LED Underwater Lights Flicker Causes and Solutions

Flickering is a common failure of LED lights, and there are many reasons that cause LED underwater lights to flicker. This article lists the common causes of LED underwater lights flickering and the corresponding solutions to help you quickly locate and solve the problem.

Before that, let me take you through what flicker is and what effects it has on our health.

What is light flicker?

Light flicker refers to the rapid flickering phenomenon that occurs when the light output fluctuates. When this phenomenon is visible to the naked eye, we will see the light brightness has been changing light and dark, or constantly be off and on.

Let’s simulate flickering. What do you see when the position of this black and white picture changes on the screen?

Light flicker diagram

Light flicker is divided into the following two kinds :

Visible flicker

The human eye can directly observe flicker in most cases when the visible light fluctuation frequency is less than 100Hz.

light visible flicker

Invisible flicker

When the fluctuation frequency of visible light exceeds 100Hz, the eye will not observe it in most cases, but it will still have an impact on the body.

It should be noted that 100Hz is only the more common critical value for visible flicker. Different people’s eyes to the degree of light sensitivity, the brightness of the lamp will affect this critical value.

How to determine whether the light is blinking?

The most widely circulated test method is to detect through the phone’s photo function. Open the phone’s camera and point it at the light that is glowing. If the phone screen in the imaging appears a lot of stripes, indicating that the light is blinking.

Cell phone photo of pool lights

But this is just an everyday method of judgment that can go wrong. Because only when the phone shutter speed and the light blinking frequency is not the same to be able to shoot strobe. If the phone shutter speed and light flashing frequency in line, you won’t see the strobe.

Strobe requires the use of professional measuring equipment to be able to detect accurate.

The effect of flashing lights on the human body

When the brightness of light is the same, a flickering light source can have a stronger visual impact on the human eye. This is why emergency vehicles like ambulances and police cars use flickering lights.

So far, there is no DC or AC power that can be completely free of fluctuations. Daily life and work contact with various types of lighting equipment will be for various reasons can not avoid flicker. But do not worry, in general, only low-frequency flicker between 0-200Hz is harmful to the human body.

We need to be alert to low-frequency flickering when discomfort occurs after eye contact with light. The lower the flickering frequency of light, the greater the effect on the human body. Whether the flicker is noticeable or not, low-frequency flicker can have an impact on human health.

Common flicker hazards include the following :

Interferes with reading and reduces observational power

When text or other objects are exposed to flickering light, we need to concentrate and spend more time before our eyes can gather enough information.

Easy eye fatigue

When the lights are flickering, you need to concentrate more to see things clearly. At this time, the human eye will blink less than usual. Over time, your eyes will become dry and tired, and you will experience blurred vision.

Poor attention span

The human eye is sensitive to flicker, and visible flickering light sources can distract a person’s attention and affect their mood. People affected by flicker may appear somewhat distracted or irritable.

May trigger migraines

A subset of people with episodic migraines have an increased probability of migraine onset with prolonged exposure to flickering light sources.

Triggers photosensitive epilepsy

About 20% of people with epilepsy are more sensitive to lights and will have an attack when exposed to lights with a flickering frequency of 3-70Hz. Normal people and most people with epilepsy do not have this problem and do not need to be overly concerned.

Aggravated autism

People with autism are very sensitive to environmental changes and flickering lights can trigger psychological rejection and lead to aggravation.

How to avoid the damage to the body due to flicker?

For people who experience discomfort from flickering lights, there are several ways to reduce the impact. One way is to increase the frequency of blinking or to close your eyes and rest. Another way is to leave the area where the flickering is occurring.

If the degree of physical discomfort increases or the above special groups, it is best to leave the flicker area until the problem has been resolved.

In addition there is a tip : the higher the brightness of the same light, the higher the frequency of flickering. High frequency of flickering on the human body is less impact.

LED underwater lights flicker common causes

There are many reasons for the flickering of underwater lights, and we will introduce you in two aspects.

Flickering caused by quality problems

Defective soldering

Dummy soldering is one of the most common failures in electronic equipment. Some LED lights are produced with only a small amount of tin soldered at the solder joints. This can sometimes result in poor contact when power is applied, causing the lights to flicker.

Welded circuit board

Some LED underwater lights that do not meet the standard manufacturing process may still work properly during factory testing. However, when exposed to environmental conditions such as temperature, humidity, and vibration, the surface of the dummy solder parts may gradually begin to have poor contact. With continued use, the resistance of the dummy solder increases and localised heating becomes severe. This will cause the solder joint to deteriorate and eventually the problem of flickering or failure to light up will occur.

LED chips quality is poor

Poor quality LED chips material and process can not be guaranteed, may produce flicker, light failure, not bright, short life and a series of problems. LED chips is the core of the lighting equipment, in the purchase of the choice of well-known LED chips manufacturer is also very important.

