LED bulb,with the characters of high light efficiency, energy-saving, environment friendly (no-mercury and harmful uv rays) and long life, are welcomed by more and more consumers. But it is difficulty for them to choose a led bulb which is really with such a good quality since the good and bad are intermingled in the market. It is bearing for someone to buy a LED bulb which has not only lower light efficiency than an energy-saving lamp, but also shorter life than an incandescent bulb. So the LED lighting applications are effected by the lighting standard, products and the government policy.
However, as a common consumer, how do you choose a good LED bulb?
Firstly, choose a famous brand. At present, great LED bulb sellers, such as from Japan, Europe, occupy a majority of market. However, not all the famous brands mean to own best products. Some type of LED bulbs, an international famous brand, its luminous efficiency is 25% lower than an energy-saving lamp`s. While most of us choose famous brands just because of their real data, such as brightness and power consumption and longevity. However, the most shortcoming of them is-- too expensive!
Secondly, the general brands. They have logos and various parameters on their packaging clearly. Generally speaking, they are willing to do good quality otherwise they would not apply for their own logos. LED lighting is a new technology, as different technologies and other factors, the qualities between them are greatly different. Probably they have the best quality of LED lights with much lower price. However, there are bad ones among them, especially for life span, not necessarily accurate. If the life span is more than 50,000 hours, it is need for you to consider the false composition.
Thirdly, cheap copies. This kind of products is packed by a white box without a brand and manufacture information on it, even without basic electrical parameters. While they are bought by some persons either, who know some about LED and buy it as it can save energy. However, they do not know that most of cheap copies do not save energy at all. Even their light efficiency is much lower than fluorescent lamps (the author testes a variety of samples of cheap copies. Their light efficiency is mostly between 35 ~ 45LM/W, while fluorescent lamps` is about 60 LM/W). Certainly, some persons buy these only for sample tests like the author! There are some interesting sidelights for buying: the customer asked, “What is the brightness of this?” “5W” the buyer answered," What is the brightness, brightness?", "5W, 5 times brightness of 1W led", "power?", " 5W, 5 times power of 1W led” .Maybe the buyer considered the brightness can be expressed by” W” as well as the power .
Write so much but do not mention how to choose a LED bulb. If you want to know immediately, skip this one. Actually the most important of a good LED bulb is the life span , besides the four elements of green lighting. Green lighting must fully contains four indexes of energy-saving, environmental protection, safety and comfort . 1, High efficiency and energy-saving means high luminous efficiency. Energy-saving, is not hard to understand, 2, Environmental protection. People thought high efficient and energy-saving can reduce the carbon emissions of power plant ,which would protect environment.Actully it is one of the important factors,and the most important is to not to contain harmful substances, such as "mercury”. 3, Safety means to not to produce ultraviolet ,infrared rays and other harmful light pollution .The electric performance is good and safety. 4. Comfortable means that the light is clear, soft, no glare and stoboflash with high CRI. 5. Long life span.
To choose a good, cost-effective LED bulb, it is better to know how the LED bulb satisfy the five requirements.
As to high efficiency and energy saving, the light efficiency of LED bulb needs to be more than 60LM/W, otherwise it can not save energy comparing to fluorescent lamps at all. It is better to exceed 90LM/W.The more, the better. (As light efficiency should be calculated in stable work rather than initial . Generally the stable’s brightness is more than 10% lower than the initial’s).To own high light efficiency, firstly, choose high light efficient LED lights. Secondly, choose high light efficiency LED power. Thirdly, choose a high photopermeability lampshade.
First, high light efficient LED lights,which is at least 110LM/W. Please note that the light efficiency of some lamps is actually LED light source efficiency, and if so the efficiency of the LED bulb is more than 130LM/W. There is some advertisement from packaging factory that the light efficiency is than 110LM/W without false. The author buys some to test. The result is far below this. We find their test method is to add 350mA constant-current to the led bulb, the flux is 110LM/W.As for this, the voltage of all the samples is more than 3.5 V. Let’s count (3.5 V x 0.35 A = 1.225 W, 110 1.225/89.79 LM/W) so that the actual efficiency is no more than 90LM.
Second, high efficient power. At present, the main LED power drive is divided into 3 kinds, reduction voltage by resistance and capacitance (RC), electronic isolating source and cyntec power supply.
1. RC reduction power contains three advantages: simple structure, high efficiency and cheap. But the defect is not to be used into higher power products, as well as stoplight and shorter life span. The most important is unsafe as the LED tube foot carries current.
The electronic cyntec source is much more better than isolating source in structure, efficiency, price and nearly no strobofalsh.Otherwise,good products are higher reliable but lower safety. As it carries current in tube foot, it may cause an electric shock if the lampshade broken.
