Why Are My LED Strip Lights Not Bright?

Why Are My LED Strip Lights Not Bright?

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LED strip lights are a great type of illumination that may be used in various situations. They have grown in popularity for both commercial and residential lighting applications and are becoming more cost-effective as it becomes easier to make LED strip lights. If you’re looking to buy LED strip lights for the first time, there are a few factors to consider in order to ensure you get the right lights for your project. It would be best if you were most concerned about the quality and brightness of the LED strip lights.

LED bulbs can lose their brightness as they get older or due to faulty internal components such as a capacitor or LED arrays or as a result of faulty cabling. LED lights can also dim if there are a lot of appliances on the circuit. Follow along as we go over the most vital components of LED strip lighting, particularly the brightness factors of every LED strip light variation. We will answer the question of “Why are my LED strip lights not bright?”

The Brightness of LED Strip Lights

LED strips are becoming increasingly brighter as technology advances. This does not imply that all LED strip lights will be highly bright. In fact, you may not even want the light to be too bright in some circumstances.

The brightness of colored LED strip lights is measured in millicandelas, while the brightness of white strip lights is measured in lumens. One candle has a brightness of about one candela. The brightness of a millicandela is measured in thousandths of a candela. Some calculators can convert millicandelas to lumens; however, the lumen value will undoubtedly be deceptively low.


On the visible spectrum, lumens measure light wavelengths in all hues. Colored strips will have lower lumen estimates since they are a single-wavelength source, and numerous wavelengths create white light. They will, however, be as dazzling as the light strip’s white counterpart.

Another metric used in measuring LED brightness is Lux. Lux is the amount of light that a light source emits illuminating an object or workspace one meter from the source. In other words, the number of lumens per square meter is measured by Lux. Lux value is determined by the amount of reflection that will occur in any given location, in addition to the light source.

Lux Definition

Depending on how you’ll be using the LED light strips, you’ll probably require a specific number of lumens. The more lumens an LED emits, the brighter a room’s lighting will be. For instance, you don’t want anything brighter than 200 lumens per foot in accent lighting, but if you want more light in other uses, you can choose how bright you want it to be. Unlike incandescent bulbs, different LED strip lights have different levels of efficiency; a wattage number isn’t necessarily a good indicator of how much light is produced.

Three main elements influence the brightness of LED strips:

  • Per LED emitter light output and efficiency
  • Length of LEDs per square foot
  • The LED light strip’s per-foot power draw

It’s a red flag if an LED light strip doesn’t have a lumens rating for brightness. You should also be cautious of low-cost LED light strips that claim to be very bright, as they may be of a lower quality and cause the LEDs to overheat and fail prematurely.

As previously stated, the number of lumens required can be calculated based on how the light is used. In every project type, you can use this general guide to determine how many lumens are needed:

  • 100 to 350 lumens per foot for accent and mood lighting
  • 175 to 525 lumens per foot for under-cabinet lighting
  • 280 to 437 lumens per foot for task lighting with a short distance from the light source
  • 500 to 1000 lumens per foot for task lighting at a greater distance from the light source
  • 375 to 562 lumens per foot for indirect lighting in a bedroom, hotel, vehicle, or lobby
  • 500 to 950 lumens per foot for industrial lighting, signage, and tube replacements
Lumens per foot for different uses

It’s vital to remember that the lumen output is specified by the company from which you purchased your LED strip lights. You won’t tell how bright they are until you buy them or read these specifications.

Factors that Affect the Brightness of LED Lights

1. LED Efficiency

The lumens plus brightness of each LED emitter is referred to as LED efficiency. In most cases, the amount of light emitted by a foot of the strip is measured in lumens. The lumen count is determined by the brightness of the light emitted by the LED strip.

Check the lux rating of each LED emitter to see how bright it is. This will inform you how brilliant the light produced will be compared to natural light. A combination of lux and lumens will give you a better understanding of how bright an LED light strip may be.

2. LED Density and Pitch

The amount of LEDs on a single strip is referred to as the density of the LEDs, which can be measured in meters or feet. The brightness of LED light strips can be measured using a metric called LED density. The brighter the light produced by a strip, the more LEDs it contains.

LED Density and Pitch

The distance between two LEDs on a strip is the LED pitch. There will be more visible hotspots and dark patches in the strip with a higher pitch, making the light appear more diffused. You can acquire the same brightness level from a single high-density LED strip by using many low-density LED strips. The two will have a distinct effect, though.

2. LED Power Draw

The power draw of an LED light strip measures how much energy an LED strip uses. This will assist you in determining the required power supply for your LED strip lights. Good LED strip lights should have a power drain of more than 4 Watts per foot or 15 Watts per meter. The cost of electricity is also determined by the power draw of an LED light strip.

