What does a life of 50,000 hours mean in the case of – LEDs?
50,000 hours would imply a service life of 5.7 years if the light is operated for 24 hours in a day, 7.6 years if the lights are on 18 hours per day and 11.4 years for 12 hours a day.
LEDs are measured as lumen depreciation as unlike conventional light sources that reduce in output and eventually fail, it is not normal for LED products to suddenly fail. Instead, the light output reduces over time.
The normal convention is to measure the life from when the output has reduced by 30%, i.e. when there is 70% light output remaining from the initial lumen output. This is often quoted as the L70 life and is measured in hours. The “median useful life” of the LED luminaire is based upon the time elapsed until 50% of the LED luminaires in use reach the stated depreciation.
What are the factors that affect the lifespan of the LEDs?
The thermal management is an important factor that can affect the lifespan of the. Appropriate heat sinks have to be designed to prevent premature failure of LEDs.
It is also important for the correct driver to match the LED chip. Running LEDs at currents higher than specified make the LED run hot. For example, if the driver produces 700mA but the LED needs 350mA, this will put stress on LED and reduce its lifespan.
Environmental temperatures and LEDs
Higher ambient temperatures than the ones that the LED is rated for will also reduce its expected life.
Unlike many conventional lamps, LEDs are semiconductors and their life span is not affected by the number of times they are turned on and off.
