What is the negative of LED lights?
The increased amount of light and type of light from LEDs has negative effects on human and animal health. In humans, this leads to disrupted sleep cycles and an array of health problems associated with a lack of sleep.
One of the most common problems when using LED is the light flickering.
The lights are basically strobing. If you are using poor quality LED bulbs or flood lights,
then you will observe the brightness goes up and down rapidly.
If the flicker frequency is below 80 to 100 Hz, then it can be observed by naked eyes.
It can be a serious issue as flickering lights might cause fatigue, headache, vomiting or even trigger epilepsy. It is difficult for our eyes to adapt such the flashing lights; thus,
we need to know why and fix the fickering problem on LED lights.
Reason 1: Loose wire connection
If the wire connection is loose between the bulb and circuit, you may encounter fashing lights. It is because the current would be periodically obstructed due to the electromagnetic interference. The way to fix it is to inspect all connection points in the circuit to see if there are some wires are about to break or disconnect.
Reason 2: Low quality LED
If you buy the abnormally cheap LED lights, you will get fickering quickly. Due to the poor soldering technique of gold wire with LED chips, the intrinsic components will be loosened easily. In addition, the shoddy LED bulbs will have poor PCB design that does not receive the current properly, so we will see rapid fluctuation of brightness.
One of the effective ways to solve this issue is to buy quality LED lights from reputative brands, and we can take a look at the brand of LED chips they use. For instance, CREE XTE or Osram Square would be the better options. They apply the eutectic soldering technology to eliminate the fickering on LED lights.
Reason 3: Loose bulbs
The LED will have flickering problem if you do not tighten them firmly in the fixture. The poor
contact between the bulbs and base will affect the transmission of current. Before inspecting the LED lights, we should shut off the bulbs as well as power supply to prevent electrical shock. If your room is completely dark after turning off the lights, we can put a portable work lights under the fixture to provide ample brightness.
Reason 4: Improper dimmer setup
Knowing your dimmer type is critical to diagnose the problematic strobing LED lights.
The pulse means the current and voltage sent to the bulbs while the width is the dimmers alternate the pulse duration to decrease the overall brightness.
In other words, it rapidly shutting on & off the lights to dim the LED lights. The poor-quality dimmer switch generates electrical signal with improper pulse width(<100Hz), and thus lead to observable flickering of LED. The strobing effect is especially significant if you further dim the lights because the duration between each pulse is longer.
It might be inevitable as it is the working principle of this type of dimmer. Digital dimming can solve this problem because it uses different working mechanism.
Constant Current Reduction (CCR) dimmer
As its named suggested, it alters the current of the circuit to produce different brightness.
It is generally worked for o to 10V DC power supply. The power supply will send the corresponding dimming signal to the lights. In this case, continuous current is supplied and no discrete pulse is formed in the circuit.
Reason 5: Power supply broken
lf you are having high power (>100W) LED flood lights for backyard or sports ground, the bad driver(power supply) will cause flickering problem. Before purchasing the LEDs, we can have a look at the driver unit, Mean Well is one of the best and reliable power supplies for LED lights. Its failure rate is approx. 0.3% in the first 2 years.
Reason 6: High wattage electrical appliance
For those who have many high-power appliances at home such as air conditioner, heater, vacuum or etc, the bulbs might flicker if you draw a lot of voltage in the same circuit. To fix this problem, we can turn off some of the devices to see if the flickering light problem is improved. No ficker LED sports lighting
Flickering problem is also very common in LED commercial & sports lighting. Their lighting standard is even higher than residential application. Apart from no visible flicker in human eyes, the LED lights must not strobe under the high-speed camera. lmagine we are taking >960 fps video and the flickering would greatly affect the picture quality.
LedsMaster’s LED sports lighting are using constant current reduction dimming. They support up to60o0 Hz high speed photography. They are applied to football stadium or other sports venues holding international competitions.
2.LED lights with buzzing noise
Buzzing is another common problem of LED lighting. If your recessed lights or other LED bulbs product such the annoying hum, it might indicate that you overload the circuit. For instance, if the dimmer is just support 300W LED lights but you connect over 200W luminaires, then buzzing would occur
Where does the sound come from? It is mainly due to vibration of the electronic components inside the lamp. They vibrate in a specific frequency such as 100 to 120Hz.
The buzzing of LED lights indicates abnormality. Once we hear it, we should inspect the lamp, as well as the circuit to ensure safety. Besides, we can also disconnect some of the luminaries to see if we can improve this problem.
3.Why are LED light bulbs are not bright?
After the painful lighting installation, it is common for the people to ask why the LED lights are dim.
This problem happens for both indoor & outdoor LED bulbs.
