The luminous efficiency of fluorescent lamps is about 55-80lm/W (the luminous efficiency of Philips T8 tubes is 72lm/W). LED fluorescent tubes can have a luminous efficiency as high as 100lm/W. Cree has announced that the luminous efficiency of their recently promoted XLampXP-G series can reach up to 130lm/W, and expected to reach 150lm/W two years later.

 

 

Not all light emitted from LED chips/LED lighting boards can 100% reflected by reflectors / projectors. Fluorescent tubes can send out 360 degree light. In spite of using reflectors, some of opposite direction light will be inevitably wasted. Generally speaking, there will be about 30% light will be wasted for fluorescent tubes. The valid / lamp luminous efficiency of them is only 70% of the initial luminous efficiency. The general beam angle of LED fluorescent tubes is 120 degree. Almost all light is effective with the help of reflectors. In the view of many manufacturers and users, 120 degree is a narrow beam angle for fluorescent tubes. But this is enough in practical cases. As we mentioned before, the luminous efficiency of Philips T8 fluorescent tubes is 72lm/W, 36W fluorescent tubes can have an output luminance of 2592lm. Then the lamp efficiency of traditional fluorescent tubes is only 70%. Thus the valid luminous efficiency of the entire lamp is about 1814.4lm. Assumed that the luminous efficiency of LED fluorescent tubes is 100lm/W, a 18W LED tubes can have a output luminance of 1800lm. Sending out light with the same brightness, LED Tube Lights only consume half power than traditional fluorescent tubes do.

 

High power efficiency: All lights except for incandescent bulbs need special power supplies, including LED lighting products. Therefore, we need to take into account of power efficiency when we estimate the whole lamp efficiency. Take Philips 36W T8 fluorescent tubes for instance, the rated power of which is 36W. But as a result of accessing to magnetic ballasts, the actual measured power is 42.4W. The rest 6.4W is consumed by core inductors. Efficiency decreases to 85%. Most of domestic core inductors can consume more than 10W power due to their low quality, the power factor of them is lower than 0.512. Normally, the power efficiency of LED drivers / power supplies is as high as 90%. One 18W LED tubes only need a driver with output power of 20W. And the power factor is 0.9.

LED connection mode (series/parallel) and wide voltage range: in order to enable LED fluorescent tubes work under wide voltage range: 85VAC-265VAC, the connection mode (series/parallel) of LED tubes is fairly important. Current power supplies generally use non-isolated step-down power supply. In wide voltage requirements, the maximum output voltage should be no more than 72VAC, the input voltage range is 85VAC-265VAC. In other words, the series string number should be less than 23. Also need to limit the number of parallel strings. Too much current will generate more heat. Normally, 6/8/12 branches with the total current less than 240mA.

 

 

Relations between LED Tunnel Light series-parallel connection and PFC power factor, wide voltage range: there are three major cases of PFC power supplies in the market: a. without PFC special circuit, the PFC is normally about 0.65; b. with passive PFC circuit, the PFC is normally around 0.92; c. with active source 7527/6561 circuit, PFC can reach up to 0.99. But this case is twice as expensive as the second one. Comprehensively, b is the most commonly used mode.

 

Precision of constant current: some constant current sources in the market have a relatively low precision, like the popular PT4107/HV9910/BP2808/SMD802 constant current plans with an error of +/- 8% or +/- 10%. In normal condition, +/- 3% is enough. In this way, 6 branches with error +/- 0.5% for each branch, or 12 branches with error +/- 0.25 for each branch can meet such requirements. High precision will also increase the production cost of LED fluorescent tubes. But for LED lamps, 17mA or 17.5mA does not make too many differences.

 

Isolated/non-isolated: generally, isolated power supplies can make as 15W. LED drivers are too large to be embedded into LED tubes with limited size. Thus isolated power supplies can only be made as 15W tops, hardly find power supplies in the market with output power greater than 15W. In terms of LED tubes, isolated drivers have very low cost-effective. Non-isolated driver is the mainstream.

 

Power efficiency: the ratio of output power to input power. This parameter is very important. Low power efficiency means that most of the input power is converted into thermal energy and wasted. Such drivers will generate a large amount of heat within tubes. LED is a type of component that vulnerable to heat. Thus LED lighting fixtures need high power efficiency, normally no less than 80%.

Whether LED tube technology has entered the second stage and mature enough that can be commercialized, no one can give out a satisfied answer at this moment. There is also no LED Panel Light company that has done a complete 10,000-hour aging test. Many LED manufacturers have very limited knowledge about their products. Large brand LED fluorescent tubes usually have one-year warranty. The warranty of domestic LED fluorescent tubes varies according to the quality of products, from 1 year to 3 years. Currently, domestic LED interior lighting industry is under an unordered development. Lacking of cleared uniform standards, it is predicted that the price battle of LED lighting products will be continued for a very long time.

 

 

What are the differences between normal fluorescent tubes and LED fluorescent tubes? LED tube lights have higher quality, more durable and can save more energy, have wide options in beam angle, higher light efficiency (the brightness of a 15W LED Tube is equivalent to the brightness of a 40W fluorescent tube), can work in high temperatures, with anti-moisture/water-proof/leak-proof function. The commonly used covers for LED tubes are Glass cover and PC (Poly Carbonate) cover. LED tube lights use the most advanced lighting technology – LED, with digital appearance desighs, saving up to 70% energy. The service life of LED tubes is nearly 10 times longer than ordinary fluorescent tubes, almost maintenance-free.

 

LED tubes use green semiconductors as light source, very environmental friendly, soft rays, pure spectrum, providing more protection for human eyes and health. The 6000K Cool White light source gives a cool feeling to our eyes, which will make people be easier to concentrate and improve their working efficiency.

 

Currently, compared with traditional fluorescent tubes, LED fluorescent tubes have following advantages: 1) save more energy; 2) long lifetime; 3) Good applicability, since the small size of LED chips, they can be made in various shape; 4) short response time (several nanoseconds); the response time of fluorescent tubes is around several milliseconds; 5) environmental protection, no health-hazard metal waste, easy for recycling; 6) emit multiple pure colors (narrow spectral range, via combinations of red/green/blue rays). Disadvantages: 1) expensive; 2) great gap between theoretically light efficiency and practical light efficiency; 3) great gap between theoretically lifetime and practical lifetime; 4) the heat dissipation problem; However, all these defects can be improved by more advanced LED technology.