Drone Image Showing Hot Spots on Solar Array

How to Succeed with Module Warranty Claims Using Drone Thermography

One of the biggest factors encouraging investment in solar projects is the long 25-30 year warranties that module manufacturers provide for their products. However, the true value of a warranty depends on how effective the claims process is for the asset owner. Whether purchasing a few dozen modules or a few thousand, how can one succeed with module warranty claims if the modules do not live up to their guaranteed production?

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"As a PV system ages, the baseline data from commissioning provides a reference point to determine the degeneration rate of solar modules at a given site. If it is determined that modules are underperforming, drone data can be used to file performance warranty claims."
Cables Connecting Solar Arrays on a Solar Farm During Drone Inspection

Investing in Solar Modules

One of the biggest factors encouraging investment in solar projects is the long 25-30 year warranties that module manufacturers provide for their products. However, the true value of a warranty depends on how effective the claims process is for the asset owner. Whether purchasing a few dozen modules or a few thousand, how can one succeed with module warranty claims if the modules do not live up to their guaranteed production?

Solar Panel Damage

The Problem with Solar Warranty Claims

Like any manufactured product, photovoltaic (PV) modules are made with certain tolerances that allow for a margin of error, meaning the product may not be produced exactly as designed. In the vast majority of cases, this margin of error is small enough that it does not create a “defective” product—one that fails to perform to the designed standard. However, some modules are produced and eventually installed with defects that cause them to degrade faster than expected or outright fail. When this occurs, the owner of the defective module will generally want the situation remedied at the expense of the manufacturer since the product does not generate its warranted production.

From the manufacturer’s perspective, the module has gone through an expensive manufacturing process, passed a quality control process, and been tested to perform as expected. According to the warranty, the customer needs to prove that the defect is a result of the manufacturing materials or workmanship in order to have a valid claim.

Maintaining Solar Assets With Drones
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As an example, according to Canadian Solar’s warranty, “claims under this warranty will only be accepted if the Buyer can prove that the malfunctioning or non-conformity of the Products results exclusively from defects in materials and/or workmanship under normal application, installation, use, and service conditions…” and “the actual power output of the Products shall be determined for verification using Standard Testing Conditions only.” The bottom line is that the customer bears the burden of proof. Additionally, First Solar’s warranty states, “power output shall be measured and normalized to STC using a method and laboratory approved by First Solar.”


So how can a system owner prove that a defective module falls under the warranty? For example, Potential-Induced Degradation (PID) is often not visible to the naked eye but can cause severe production loss in a short amount of time compared to the expected life of the system. As the system size increases, so does the difficulty of identifying, documenting, and resolving these problems.

Drone Thermal Imaging of a Solar Farm Showing Hot Spots on Panels

How to Get Your Module Warranty Claims Approved

To begin the warranty claim process, especially with a large system, the owner needs to have all relevant documentation in order. This includes purchasing invoices, module serial numbers, design and construction documents, records of maintenance performed to date, and especially proof of the malfunction or underperformance. One lawyer experienced in these types of cases gave a sage warning: “Having good records is far easier than locating long-lost employees who haven’t retained this important information.”

A good next step is to reach out to the manufacturer and agree upon a method of testing performance that will satisfy the warranty claim. Instead of removing panels to ship them to a third-party testing lab, many tests can be performed in the field and still provide high-quality results that manufacturers can accept.

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Speak With a Drone Expert Today!​

Aerial thermography coupled with visual RGB photos is a highly utilized solution for documenting the asset over time and discovering performance issues. However, not all thermographic images are created equal. It is critically important to use a licensed thermographer with equipment that complies with IEC Standard 62446, “Grid connected photovoltaic systems – Minimum requirements for system documentation, commissioning tests and inspection.” Such a thermographer would understand how to obtain the resolution necessary to satisfy the manufacturers’ requirements and avoid common errors made by inexperienced thermographers, such as reflections, poor irradiance during testing, and angle of image acquisition. Another example of quality thermography is the temperature difference or Delta T. When a module or cells within a module are imaged, the recorded temperature needs to be compared to an accurate baseline, such as nearby cells or modules under the same conditions. One company explains that while manufacturers’ criteria varies, “a commonly used threshold is a temperature delta of at least 20 degrees Celsius between the overheated and normally functioning cells.” Expert thermography equipment is able to establish the temperature of normal cells and overheated cells and display those results in an image that can be used to support a warranty claim.

While drone thermography will be acceptable proof for most warranty claims, at times manufacturers require more tests to verify that the thermal image is detecting a manufacturing defect. In such a case, the imagery from the drone flight provides an extremely helpful baseline of data to perform I-V curve testing and electroluminescence imaging. Being able to locate exactly which modules to test can save significant time and money in the warranty claim process.

With all the required documentation in hand, asset owners can successfully submit claims to the manufacturer and work on how the defects will be remedied. Typically, the manufacturer reserves the right to remedy, replace, or compensate for the defective products. Not all of these options may be satisfactory for your particular project. For example, compensation for the cost of a module is not the same as compensation for the loss of energy that the module would produce over its lifespan. Additionally, replacing lower wattage modules from a few years ago with higher wattage modules of today may cause performance issues in the rest of the string or array. Be sure to reach an agreement on how these challenges will be addressed before accepting a resolution from the manufacturer.

Solar Cell Hotspot from Drone Inspection

Getting Started with Module Warranty Claims Using Drone Thermography

PV module warranty claims can become a very headache inducing and challenging process. Preparing for such claims from the beginning of the purchasing and construction phases of the project is essential to avoid problems down the road. Remember, documentation is everything. No one will simply accept a company’s word that they followed appropriate procedures if they don’t have the records to prove it.

With so many challenges surrounding solar warranty claims, it is important to look to experienced drone service providers for help. At The Drone Life, we provide personalized consulting and customized aerial service solutions for all your solar needs. Our team of professionals is ready and equipped to address your inquiries on a range of topics, including warranty claims. Schedule a free consultation with us today to get started.

Maintaining Solar Assets With Drones
What's included in YOUR GUIDE...

Techniques for Exposing Warrantiable Items on Your PV Sites.

A Proven Roadmap for Successfully Implementing Drones in Solar.

Strategies for Identifying DC Losses and Avoiding Downtime.

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