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Originally Posted by Al in Ohio
I just bought five 30R LED flood lights (rated 22 year life) ...
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So here's another scam being 'sold' to an uninformed public. Does the public know what 'rated lifetime' means? Probably not what most people think.
Capacitor selection helps achieve long lifetimes for LED lights | EDN
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ENERGY STAR is specifying a lifetime requirement of more than 25,000 hours for residential applications and more than 35,000 hours for commercial applications. They describe the L70* characteristic for the lamp. This means that the relative light output must not fall below 70% of its initial brightness value in less than the rated lifetime of the system.
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So all that means is that based on accelerated life testing, they expect the LED to still put out 70% as many lumens after 22 years of X/Hr/day use as it did when it was new.
It has nothing to do with the reliability of the circuit that drives the LED. And according to that article, electrolytic capacitors are used to reduce costs, and those LEDS get hot inside (even at ~ 4x more efficient than filament bulbs, they are still wasting most of the input energy as heat), and electrolytic capacitors are highly degraded by heat.
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If we look inside the power supply on the solder side of the PCB, it might be as high as 100°C, matched by the output capacitor which also shows a case temperature (Tcase) of 100°C. ...
Even the best capacitor on the previous chart would last only 15,000 hours at 100°C.
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And cheaper caps will only reach ~ 2,000 hours. With all the talk about how the price of LED bulbs have come down, I imagine they must be pinching pennies to compete on the shelf. I'm hoping this issue will be addressed in the future, another reason I want to hang on to my incandescents for a few more years.
-ERD50