The advantages and disadvantages of the LED Light Tube with built-in power

Currently, almost all the LED light tubes in the market are manufactured with built-in power supply. What is the built-in power supply? It refers to the power supply can be placed inside the LED light tubes. The biggest advantage of such built-in can be made is a direct replacement for existing fluorescent tubes without make any changes to the original circuit. So, the built-in power is usually designed for strip shape so that it can be easily placed into the semi-circular LED light tube. Now, there are two kinds of built-in power supply. One is non-isolated series (picture 1) and the other is isolated series (picture 2).


non-isolated series

( picture 1)

The non-isolated series means that the LED load end is directly connected to the 220V input. So, there is the danger of electric shock when touching load end. For this reason, the non-isolated series usually cannot pass the CE and UL identification easily.


isolated series

( picture 2)

The isolated series means that the input and output are isolated by a frequency or high frequency transformer in order to avoid the risk of electric shock. So, it can be verified easily from CE and UL.


1. The power consumption of built-in LED light tube

We know that the traditional fluorescent lamp is started by a series iron-core inductor and a parallel starter. For this circuit, you only need to unplug the starter when replacing the traditional fluorescent lamp with LED light tube.  However, the iron-core inductor is still in the circuit and brought nearly 6.4W to 10W power consumption. As a result, the efficiency of power-saving of LED light tube is greatly reduced by the additional power consumption. Let us make a comparison between 20W built-in LED light tube and 36W traditional fluorescent lamp. The test data show as below:


parameter traditional fluorescent lamp 36W
built-in none-isolated power built-in power plus ballast external power
power 42.4W 25.6W 30.5 22.18
efficiency 84% 78% 65% 90%
power factor 0.51 0.946 0.916 0.99


2. Heat and life

Another disadvantage of built-in power supply is short life. The light tube must be designed for semi-cylindrical shape because the power must be placed inside the light tube. Such semi-cylindrical surface area is not enough for heat radiating.




Moreover, power inside the light tube will also produce some heat. So, the life of built-in power LED light tube will be shortened greatly by its bad performance of heat radiating. The facts have proved that the lifetime of the built-in power LED light tube is not more than 10,000 hours.

3. Cost

Compared the life of 10,000 hours of built-in power to the life of 50,000 hours of external power, the use of cost obviously high five times. Besides, built-in power LED light tube must be abandoned when power or LED is damaged.

In addition, the built-in power increases the cost of recycling electronic waste because the power section must be ripped out and dealt with separately.


4. Other functions

External power supply is not only for high efficiency and long life, but also has the special function of manual dimming or automatical dimming.


In a word , the disadvantage of built-in power LED light tube is very serious. Unfortunately, most people just covet it may be 10% cheaper at the time of purchasing, regardless of its high cost of use.

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