Quick Answer
Most solar panel manufacturers offer warranty extensions for degraded panels, but the specific policies and conditions vary between companies. Typically, panels that degrade by 10-20% can be eligible for warranty extensions, but the exact percentage and eligibility requirements depend on the manufacturer.
Manufacturer Warranty Policies
Solar panel manufacturers like SunPower, Tesla, and Trina Solar offer warranty extensions for degraded panels. For instance, SunPower’s 25-year warranty covers panels that degrade by 10-15% below their expected output, while Tesla’s warranty extension policy covers panels that degrade by 10-20% below the expected output. These policies may vary depending on the specific panel model, installation location, and other factors.
Measuring Degradation
To determine the degradation of a solar panel, you can use the performance ratio method, which involves comparing the actual energy output to the expected energy output based on the panel’s specifications. You can also use the module degradation factor (MDF) to measure degradation, which is a measure of how much the panel’s energy output has decreased over time. A higher MDF indicates greater degradation.
Panel Inspection and Testing
To determine if a solar panel is eligible for a warranty extension, you’ll typically need to inspect and test the panel to measure its degradation. This may involve using specialized equipment such as a multimeter or a solar panel tester to measure the panel’s voltage, current, and power output. You may also need to provide documentation of the panel’s installation, maintenance history, and other relevant information to support your warranty claim.
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