What are the most common defects of solar panels?

Solar panels are very reliable and have proven to be not only good for the environment, but also a great investment.

Their reliability is mainly due to the fact that they are devices without moving parts. This almost completely eliminates the risk of mechanical failure and allows the panels to require very little maintenance for long periods of time.

However, nothing is perfect and solar panels can develop faults throughout their useful life. We have compiled a list of the most common problems that can occur in your solar system.


The most common failures of solar panels.


Solar panel lamination protects the solar cells by vacuum sealing and fusing the solar cell, glass sheet, and back sheet together. Although these joints are generally extremely secure, if the lamination process has not been carried out correctly, delamination can occur, that is, the separation of the joint between these components.

Delamination usually begins at the edge of the panel and progresses inward. Without a secure seal, moisture and air can be drawn into the system causing corrosion and a substantial reduction in panel performance. If you see dark spots on your panels, this could be a sign that your panels are experiencing delamination and you should contact your installer for an on-site inspection.


Microcracks are extremely small cracks in solar cells that result from shipping or installation, if not done with sufficient care, or manufacturing defects.

While these micro cracks do not cause an immediate loss of power output, weather changes and general wear and tear can contribute to their growth over time and make them a bigger problem. Hiring an experienced and trusted installer will help reduce the risk of micro-cracking during installation.

Hot spots.

Hot spots, one of the most common problems with solar systems, occur when areas of a solar panel become overloaded and reach high temperatures relative to the rest of the panel. When current flows through the solar cells, any resistance inside the cells converts this current into heat losses.

Imperfections in the panels, such as cracks, bad welds, or dirt buildup can cause this resistance to build up in a concentrated area, causing a hot spot. It is important to fix them immediately if they appear because if left unchecked, they can cause your system to break down or even become irreparable.

Snail slime.

Occasionally, solar panels may develop small brown lines on the surface, called “Snail slimebecause they give the impression that the snails have crossed the panel. Snail marks usually appear within a few years and can have multiple causes, often attributed to poor quality panels.

Flaws in these panels can allow moisture to penetrate through the backsheet, causing oxidation between the silver paste, a key material used in manufacturing, and the potting material.

This reaction causes the front of the panel to chemically degrade, reducing system performance and eventually causing premature failure. Snail slime is often associated with micro cracks and can create hot spots. Purchasing good quality panels can greatly reduce the risk of this type of problem occurring.

Potentially induced degradation.

Potential Induced Degradation, or PID, occurs due to the high voltage difference between the grounded sheet of glass and the solar cells.

When this happens, the primary power circuit can produce a partial voltage discharge, reducing performance and accelerating panel aging.

DPI usually occurs shortly after solar systems are installed and can be aggravated by long connections, high temperatures and high humidity. Fortunately, if detected early, this problem can be fixed or prevented.

Electrical problems.

Sometimes improper installation of your solar system can lead to electrical problems. Problems such as loose wires or damage to wiring caused by corrosion or oxidation can end up reducing the output of your system.

If you think your system may be affected by electrical problems, it is best to contact your installer. Attempting to fix the problem yourself will put you at unnecessary risk which your installer or a licensed electrician is trained to fix.

Investor issues.

A solar inverter converts solar energy into alternating current that you can use in your home. While the panels themselves typically last 25-30 years, inverters are somewhat less durable and typically need to be replaced every 10-15 years for string inverters and up to 25 years for micro-inverters. Be sure to have them checked if you notice a problem with your panels producing electricity during these times.

unwanted fauna.

Finally, even if you love wild animals visiting your home, sometimes they can be a nuisance to your solar system. Birds and squirrels can cause you problems. By building their nests in the space between panels and the roof, they can wreak havoc on wiring and other sensitive electronics. Solar panel protectors are a simple and effective way to protect against this problem.

Solar panels are made to last.

Photovoltaic systems are incredibly reliable and require minimal maintenance throughout their lifespan.

However, like any other electrical device, they are vulnerable to manufacturing defects and general wear and tear.

Typical repair costs for these types of problems can vary depending on the severity of the problem. If you notice any of these issues, be sure to contact your installer to have your system inspected as soon as possible.

Trusted installers and crews can greatly reduce the risk of many of these issues.

You should always perform regular checks and keep the panels free of debris, so they will provide you with clean, reliable power for decades.

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