The importance of cleaning dirt from photovoltaic panels

Photovoltaic energy has long been one of the most efficient and cheapest on the market. Although its maintenance is simple, to guarantee the effectiveness and good performance of photovoltaic cells it is essential to carry out periodic cleaning that, in addition, will extend their useful life. We explain how to clean solar panels so that you can keep your solar self-consumption installation in the best condition.

Dust on photovoltaic panels, a silent enemy

Anyone who has owned solar panels has probably been through this at some point. One week without any warning, the energy efficiency of the solar panels decreases significantly. And it doesn't go back up. What's going on? Have the panels broken? Probably not, it will probably be dust accumulated on the surface of the panel, perhaps as a result of a storm that has carried sand, sediment, or dust, or it could just be pollution. This is something that happens frequently, especially if the panels are not tilted very much.

The result in any case is the same: Photovoltaic panels covered with a thin (though sometimes not so thin) layer of dust. This prevents photons from the sun from hitting the photovoltaic cell, which in turn is unable to complete its function of capturing them. It will generally be enough to clean the dust from the panels once a year at most, although in places with frequent rainfall this may not even be necessary.

Bird droppings can corrode components

Birds can dirty solar panels. They will rarely land on them if they can avoid it, and they will not nest on their surface either, but it is likely that from time to time some excrement may fall on the cells, and in this case it is advisable to remove it as soon as possible because it can be corrosive.

Animal droppings contain a remarkable mixture of elements, and many of them can react with the top layers of photovoltaic cells or with the adhesives and protective coatings usually present in these components. And if we don't clean it, the excrement can damage the panel.

Leaves and other debris that can accumulate on photovoltaic panels

It is not too common unless the panels are almost horizontal or the leaves are sticky, but sometimes the leaves get attached or stuck to the panels. It is also possible for seeds or even other organic plant debris blown by the wind to get trapped.

When should they be removed? When we see them and we can access the photovoltaic panels. These debris do not necessarily pose an immediate threat, but they present a surface on which other sediments can settle. Even animals such as worms or spiders may use these elements to build nests. And that can deteriorate the panel in the long run.

How should photovoltaic modules be cleaned?

To clean the solar panels with a view to maximising their useful life, there are certain steps you can take, as detailed below. Please remember that we are only talking about their cleaning, we will not getting involved in the complete maintenance of the panels, cables or inverters.

Step 1. Safety for Cleaning Solar Panels

When cleaning the panels, the first thing to do is to disconnect the circuit that connects the panel to the house or the rest of the electrical system, so you can work safely and without electricity. And if the panels are at a height, you will need to anchor oneself, use a helmet and specialised equipment, or directly call a specialised service if you see that the job is too complex.

Step 2. Remove Large Objects

Once you have safe access to the solar panels, you can remove any large debris such as leaves, bird droppings and other elements that are easy to take with your hands.

We must pay attention to those elements that can break into pieces or break easily, such as clods of earth, and be especially careful with those elements that can compromise our safety, such as wasp or bee nests.

Step 3. Blow air over the surface

Now you need to remove as much dust from the surface as you can, without rubbing it. At this point, you should avoid moving the dirt with a cloth so as not to scratch the cells. Alternatively, it is better to blow with a bellows or even a hairdryer in the heat-free mode. What we are looking for is to remove solid debris from the surface in a simple and non-invasive way. Like dusting a delicate object.

Step 4. Rinse the panels with water

You can use a hose or a bucket of water, and pour water from above on the photovoltaic cells as if it were rain. You should avoiding high pressure at all costs, so you should not use a Karcher-type pistol. The reason? The panels have joints filled with a sealant and this could be removed by pressure.

An important point is to avoid using cold water solar to clean solar panels that have been in the sun in hot weather. Pouring water at 20°C on top of a module that is around 50°C subjects it to thermal stress that can fracture the module.

Step 5. Gently clean the panels with a soft-bristled brush

There are a number of products on the market for cleaning photovoltaic panels, although it is advisable to read the instructions for each module because the manufacturer could recommend or advise against using a certain product. In principle, there are no problems or contraindications to the use of soapy mixtures.

Of course, when scrubbing it is advisable to use a soft-bristled brush and not exert too much pressure. If the brush bristles scrape away the adhesives that hold the cells together, they could affect the integrity of the panel in the long run.

Step 6. Rinsing the panel

Again, use water without pressure to clean the remains of soap or the cleaning product chosen. This point is very important because a patina of soap for a whole year could damage the panel. It's a good idea to look closely at each cell to see the finish and go over the rinsing if necessary.