How to Reckon LXXBXX Lifespan of Fixture in Fast Way

Street light bidding would always have a LXXBXX lifespan requirement for LEDs in LED fixtures. How could we figure out LXXBXX lifespan in a fast way?

1. Finding out fixture thermal-test report @25°C. For example, like our ST36-150 street light. See below. You could see that at 26.375°C, the max temperature of LEDs is less than 66°C.  

2. ST36 is using the 3030 type of LEDs. If the bidding requires L80B50 over 100,000 hrs, let’s check if below brand 3030 could do it. Below is a chart of Presumption of Lifetime(B50). In the fixture temperature test report, we already know the maximum LED case temperature is less than 66°C. The junction temperature of LEDs would be higher than LED case temperature. I usually add about 10 DEG. Let’s say the junction temperature is 76 DEG. We could see L80B50 at the 80DEG junction temperature of the LED is 184,647 hours. So we could definitely say this brand of LED would meet this requirement.  

By using this way, it could figure out LED lifetime in a short time. All you need to do is check fixture temperature report and LED LXXBXX lifespan presumption chart.