If you've found your way here, you're likely grappling with the annoying issue of flickering LED strip lights. Whether you're dealing with an older strip or have just installed a brand new one, the problem can manifest in various ways. Some flicker is readily apparent, causing distractions to the naked eye, while others may only become apparent when viewed through a camera lens.
For professionals working with LED lighting, encountering LED light strip flicker can be a true nightmare. Imagine completing an installation, eagerly turning on your strip lights, only to be greeted by the disheartening sight of flickering lights resembling a malfunctioning neon sign.
In the following sections of this article, we will delve into the different types of flicker you might encounter and explore potential causes and solutions to this vexing issue.
What Different Types of LED Strip Flicker We Have
Before we delve into the causes and solutions for flickering LED lights, it's essential to understand what flickering actually entails.
Flickering refers to the rapid on/off cycling of a light source. Essentially, your LED strip is continuously receiving and losing power in a repetitive manner. While intentional flashing of lights in a club or at a concert is designed to enhance the visual experience, the unintentional "strobe effect" in a home setting can be quite bothersome.
There are two primary categories of flicker: visible and invisible. When the flicker frequency falls below 100 Hz, it becomes visible to the naked eye. This means that the light appears to switch on and off up to 100 times per second.
Conversely, flicker that occurs at frequencies above 100 Hz remains invisible to the naked eye but can still affect individuals, albeit in different ways. This "invisible" flicker is typically detectable through the lens of a camera. People may react variably to this phenomenon, experiencing symptoms such as headaches, migraines, dizziness, and eye strain. Notably, for individuals with epilepsy, this flashing can even trigger a seizure.
Possible Causes of LED Strip Flicker
LED strip lights are often reliable and durable for the most part. However, it is common for them to flicker. I know how worried I get when they flicker; hence, to help you out, I’ve listed a few reasons why they might be flickering.
Poor Connection
One of the noticeable instances of LED strip flicker occurs immediately after plugging in the lights, and it's quite evident to the naked eye, especially when connections are not up to par. The primary culprit behind this type of flicker is inadequate or loose connections, making it the most common and easily identifiable issue. Poor connections can disrupt the flow of electricity intermittently, leading to flickering. This problem is particularly prevalent when connections have not been soldered properly.
Optimal soldering plays a crucial role in mitigating the risk of poor connections. Soldered joints are not only more stable but also capable of handling higher current loads. However, it's worth noting that even connections made using screw connectors can become loose over time.
To diagnose whether poor soldering is the culprit on the low-current side, you can employ a simple test. Gently press on the unsoldered connector with your finger. If the flickering is indeed caused by a connection issue, you'll observe the LED strip flickering, the flicker pattern changing, or the light extinguishing altogether. When dealing with a soldered joint that's causing the problem, the solution lies in reheating and re-soldering the compromised joint to reestablish a solid connection.
Faulty Power Supply or Adapter
A common yet easily detectable issue contributing to LED strip flicker is a faulty power supply or adapter. If you notice flickering in your LED strip and also hear noise emanating from the adapter or detect that the adapter is unusually hot, it's likely due to an excessive load or a defective power supply causing voltage fluctuations.
Diagnosing this problem is relatively straightforward. You can perform a simple test to determine if the power supply is at fault. Replacing the adapter or power supply can often resolve the issue effectively. Alternatively, reducing the length of the LED strip can help alleviate the load on the power supply, potentially mitigating the flickering problem.
Overload
Another prevalent cause of LED strip flickering is the overloading of the LED driver, or in some cases, using a power adapter with a higher rating than necessary. High-quality LED drivers typically come equipped with overload protection mechanisms. When an overload occurs, the LED driver intermittently switches on and off, resulting in the LED strip appearing to flicker. Furthermore, a poorly matched or incorrectly powered LED driver can also lead to flickering issues.
To prevent overloading problems, it's essential to choose a DC power supply (VDC) with a margin of approximately 15% above the maximum load requirement. This extra capacity ensures that the LED driver can adequately handle the load without experiencing overload-related flickering.
Additionally, if you transition from a 12V 2A power adapter to a 24V 1A or 1.5A adapter, you might notice the LED strip becoming brighter but also flickering. The solution in such cases is to select a power adapter that is correctly rated for your specific LED strip to maintain consistent and flicker-free performance.
Drop of Voltage
Flickering that extends across the entire LED strip and is accompanied by a noticeable reduction in brightness can often be attributed to a phenomenon known as voltage drop. This occurs when the excessive length of the LED strip results in a drop in voltage along the length of the strip, causing both dimming and flickering.
To determine if voltage drop is the issue, you can conduct a simple test. Remove one section or strip from the end of the LED strip and observe whether the remaining portion operates normally. It's important to note that LEDs have a minimum voltage requirement for proper functioning. An excessive run length not only causes dimming and potential flickering due to voltage drop but can also impose excessive load and wear on the LED strips, connectors, and power supplies.
When multiple strip connectors are used, voltage drop becomes more pronounced. This is why soldering the strip connections is often recommended. Soldered connections can carry more current and generate less resistance at the connections, helping to mitigate voltage drop issues and maintain consistent brightness and performance across the entire LED strip.
