As a core facility of green city construction, solar street light not only relies on clean energy to realize lighting, but also has to withstand the test of complex outdoor environment for a long time. If we skip or simplify the testing process, it may lead to frequent problems such as insufficient brightness, interrupted range, and damaged components after installation, which not only increases the maintenance cost, but also poses a hidden danger to the safety of pedestrians and vehicles. Therefore, a set of scientific and comprehensive testing process is a key prerequisite to ensure the stable operation of solar street lights, and to determine whether the test is “perfect”, you need to first clarify the core value behind it.
solar led street lights
The core function of solar street lights is to safeguard nighttime illumination. If untested, there may be problems of insufficient brightness, uneven illumination, or sudden extinguishing, leading to “dark zones” on the road and increasing the risk of pedestrians tripping and vehicles chasing their tails. At the same time, untested circuits and batteries may also have short-circuit and leakage hazards, especially in rainy days or humid environments, which may lead to electrocution accidents. Through testing, problems such as brightness and circuit stability can be checked in advance to ensure that the street light becomes a “safety line of defense” for nighttime travel rather than a source of hidden danger.
The core advantage of solar street lights is the use of clean energy to achieve efficient lighting, but poor quality products may have low conversion efficiency of photovoltaic panels, poor battery energy storage capacity and other problems — the daytime charging is not enough, the night bright 1-2 hours on the off, or the brightness does not reach the road lighting standards, so that ” Solar lighting” is reduced to a mere decoration. Testing can verify the efficiency of PV panels and battery life through professional means, and screen out truly efficient products to ensure that solar energy resources are fully utilized, in line with the core objective of environmental protection and energy saving.
Many people mistakenly think that “no testing can save costs”, but the opposite is true. After the installation of untested street lights, frequent component failures (e.g. battery bulging, PV panel damage) may occur, requiring repeated repairs and replacements, which not only generates high labor and accessory costs, but also may lead to temporary road control due to street light shutdown, indirectly increasing management costs.
The test can be found in advance product defects, screening out durable, stable street lamps, extend the service life (quality products can be stable operation of 5-8 years), in the long run, on the contrary, can significantly reduce the overall investment costs.
Solar street lights need to be exposed to wind, rain, high temperature, cold and other complex environments for a long time – rainy weather in the south may lead to short-circuiting of un-water proofed street lights, low temperatures of minus 20 degrees Celsius in the north may make poor-quality batteries ineffective, and dust from sandstorms may also clog photovoltaic panels and affect charging. By simulating different extreme environments (e.g. IP waterproof and dust proof test, high and low temperature cycling test), the test can verify the street light’s adaptability to all kinds of outdoor conditions, ensure that it can work stably in different regions and climates, and avoid “one-off scrapping” due to the lack of adaptation to the environment.
The essence of street lights is to provide safe and even lighting, and insufficient brightness or uneven distribution will lose its core value. The testing of this indicator should be carried out in terms of “output intensity” and “coverage”. Professional tools and clear standards are used to ensure that street lights meet the lighting needs of different scenarios.
Brightness is usually measured in “lumen (lm)”, and street lights in different scenarios have clear brightness requirements, for example, main road street lights need to reach 2000-4000 lm, and neighborhood street lights need to reach 800-1500 lm. During the test, technicians will use a photometer to measure the brightness of the street light at a distance of 5 meters, 10 meters, and 15 meters, When testing, technicians will use photometers to measure the brightness at 5m, 10m and 15m away from the street light, not only to ensure that the values are in line with the standards of the corresponding scenarios, but also to avoid the waste of energy and glare caused by excessive brightness, so as to realize the lighting effect of “adequate and efficient”.
solar led street lights
Even if the brightness is up to standard, if the light distribution is uneven, there will be “near bright and far dark” or “local shadows”, which will bring safety hazards to pedestrians and vehicles. At this time, you need to use the illuminance meter and distribution photometer for testing, the specific method is in the street lights coverage area, 1 m × 1 m grid division test points, point by point measurement of illuminance (unit: lux lux), and ultimately through the data to determine whether the light is uniform. Generally speaking, the difference in illuminance of each test point of the qualified solar street light should be no more than 30%, to ensure that there is no obvious difference between light and darkness in the coverage area.