Electronic components of poor quality

Inferior electronic components have a higher probability of failure and are more prone to problems such as flickering, light failure, and non-brightness. It’s important to note that all manufacturers of electronic components have a small probability of performance problems. The electronics manufacturing industry cannot guarantee a 100% yield rate. However, the failure rate of products after factory testing is very low. If you encounter any issues within the warranty period, you can contact the seller to solve the problem.

Drive power failure

Drive power supply is a converter, the role is to convert electrical energy into a standard voltage and current, so that the LED light. When the driver power supply produces a fault, the output voltage is unstable, resulting in LED lights flickering.


LED underwater lights work underwater for a long time, if the waterproof design, material, any part of the production process is defective, it will lead to water gradually penetrate into the lamp body, damaging the LED chip or other electronic components. After drying the light may still flicker, this damage is not recoverable.

Flicker caused during construction and use

Dimmer incompatibility

You must use the right dimmer to operate your LED lights. If you plan to use an old dimmer from another lamp for your LED lamp, it is best to check the compatibility of the lamp and the dimmer before doing so. They are compatible with the problem, may also occur flicker.

Poor wiring contact

Poor wiring connections during installation may also cause flickering problems with underwater lights. In addition after using for a long time, if the line quality is faulty or corroded, the underwater lights flicker and the probability of short circuit will be greatly increased.

Temperature is too high

When the underwater lights have poor heat dissipation, if they work in high ambient temperatures for a long time, the aging of the light will accelerate and may produce flickering problems.

This is not necessarily a quality issue. Choosing pool lights that are heat resistant can solve this problem because they have better overall heat dissipation capabilities. In addition, underwater lights made of metal have better heat dissipation capabilities than those made of plastic, all specifications being equal.

Better heat dissipation will increase the cost of manufacturing, resulting in a higher selling price for underwater lights. It is best to give preference to metal pool lights when you have enough budget.

Unstable voltage

Interference from high-powered appliances or regulation of electricity consumption may cause voltage instability.

There are many electrical appliances in modern society, which greatly facilitate or enrich our lives. Some electrical devices have high power, such as air conditioners, ovens, microwave ovens, etc. When you turn on these appliances, the circuit can be unstable. When you turn on these appliances, a sudden shock in the circuit system may cause the lights to flicker.

Some countries regulate power delivery to reduce the amount of electricity flowing to certain areas and to preserve the power supply in key areas during peak periods. If many electrical devices are on and in use, the LED lights may flicker due to insufficient power supply.

How to solve the flicker problem of LED underwater lights?

Flicker problems due to quality issues require replacement of the entire light, electronic parts or just the light source part. Underwater lights with standard interface (E27, MR16) design support replacement of light source. It is recommended that you purchase a quality underwater light, they are of consistent quality and have a long warranty.

If construction or use problems generate the flicker, you need to carefully examine it and take the appropriate solution according to the problem :

Replacing a compatible LED dimmer

The best option is to contact your underwater light seller, which is the easiest way to go. If you must buy from a third party, you can consult an electrician or underwater light seller for technical support to help you get the right dimmer.

Check the wiring

This is a more laborious task and requires careful handling. Turn off the power and tighten all the wiring connections, and gradually troubleshoot all the wiring until you find out where the problem is. If you are not familiar with the circuitry, it is recommended that you contact a professional electrician to handle this. Remember, your safety is the most important thing.

Enhance heat dissipation or reduce the working environment temperature

The easiest thing to do is to replace the heat-resistant underwater lights. If the flicker is generated by overheating is plastic lights, it is best to replace them with metal lights.

heat-resistant underwater light

If you are still planning to use ordinary plastic underwater lights due to price and other factors, it will become useful to improve their working environment. Increase ventilation, shade from the sun, reduce the duration of work in a hot environment, you can choose according to your situation.

Improving voltage problems

If the problem lasts for a short period of time and occurs rarely and has little impact on your health and life, you can leave it alone. Otherwise you’d better contact an electrician to customize a new solution for your entire home or local circuit.


There are many causes of flicker, and only the common causes and solutions are listed above. It is not easy for the average person to find and solve flicker problems. If you are experiencing flickering problems with your LED underwater lights, in addition to contacting an electrician you can also ask for help from WAKING’s electrical engineers and we will be happy to assist you in solving the problem.

If your light is flickering due to quality issues, you may want to consider purchasing a new product to replace it. We have a wide range of underwater lights and have also developed low-voltage LED replacements for industry-standard products such as the Pentair GloBrite, Pentair IntelliBrite, Hayward ColorLogic 80, Jandy Radiant, and more.

Are you looking for a professional underwater light supplier? Contact us now!

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