Dimmers
Dimming LED strips often leads to flickering issues. If you encounter flickering when dimming your LED strips, it's essential to take a few steps to address the problem effectively. First and foremost, confirm that both the LED strip and the driver are compatible with dimming. Compatibility issues can be a major source of flickering.
For those using wireless controllers, ensure that the controller and dimmer protocols are also compatible. Incompatibilities between these components can result in flickering problems.
Additionally, if your LED strip lights intermittently turn on and off unexpectedly, the culprit may be a malfunctioning dimmer or LED driver. You can troubleshoot this by bypassing the dimmer initially and connecting a constant current driver. If the LED strip functions correctly without flickering when connected to the constant current driver, it indicates that the dimmer is faulty and should be replaced. However, if the problem persists even with the constant current driver, then replacing the LED driver is the recommended course of action.
Faulty LED Strip
While not as common, another potential source of LED strip flickering is a faulty LED strip itself. This can occur even with newly purchased LED strips that have not been used outside of the factory environment. LED strips undergo testing at the factory, but issues can arise due to mishandling during packaging, unpacking, or installation.
When an LED strip is excessively twisted or folded, especially near the LED chips, problems may arise either immediately or after some time, as the strip experiences temperature fluctuations from warming up and cooling down. The same applies to LED strip joints, where one LED strip is soldered to the next.
Typically, the LED chip and its holder are the culprits in these scenarios. The LED chip is responsible for producing light, and a gold wire connects it to the LED holder. When the connection between the LED chip and holder is faulty, electricity may intermittently flow or be disrupted, causing the LED to flicker. If you notice a specific section of the LED strip flashing, gently press that part of the LED with your finger. You may observe the flickering pattern changing or disappearing altogether. This method helps pinpoint the exact location of the problem within the LED strip.
Fixing Invisible Flickering of LED Stripe
As previously mentioned, the phenomenon of invisible flickering in LED strips becomes apparent when viewed through smartphone camera. This particular issue is associated with AC (alternating current) LED strips. AC power, by nature, undergoes frequent changes in direction, typically alternating 50-60 times per second, depending on your geographical location. This oscillation is typically represented as a sine wave. In contrast, DC (direct current) flows continuously in a single direction without reversals. When devices are connected to AC power, they experience momentary power interruptions during each change in the current's direction. Consequently, all lights connected to AC power sources, including LED strips, effectively flicker because electricity is constantly flowing back and forth.
The perception of this flicker and the extent to which it is deemed bothersome can vary depending on individual characteristics and sensitivities. Different people may have varying levels of tolerance for this flicker and may find it more or less disturbing based on their personal preferences and sensitivities.
Invisible flickering in LED strips can be attributed to PWM (Pulse Width Modulation) signal dimming. PWM is a deliberate technique for manipulating DC power between the on and off states. By altering the proportion of time an LED is in the on and off states, PWM can create the perception of varying brightness levels. However, it's important to note that LEDs are either at 0% brightness (off) or 100% brightness (on). To give the illusion of 50% brightness, the LED is switched between 0% and 100% brightness states, alternating rapidly.
Typically, this type of flicker is not visible to the naked eye and doesn't pose a problem in everyday use. However, it can become problematic when recording video because the invisible flicker becomes apparent due to a mismatch between the camera's frames per second (FPS) and the frequency of the electrical current. This effect is known as the "strobe effect."
Many LED strip dimmers and "color changing" controllers, whether for CCT (Correlated Color Temperature) or RGB (Red, Green, Blue) LED strips, operate using PWM on the low voltage DC side of the circuit to achieve their desired effects. Unfortunately, a significant number of PWM dimmers use frequencies that are too low for video recording purposes. To effectively eliminate the impact of PWM flicker in videos, a PWM frequency of 25,000 Hz or higher is recommended. However, many PWM dimmers do not offer adjustable PWM frequencies, which can be a limitation when trying to address this issue.
When working with LED strips, it's advisable to use low-voltage LED strips and high-quality LED drivers whenever possible. These LED drivers are responsible for converting high-voltage AC into a stable low-voltage power source, ensuring that the LED strips operate without flickering issues.
Additionally, it's essential to consider the type of dimming power supplies used, particularly those with CCR (Constant Current Reduction) output signals. CCR maintains a continuous flow of current through the LED, keeping the LED constantly ON, unlike PWM (Pulse Width Modulation), where the LED rapidly switches between ON and OFF states. In CCR, the brightness of the LED is adjusted by varying the current level, providing a flicker-free lighting experience.
If PWM dimming is preferred, opt for dimming power supplies with high-frequency PWM output signals. In PWM dimming, the LED turns ON and OFF at its rated current, but at a high frequency. This rapid switching is typically at a frequency high enough that the human eye cannot perceive it. The level of brightness achieved is determined by the duty cycle, which represents the ratio of time the LED is ON to the total cycle time. To minimize the chances of flicker being visible in video recordings, select PWM frequencies greater than 25 kHz, as cameras typically cannot detect flicker at such high frequencies.