- Jan 20, 2018 -
When a manufacturer said the LEF will last x number for hours there are two factors on the product side Ln where n = the % of the original output. So L90 would be 90%. Some manufacturers can be a bit slippery with this figure and there isn't any constency with what number they have to use. So two manufacturers could say 40,000 hours but one could be to 75% original output the other could be 40%, obviously that's a big differenc. The other is Bn where n = the number of failure B50 would be point at which 50% of the test batch has failed. The higher the B Number the more likely it is that you will see the stated life time figures. Professional grade products will often say for example 50,000 hours L75 B70. But consumer level products often dont.
as you say the electronics are the weakest link although many of the components are in theory rated up to 50,000 - 100,000 hours so they shouldn't effect the life too much. An important point to consider from the above is that LEDs do not die ( the electronics might) they just get dimmer and dimmer to the point they are not fit for purpose. Your purpose might be different from others and you might find them too dim later of earlier than others even if your product is with in the manufacturers stated life times.
from personal experience I have had 6 early generation LED bulbs form Phillips for about 6 years and they are all still fully functional and no sign of diminishing yet. ( they were free but even if I had paid for them I'm sure they would have been worth it)