A Complete Guide to Cleaning Solar Street Lights

As a benchmark product in the field of new energy lighting, solar street lights achieve energy circulation through the photoelectric conversion of photovoltaic panels: when sunlight shines on the photovoltaic panels, the semiconductor material absorbs photons to generate electron-hole pairs, which form direct current under the action of the PN junction electric field. After optimization by the controller, it is stored in the battery to provide stable power for the LED lights at night. This zero-carbon emission and renewable energy supply model makes solar street lights the preferred solution for smart city construction and rural lighting projects.

The conversion efficiency of photovoltaic panels is negatively correlated with the degree of contamination on their surface area. According to the measured data of the photovoltaic industry:

Mild ash accumulation (≤5g/m²) can lead to a 3% to 5% loss in power generation efficiency.

Moderate pollution (such as bird droppings and tree SAP) can cause local hot spot effects, with efficiency dropping by 15% to 25%.

The efficiency of the board surface that has not been cleaned for a long time (with a dust accumulation thickness greater than 0.1mm) can decline by more than 30%.

This efficiency decline will create a vicious cycle: insufficient charging causes the battery to remain in a state of undercharging for a long time, accelerating the sulfation of the plates, and ultimately reducing the lighting time of solar street lights by 40% to 60%, seriously affecting road safety.

The Best Time and Frequency for Cleaning Solar Street Lights

When is the Best Time to Clean Solar Street Lights?

The choice of cleaning timing directly affects the cleaning effect and operational safety. It is preferred to clean in the morning or evening. At this time, the temperature of the solar panels is relatively low, and the cleaning water will not evaporate quickly, which can prevent water stains from remaining and forming water marks, ensuring the cleaning effect.

Cleaning must be strictly avoided during hot midday or strong wind weather. At high temperatures, the glass of photovoltaic panels is at a relatively high temperature. Watering at this time can easily cause thermal stress, leading to glass breakage. Strong wind weather will increase the safety risks of high-altitude operations and may also cause cleaning tools to lose control and scratch photovoltaic panels.

Suggested Cleaning Frequency for Solar Street Lights (Based on Environmental Differences)

The dust accumulation rate of solar street lights varies greatly in different environments, and the cleaning frequency needs to be determined specifically. The following are frequency suggestions based on industry practice:

Solar Street Light Cleaning Tools and Material Selection

Recommended Cleaning Tools

The core of choosing cleaning tools is "soft, non-damaging and easy to operate", to avoid causing damage to the glass and surface coating of photovoltaic panels. The specific recommended tools are as follows

• Soft-bristled brushes or sponges: Prefer soft-bristled brushes (such as wool brushes) or sponges to gently remove surface dust and minor stains, avoiding scratching the glass. It is recommended to use professional photovoltaic panel cleaning brushes.
• Soft cloth or professional cleaning cloth: For wiping off residual water stains in the later stage of cleaning, it is recommended to choose a microfiber cleaning cloth, which has strong adsorption and will not shed fibers. Avoid using rough ordinary cloths.
• Long-handled cleaning pole: For solar street lights installed at heights, using a long-handled cleaning pole can avoid high-altitude operations and enhance operational safety. It is recommended to choose a telescopic pole body to meet different height requirements.
• Low-pressure water source (such as hose) : It is used for the initial flushing of loose impurities. The solar street lightmanufacturer reminds that low-pressure water flow should be used to avoid high-pressure impact damaging the sealing structure of the photovoltaic panel.

Suggestions for Choosing Cleaning Agents

The selection of cleaning agents should follow the principle of "neutral and mild". Solar street light manufacturers recommend using a neutral pH value (6-8) cleaner or a small amount of mild detergent (such as neutral dishwashing liquid), which can be diluted and used to effectively remove stains.

The use of strong acid and strong alkali cleaners (such as hydrochloric acid and caustic soda solution) must be strictly prohibited. These substances can corrode the anti-reflective coating and sealant on the surface of photovoltaic panels, causing damage to the equipment. At the same time, the use of high-pressure water guns is strictly prohibited. High-pressure water flow can damage the sealing performance of photovoltaic panels and cause internal water ingress faults.

Detailed Cleaning Steps for Solar Street Lights

The correct cleaning method can not only extend the service life of solar street lights but also ensure their efficient operation. By following the standardized procedures below, both cleaning effectiveness and equipment protection can be achieved

Step 1: Safety Power-off and Protective Preparations ‌

Before starting the operation, the power supply of the solar street light system must be cut off, including disconnecting the battery from the controller to completely eliminate the risk of electric shock.

