What Are The Aging Test Standards For LED Street Lights?

LED street lights serve as the core lighting equipment for urban roadways and rural illumination projects. Their long-term performance stability directly impacts nighttime travel safety and project operational costs. Aging test standards, as the primary basis for measuring product durability, encompass critical dimensions such as lumen maintenance, color retention, and thermal management. These standards provide essential references for manufacturers to optimize designs and for procurement parties to make informed selections.

Definition and Value of LED Street Light Aging Tests

What is LED Street Light Aging Testing?

LED street light aging testing involves simulating real outdoor conditions—such as temperature fluctuations, humidity variations, and continuous operation—to conduct long-term performance evaluations. This process monitors how key parameters change over time, thereby assessing the product's stability throughout its specified lifespan.

Unlike standard LED product testing, street light applications present unique challenges. They endure prolonged exposure to harsh outdoor conditions—including wind, rain, dust, UV radiation, and daily temperature fluctuations—while typically operating for 10–12 hours daily. Consequently, aging test standards prioritize “extreme environment adaptability” and “long-term stability,” forming the core requirements for solar street light durability testing.

Core Purpose of Aging Tests

The core value of aging tests lies in predicting product performance degradation trends to ensure quality, manifested in three aspects: First, verifying product reliability to guarantee core performance remains stable without significant decline throughout the specified lifespan (typically 5-10 years). Second, mitigating usage risks by preventing safety hazards in road lighting caused by issues like insufficient brightness or color distortion after prolonged use. Third, it provides quality evidence, offering objective data support for manufacturers to optimize product design and for purchasers to implement LED street light selection standards.

Key Standards for LED Street Light Aging Tests

Luminous Flux Maintenance Standard

Luminous flux maintenance refers to a street light's ability to retain its initial brightness during prolonged operation. It serves as the core metric for assessing the longevity of lighting performance and is the central evaluation focus in luminous flux maintenance tests for solar-powered LED street lights. Excessively rapid brightness decay directly reduces road visibility, increasing risks during nighttime travel.

Core Test Metrics and Evaluation Criteria

The industry commonly uses the “luminous flux maintenance rate after a specified operating period” as the evaluation basis. Common test durations and standard requirements are shown in the table below. Luminous flux maintenance testing must be conducted in laboratories simulating outdoor environments. The 5000-hour aging test for LED street lights is a critical milestone for preliminary verification of short-term product stability.

The specific process involves placing the luminaire in an environment with specified temperature (typically 25°C ± 2°C) and humidity (50% ± 5%). The luminaire is continuously illuminated at rated voltage and power, with luminous flux measurements taken every 1000 hours. Calculate the lumen maintenance rate at different time intervals (Maintenance Rate = Measured Luminous Flux / Initial Luminous Flux × 100%) to determine compliance with standard requirements.

Color Retention Standard

The color retention capability of LED solar street lights refers to their stability in maintaining initial light color (color temperature and color rendering) during long-term operation. Compliance with this metric directly correlates with the results of street light color temperature stability and Color Rendering Index (CRI) testing. Light color distortion not only compromises visual comfort but may also cause drivers to misjudge the colors of traffic signs and obstacles, potentially leading to safety incidents.

Core Evaluation Metrics

Color maintenance testing centers on two core metrics:

First, the Color Rendering Index (CRI) measures an LED's ability to reproduce true object colors. Ranging from 0 to 100, higher values indicate superior color rendering. LED street light CRI testing explicitly requires CRI ≥ 70 for road lighting applications, with premium products achieving CRI ≥ 80.

Second is color temperature stability. Conventional LED solar street lights operate within a color temperature range of 3000K-6000K. Testing standards mandate that color temperature deviation after prolonged operation must not exceed ±300K, preventing undesirable “yellowish” or “bluish” color shifts. Color maintenance testing is conducted concurrently with lumen maintenance testing. At specific operational milestones (e.g., 5000 hours, 10000 hours), a spectrophotometer measures CRI and color temperature values. After 10000 hours of operation, compliance with color maintenance standards is confirmed if CRI degradation does not exceed 10% of the initial value and color temperature deviation remains within ±300K.

Thermal Management Aging Standards

Solar street lights generate significant heat during operation. Insufficient heat dissipation can elevate LED junction temperatures, accelerating lumen depreciation, shortening lifespan, and potentially causing circuit failures. Therefore, thermal management testing is a critical component in evaluating LED street light durability and ensuring long-term stable operation.