In order to clarify the test standards for different scenarios, the following table organizes the core test parameters, which can be directly used as a reference basis for testing:
| Test Item | Core Instrument | Key Standard | Applicable Scenario |
| Brightness Test | Photometer | 2000–4000 lm | Urban Main Roads |
| Brightness Test | Photometer | 800–1500 lm | Residential Walkways, Parks |
| Light Distribution Test | Illuminance Meter, Goniophotometer | Illuminance difference ≤ 30% | All Outdoor Lighting Scenarios |
Solar street lights rely on PV panels for charging during the day and on battery discharge for lighting at night, and the performance of the battery directly determines the endurance and service life of the street light. Battery testing should be centered on “capacity”, “cycle life” and “environmental adaptability” to verify the reliability of the battery under different conditions and avoid “strike” of the street light due to battery problems. Avoid “strike” of street light due to battery problem.
Battery capacity is measured in “Ampere-hour (Ah)”. For example, a 100Ah battery can theoretically deliver 10A of current continuously for 10 hours. During the test, the technician will fully charge the battery and discharge it to the lowest protection voltage at a constant current. The actual capacity is calculated by recording the discharge time and current, and the deviation of the qualified battery’s actual capacity from the labeled capacity should be no more than ±5%, which ensures that the street light can meet the lighting demand for the whole night under the state of full charge, and there will not be any power outage half way through the night.
The cycle life of a battery refers to the number of times it is “fully charged – fully discharged”, the more times means the longer service life, which effectively reduces the cost of replacing the battery later. In the routine test, technicians will simulate the daily charging and discharging process, and record the number of cycles when the battery capacity declines to 80% of the initial capacity. The cycle life of a high-quality solar street light battery should be ≥1500 times, calculated by 1 cycle per day, it can be used stably for more than 4 years, which is in line with the long-term use requirements of outdoor lighting equipment.
solar led street lights
Outdoor temperature fluctuation, high temperature in summer may lead to battery bulging and capacity decline, while low temperature in winter may lead to lower battery activity and weakened discharge capacity, so environmental adaptability test is crucial. The test mainly includes high-temperature test and low-temperature test. The high-temperature test requires the battery to be placed in a 60℃ environment for 50 times of continuous charging and discharging to observe the capacity change; the low-temperature test requires the battery to be placed in a -20℃ environment and discharged after 12 hours of static, to test the actual capacity, and the qualified battery’s capacity degradation should be ≤20% in high and low temperatures, to ensure that the battery can work stably in different climatic conditions.
PV panels are the “energy source” of solar street lights, and their conversion efficiency directly affects the charging speed and power reserve. If the conversion efficiency is low, even if there is sufficient light during the daytime, it may not be able to fully charge the batteries, resulting in insufficient lighting at night. Therefore, PV panel testing needs to focus on the two dimensions of “conversion efficiency” and “low light performance” to ensure that it can efficiently capture energy under different light conditions.
Conversion efficiency refers to the percentage of solar energy converted into electricity by a PV panel. Currently, the conversion efficiency of mainstream monocrystalline silicon PV panels ranges from 18%-23%, which is a core performance indicator in the industry. During the test, technicians will measure the output power of the PV panel under standard lighting conditions (irradiance 1000W/㎡, temperature 25℃), and then calculate the conversion efficiency by combining its area and light intensity. For example, if a 1㎡ PV panel has an output power of 200W under standard conditions, the conversion efficiency is 20%, which is necessary to ensure that the test value reaches the range of the conversion efficiency of the product labeling to avoid the problem of “false labeling”. The test value should be ensured to reach the range of conversion efficiency labeled by the product to avoid the problem of “false labeling”.
