top of page

The most common solar panel defects

Solar panels are incredibly reliable, and have proven to be not only great for the environment, but a superb investment as well. Their reliability comes from the fact that they are solid state electronic devices, meaning that there are no moving parts. This nearly eliminates the risk of mechanical failure and allows panels to be extremely low maintenance for long periods of time. However, nothing is perfect, and solar panels can develop defects over the course of their lifetime. We’ve put together a list of the most common problems that can occur with your solar system.


Lamination of solar panels keeps the solar cells protected by vacuum sealing and fusing the solar cell, the glass sheet, and the back sheet. While these seals are typically extremely secure, if the lamination process was not done properly, delamination–the separation of the bond between these components–can occur. Delamination normally starts at the edge of the panel, and gradually works its way inward. Without a secure seal, moisture and air can make their way into the system, causing corrosion and substantial reduction in panel performance. If you see dark spots on your panels, this could be a sign that your panels are undergoing delamination and you should contact your installer for an inspection.

Micro cracks

Micro cracks are extremely small tears in solar cells stemming from haphazard shipping and installation or defects in manufacturing. While these micro cracks do not lead to immediate loss in energy production, changes in weather and general wear and tear can contribute to their growth over time and make them a larger issue. Hiring an experienced and trustworthy installer, such as one on the EnergySage Marketplace, will help lessen the risk of micro cracks during installation.

Hot spots

Hot spots, one of the most common issues with solar systems, occur when areas on a solar panel become overloaded and reach high temperatures relative to the rest of the panel. When current flows through solar cells, any resistance within the cells converts this current into heat losses. Imperfections in panels, such as cracks, poor soldering, or the accumulation of dirt, can cause this resistance to increase in a concentrated area, causing a hot spot. It’s important to deal with these right away if they appear because, if left unchecked, they can cause degradation of your system or even render it irreparable.

Snail trails

Occasionally, solar panels can develop small brown lines on the surface, which are termed “snail trails” because they give the appearance that snails have passed over the panel. Snail trails typically appear after only a few years and can have multiple causes, which are often attributed to lower quality panels. Defects in these panels can allow moisture to enter through the back sheet, causing oxidation between silver paste, a key material used in manufacturing, and the encapsulation material. This reaction causes the front of the panel to chemically break down, reducing the performance of the system and ultimately causing it to fail prematurely. Snail trails are often associated with micro cracks and can create hot spots. Purchasing reputable panels can substantially lower your risk of snail trails.

Potential induced degradation

Potential Induced Degradation, or PID, occurs due to the high voltage difference between the grounded glass sheet and the solar cells. When this happens, the primary power circuit can produce a partial voltage discharge, which reduces the performance and accelerates the aging of the panel. PID generally occurs shortly after solar systems are installed and can be exacerbated by long string connections, hot temperatures, and high humidity. Fortunately, if spotted at an early stage, solar professionals can help to reverse or prevent this problem.

Electrical issues

Occasionally, poor installation of your solar system can lead to electrical issues. Problems such as loose wiring or wiring damage caused by corrosion or oxidation can ultimately lower the production of your system. If you think your system may be affected by electrical issues, it’s best to contact your installer. Assessing the situation yourself will put you at unnecessary risk that your installer or a licensed electrician are trained to handle.

Inverter problems

Inverters help to convert solar energy into alternative current usable in your home. While the panels themselves usually last between 25 and 30 years, inverters are slightly less durable, and usually need to be replaced every 10 to 15 years for string inverters and up to 25 years for micro inverters. Make sure to get these checked if you notice an issue with your panels’ electricity production around these times.

Unwanted wildlife

Finally, while you may enjoy your neighborhood wildlife, they can sometimes be a nuisance when it comes to your solar system. Birds and squirrels are some of the biggest culprits for causing problems. By building nests in the space between your panels and your roof, they can wreak havoc on wiring and other sensitive electronics. Critter guards are a simple and effective way to protect against this problem.

Solar panels are built to last

When all is said and done, photovoltaic systems are amazingly reliable and require minimal maintenance over the course of their lifetimes. Still, like any other electrical device, they’re vulnerable to manufacturing defects and general wear and tear. Typical costs to repair these kinds of issues range from about $100 to $350, although costs can vary depending on the severity of the issue. If you notice any of these issues, be sure to contact your installer to get your system inspected as soon as possible. Using reputable installers and equipment can significantly lower your risk of experiencing many of these problems. As long as you get your panels inspected regularly and keep them clear of debris, they should provide dependable, clean energy for decades to come.


bottom of page