I've used some generic blue led modules to build a big clock with 7 segment displays.This modules have 5 piranha leds and resistors in a weatherproof enclosure (a brick of molten plastic).Modules look like this:They are rated for 12V, and a real datasheet is not available.After a year and a half of constant use, I've noticed that some of the leds are burnt, and most are not as bright as the new ones.
The display uses a sheet of white hight impact polyestyrene as a diffuser, and I've noticed that it turned light yellow where the led light it.So my first suspicion is that the modules are dissipating heat, and this is shorting their life. Or is it the UV light that yellowed the plastic?Modules are not warm to the touch. And there is no sign of heat on the MDF piece they are glued with hot glue. The sign is place inside, and summer temperatures can go up to 32 degrees celcius.
Would SMD LED strips last longer?
This modules include the resistors inside (you can see them inside the melted plastic brick).
12V come directly from a commercial switching power source with 2.5 amps capacity (Can this be blamed?).
Each led module consumes 40mA, and I have 42 modules.
Thanks fungus. In most of the cases a pair of leds dies, and the other 3 survive.
You are right, I was a victim of "EL CHEAPO" Leds Made in China.Problem is....everything I can buy arround here are from the same origin.