3. LED Light Strip Length

The brightness of an LED strip is also determined by its length. A phenomenon known as Voltage Drop occurs when the distance between the LED light strip and the power supply is greater than 20 feet. The segment of the LED strip that is the furthest away from the power source emits more light than the rest of the strip because it is more diffused. Sometimes it will just flicker and then die out completely. This is why it is important to not overdo it when connecting LED strip lights.

Dimming LED Light Strip

When used with the right equipment, all LED strip lights, unlike LED bulbs, may be dimmed. The primary issue with dimming LED strip lights is that most power supplies are designed to produce a constant voltage (12 or 24v). This means that adjusting the voltage into the power supply with a typical dimmer will not work since it readjusts itself to maintain a constant output. As a result, most dimming must take place on the low-voltage side.

Traditional phase-cut wall-dimmers or DC low-voltage dimmers are the two options for dimming LED strip lights. When the dimming input signal comes from a regular wall-switch dimmer, the AC phase-cut dimmer technique is often the best option for residential and commercial lighting applications. A TRIAC (triode for alternating current) dimmable power source is required for this configuration. The TRIAC dimmer is a high-speed switch used to regulate the amount of electrical energy that a light bulb receives. The point at which the device’s ability to conduct electricity is determined by a “trigger,” thus “chopping up” the voltage waveform and preventing the voltage from being provided at full load.

A DC low-voltage dimmer or RGB (red, green, and blue) controller is usually a manual or digital dimmer module between the DC power source and the LED light strip. This method is the best choice for color-changing applications or more minor permanent lighting installations.

RGB Controller

Do LED Lights Dim Over Time?

Due to lumen degradation, LED bulbs will get progressively dimmer over time until they no longer provide light at all. The L70 rating of most LEDs indicates how long the bulb will last until it reaches 70% of its initial light output. On one end of the spectrum, a 50,000-hour LED can last six years without needing to be replaced if it is left on all the time. LED bulbs generally last much longer than incandescent and other types of bulbs.

What Causes the Brightness of LED Light Bulbs to Dim Over Time?

The human eye can only sense a brightness decrease of 20%, according to the Alliance for Solid-State Illumination. When an LED reaches a saturation point of 70%, it will still generate light, but it may no longer be useful. Furthermore, lumen degradation is not linear, and while it may begin slowly, the light will fade faster and faster beyond 70%.

Most LEDs are built of Gallium Nitride (InGaN) and use a semiconductor to produce light. Integrated circuits and high-efficiency power transistors employ InGaN as a semiconductor with a large bandgap. Threading dislocations occur in this Gallium Nitride during the production process. These unusual dislocations disrupt the structure of the semiconductor. Threading dislocations are terrible because the positive and negative electrons can still meet but don’t create light. The quantum efficiency of semiconductors, which is the percentage of electron-hole pairings, is harmed due to this. Thus, from the beginning of the manufacturing process onward, sections of the semiconductor cannot emit light.

Furthermore, these dislocations worsen over time, adding more dislocations as time passes. This means that quantum efficiency and light output eventually decrease.

Why Are My LED Strip Lights Not Bright?

The nemesis of LED lights is excessive heat, which has both short- and long-term effects on a bulb’s lifespan. Most LEDs have a heat sink that distributes heat away from the diode to avoid overheating. Aside from that, if you want to preserve your LEDs in good working order, keep the temperature of the strip below 140 degrees Fahrenheit (60 degrees Celsius). Excessive heat can cause color changes and a loss in light output in the near term. This is because the bulb’s internal components fail due to the heat. Heat and lumen output has a negative relationship: as a bulb’s temperature rises, its lumen output falls.

Furthermore, the temperature at which an LED is exposed might impact its duration. The creation of threading dislocations is accelerated by excessive heat and insufficient cooling. As you may be aware, threading dislocations directly impact lumen output. As a result, higher-temperature semiconductors will degrade lumens more quickly. You can try to reset your LED strip as well.


We hope this article helped you understand what affects the brightness levels of LED strip lights, and was able to answer the common question, “why are my LED strip lights not bright?” We also hope this helped inform any decisions you might be making soon about which LED strip lights to buy for your particular projects or needs. Successfully choosing the best and brightest LED strip light includes the intended application, color, efficiency, convenience of use, and budget. You want to make sure you receive what you desire in a light, and you can buy the top-quality LED strip lights from reputable providers. Your LED strip lights will survive for many years when installed correctly and cooled appropriately.