Solar panels are a reliable way to generate electricity more sustainably. And with climate change at the forefront of our minds, it’s no surprise that more and more people are opting for clean, renewable energy sources like solar. But nothing is perfect, and owners may occasionally find themselves dealing with issues. Here, we look at some of the most common solar panel problems and how to fix them.


It’s natural for debris to collect on any structure or object that’s outdoors, and solar panels are no exception. The type of debris will vary depending on where you live in the UK.

  • In a city: pollution, especially from traffic
  • Near the coast: salt or seagull droppings
  • Near a river or wetland: algae, mould or mildew
  • Near a forest or wooded area: dead leaves

However, it’s important to keep this from building up, as too much dirt can make it more difficult for sunlight to be absorbed and reduce the efficiency of the panels. Luckily, a rain shower is often enough to remove most debris. In addition, the majority of solar panels in the UK are self-cleaning, with a coating that helps the rain droplets to remove dirt as they roll off, without depositing any minerals.

You may need to get further cleaning done if there’s a thick layer or one panel is more badly affected than the others. This can be done with water and a soft brush or broom, but never with any detergent. Detergent can leave a film behind, which acts as a sticky surface to attract more dirt and means less sunlight can be absorbed. It’s best to hire a professional who has experience with solar panels as they’ll know exactly how to clean and maintain them, plus it can be dangerous to climb on the roof yourself.

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Snail trails

Despite the name, snail trails aren’t caused by actual snails. These trails are brown lines which make it look like a snail has crossed the panels, and they’re caused by defective silver paste used in the manufacturing process. This causes moisture production, which in turn causes oxidation. The effects of this travel from the back of the panel to the front, where the brown lines appear.

They can have a detrimental effect on panels, reducing the amount of electricity they produce, and can also cause physical damage if they build up too much.

Snail trails can appear a few years after the panels are installed. They can be prevented with regular cleaning and inspection of the panels to make sure they’re clear and undamaged.

Animals and birds

Birds and animals such as rodents and squirrels may find their way on to your solar panels and build nests underneath them. This reduces solar panel efficiency. Their mess, droppings, scratching and, in the case of birds, pecking can cause damage to the panels and even the wiring. The droppings in particular can cause a green algae to form, which must be removed by a professional.

Ask a professional to attach barriers to the panels so it’s impossible for animals or birds to get underneath them.

If you don’t have panels yet but are looking to get them installed, you could get them built into the roof (known as roof-integrated panels) so animals and birds don’t have a space to squeeze through.

Inverter issues

Solar inverters are an important part of the solar panel set-up. They take the direct current (DC) which the panels absorb and convert it into an alternate current (AC), which provides the power for your property. The DC is too powerful for a lot of home appliances, so converting it makes it safer. Inverters also ensure that as much electricity as possible is used and not wasted.

If elements of the inverter fail, they can leave you unable to use the electricity generated for your home. If your inverter is showing an error message:

  • Refer to the manual, which should be able to tell you what the error message means.
  • Check if the inverter is still within warranty.
  • If so, check the terms before taking any action so you don’t invalidate the warranty. Contact the manufacturer for advice and information, and to arrange a repair or replacement if needed.
  • If the inverter isn’t within warranty, contact the manufacturer so they can advise you on whether it can be repaired or if you need a replacement.

While it’s true that solar inverters don’t have as long a lifespan as solar panels, there are still things you can do to help your inverter last as long as possible.

  • Choose an inverter which can handle the voltage requirements of your property.
  • Make sure standalone inverters are installed away from damp or warm environments. (A good engineer will keep this in mind.)
  • Check the battery regularly to make sure it’s in good condition.
  • Don’t immediately jump to the conclusion you need to replace the whole inverter if it stops working. Chances are it’s one part that needs to be replaced. Contact the supplier who originally installed it, as they’re in the best position to assess this.

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Weather conditions

While solar panels are built to withstand everyday weather, they may be damaged by more extreme conditions like thunderstorms, very high humidity, high winds, heavy snow and hail. This sort of weather can lead to:

  • High-voltage surges. A high-voltage surge occurs when the voltage increases by 10% or more than the normal mains supply. These can happen during thunderstorms and are the result of an indirect lightning strike. Direct lightning strikes are more rare. High-voltage surges speed up wear and tear of panels.
  • Damage from flying debris. Most solar panels are built to withstand winds of up to 120 mph, so the high winds themselves are normally a problem. However, the debris that these winds pick up can smash into the panels, breaking them or reducing their efficiency.  
  • Microcracks. Microcracks are tiny cracks on a solar panel. Left too long, they can become larger cracks which affect the efficiency of the panel. They can also be caused by poor handling during the installation process, which is why it’s so important to choose a trusted supplier. Manufacturers are trying to develop technology which reduces the chance of microcracks occurring.

Solar panel insurance

Solar panel insurance protects your system from a number of issues (but not normally accidental damage). It’s usually included in your home insurance policy. Make sure you notify your home insurance provider once your solar panel system has been installed, or you may invalidate your policy.

When it comes to common solar panel problems, prevention is better than cure. Make sure you hire a reputable professional who can install your solar panels securely. It’s also worth getting a regular inspection so an expert can check the panels are connected and working as they should be. At Otovo we only work with trusted, certified installers, who are audited to ensure they maintain high standards.

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