How to Test Solar Road Studs Waterproof Performance?

Among road traffic safety facilities, solar-powered road studs play a crucial role in guiding and warning vehicles at night. Whether it is urban main roads, expressways, mountain roads or tunnel entrances and exits, solar-powered road studs need to be exposed to the outdoor environment for a long time.

Natural conditions such as rain erosion, water accumulation and melting of ice and snow will directly test the sealing ability of road studs. Once the waterproofing fails and water seeps into the interior, it may cause the LED lights to go out and the battery life to be shortened at best, and at worst, it may lead to a short circuit in the circuit board and the complete scrapping of the road studs. What's more serious is that the malfunction of road studs can cause unclear road signs at night, increasing the risk of traffic accidents.

Therefore, professional waterproof performance testing is not an "additional process" for manufacturers, but a core link to ensure the service life of solar-powered road studs and road safety. Among them, the IP68 protection level is currently recognized as the core standard in the industry. However, merely meeting IP68 is not enough - a complete waterproof test must cover multiple dimensions such as "short-term immersion, long-term verification, and adaptation to extreme environments" in order to truly screen out qualified products.

Solar Road Studs Waterproof Testing Method

The waterproof test of solar road studs essentially involves artificially simulating different water environments to verify the reliability of their sealing structure. Among them, "immersion test" is the most fundamental and crucial method. According to the test intensity, it can be divided into two categories: "IP68 standard test" and "long-term immersion test".
 

IP68 Standard Waterproof Test

IP68 is one of the highest levels in the "Enclosure Protection Class (IP Code)". The number "6" indicates complete dust resistance, and "8" means "it can still operate normally after being immersed in water for a long time under specified pressure". However, the IP68 test parameters of different manufacturers vary. It is necessary to clarify the specific standards to ensure the validity of the test.
 

The core parameter differences in IP68 testing

Different solar road stud manufacturers have slightly different standards for IP68, mainly reflected in "immersion depth" and "duration". The specific differences are shown in the following table:

The specific operation process of IP68 testing

Professional IP68 testing is not simply "soaking in water". It requires following strict operating procedures to ensure the accuracy of the test results:
 

Preparations before testing: Inspect the appearance of the solar-powered road studs to ensure that the outer shell has no cracks and the interfaces are not loose. Power on the road studs and confirm that the LED lights and solar panels are in normal working condition (to avoid misjudging the cause of the fault after testing).

Water environment control: Use normal temperature clear water (20-25℃), and avoid using sewage or liquids containing corrosive substances to prevent affecting the test results. If the test depth exceeds 2 meters, a professional water tank with pressure monitoring should be used to record the water pressure data in real time.

Road stud fixation: Fully immerse the road studs in water and fix them through brackets to prevent them from floating or touching the water tank wall (to avoid uneven pressure on local seals and false water seepage).

Soaking and observation: Continuously soak for the set time. During this period, observe the water surface every 5 minutes for any bubbles (bubbles may indicate seal failure and air leakage).

Preliminary inspection after testing: After the soaking is completed, remove the solar road studs and dry the surface. Immediately observe whether there are any water droplets remaining at key parts such as the shell interface and cable entry and exit.
 

Long-term Immersion Test

The IP68 standard test is a "short-term verification", while the long-term immersion test is aimed at "continuous water accumulation" scenarios - such as prolonged water accumulation on roads during the rainy season and condensation water accumulation in tunnels. In such scenarios, solar-powered road studs may need to be in a humid environment for several consecutive days.
 

A typical solution for long-term immersion testing

• Test duration: 7 days (simulating road waterlogging caused by continuous rainfall for a week).
• Immersion depth: 1.5 meters (the maximum water depth covering most roads).
• Water quality control: Use a solution that simulates rainwater (with a small amount of minerals added, approaching the pH level of natural rainwater).
• Daily observation: Check once at 9 a.m. and once at 5 p.m. every day, and record whether there is any surface water seepage or abnormal flashing of LED lights on the road studs.
• Mid-term inspection: On the third day, remove the road studs, cut off the power, disassemble the casing (only open the non-sealed critical parts), check if there is any moisture inside. After confirming there are no problems, reassemble and continue to soak.

The significance of long-term immersion testing

Short-term soaking may not expose the problem of "slow water seepage" - for instance, there are tiny gaps in the sealing strip, and water is difficult to seep in in the short term, but after long-term soaking, water will gradually seep into the interior.
 

Once, a batch of solar led road studs passed the IP68 test for 1 meter and 30 minutes. However, on the fifth day of the long-term immersion test, 20% of the circuit boards of the road studs were slightly damp, resulting in a 30% reduction in LED brightness. If such road studs are put into direct use, they are very likely to fail within 1 to 2 months during the rainy season.

Check the Solar Road Studs After Testing

After the immersion test is completed, it cannot be judged as qualified merely based on "no water seepage on the surface" - it is necessary to conduct "visual inspection" and "functional inspection" to comprehensively verify whether the interior of the solar road studs is damaged and ensure that they can still work normally.
 

Visual Inspection

The core of the visual inspection is "disassembly verification", which must be completed within one hour after the test (to avoid the disappearance of marks due to water evaporation), with a focus on the condition of the internal key components.
 

