Solar Panel Troubleshooting: Is Delamination Causing Low Output?

  • Post last modified:March 30, 2026

Solar Panel Troubleshooting: Is Delamination Causing Low Output?

Solar energy systems are designed to be long-term investments, often boasting warranties that span 25 years or more. However, the reality of outdoor exposure means that photovoltaic (PV) modules are constantly battling the elements. If you have noticed a significant drop in your system’s energy production, you are likely searching for answers. One of the most insidious and common issues in aging or poorly manufactured modules is delamination. In this comprehensive guide, we will explore “Solar Panel Troubleshooting: Is Delamination Causing Low Output?” and provide you with the technical insights needed to diagnose and address this problem.

Understanding Solar Panel Delamination

To understand delamination, one must first understand the anatomy of a solar panel. A standard crystalline silicon solar panel is a “sandwich” of several layers bonded together under high heat and pressure. These layers typically include:

  • Tempered Glass: The top layer that protects the cells from physical impact.
  • Encapsulant (usually EVA or POE): A thin layer of adhesive polymer that cushions the solar cells and bonds them to the glass and backsheet.
  • Solar Cells: The semiconductor material that converts sunlight into electricity.
  • Backsheet: A polymer layer on the bottom that provides electrical insulation and moisture protection.
  • Frame: Usually aluminum, providing structural integrity.

Delamination occurs when the bond between these layers—most commonly between the encapsulant and the solar cells or the glass—begins to fail. When these layers separate, air and moisture gaps are created. This physical separation is not just a cosmetic flaw; it is a fundamental threat to the electrical performance and safety of the entire solar array.

How Delamination Affects Energy Production

When troubleshooting low output, it is essential to connect the physical symptoms to electrical consequences. Delamination impacts energy production through several mechanisms:

1. Increased Light Reflection

The encapsulant is designed to have an optical index similar to glass, ensuring that maximum sunlight reaches the solar cells. When delamination occurs, an air pocket is formed. Light traveling through glass and hitting an air pocket undergoes “total internal reflection” or scattering. This means fewer photons reach the semiconductor material, directly reducing the current (Amperage) produced by the cell.

2. Moisture Ingress and Corrosion

Once the bond is broken, moisture can migrate into the module. This moisture reacts with the metal ribbons and busbars that connect the cells. Corrosion increases electrical resistance, which leads to voltage drops and heat generation. In severe cases, corrosion can completely sever the electrical path, leading to a total failure of a string within the module.

3. Formation of Hot Spots

Delamination often happens unevenly. If one part of a cell is delaminated and producing less current than the rest of the string, that cell can become a “load” rather than a “source.” It begins to dissipate energy as heat. These “hot spots” can reach temperatures high enough to melt the backsheet or crack the glass, posing a significant fire risk.

Identifying the Visual Signs of Delamination

Before diving into electrical testing, a thorough visual inspection is the first step in solar panel troubleshooting. Delamination often leaves distinct footprints:

  • Bubbles and Blisters: Look for small pockets of air or raised areas on the surface of the panel or the backsheet. These often start at the edges of the cells or near the frame.
  • Discoloration (Browning or Yellowing): When the encapsulant (EVA) begins to fail and delaminate, it often undergoes a chemical change due to UV exposure and heat. This is known as “EVA browning.” The darker the area, the more the light is being blocked.
  • Cloudiness: A milky or foggy appearance across the cells indicates that the adhesive is no longer in contact with the glass.
  • Peeling Backsheet: In some cases, the entire rear layer of the panel may begin to flake or peel away, exposing the internal wiring to the environment.

The Root Causes: Why Do Solar Panels Delaminate?

Understanding why delamination happens can help you determine if the issue is a localized fluke or a systemic failure across your entire installation. The causes generally fall into three categories:

Manufacturing Defects

This is the most common cause. If the lamination process was not performed at the correct temperature or for the correct duration, the chemical cross-linking of the encapsulant may be incomplete. Furthermore, using low-quality adhesives or contaminated raw materials can lead to premature bond failure. If you are seeing widespread delamination in a system less than 10 years old, it is likely a manufacturing issue.

Environmental Stress (Thermal Cycling)

Solar panels are subject to extreme temperature swings. They heat up under the sun and cool down rapidly at night or during rain. Different materials (glass, silicon, plastic) expand and contract at different rates. This “coefficient of thermal expansion” mismatch puts constant mechanical stress on the adhesive layers. Over thousands of cycles, these stresses can pull the layers apart.

Moisture and Humidity

In coastal or high-humidity environments, moisture is the enemy. If the edge seal of the panel is compromised, water vapor can penetrate the laminate. Moisture acts as a catalyst for the breakdown of the polymer bonds, accelerating the delamination process.

Step-by-Step Troubleshooting Guide for Low Output

If you suspect delamination is causing your low output, follow this systematic troubleshooting approach:

Step 1: Monitor System Data

Check your inverter’s monitoring software. Is the low output consistent across the whole system, or is it isolated to one string? If one string is performing 20-30% worse than the others, that is where you should begin your physical inspection.

