Methods for cleaning solar panel stains in residences

Methods for cleaning solar panel stains in residences

First, preparations before cleaning

Safety assessment

Roof conditions: If the solar panels are installed on the roof, the load-bearing capacity and anti-slip performance of the roof need to be inspected. If the roof has a large slope or shows signs of aging or damage, it is recommended to contact professionals for assistance in cleaning to avoid the risk of slipping or falling.

Weather selection: Choose a sunny or cloudy day for cleaning. Avoid working under high temperatures (such as direct sunlight at noon) or extreme weather conditions (such as thunderstorms or strong winds). At high temperatures, the cleaning agent may evaporate rapidly, affecting the cleaning effect. Extreme weather poses safety risks.

Power-off operation: If the solar system is connected to the power grid, the inverter must be turned off or the DC side circuit breaker disconnected before cleaning to ensure the system is powered off and avoid the risk of electric shock.

Tool and material preparation

Cleaning tools

Soft cleaning brush: Choose a brush with soft bristles (such as a bristle brush or a dedicated photovoltaic cleaning brush) to avoid scratching the surface of the solar panel.

Rubber wiper: It is used to remove residual water after cleaning and prevent water stains from remaining.

Long-handled tools: If the solar panels are installed at a relatively high position, it is advisable to prepare cleaning tools with telescopic rods for easy operation.

Cleaning agent

Neutral detergent: Use a neutral detergent with a pH value close to 7 (such as a diluted solution of dishwashing liquid), and avoid acidic or alkaline detergents from corroding the glass or sealant.

Pure water: If the stain is light, pure water (such as distilled water or filtered tap water) can be directly used for cleaning.

Auxiliary tools

Bucket: Used for holding detergent or pure water.

Cloth: Choose a cotton or microfiber cloth with strong water absorption and no shedding for wiping edges or local stains.

Safety equipment: Wear rubber gloves and anti-slip shoes. Use safety belts and fall preventers when necessary.

Second, cleaning steps

Preliminary dust removal

Use a soft cleaning brush or a dry cloth to gently brush off loose stains such as dust and fallen leaves on the surface of the solar panel. Be careful not to press hard to prevent scratching the glass.

If there are many stains, a low-pressure water gun (such as a household spray bottle) can be used to rinse from the top of the board down, using the water flow to carry away the dust.

Apply the cleaner

Dilute the neutral detergent in a bucket according to the instructions and stir well.

Dip a soft cleaning brush in the cleaner and apply it evenly from the top of the solar panel in the same direction (such as from left to right), avoiding back-and-forth wiping to prevent the stain from spreading.

Pay special attention to cleaning the areas prone to dust accumulation such as the gaps between the frames and around the junction boxes.

Stain removal

For stubborn stains (such as bird droppings and resin), a soft brush can be used to gently scrub. If necessary, a cloth dipped in detergent can be used for local wiping.

Avoid using hard tools (such as steel wool balls) or sharp objects to scrape, to prevent scratching the glass or damaging the coating.

Rinse and dry

Rinse the solar panels from top to bottom with clean water (such as tap water) to ensure that the cleaning agent is completely removed.

Use a rubber wiper to scrape off the water from the top down to prevent water stains from remaining. If the board surface is large, it can be operated in sections.

Wipe the frame, junction box and other parts with a clean cloth to ensure there is no moisture residue.

Inspection and re-inspection

After cleaning is completed, check whether the surface of the solar panel is clean, free of stains, water marks or scratches.

Reconnect the power supply and observe whether the system is operating normally (such as the inverter indicator light and power generation monitoring data).

Third, special stain treatment methods

Oil stain

If the surface of the solar panel is stained with oil (such as kitchen fumes), it can be wiped and scrubbed several times with a neutral cleaner. If necessary, a small amount of alcohol (such as medical alcohol) can be used to assist in cleaning, but alcohol should be avoided from coming into contact with the sealant or junction box.

Bird droppings or resin

Bird droppings or resin are difficult to remove after drying. They should first be softened with clean water and then gently scrubbed with a soft brush. If it still cannot be removed, you can soak it in a special photovoltaic cleaner (which must be neutral) for a while before treatment.

Snow or ice layer

If the surface of the solar panel is covered with snow or ice, avoid hitting it with hard objects. You can gently sweep away the snow with a soft brush or wait for it to melt naturally before cleaning. If you need to accelerate the melting process, you can rinse it with warm water (not exceeding 40℃), but be sure to avoid excessive temperature differences that may cause the glass to break.

Fourth, cleaning frequency and precautions

Cleaning frequency

Adjust the cleaning frequency according to the surrounding environment of the residence (such as industrial areas, areas with frequent sand and dust) and the season. It is generally recommended to clean once every quarter. In areas with frequent sand and dust, cleaning can be done once a month.

If a significant decrease in power generation is detected (such as a reduction of more than 10% compared to historical data), it is advisable to check whether the solar panels need cleaning.

Precautions

Avoid high-temperature cleaning: At high temperatures, the cleaning agent or water evaporates too quickly, which may leave water stains or cleaning agent residues, affecting the power generation efficiency.

Prevent scratches: The surface glass of solar panels is usually specially treated. Scratches will affect the light transmittance and reduce the power generation efficiency.

Avoid stepping on: When cleaning, avoid stepping directly on the solar panels to prevent deformation or hidden cracking of the components. If you need to stand on the board surface, you should lay anti-slip MATS and distribute the pressure.

Regular inspection: When cleaning, you can also check whether the frame of the solar panel is loose, whether the sealant is aged, and whether water has entered the junction box, etc. If any problems are found, repair them in time.

Fifth, long-term maintenance suggestions

Management of the surrounding environment

Prune the trees around the solar panels to prevent branches and leaves from blocking or resin from dripping.

Regularly clean the roof drainage ditches to prevent water from flowing back under the solar panels.

Professional maintenance

Every year, contact professionals to conduct a comprehensive inspection of the solar energy system, including electrical performance, component attenuation rate, etc.

If a significant drop in component power is found (such as below 80% of the initial power), replacement or repair may be considered.