Let’s explore the following reasons.
a. lmproper power supply for LED lights
If the LED is not working in the rated voltage & current, then the LED lights cannot reach the
maximum brightness. When buying the LED lights from manufacturer and you wish to use your own driver, you need to clearly know what is the power, voltage and current input of the LEDs. If the power rating of the driver does not match that of LED, the flood light bulbs will not be bright, or even burnt out. Therefore, it is highly recommended to adopt the original setting of the whole LED lights.
b. Loose wire connection
Similar to the LED bulb fickering, if the wires are not firmly connected, then some of the LED chips inside the lights will not on, and thus reduces the overall lumen output.
c. Aging of LED lights reduce overall brightness
The LED lights are not bright if they have used for a long period of time. The reason is that the
electronics inside the lamp starts to deteriorate, and thus they no longer product the 100% lumens. If a LED light is rated as 80,000 hours at L70, the lumen output will fall to 70% of the original value after 8ok hours.
It is the normal wearing of LED lights. Nowadays, majority of LED have the life span of 50,000 to100,000 hours, which is equivalent to 2o to 30 years depending on how long you switch on the bulbs.
d. High ambient temperature lead to dim LED lights
Householder might also complain their LED lamps are not bright if the ambient temperature is high. According to the scientific research,LED produces the maximum brightness at around 25’C junction temperature.
If the working environment is very hot such as 40’℃ to 60℃, the lumen output of white light drops to approx. 65% to 80% of its maximum value.
On the contrary, cold environment is beneficial to LED because it can be even brighter than its original value.
For industrial application such as foundry and nuclear power station, the ambient temperature can be over 80C. Thus, special reinforcement on LED luminaires is required.
4.Dimmer does not work with my LED
Some may complaint the LED lights cannot be dimed after connecting to dimmer switch. Firstly, we need to check if the bulb is dimmable. Before you buy the LEDs, you can clearly see the bulb is stated as “dimmable” if they are. lf you connect a dimmer switch to non-dimmable LED bulbs, it will usually remain 100% on, no matter how to adjust the brightness on the switch. It is because the PCB of the that LED is not designed for dimming circuit. In addition, it is quite risky to do so because it might damage the LED due to the improper current and voltage during dimming.
- How to reduce glare from LED lights?
Glare means the strong blinding lights coming out from the light source. It can blur our vision and affect our living quality. For instance, it would be very difficult to read the words on the magazine due to the refection. Also, white reflective glare of the lights will create white spot on the TV screen.
How to calculate the power of LED bulb required for my home
Reducing the brightness is one of the ordinary ways to fix glare. For home lighting, we can avoid unnecessarily bright lighting by calculating the number of LED bulbs you need. If you have a 20 sq. meter living room, then the lumen required is approx. 20 sq. meterx 150 lux = 3000 lumens.Since most of the LED lights have the luminous efficacy of 130 lm/W, the power of LED bulb required is3000/130 = 23W. We can add around 20 to 30% to this value (23W) to compensate the reflection of wall and other kinds of energy loss.
If you have a garage, then it is suggested to use the lux level of 500. Since we need to do the repair task in the workshop, we will need brighter lights.
Another way to reduce the glare is to add the barn door near the LED bulbs, to make the light beam more directional. We can create a 3-wall cover for the lamps, so we will not directly see the light source on the side of the lamp. It is especially useful for outdoor food lights.
- Blue light pollution
Blue light is another widespread problem of LED light. Although blue light can improve our reaction time and mood, it does impact our health at night. The LED blue lights can suppress the melatonin production inside the body, and thus affect our sleep cycle and quality. The blue light might also damage retina for prolonged exposure. The leakage of blue light will also pollute the sky and cause skyglow at night.
To reduce the amount of blue lights, we can select the LED bulbs with lower color temperature such as from 3500K to 5000K. The LED would produce more blue light for the color temperature over 60ooK. Depending on your need and preference, you can select the warm white LED(around3000 to 3500K) to create relaxing atmosphere.
7.How to improve uniformity of LED lights?
Another common problem is the low uniformity of LED lights.
What is uniformity? It basically shows how even the light distribution in an area.
As we can see from the above comparison, the left tennis court has low lighting uniformity.
There are four observable light spots on the ground. In such the low uniformity, our eyes will not be able to see the whole ground. The uneven dim & bright lights will also fatigue our eyes because our eyes need to adapt to this change continuously.
One of the common ways to fix this low uniformity problem is to use the LED with large beam angle. It is because the lights can spread outward the lamp. To further improve the uniformity, we can even use the secondary reflection to light up the area. For example, we can direct the flood lights upward to ceiling, and thus use the reflected lights to illuminate the indoor areas, such as home or sports field. So, you will get a highly uniform illumination because the ceiling acts like a diffuser that soften the lights. However, the limitation is that we will need more LED lights because some of the lumen is absorbed by ceiling and the light beams are scattered in different directions.
- Pricey LED lights
When we compare the price of LED with other light sources such as metal halide, halogen of CFL, we will find that LED is usually more expensive than other. It is because their material used and working mechanism are different.
Frankly speaking, although the initial cost of buying LED is much higher, you will recognize this is not the problem because it lasts longer and saves energy!
A common LED light has the service of 50,000 to 80,000 hours, we can compare this value with 1,000 to 2,000 hours incandescent bulbs. Plus, the power consumption of LED is approx. 1/10 of incandescent to generate the same brightness.
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