handful of documented ways. Jordan et al. (2017) reviewed the field literature and found encapsulant discoloration the most common degradation mode overall, hotspots the top concern in systems installed in the previous 10 years, and delamination plus diode and junction box problems more frequent in hot, humid climates.
- Microcracks: form inside cells from mechanical stress, hail, snow load or shipping, and are usually invisible to the naked eye. IEC 61215 tests a 2,400 Pa static load and 25 mm ice balls at 23 m/s, so larger hail is outside what a certified panel was tested against. IEA PVPS found cracks typically cost under 3% of power per year, but about 7% per year for affected modules in cold, snowy climates (2017).
- Hotspots: a cell driven into reverse bias, whether from a crack, a failing bypass diode or a solder bond failure, dumps energy as heat. IEA PVPS notes this can cause browning, burn marks and, in the worst case, fire.
- Delamination: separates the encapsulant from the glass or backsheet, opening moisture pathways. It shows as bubbles or wrinkles. IEC 61215's damp-heat test (85 degrees C, 85% humidity, 1,000 hours) is meant to screen for it, but certified panels can still delaminate in the field.
- Discoloration: an amber or brown tint through the glass is encapsulant discoloration, the most common mode in older systems. Localized dark spots or burn marks point to a hotspot instead. Snail trails are discolored silver paste along cell cracks: the discoloration itself doesn't cut power, but the cracks it traces can (IEA PVPS, 2017).
| Damage type | Visible from ground? | Detection method | Urgency |
|---|---|---|---|
| Microcracks | No | EL imaging, yield anomaly | Low-medium, watch trend |
| Hotspots | Sometimes (dark patches) | Thermal camera, monitoring | High, can progress to burn marks and fire |
| Delamination | Yes (bubbles, wrinkles) | Visual inspection | Medium, moisture ingress |
| Discoloration | Yes (amber/brown tint) | Visual inspection | Low unless localized (hotspot) |
How Does a Yield Drop Signal Damage Before You Can See It?
The most sensitive damage detector on your roof is the monitoring platform you already own. Many cracks can't be seen from the ground, and a crack often doesn't show in a one-off power measurement either, so a trend against identical neighbors is the cheapest early check you have.
Knowing which figure moved narrows the diagnosis before anyone climbs anything, and reading solar inverter data walks through the distinction that matters most here: falling current usually means dirt, while voltage stepping down on one string means damage.
Watch for a single panel that persistently trails its neighbors (identical panels should track closely at the same irradiance; this guide uses a 10% gap as a working threshold, not a standard, and a persistent gap points to a cracked cell or early delamination), a gradual decline that its neighbors don't share (damage, not a seasonal shift, since season affects all panels equally), a sudden step-change drop (hail, a failed bypass diode or a connector failure; on a typical 3-diode module one shunted bypass diode cuts the module's output by a third, per IEA PVPS Task 13, 2014), or intermittent faults (fine in sun, weak under shade or cloud - a bypass diode issue).
The SolarEdge P370 optimizer and Tigo TS4-A-O give per-panel monitoring, so a damaged module shows up as an outlier against its neighbors, which string-level data averages away.
How Do You Inspect Solar Panels for Physical Damage Safely?
Never walk on panels and never work on a wet roof. Start from the ground with binoculars or a zoom camera in bright overcast light, since direct sun throws glare that masks surface detail. Check glass integrity (cracks let moisture in and trigger a warranty claim), cell surface (dark patches from microcracks, burn marks from hotspots, snail trails along busbars), frame and edges (warping or separation from the glass, the first moisture ingress point), and backsheet from an attic or with a drone (yellowing or blistering removes electrical insulation and creates shock risk).
If ground inspection is inconclusive but your data shows a clear anomaly, use electroluminescence (EL) imaging, which passes a small current through the panel in darkness and photographs the infrared emission; cracks appear as dark, lightless regions. Outdoor infrared thermography is the other imaging tool: it finds hotspots and bypass diode faults, and the thermography procedure is covered by IEC TS 62446-3. IEC 62446-1 sets out the commissioning documentation and inspection a grid-connected system should have been handed over with, which gives you a baseline to compare a damaged panel against.
When Should You Call a Professional vs Handle It Yourself?
Some checks are yours; others need a certified installer. DIY-safe: ground-level inspection, reviewing monitoring data, time-stamped photos. Call a professional for: any suspected hotspot (stop using the system), cracked glass, exposed wiring, bypass diode diagnosis (IV curve tracing), or anything requiring roof access. Don't sit on burn marks: they can progress, and waiting hands an insurer or manufacturer an argument that the damage got worse through neglect.
How Do You Handle Insurance Claims and Warranty Replacements?
Build documentation the moment you suspect damage: time-stamped photos, a monitoring export covering 30 days before and after the event, weather records, and the panel's model and serial numbers.
Product warranties differ by maker: the Jinko Tiger Neo datasheet lists a 12-year product warranty and the REC Alpha Pure-R lists 20 to 25 years (the longer term needs a certified installer), each with a separate linear power warranty (30 and 25 years) for output below the guaranteed floor. Contact your original installer first, since they often have direct manufacturer contacts; if they've closed shop, go straight to the manufacturer's warranty portal using the serial number.
Homeowner's insurance may cover damage from some covered perils under dwelling or other structures coverage, but wind and hail may not be covered depending on the policy, and improper installation and wear and tear are excluded (Progressive). Tell your insurer about the installation, and check your policy for the claim deadline. Tie the damage to a specific external event (a dated hailstorm) rather than vague "panel failure" language, because wear and tear is excluded - normal aging follows a slow curve (median about 0.5%/year in Jordan and Kurtz, NREL), while damage causes drops that break the pattern.
Speed matters: check for hotspot burn marks first and shut down the inverter if you see any; export monitoring data immediately, since some platforms may keep fine-grained data only for a limited time; photograph everything with a timestamp; and check your warranty terms before cleaning or repairing a damaged panel yourself, since work by anyone other than an authorized installer may void coverage.
For yield recovery after repair, see our guide on recovering lost solar yield; soiling mimics damage in the data, so our guide on cleaning solar panels explains the difference, and our maintenance guide covers the full preventive schedule.
Summary
Damaged solar panels show their worst effects in monitoring data before they show on the roof. A persistent yield gap between one panel and its identical neighbors is a more reliable early signal than any visual check. When physical signs appear - cracked glass, burn marks, snail trails, bubbling delamination, or yellowing - treat them as documentation triggers, not watch-and-wait situations. Per-panel tools like the SolarEdge P370 and Tigo TS4-A-O make a lagging module easy to spot. Shut down the system at the first sign of hotspot burn marks, and document everything with photos, monitoring exports, and weather records before filing, since that evidence decides how fast and how fully you're made whole.