LED lamp needs correct understanding on its light efficiency value

　　Talking light efficiency on the level of LED light, there will have the problem of nominal luminous efficiency and actual luminous efficiency. For example, the round-off power of an LED tube is 2W and its total power of LED lamp beads is 16W. The total luminous flux of the lamp beads is 1600LM. After passing through PC lampshade, the flux is 1400LM. Then there will have the following three cases on the labeling of LED tube for different manufacturers:

　　1. One LED lighting manufacturers marked its luminous efficiency as 100LM / W on the LED lamp. The algorithm used is 1600LM dividing by 16W (the power of lamp beads), which seems to be right.

　　2. One LED lighting manufacturers marked its luminous efficiency as 89LM / W on the LED lamp because the algorithm used is 1600LM dividing by 18W (the power of lamp beads 16W plus the power 2W), which also seems to be right.

　　3. One LED lighting manufacturers marked its luminous efficiency as 78LM / W on the LED lamp because the algorithm used is 1400LM dividing by 18W (the power of lamp beads 16W plus the power 2W), which seems to be right too.

　　Then which data is correct? ENELTEC will tell you that the light efficiency of lamp is the ratio between luminous flux of the lamp and the total electric power the light consumes. Therefore, only the third one is the right light efficiency value.