Why Your Solar Panel Output Is Low (Delamination Explained)

  • Post last modified:March 30, 2026

Why Your Solar Panel Output Is Low: The Hidden Danger of Delamination Explained

Investing in solar energy is one of the most significant steps a homeowner or industrial facility manager can take toward sustainability and energy independence. However, the frustration begins when those high-efficiency ratings on the spec sheet don’t translate to the real-world power output you see on your monitoring app. If you have noticed a steady decline in energy production that cannot be explained by seasonal changes, dirt, or shading, you may be facing a silent killer of photovoltaic (PV) modules: delamination.

Delamination is more than just a cosmetic flaw; it is a structural failure that compromises the electrical integrity of a solar panel. In this comprehensive guide, we will explore why your solar panel output is low, the science behind delamination, how to identify it, and what can be done to prevent this costly issue.

Understanding the Anatomy of a Solar Panel

To understand why delamination happens, we first need to look at how a solar panel is constructed. A standard crystalline silicon solar panel is not a single solid block. Instead, it is a sophisticated “sandwich” of different materials bonded together under heat and pressure. The layers typically include:

  • Tempered Glass: The top layer that protects the cells from the elements while allowing sunlight to pass through.
  • Encapsulant (usually EVA): A thin layer of Ethylene Vinyl Acetate (EVA) that acts as a bonding agent, cushioning the solar cells and protecting them from moisture.
  • Solar Cells: The silicon wafers that actually convert sunlight into electricity.
  • Lower Encapsulant Layer: Another layer of EVA to bond the cells to the backsheet.
  • Backsheet: A polymer layer (often TPT or Tedlar) that provides electrical insulation and protects the underside of the panel.

Delamination occurs when the bond between these layers—most commonly between the glass and the encapsulant or the encapsulant and the cells—begins to fail. When these layers separate, air and moisture are allowed to enter the module, leading to a cascade of performance issues.

Why Delamination Causes Low Solar Output

You might wonder why a simple peeling of layers would affect the electrical output of a panel. The impact is actually multi-faceted, affecting both the optical and electrical properties of the system.

1. Increased Light Reflection

Solar panels are designed to absorb as much light as possible. Manufacturers use anti-reflective coatings and specific bonding agents that have a refractive index matched to the glass and silicon. When delamination occurs, an air gap is created between the glass and the cells. Because air has a different refractive index than the encapsulant, light “bounces” off the interface instead of passing through to the cell. This reduction in light absorption directly translates to lower current generation.

2. Moisture Ingress and Corrosion

The encapsulant’s primary job is to keep moisture out. Once the bond fails, atmospheric moisture finds its way into the panel. This moisture reacts with the metal “fingers” and “busbars” (the silver grids on the cells) that collect electricity. This leads to oxidation and corrosion. As the metal corrodes, its resistance increases, making it harder for electricity to flow, which drastically reduces the total power output.

3. Internal Arcing and Hot Spots

As delamination progresses and corrosion sets in, the electrical connections within the panel become unstable. This can lead to “hot spots”—localized areas of high temperature where the energy is being dissipated as heat rather than being sent to the inverter. In extreme cases, this can lead to internal arcing, which can permanently damage the solar cells or even pose a fire risk.

4. Potential Induced Degradation (PID)

While delamination and PID are different phenomena, delamination can accelerate PID. When moisture enters the module due to a failed bond, it increases the conductivity of the internal materials, allowing leakage currents to flow from the cells to the frame. This disrupts the voltage potential of the cells and can lead to a massive drop in efficiency across the entire string of panels.

How to Identify Delamination: Signs and Symptoms

Early detection is key to managing solar panel health. While some delamination is obvious, other forms require technical tools to spot. If you suspect your solar panel output is low, look for these indicators:

Visual Bubbles and Peeling

One of the most common signs is the appearance of small bubbles or “blisters” under the glass. This indicates that the EVA has detached from the glass surface. You may also see the backsheet peeling away from the edges of the frame.

Discoloration or “Browning”

As the encapsulant breaks down due to moisture and heat, it often changes color. You might see yellow, brown, or even milky white patches on the cells. This browning is a chemical reaction (often acetic acid formation in EVA) that signifies the protective layer is no longer doing its job.

Snail Trails

Snail trails are dark, discolored lines that appear on the surface of the cells, looking like the path left by a snail. These are often micro-cracks that have been exacerbated by moisture entering through delaminated sections, leading to localized oxidation of the silver paste used in the cell grid.

Infrared (Thermal) Imaging

Professional installers use thermal cameras to find delamination. A delaminated area will often show up as a “hot spot” because the lack of physical contact between layers prevents heat from dissipating evenly, or because the internal resistance has increased due to corrosion.

The Root Causes: Why Do Panels Delaminate?

