An operations team that says “the array feels like it’s underperforming” has an opinion; an operations team that can show a specific string is producing 14% below its modeled output has a warranty claim. Getting from one to the other requires a measurement sequence, not a gut feeling — and skipping steps is how legitimate delamination losses get dismissed as “normal seasonal variation.”

Step 1: Establish What the Panel Should Be Producing

Before flagging underperformance, pull the module’s rated output and its documented annual degradation curve — most crystalline silicon modules are warrantied for no more than roughly 0.5% output loss per year after an initial first-year settling loss. Multiply the panel’s nameplate wattage by (1 minus the cumulative expected degradation for its age) to get a modeled expected output at current conditions, adjusted for irradiance and temperature at the time of the measurement. A panel producing meaningfully below that modeled figure — not just below its original nameplate rating — is the actual signal worth investigating, since some gap between nameplate and current output is expected and contractually normal.

Step 2: Isolate the Loss to a String, Then a Panel

Array-level output data alone can’t tell you whether a shortfall is one bad panel or a systemic issue like soiling or shading across the whole field. Compare string-level production data (most commercial inverters or combiner-box monitoring report at this granularity) against sibling strings with matching orientation and shading conditions. A single string underperforming its otherwise-identical neighbors by a meaningful margin points at a component-level problem within that string; if every string shows a similar proportional shortfall, look at whole-array causes — inverter clipping, soiling, or a monitoring calibration error — before suspecting delamination in any individual module.

Step 3: Confirm the Suspected Panel With an I-V Curve Trace

Once a string is isolated, an I-V curve trace on individual panels within it distinguishes a delamination-driven loss from other causes. Delamination typically produces a curve with reduced current output across the operating range and an increased series resistance signature — a curve that droops earlier than expected rather than one that simply shifts down uniformly, which would suggest soiling or partial shading instead. Recording the trace against the panel’s original factory flash-test data, when available, gives the clearest before/after comparison; without it, comparison against an adjacent, visually healthy panel of the same model and age is the next-best baseline.

Step 4: Convert the Measured Loss Into a Dollar Figure

A warranty claim is stronger with a quantified financial impact attached, not just a percentage. Multiply the measured output shortfall (in kW) by the site’s effective sun-hours per year and the applicable power purchase or offset rate to produce an estimated annual revenue or savings loss attributable to the affected panel or string. For a portfolio with many arrays, tracking this figure per site over time also flags whether a manufacturer’s modules are showing a pattern of premature degradation across multiple installations — evidence that strengthens a claim considerably compared with a single isolated data point.

Step 5: Document the Physical Evidence Alongside the Electrical Data

Electrical measurements establish that a loss exists; physical documentation establishes why. Photograph the suspect panel’s front and rear, noting the serial number, installation date, and location within the array. Where available, electroluminescence imaging reveals internal dark zones tied to delamination-driven corrosion or micro-cracking that aren’t visible under normal light — this evidence is often what separates a fast manufacturer warranty approval from a prolonged dispute over root cause, since it directly shows internal bond failure rather than surface weathering.

Step 6: Build the Claim Package in the Order a Reviewer Expects

Manufacturer warranty reviewers typically want, in this order: the modeled-versus-actual output comparison from Step 1, the string-isolation data from Step 2, the I-V curve trace from Step 3, the electroluminescence or thermal imaging from Step 5, and finally the financial impact estimate from Step 4 as supporting context rather than the primary evidence. Submitting photographs alone, without the underlying electrical measurement showing an actual performance gap, is one of the most common reasons a legitimate claim gets delayed for additional information. Email Us if your team wants a second opinion on interpreting I-V trace results before submitting a claim package.

What Drives the Underlying Bond Failure

The measurement protocol above confirms and quantifies a loss; understanding the mechanism helps with prevention on future installations. Thermal cycling stresses the bond between the glass, encapsulant, and cell layers where materials with different expansion rates are forced to move together, and sustained UV and heat exposure over years gradually embrittles the encapsulant polymer, reducing its ability to absorb that stress. Moisture ingress that follows an initial bond weakness compounds the damage through hydrolysis and metallic-contact corrosion, which is part of why a delamination-driven loss typically worsens over time rather than stabilizing.

Reducing Future Claims Through Bond Quality

Since delamination is fundamentally an adhesive and encapsulant durability problem, module and system-integrator selection around bond quality matters as much as panel efficiency ratings. Incure’s UV-curable adhesive and encapsulation chemistries are formulated for the same multi-decade UV, thermal-cycling, and moisture-resistance requirements this measurement protocol is designed to catch failures of — see our companion guide on reading cloudiness and bubbling as early visual signs of delamination for the physical-inspection side of this diagnostic process, and how CTE mismatch drives adhesive bond failure for the underlying thermal-stress mechanism.

Contact Our Team to discuss adhesive and encapsulant specification for improving long-term module bond reliability across a fleet.

Visit www.incurelab.com for more information.