In actual use, street lights will encounter cloudy days, rainy days or early morning, evening and other low light scenes, at this time the low light performance of the PV panels is particularly important, if the power can not be generated under low light, which may lead to insufficient battery power reserves. During the test, technicians will reduce the light intensity to 200W/㎡ (about the light intensity on cloudy days) and measure the output power of the PV panels. Qualified PV panels should maintain a conversion efficiency of more than 70% of the standard conditions under low light conditions to ensure that even if there is insufficient light, a certain amount of power can be supplied to the batteries to maintain the basic lighting needs.
Solar street lights are exposed outdoors for a long time and need to withstand wind, sun, rain, dust and other losses. If the durability is insufficient, problems such as bending of poles, rupture of lampshades and rusting of components may occur, which will shorten the service life and increase the maintenance cost. Therefore, the durability test mainly focuses on “structural strength” and “component damage resistance”, verifying the overall street light and each component’s ability to resist wear and tear.
Structural strength is directly related to the safety of street lights, especially the pole and connection parts, which need to be able to withstand strong wind and accidental impact. The wind resistance test simulates a 12-level wind (wind speed 32.7m/s) and applies a horizontal force to the pole to observe whether the pole bends or breaks and whether the connection parts are loose; the impact resistance test uses a 1kg steel ball to fall freely from a height of 1 meter and hit the lampshade to observe whether the lampshade is broken or cracked. The maximum bending degree of qualified street light poles should be ≤1/500, and the lampshade should not be obviously broken after impact, so as to ensure that it can still maintain structural stability under extreme weather or accidental circumstances.
In addition to structural strength, the corrosion and aging resistance of components will also affect durability, especially metal and plastic components. Anti-corrosion test will soak metal parts such as light poles and brackets in salt spray for 48 hours, and the surface corrosion area should be ≤5% after the test, so as to avoid loosening of the structure due to rust; anti-aging test will place plastic parts (such as lamp shades and battery shells) in an ultraviolet aging box to simulate outdoor illumination for 3 years, and the parts will not be brittle or deformed after the test, so as to ensure that they can still maintain their original performance after long-term use.
Weatherability mainly measures the protection ability of street lights against dust and moisture. Dust in the outdoor environment may block the PV panels or enter the interior to affect the circuitry, while rainwater may lead to a short circuit, so weatherability is an important guarantee for the stable operation of street lights. The core standard is “IP (Ingress Protection) Protection Grade”, IP grade consists of two digits, the first represents the dust proof grade, the second represents the waterproof grade, which needs to be verified by professional test to verify the actual protection ability.
The two digits of the IP rating each have a clear meaning. The first digit (dust protection) ranges from 0 to 6, with 0 being unprotected and 6 being completely dust-proof (no dust ingress). The second digit (waterproof) from 0 to 8, 0 for unprotected, 5 for anti-low-pressure water spray (can withstand any direction of low-pressure water flow), 6 for anti-power water spray (can withstand any direction of the power of water flow). For solar street lights, considering the complex outdoor environment, the minimum IP65 rating is required, and if installed in rainy and dusty areas, it is recommended to choose IP67 rating for stronger protection.
The waterproof test method is to use a nozzle with a diameter of 6.3mm to spray water in all directions of the street light for 3 minutes at a flow rate of 12.5L/min at a distance of 3 meters, and the dust proof test method is to put the street light into a dust box for 8 hours, and the interior should be free of dust after the test. This grade is applicable to ordinary city roads, neighborhoods and other scenes.
For IP67 level, the dust proof test method is the same as IP65 level, the same need to put the street light in the dust box for 8 hours and no dust inside after the test; the waterproof test method is to completely immerse the street light in 1 meter deep water for 30 minutes, and after the test, it is required that there is no water inside, and the level is applicable to rainy areas, roads near water sources and other scenes.
A perfect set of solar street light test is not a single index “pass”, but the brightness, battery, photovoltaic panel, durability, weather resistance 5 indicators of the “full compliance”, behind it is the multiple guarantees for safety, efficiency, cost, reliability. Only through such tests can we ensure that solar street lights, after installation, can meet the needs of safe lighting, but also long-term stable operation, reduce the cost of maintenance in the later stages, and really help the green and sustainable development of the city.
