Even after 12 million flashes, the long-term stability of the MBJ LED light source still looks perfect.
One of the main advantages of MBJ LED light sources for sun simulators is their excellent long-term stability compared to xenon flash tubes.
To prove the life expectancy and long-term effect on the spectral match of LEDs, an MBJ Sun Simulator LED light source is currently undergoing an accelerated lifetime test. So far, the counter shows 12 million flashes with a cycle time of 2.7 s, a flash duration of 195 ms, and no change in LED settings.
The figure shows the results after 12 million flashes, which corresponds to about 8 years of operation in a module production when testing 3 modules in a minute: the spectral match in all wavelengths bands is very stable and still very well within the class A+ conditions of 0.875 (blue line) to 1.125 (red line) required by the IEC 60904-9 Ed.3 standard.
During this time, it is not necessary to change the LED light source once! This means a real big saving in maintenance costs and in downtime that a lamp exchange entail.
Comparison
In comparison, the life of xenon lamps is much shorter. It is recommended that xenon lamps in a sun simulator be replaced after 100,000 flashes. Even assuming that in production lamp replacement occurs only after 300,000 flashes, the lifetime is equivalent to only ~69 days. (If the spectral match is still within the standards limits at all). This means that over a period of 10 years, about 240 xenon flash tubes are needed, assuming 4 flash tubes per sun simulator in a typical sun simulator for the larger area solar modules.
Due to the significantly longer lifetime, less maintenance costs for the hardware and less downtime for maintenance, the investment of an MBJ LED Sun Simulator will pay for itself in only a few years.