Why is it worth entering PV cleaning? Growing market, recurring revenues, and scalable business models through modern robotic technology.
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It all comes down to the right brush
A central factor for the performance of PV cleaning is the rotational speed (rpm – “rounds per minute”), which directly affects the mechanical action. Equally important is the circumferential speed (m/s), as it describes the actual relative movement of the bristles to the module surface.
Excessive circumferential speed can accelerate bristle wear and even cause micro-damage, while insufficient speed significantly reduces cleaning effectiveness. A balanced setting is therefore crucial: lower speeds are preferable for sensitive surfaces or delicate tasks, whereas higher speeds provide more efficiency for robust surfaces.
In practice, 300 rpm for the solarROBOT compact and 400 rpm for the solarROBOT pro have proven ideal for PV cleaning robots, as they ensure both efficiency and gentle solar cleaning.
"When it comes to photovoltaic cleaning brushes, it's not just a single factor that determines the cleaning result. Bristle material, brush diameter, rotation speed, and water flow must be coordinated with each other and adapted to the respective module surface."
The brush diameter also has a major impact on cleaning performance. With the same rotational speed, a larger diameter increases the peripheral speed and provides better surface coverage. At the same time, however, the weight increases, and with it the energy requirement. In photovoltaic cleaning, typical brush diameters range between 150 mm and 300 mm—depending on the drive system and module configuration. In high-quality systems, a combination of high rotation and large diameter is deliberately chosen to thoroughly remove even stubborn soiling. For example, the large PV cleaning robot solarROBOT pro has a diameter of 300 mm, and even its smaller brother, compact, still has an impressive diameter of 280 mm.
The bristle material significantly determines the performance of a PV cleaning brush. Commonly used are:
They are the first choice for gentle yet thorough cleaning of PV modules.
They are used for robust cleaning tasks and heavier soiling.
The choice of bristle material should always depend on the degree of soiling, the module coating, and the environmental conditions.
Not only the material itself, but also the arrangement, thickness, and length of the bristles influence cleaning performance.
Dense vs. loose – dense increases the contact surface, loose improves dirt absorption.
Helix/Spiral shape – consistent results, good self-cleaning, prevents dirt accumulation, ideal for uneven or sloped surfaces.
Segmented – targeted dirt removal through higher point load.
Thick and long – different bristle thicknesses allow for a combination of abrasive and gentle cleaning. Homogeneous bristle fields ensure even load distribution and facilitate maintenance.
The optimal photovoltaic cleaning brush combines the appropriate brush diameter, the correct speed, the suitable bristle material, and a well-thought-out arrangement with effective water guidance. Only when all these factors work together harmoniously is efficient, gentle, and sustainable cleaning of solar modules possible.
If you are unsure, you should conduct a PV cleaning brush test before purchasing or seek direct advice from the manufacturer. When buying a cleaning robot, it is worth taking a close look at the installed brush system, as it significantly influences the cleaning results.
Would you like to learn more about the possibilities of a cleaning robot or our cleaning systems? Then please contact us; we would be happy to advise you!
Whether it’s an agricultural rooftop system, a commercial roof or a large solar park—the economically optimal cleaning solution depends on system size, location and degree of soiling. Together, we analyze your system and recommend the right cleaning concept.
Our cleaning solutions at a glance
solarROBOT compact
For agricultural as well as small and medium rooftop systems up to approx. 200 kWp. The cleaning robot can be used independently by the system operator and is supplied including a charging station. CE-certified and developed specifically for cost-effective in-house operation.
solarROBOT pro
For medium-sized commercial and ground-mounted systems. With a working width of up to 2 meters and semi-automated operation, the solarROBOT Pro is ideal for efficient cleaning of larger module areas.
solarROBOT ultimate
For large-scale systems and ground-mounted projects. With a working width of 2.4 meters, maintenance-free chain drive and high area performance, the solarROBOT Ultimate was developed for professional use on large PV systems.
solarBRUSH 600
The handheld cleaning solution for special constructions, complex roof geometries and professional cleaning service providers. Ideal for applications where cleaning robots cannot be used due to the design.
For agricultural as well as small and medium rooftop systems up to approx. 200 kWp. The cleaning robot can be used independently by the system operator and is supplied including a charging station. CE-certified and developed specifically for cost-effective in-house operation.
For large-scale systems and ground-mounted projects. With a working width of 2.4 meters, maintenance-free chain drive and high area performance, the solarROBOT Ultimate was developed for professional use on large PV systems.
The handheld cleaning solution for special constructions, complex roof geometries and professional cleaning service providers. Ideal for applications where cleaning robots cannot be used due to the design.
All systems clean without chemicals or soap using pure water and enable gentle, material-friendly cleaning of PV systems.
We analyze your system portfolio, calculate your individual cleaning needs and recommend the economically optimal cleaning concept—from a single system to a multi-site park.
That depends on system type, location and degree of soiling. While an individual profitability calculation is recommended for smaller systems, professional cleaning is already economically sensible after a short time for many agricultural, commercial and large ground-mounted systems.
No. Rain mainly removes loose dust particles. Stubborn soiling such as bird droppings, ammonia deposits, lichens or baked-on dust crusts often remain permanently stuck to the modules and can significantly reduce energy yield.
The optimal cleaning interval depends on location, roof pitch and surrounding conditions. Agricultural systems often benefit from two cleanings per year, while for commercial and ground-mounted systems the individual soiling situation is decisive.
Yes. Heavy soiling can promote local shading and thus cause so-called hotspots. These lead to increased temperatures in individual solar cells and can impair the performance and service life of the modules in the long term.
Documented cleaning and maintenance measures create transparency about the system condition and can serve as proof of regular maintenance in the context of servicing, operator duties or in the event of an insurance claim.
Calculate your individual yield loss with the hyCLEANER solar loss calculator.
We recommend the economically right cleaning concept for your system.
Why is it worth entering PV cleaning? Growing market, recurring revenues, and scalable business models through modern robotic technology.
How much does a dirty solar system cost? Example calculations for agriculture, commercial roofs and ground-mounted systems – incl. yield losses and cleaning intervals.
Photovoltaic expert Pascal Kierstein explains the most common defects in commercial PV systems and shows how operators can prevent damage.