Core Test Metrics

The core metrics, corresponding requirements, and testing procedures for thermal management aging are outlined below. Key metrics include maximum junction temperature, temperature rise rate, and thermal equilibrium stability. For maximum junction temperature, the permissible upper limit for LED chips is typically 125°C. Testing requires that after prolonged operation, the chip junction temperature does not exceed 110°C.

The temperature rise rate requires that, when illuminated at rated power, the LED temperature should rise from room temperature to a stable temperature within ≤30 minutes, with post-stabilization temperature fluctuations not exceeding ±2℃. Thermal equilibrium stability requires that after continuous illumination for 1000 hours, the thermal efficiency of the dissipation system should not degrade by more than 5%.

The corresponding test procedure simulates outdoor high-temperature conditions. Specifically, the LED street light is placed in a high-temperature laboratory with an ambient temperature set to 45°C ± 2°C (simulating summer outdoor heat). It is continuously illuminated at rated power while thermocouple sensors monitor the LED junction temperature and heat sink surface temperature in real time. Heat dissipation efficiency is tested every 2000 hours to evaluate the long-term stability of the thermal management system.
 

Supplementary Aging Standards

Environmental Adaptability Aging Test

This test addresses harsh outdoor conditions including wind, rain, dust, and UV exposure, comprising two core requirements. The IP65 waterproof and dustproof test requires the luminaire to operate continuously for 1000 hours under spray and dust conditions per IP65 standards, ensuring no water ingress or dust penetration.

UV resistance testing requires exposing the luminaire housing and lens to 500 hours of irradiation in a UV aging chamber. This verifies the luminaire's sealing integrity, corrosion resistance, and UV protection by ensuring no cracking, discoloration, or brittle aging occurs.

Electrical Performance Stability Testing

Electrical performance stability testing focuses on power safety and parameter consistency during long-term operation, serving as the core component of solar LED street light electrical aging tests. Specific requirements encompass voltage fluctuation adaptability and power stability. Voltage fluctuation adaptability mandates that the street light illuminates normally without flickering or extinguishing when voltage fluctuates within ±10% of the rated voltage. Power stability requires that after 10,000 hours of operation, the deviation between actual power and rated power does not exceed ±5%, ensuring stable operation even in complex grid environments.

FAQ

How Long Does LED Street Light Aging Testing Typically Take?

Standard aging tests last 10,000 hours (approximately 14 months), sufficient for evaluating a 5-year service life. To validate a 10-year lifespan, testing must be extended to 20,000 hours (approximately 28 months). To enhance testing efficiency, the industry now widely employs accelerated aging techniques for LED street lights (e.g., elevated ambient temperatures or increased power levels). This can reduce testing duration to 3-6 months. However, it is crucial to ensure the accelerated conditions correlate with actual operating environments to prevent distorted test results.

Can Products That Pass Aging Tests Guarantee The Expected Lifespan?

Not necessarily. Aging tests are conducted in simulated environments, while actual usage conditions may be more complex and affect the product's real-world lifespan. However, products that pass rigorous aging tests have demonstrated verified performance stability, making them far more likely to meet LED street light lifespan assessment standards than those that fail testing.

What Is The Relationship Between Aging Test Standards And The Lifespan Of LED Street Lights?

Aging test standards form the core basis for assessing LED street light lifespan. For instance, industry-standard requirements stipulate a luminous flux maintenance rate ≥80% after 10,000 hours, corresponding to a 5-year lifespan. A rate ≥70% after 20,000 hours corresponds to a 10-year lifespan. Simply put, longer and more stringent aging test durations correlate with extended expected product lifespans.

LED street light aging test standards serve as the core guidelines for ensuring product performance, lighting safety, and service life. Key dimensions covered—such as lumen maintenance and thermal management testing—precisely align with the unique demands of outdoor lighting scenarios. Both manufacturers and purchasers should prioritize this standard's guidance. By integrating LED street light selection criteria with actual project environments, they should prioritize solar LED street lights that pass comprehensive aging tests—including IP65 waterproof/dust proof testing and UV resistance testing. This approach drives product quality improvement and healthy industry development, ensuring a balance between lighting performance and operational efficiency.