When working at heights, a safety helmet must be worn, a safety rope should be fastened, and it is necessary to ensure that the working platform is stable. It is recommended that two people work together, with one person operating and the other supervising.

Step 2: Low-pressure Pre-flushing for Dust Removal ‌

Use a low-pressure hose (pressure ≤0.3MPa) to slowly flush from the top of the photovoltaic panel downward to remove loose impurities such as surface dust and fallen leaves.

Focus on controlling the water flow Angle to avoid direct impact on the edge sealing strips of the photovoltaic panels and prevent water from seeping into the internal circuits.

Step 3: Deep Clean ‌with Neutral Detergent

Dilute the neutral cleaner at a ratio of 1:50 and then wipe it unidirectionally along the texture of the photovoltaic panel with a soft-bristled brush or a microfiber sponge.

For stubborn stains, the "dot application method" can be used: directly apply the cleaner to the stained area, leave it for 2 minutes, and then gently brush it. The use of hard tools such as steel wool balls is strictly prohibited.

Step 4: Secondary Rinsing and Natural Drying ‌

Immediately rinse thoroughly with low-pressure clean water after cleaning to ensure no detergent residue remains. When rinsing, keep the water flow at a 45° Angle to the board surface.

During the natural drying period, avoid manual wiping. In high-temperature weather (> 35℃), it is recommended to carry out the operation in the early morning or evening to prevent water stains from crystallizing.

Special Circumstances of Solar Street Lights and Common Dirt Treatment Methods

Deal with Stubborn Stains Such as Bird Droppings and Oil Stains

Stubborn stains such as bird droppings and oil stains have strong adhesion and some are corrosive, so they need to be dealt with promptly. When dealing with it, first soak the stained area in clean water for 1-2 minutes to soften the stain. Then, use a soft brush to dip a small amount of mild detergent and gently rub the stained area repeatedly until it is removed.

It is particularly important to note that it is strictly prohibited to use hard objects such as blades and steel wool balls to scrape off stains. Such items can severely scratch the glass of photovoltaic panels, damage the surface coating, and lead to a significant decrease in power generation efficiency.

Maintenance Strategies for High-altitude or Salt Spray Environments

In high-altitude areas, ultraviolet rays are strong, and dust accumulation is prone to drying and caking. In the salt spray environment by the seaside, salt frost is prone to adhere to the surface of photovoltaic panels and is corrosive. Special maintenance strategies need to be adopted in these two types of environments:

Shorten the cleaning cycle, conduct a comprehensive cleaning every 1-2 months, and check the surface condition of the photovoltaic panels at least once a month.

When cleaning, pay special attention to inspecting the sealant at the edges of the photovoltaic panels. If salt frost or corrosion cracking is found, the sealant should be replaced in time to prevent water from entering and damaging the components.

Automatic and Intelligent Cleaning Solutions for Solar Street Lights

What is A Self-cleaning Solar Street Light?

For scenarios with severe dust and high manual maintenance costs (such as the edge of deserts and mining areas), solar street lights equipped with automatic cleaning devices have been launched on the market. This type of street light is equipped with an automatic brush arm or high-pressure spray system. It can be set to clean at fixed times every day or automatically start the cleaning program based on the data from the dust accumulation sensor, without the need for manual intervention.

The Advantages of Self-cleaning Solar Street Lights

• Reduce manual maintenance costs: Decrease the number of high-altitude operations, save labor and time costs, and is especially suitable for remote or large-scale installation scenarios.
• Keep photovoltaic panels clean for a long time: Regular cleaning can prevent stains from adhering for a long time and ensure that the photovoltaic panels are always in the best conversion efficiency state.
• Enhance overall system efficiency: Stable power generation efficiency can ensure the duration and brightness of lighting, extend the battery life, and improve the operational stability of the entire solar street lightsystem.

The cleaning work of solar street lights is a fundamental task for enhancing power generation efficiency and lighting performance, and it is also the key to ensuring the long-term stable operation of the equipment. The accumulation of dirt, dust and other debris not only reduces the efficiency of power generation, but also accelerates the wear and tear of equipment and increases the cost of later maintenance.

Establishing a scientific cleaning cycle (adjusting the frequency according to environmental differences) and standardized cleaning methods can effectively restore the conversion efficiency of photovoltaic panels and significantly extend the system's lifespan. For special scenarios, upgrading the automatic cleaning solution can further reduce the cost of manual maintenance and enhance the stability of system operation.

In addition, by conducting regular inspections of core components such as batteries, LED lights, and controllers, as well as pruning the surrounding shading vegetation, a complete maintenance system can be formed, which can maximize the investment value of solar street lights and provide a continuous and reliable guarantee for green lighting in both urban and rural areas.