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How to Clean Solar Panels

Author: Amy Hambleton
October 23, 2018
In this article, we’ll explain how to clean your solar panels and how often you should do it.

The solar panels’ performance is entirely related to a set of environmental factors: solar radiation, humidity, temperature, shade, wind speed and more.

Another element that deeply influences the performance of an array is soiling. Soiling loss factor is associated with losses due to dust, dirt, sandstorms, bird droppings and smog.

Depending on the region where the solar PV system is installed the soiling loss factor will vary, mainly depending on the amount of dust in that location.

In Australia, we have many regions with deserts, sand and dust. These fine particles adhere to the solar module frame and glass, making it less efficient and therefore, producing less energy.

As an example, below you can see the I/V curve of the system and the MPP before and after cleaning the modules. The reduction in power output is noticeable.


I:V Curve Clean Solar Panels

We are talking about a reduction of nearly 30% output in this case, which is way too much.

Although this study was made to find out the impact of soiling on the modules’ power output, the usual reduction expected for soiling can vary from 1% to 10 % annually.

This is why cleaning your solar panels is crucial!

Here we will tell you some basic tips to do the cleaning easier and better!


You might also like: This is How to Turn Your Solar PV System ON and OFF


Solar Maintenance Procedure

There are two main phases during the maintenance of solar modules: inspection and cleaning.


1. Inspection

During the inspection phase, it is necessary to follow these steps:

  1. Verify that every module is in good condition and that there is no sign of any damage on the glass surface.
  2. Make sure your modules are not being shaded by new objects that were not considered during the design phase (check that with your solar installer at the moment you install the system).
  3. Verify that no sharp objects are in contact with the surface of the modules.
  4. Check for any sign of burns on the backs of the panels or on the PV cables.
  5. Ensure the mounting system is well-adjusted to the modules.
  6. Look for any signs of corrosion on the frames or in the cells.
  7. Check if the wiring behind and towards the combiner box is in good state condition (no sign of damage due to rodents’ bites, corrosion, heat or humidity)

Once you ensure that all these aspects are checked, then you can move onto the cleaning phase. If any of these elements are present in the installation, you must call your solar installer for assistance before cleaning.


2. Cleaning

The cleaning phase must take into account the following considerations:

  1. First and most importantly, before even looking for a sponge, disconnect the solar array by turning off the switch on the combiner box. It is crucial for your safety to do so.
  2. Use a dry or wet sponge to do the cleaning of the panels.
  3. Use deionized water to wet the sponge. You must not use water with a high mineral content since those particles will adhere to the glass, becoming a focus of humidity or dirt.
  4. Never use a high-pressure hose to clean the modules.
  5. Try to avoid considerable temperature differences between the water that you use to clean the modules and the temperature of the panel.
  6. Never use an abrasive or chemical material to clean the modules.
  7. Never, EVER clean a solar module with broken glass or with signs of exposed wires. This is dangerous and could lead to an electric shock hazard.


How Often You Should Clean Solar Panels

When you choose to clean your solar panels, it is advisable to do it during early morning (6:00 am) or late afternoon (5:00 pm).

This will reduce the possibility of electrical shock hazard, will reduce the energy output that you lose during the maintenance procedures and will also make the manipulation of the modules even easier since the temperature on them will be much lower (panels can reach temperatures of up to 70 ºC or more, so they can get pretty hot!)

The right maintenance schedule for PV modules should be once every 6-12 months.


The maintenance of solar panels involves two main phases: inspection and cleaning.

Within the inspection phase, it is crucial to check for damage, burns or mechanical instability in the PV system. During the cleaning phase, it is essential to turn off the DC switch on the combiner box and use deionized water to clean your modules.

It is also advisable that at least two people be present during the maintenance.

Your solar installer will design the system with a ground wire connected to the aluminium frames of the PV modules to eliminate the possibility of shock hazards when touching the frames, so you can be confident to touch the modules.

However, never forget that PV panels will still be generating electricity, so be careful not to touch any exposed surface.

Next Step

If you want to see how much solar or battery storage could save you over the next 5 years, then take our solar saving calculator quiz below!

Or talk to an Instyle Solar expert about the best solutions for home energy storage or PV-panels.

Otherwise, head back to the solar blog to find even more great educational content.

Photo credit: Depositphotos
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