If solar panels are supposed to last 25 years, why do they fail early? Delamination is usually the result of one of three factors: manufacturing defects, environmental stress, or poor material quality.

1. Poor Manufacturing Processes

The lamination process requires precise control of temperature, vacuum pressure, and time. If the “cook time” for the EVA is too short, the polymer doesn’t cross-link properly, resulting in a weak bond. If the environment isn’t clean, dust or oils can contaminate the layers, preventing a solid seal from forming in the first place.

2. Thermal Cycling

Solar panels live in harsh environments. They heat up under the sun and cool down rapidly at night or during rain. This “thermal cycling” causes the different materials (glass, silicon, plastic) to expand and contract at different rates. Over thousands of cycles, this mechanical stress can literally pull the layers apart if the adhesive isn’t strong enough.

3. UV Degradation

While solar panels are designed to harness UV rays, those same rays can break down the chemical bonds in low-quality encapsulants. Over time, UV exposure can make the bonding agent brittle, leading to cracking and eventual separation from the glass or backsheet.

Can Delaminated Solar Panels Be Repaired?

The short answer for most residential and commercial users is: **No.**

Because solar panels are hermetically sealed units, once the internal layers have separated and moisture has entered, the damage to the silicon cells and metallic traces is usually irreversible. Attempting to “reglue” the edges or patch the backsheet is generally a temporary fix that does not restore the lost efficiency or stop the internal corrosion.

If your panels are under warranty, delamination is typically considered a manufacturing defect. This is why it is vital to keep your purchase records and work with reputable manufacturers who offer 20-to-25-year performance and product warranties. If you notice these signs, you should [Contact Our Team](https://www.incurelab.com/contact) or your original installer to begin a warranty claim.

Prevention: How to Choose High-Quality Modules

The best way to deal with delamination is to prevent it from happening in the first place. When shopping for solar panels or designing a large-scale array, consider the following:

Look for POE Encapsulants

While EVA is the industry standard, many high-end manufacturers are moving toward **Polyolefin Elastomer (POE)**. POE has much better resistance to moisture ingress and does not produce acetic acid when it degrades, making it far less likely to cause corrosion or delamination over time.

Check for IEC 61215 Certification

Ensure your panels have passed the IEC 61215 standard. This test includes a “Damp Heat” test, where panels are subjected to 85% humidity and 85°C temperatures for 1,000 hours. Panels that pass this are significantly less likely to suffer from delamination in the field.

Glass-to-Glass Modules

Bifacial or “dual-glass” panels replace the plastic backsheet with a second layer of tempered glass. These modules are generally much more resistant to delamination because glass-to-glass bonding is more stable than glass-to-plastic, and glass is entirely impermeable to moisture.

The Role of Advanced Adhesives in Solar Longevity

In the industrial manufacturing of solar components, the choice of adhesive is everything. At the core of every long-lasting solar panel is a commitment to material science. High-performance bonding agents must be able to withstand extreme temperature swings, intense UV radiation, and physical vibration.

As the solar industry evolves, companies are looking toward UV-curable adhesives and specialized sealants that offer faster production times without sacrificing the bond’s structural integrity. These advancements in adhesive technology are what allow modern panels to push past the 30-year lifespan mark, ensuring that the “sandwich” stays together through the harshest winters and the hottest summers.

Maintenance Tips to Protect Your Output

While you can’t fix the chemistry of the internal bond, you can take steps to ensure your panels aren’t under unnecessary stress:

  • Regular Cleaning: Dirt and bird droppings can create “partial shading,” which causes localized heating. This heat can stress the bond in that specific area, potentially leading to localized delamination.
  • Proper Ventilation: Ensure panels are installed with enough space underneath for airflow. Overheating is a major contributor to the breakdown of the EVA layer.
  • Annual Inspections: Have a professional perform a thermal drone scan or a visual inspection once a year to catch signs of peeling or browning before the entire string’s output is affected.

Conclusion

Low solar panel output is often a puzzle with many pieces, but delamination is one of the most serious issues you can encounter. By understanding that your panels are a complex laminate of materials, you can better appreciate the importance of quality manufacturing and the role that environment plays in their degradation.

If you have noticed a dip in your energy production, don’t just blame the weather. Inspect your panels for bubbles, browning, or peeling. If you catch delamination early, you may be able to replace the modules under warranty before your energy savings disappear entirely. For those in the manufacturing or maintenance sector looking for the highest quality bonding and sealing solutions to prevent such failures, choosing the right partner is essential.

Ensuring the longevity of solar energy systems requires a deep understanding of the materials that hold them together. From the glass on top to the backsheet on the bottom, every layer must remain perfectly bonded to ensure the sun’s energy is captured efficiently for decades to come.

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