The electronic isolating source, nevertheless the efficiency is a little lower than cyntec source, has no strobeflash, and it is safe and reliable with isolating circuit.
We suggest to choose the constant-current isolating source, as the most important must be reliable and safety. And the harmonic wave of cyntec source, isolating circuit of harmonic, lightning surge with high frequency interference light index is far better than other two drivers. In practical applications, the isolate damaged more.
It is better for a LED bulb lower than 7w power to used the constant-current isolating source with more than 80% higher efficiency.
Third, lampshade. The high transmission and glare of lampshade are relatively as high transmission will cause glare. It is better to be the critical point, where high transmission without glare .Generally it is used with white lampshades of high brightness and no glare. Either it is used with the diffusion PC lampshade such as TOSHIBA LEL - AW6N / 2.But from this kind of PC lampshade, we can see bright spot and LED aperture around. As a consumer which kind of LED lampshade is decided by yourself, fragile glass lampshade, or non-friable PC lampshade with bright spot. Or we will have a real PC lampshade with non-bright spot and uniform light. It is the best choice and We have been working on it.
2, Environmental protection.Efficent energy-saving means environmental protection .It is very simple. Another big advantage is LED which does not contain mercury like most of LED bulbs, not mention so much .
3, Safety. It contains 2 sides: reliability, security.
First, safety light with no harmful light, such as UV and infrared light. 99% of fluorescent tubes contain mercury, and output UV, more or less. But LED does not, even do all the LED bulb, except for the special UV LED light.
Second, electrical safety. It was mentioned above that it is better to choose isolation constant current so as LED can reliable work in order to prevent damage by the wave and glare. That makes it easy to pass the safety standard of LVD and EMC, and it is much more effective security.
4. Comfortable.How shall we get clear, soft, no glare and stroboflash and high CRI high ?Good lampshade transmits soft and no glare light. Scattering light can stop glare as it reduces the brightness between background and light. High frequency with current LED drive power will not cause strobeflash .High CRI LED light is much more clearly and accurately.
5. Long life span. Normally the life span of LED bulb is more than 20,000 hours, 70% lumen rate, namely L70.LED Lifetime (Decay to 70%) .The life span by the U.S. Energy Star Standard is not less than 70%, 25,000 hours. It is proved by practice that temperature mostly effects LED lamp life. When in 50 ° c, the temperature rise 5° c, the life will reduce 18%. Heat is the most important for LED lamps. Certainly, it is the best to reduce the heat to avoid using large cooling device. In the temperature of 30 ° c, the surface temperature of working PHILIPS (PHILIPS 5E27A60) reaches 65 ° c, with the temperature of more than 80 ° c in LED light-source core. The PHILIPS life span is 25,000 hours - 25 years. Our products XineLam (XEL - A40) ,with the highest work surface temperature is 48 ° c , is only 68 ° c in LED light-source core. XEL A40 life span is 36000 hours - 18 years, this is actually a nominal life, according to Arrhenius model.(the average temperature setting 20 ° c. However, the quantity of LED light may affect the life span, including IC, phosphor, silica, bracket and packaging process, and the power drive source. The electrolytic capacitor life is almost equivalent to the power drive life. So choose a good electrolytic capacitor, is vital to the LED bulb. Recent years , lots of enterprises are researching the power driver without electrolytic capacitor. - - - - Above 36,000 hours -18 years means 5.5 hours per day. While 5E27A60 PHILIPS—25000 hours , 25 years ,may refer to 2.7 hours per day.
Up to now, you may still not know how to choose a good LED bulbs. Simply speaking, if you only need some for self-used, please pay attention to the following:
1. See the appearance. Even good performance without good appearance, you will not like it.
2. Parameters. The most important is: Lumen (flux), power consumption (W) ,Lumen/W means high efficiency (the more, the better ),life span; lamp holder etc.
3. Light: the brightness, color, glare, light spot, additional flare, softy or clear.
4. Temperature: the surface temperature in stable work. You can touch it. The lower, the better.( Please take care that most LED light bulbs is hot!)
Two more, LED light bulb is divided into the adjustable type and not .Usually you can find the mark in the gift box. Please pay more attention and choose the suitable one. In humidity region, you should choose the lamp holder with nickel plating copper, the iron and nickel lamp is easy to rust (sees attached picture).Test method – by a piece of magnet !
If you need more, or you want to distribution, or you are professional of LED bulbs, please buy our samples to compare with other brands! May you refer to it only, not copy, as we have the appearance design patent.
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Maybe you are an ordinary consumers, choose LED bulbs by the way of “ look 3 and touch 1”!