Step 2: Clean the Modules

Before blaming delamination, ensure the low output isn’t simply due to “soiling” (dust, bird droppings, or pollen). A clean panel is necessary for an accurate visual assessment. If the output remains low after cleaning, proceed to the next step.

Step 3: Visual Inspection

Use a ladder or binoculars to look for the bubbles, browning, or cloudiness mentioned earlier. Document these findings with photos, as they will be required for any warranty claims.

Step 4: Thermal Imaging (IR Camera)

An infrared camera is one of the most powerful tools for solar panel troubleshooting. Because delaminated areas often lead to higher resistance or cell mismatch, they show up as “hot spots.” A panel with significant delamination will show irregular heat patterns compared to a healthy panel. If you need a professional assessment of your system’s health, Contact Our Team to discuss diagnostic solutions.

Step 5: I-V Curve Tracing

For a definitive diagnosis, a technician can perform an I-V curve trace. This measures the current and voltage relationship of the module. Delamination typically causes a “stair-step” pattern in the curve or a significant reduction in the Short Circuit Current (Isc), confirming that the physical damage is indeed impeding electrical flow.

Advanced Diagnostic Tools: Beyond the Naked Eye

While visual signs are often present, some delamination starts at a microscopic level. Electroluminescence (EL) imaging is a laboratory-grade technique that can be used in the field. It works like an X-ray for solar panels. By running a current through the panel in reverse, the cells glow in the infrared spectrum. Delaminated areas or microcracks will appear as dark spots, showing exactly where the energy flow is being interrupted.

Furthermore, Insulation Resistance (ISO) testing is crucial. Delamination often leads to “ground faults.” If moisture enters a delaminated area, the electricity can leak to the aluminum frame. This is a safety hazard and will often cause the inverter to shut down entirely to prevent fire or shock.

Delamination vs. Other Issues

It is important to distinguish delamination from other common PV issues during your troubleshooting process:

  • Potential Induced Degradation (PID): This is an electrical phenomenon that reduces output but doesn’t usually show physical peeling. It is caused by voltage leakage from the cells to the frame.
  • Snail Trails: These look like brown lines across the cells. While they are often associated with microcracks, they are a chemical reaction in the encapsulant but don’t always mean the layers have separated.
  • Microcracks: These are tiny cracks in the silicon wafers. They can be caused by hail or improper handling. While microcracks can *lead* to delamination, they are a different failure mode.
  • Shading: Even a small amount of shade from a new chimney or a growing tree can mimic the output loss of delamination. Always check for shadows before assuming the panel is failing.

Repair vs. Replacement: What Are Your Options?

Once you have confirmed that delamination is the cause of your low output, the next question is: can it be fixed?

Can You Repair Delamination?

In short, no. Once the chemical bond between the layers of a solar panel has failed and moisture has entered, the damage is irreversible. There are no “glues” or “sealants” that can be injected into the panel to restore its original integrity or optical properties. Attempting to DIY a repair on a delaminated panel can void warranties and create safety risks.

Warranty Claims

Most reputable solar panel manufacturers provide a “Power Output Warranty” (usually 25 years) and a “Product/Workmanship Warranty” (usually 10-12 years). Delamination is generally considered a manufacturing defect. if your panels are within the warranty period, you should be eligible for a replacement. This is why documenting your troubleshooting process with photos and serial numbers is vital.

Replacement Strategy

If only one or two panels are delaminating in an older system, it may be most cost-effective to simply replace those individual modules. However, if the delamination is a result of a specific “batch” issue from the manufacturer, you may need to prepare for a full system replacement as other panels will likely fail soon.

The Role of High-Quality Encapsulants in Preventing Failure

The best way to deal with delamination is to prevent it from the start. This begins at the manufacturing level. The choice of encapsulant is the single most important factor in preventing delamination. High-quality Ethylene Vinyl Acetate (EVA) and more modern Polyolefin Elastomer (POE) materials offer better resistance to UV degradation and moisture.

When choosing panels for a new installation, look for manufacturers that use advanced lamination technologies. Panels that have passed “Extended Damp Heat” and “Thermal Cycling” tests (often 2x or 3x the IEC standard) are much less likely to suffer from delamination over their lifetime. Quality adhesives ensure that the bond remains strong even in the face of extreme weather and humidity.

Conclusion

Solar panel troubleshooting is a process of elimination. If you are experiencing low output, delamination is a prime suspect, especially in older installations or modules from lesser-known manufacturers. By identifying the visual cues of bubbles, browning, and cloudiness, and confirming the impact with thermal imaging or I-V curve tracing, you can take the necessary steps to protect your investment.

While delamination cannot be repaired, identifying it early allows you to file warranty claims and prevent further system degradation or safety hazards. Always prioritize safety and consult with professionals when dealing with electrical components.

Maintaining a high-performing solar array requires vigilance and an understanding of the materials at play. By choosing quality components and performing regular inspections, you can ensure that your transition to renewable energy remains a profitable and reliable journey for decades to come.

Visit [www.incurelab.com](https://www.incurelab.com) for more information.