Working temperature of LED chips is one of major factors that lead to light attenuation of LED lamps. In accordance with the aging test results of single white-ray LED lamps, if the surrounding working temperature is 30 centigrade, then the bracket temperature of single white-ray LED chip will not be more than 45 centigrade. In this condition, the service life of this single LED chip is “ideal”.
If there are more than 100 white-ray LED chips work together. The distance between them is supposed 11.4mm. Then the bracket temperature of LED chips on the edge may not surpass 45 centigrade, but the temperature of LED chips in the center will be more than 65 centigrade. Theoretically, in this situation, LEDs in the center will suffer a much fast light attenuation then LEDs on the edge.
As we all know, LED cannot stand the heat. The higher the temperature, the shorter the lifetime of LED chips, vise visa. The ideal working temperature of LED chips is from -5 centigrade to 0 centigrade, which is impossible. So that, after learning the ideal operation parameters, designers and engineers need to strengthen the heat dissipation performance of the entire lighting fixture.
Another factor that may cause fast light attenuation of LED lamps is the electronic parameter of LED chips. Working under low input current, white-ray LED chips generate low heat, and consequently low brightness. The driving current of LED solar-related LED lamps is around 5-10mA. LED lamps utilized a large number of LED chips, like more than 500 hundreds, may need higher driving current: 10-15mA or more. The driving current of general lighting applications is around 15-18mA. Very few engineers would like to make the driving current more than 20mA.
Corresponding experimental data shows that, under 14mA driving current, without any cooling solutions, the internal working temperature is 71 centigrade, the light attenuation of good quality LED chips is almost aero after 1000-hour constant work, and only 3% after 2000-hour constant work. However, this is the worst working condition that good quality (low light attenuation) white-ray LEDs can endured. Working conditions worse than this will cause huge damages to low light attenuation LED chips, speeding up the light attenuation of LED lamps.