LED par over time

[TOTAL AQUARIUMS]

I know the LEDs are still relatively new to the hobby but the original solaris lights have been out for awhile now. Has anyone posted up par ratings after a year or so of run time? I've been following a lot of the DIY LED threads as I'm sure most of us have and initially they look very promising. I am hearing that the par might drop at an accelerated rate as compared to halides. If there is a drop off, is it exponential or a slow degradation over time? I can't find anything showing long term readings on LEDs.

Any members on here with LEDs for around a year feel free to chime in with your experiences and observations. I would love hard scientific evidence to support anything at this point, but general observations will also work or maybe give a starting point.

 

[Marteen]

You wouldn't expect to see a drop off in LED performance until at least 10 years. They are rated to run for 50,000 hours or roughly 13 years of normal performance. That is taking into consideration you aren't overdriving them or cooling them inadequately. LED's should last much longer than any MH bulb you'll find.

 

[TOTAL AQUARIUMS]

I know they will produce light for 50,000 hours but the PAR can drop before the light dims. I actually did the math on it and at 50,000 hours for 8hrs a day (average)you have 17.12 years roughly. I'm also working on electric costs of halides versus the LEDs over the same time.

 

[reefman]

i dont think its the par that drops over time thats a concern. its the increase drop in intensity over the depth thats more of a concern to me. led can retains its performance many time other lightings. i believe wingo has some data on this.

 

[TOTAL AQUARIUMS]

There has to be some sort of degradation of PAR over time if the light has a limited useful life. Also, I'd imagine each type of LED is going to have a variance depending on what materials are used in it's construction.

 

[Aqua Pro Builder]

I cannot say if the par will drop,significantly or not, as I have not performed a test on it nor did I spent enough time thinking about it. However, there is an failure event for white LED to shift color over time. The shift affects lumens more than par I think. Most white LED will shift to more blue over time in LED technology. Some LEDs even start to have this issue as soon as 1,000 hours of operations.

In such failure event, Lumens drop will be more dramatic than par(if it even dops at all) as lumens are multiply by a function to show the sensitivity of our eyes for the same amount of light energy while par meters does not apply that function.