Standards for appearance inspection of key components

The inspection methods and qualification standards for different components vary, as detailed in the following table:

Precautions for visual inspection

Disassembly sequence: It is necessary to operate in accordance with the disassembly steps specified by the manufacturer to avoid violent disassembly that may damage the sealing structure (for example, remove the screws first, then slowly separate the shell, and do not directly pry the interface).
 

Humidity detection: If conditions permit, a portable hygrometer can be used to measure the internal air humidity. Under normal circumstances, it should be consistent with the ambient humidity (with a difference not exceeding 5%). If the humidity exceeds the standard, it indicates that there is hidden water seepage.

Marking record: Mark the non-conforming road studs, record the "non-conforming components" and "problem phenomena", which is convenient for subsequent analysis of the cause of seal failure (such as aging of the rubber strip or misalignment of the interface).
 

Solar Road Studs Functional Inspection

A qualified appearance only indicates "no visible damage". Functional tests must also be passed to confirm that the core performance of the road studs, such as lighting and endurance, has not been affected.
 

Lighting test

The lighting test should be conducted in a darkroom environment (to avoid interference from external light). The specific steps are as follows:

Power-on test: Connect the road studs to the standard voltage (usually 12V), and observe whether the LED lights can light up normally, without any flickering, uneven brightness or other conditions.

Luminance measurement: Use an illuminance meter to measure the luminance at a distance of 1 meter from the road stud and compare it with the data before the test - the qualified standard is "luminance attenuation does not exceed 10%".

Mode switching: If the road stud supports both "constant on" and "flashing" modes, each mode needs to be switched and tested for 5 minutes to ensure smooth mode switching without any lag or delay.
 

Battery life test

The endurance of solar-powered road studs directly affects their use at night. After testing, it is necessary to verify whether their energy storage function is normal.

Charging preparation: Place the solar-powered road studs in an environment simulating sunlight (with a light intensity of 1000W/㎡) and charge for 4 hours (simulating the normal daylight duration during the day).
 

Constant on mode: Records the time from when the road stud is lit to when it is off. The qualification standard is "no less than 8 hours" (covering the core demand from 19:00 at night to 3:00 the next day).

Flashing mode: Record the flashing frequency of the road studs (normally once per second) and the duration. The qualified standard is "the flashing frequency remains unchanged and the duration is no less than 12 hours."

Secondary charging: After the battery life test is completed, charge it again for 4 hours to confirm that the solar road studs can restore normal battery life and rule out the problem of "battery capacity attenuation due to water seepage".
 

Additional Considerations for Comprehensive Testing of Solar Road Studs

The outdoor environment is complex and changeable. Merely conducting "immersion + appearance + function" tests is not enough - it is necessary to combine "extreme temperature" and "durability tests" to verify the stability of the waterproof performance of solar road studs under harsh conditions.
 

Extreme Temperature Adaptation Test

The temperature varies greatly from region to region. For instance, the low temperature in winter can reach -20 ℃, while the high temperature on the road surface in summer can exceed 60℃. Temperature changes can affect the performance of sealing materials (such as rubber strips becoming harder at low temperatures and softening at high temperatures), thereby influencing the waterproofing effect.
 

The core parameters of extreme temperature testing

The industry-standard extreme temperature testing schemes are as follows:
 

• Low-temperature test: Place the solar-powered road studs in a constant temperature box at -20 ℃ for 4 hours. After taking it out, immediately put it into water 1 meter deep and soak for 30 minutes to check if there is any seepage.
• High-temperature test: Place the solar-powered road studs in a constant temperature box at 80℃ for 4 hours. After taking it out, cool it to room temperature, then immerse it in water 1 meter deep for 30 minutes and check if there is any seepage.
• Cyclic test: Repeat the process of "low temperature - soaking - high temperature - soaking" three times to simulate the temperature changes during the transition of seasons.

Combined Testing of Durability and Water Resistance

Solar-powered road studs may suffer physical damage during use, such as being run over by vehicles and hit by crushed stones. These damages may disrupt the sealing structure (for instance, the deformation of the outer shell may cause the rubber strip to fall off). Therefore, it is necessary to combine the "durability test" with the "waterproof test" to verify the waterproof capacity of the road studs after they are damaged.
 

Common durability testing and waterproofing collaborative solutions

The necessity of collaborative testing

In a highway project, there was once such a problem: A batch of road studs passed the IP68 test and the pressure resistance test separately, but after being put into use for three months, due to frequent rolling, the outer shell was slightly deformed, the sealing rubber strips shifted, and large-scale water seepage occurred during the rainy season.

If the manufacturer conducts a "pressure resistance + water resistance" coordinated test before leaving the factory, this problem can be detected in advance. It is evident that a single test cannot fully simulate the actual road scenario, and coordinated testing is the key to ensuring long-term reliability.

Summary

Throughout the entire testing process, from IP68 standard immersion to long-term verification, from appearance and function checks to adaptation to extreme environments, every step is addressing a core issue: whether solar-powered road studs can operate continuously and stably in complex outdoor environments.

For both the engineering party and the purchasing party, whether the product has passed the professional waterproof test should be the core indicator for screening products - because a qualified solar-powered road stud not only needs to meet the standards in the laboratory, but also must be able to stand the test in actual scenarios such as rain, water accumulation, low temperature and heavy rolling.

For manufacturers, a complete waterproof test is not a cost burden but a guarantee of brand reputation. By publicly disclosing the testing process and providing test reports, not only can the product quality be proven to customers, but also the standardization development of the entire industry can be promoted.