Projected LED Lifespan

[JamesL]

I have taken the plunge into the work of LED lights for my tank. And after buying them, it dawned on me that I don't really know how long LED lights are supposed to "last" or be usable for photosynthesis for the corals.

So I am taking the slightly lazy web approach to see what people have heard. I realize that LED lighting (as main lights at least) is fairly new for the aquarium hobby, so there won't be much long term data out there. I am coming from a metal halide mentality of needing to replace the bulbs every 6 months or so, and that definitely doesn't hold true for LEDs (it better not, or the wife will kill me ).

Thoughts/predictions?

[jestep]

What LED's are they?

High quality ones like Cree, Rebel's, GE's, etc., that are properly cooled and not overdriven can last more than 50,000 hours (~6 years continuously) and even after that they may still be at 80% of their rated intensity.

As long as you don't burn them out 10 years is not an unreasonable expectation based on normal usage.

[JamesL]

It is a BuildMyLED fixture. And the 6 years is about what I was expecting (since my MH fixture - not bulbs, but fixture lasted about that long).

[BuildMyLED]

Jestep pretty much nailed it. High quality LEDs will have passed a stringent set of reliability tests known as LM-80. Once an LED manufacturer has tested a product for at least 6k hours, they are able to start projecting LED lifespan based on a set of algorithms (which is defined by TM-21). In general, every LED manufacturing company claims their LEDs will last 50K hours to the L70 point (meaning the LED is generating 70% of the original output), but a small minority of companies actually have certified LM-80 results. Keep in mind, all of these tests only apply to the actual LED. To Jestep's comment, imagine two LED fixture companies both source the exact same LED from Philips. If one company has a poorly designed thermal management system, and one company uses a state-of-the-art thermal management system, the LEDs in the first fixture will not last as long as the LEDs in the second fixture. However, both companies are claiming a 50k hour lifespan, but this is obviously not accurate. Hence, one of my previous employees is currently chairing a committee for the IES (Illuminating Engineering Society) that is defining how to apply lumen maintenance projections to the lighting system, which is where the rubber really meets the road. These test procedures will really help consumers make informed purchase decisions concerning lifetime projections, but I only expect to see commercial lighting companies invest in these tests (which can cost tens of thousands of $$$s).

Having said that, a well-designed LED lighting system should last for many, many years in a controlled environment

Nick

[BuildMyLED]

PS - In my opinion, the LEDs are not the weakest link in most lighting systems, even though they garner the most attention. The electronic equipment (i.e. drivers) and mechanical equipment (i.e. active cooling systems) will be the first items to fail in reef applications.

Nick

[JamesL]

Thanks all for the feedback. The lifespan of the LED wasn't as big of an issue, I was more thinking of spectrum shifts. As MH bulbs get older, the light spectrum tends to change (to a more favorable spectrum for algae). I guess this is not a concern for LEDs?

[Timfish]

The problem I've seen both with fixtures I've built and with fixtures I've purchased is fan failure or fans blowing or sucking salt spray into the fixture (LEDs tend to be mounted closer to the water). Assuming there are no heating or salt issues and a 12 hour lighting cycle I'm expecting 11.7 years but considering thier safety over T5 and MH and from my calculations pay off is from 4 to 6 years over T5 and MH even a life expectancy of 6 years makes them a good argument in my book.

[BuildMyLED]

Thanks all for the feedback. The lifespan of the LED wasn't as big of an issue, I was more thinking of spectrum shifts. As MH bulbs get older, the light spectrum tends to change (to a more favorable spectrum for algae). I guess this is not a concern for LEDs?

Yes, LEDs can definitely shift color over time, but a quality LED lighting system should not see the major color shifts associated with MH arc tube deterioration. LED color shift can be traced to both the LED construction (materials used to build the LED package) and to fixture construction (i.e. optics materials).

Nick

[JamesL]

Thanks all for the feedback. The lifespan of the LED wasn't as big of an issue, I was more thinking of spectrum shifts. As MH bulbs get older, the light spectrum tends to change (to a more favorable spectrum for algae). I guess this is not a concern for LEDs?

Yes, LEDs can definitely shift color over time, but a quality LED lighting system should not see the major color shifts associated with MH arc tube deterioration. LED color shift can be traced to both the LED construction (materials used to build the LED package) and to fixture construction (i.e. optics materials).

Nick

Good to know. I am looking to a long life with my pair of BuildMyLED fixtures

[+JoseZ]

What kind of corals are you keeping under these lights? I've also been thinking of getting 2 bml fixtures for my 120g. How have your corals been doing?

[Timfish]

So far everything I've kept under T5 or MH has done as well or better under LED with the caveot of getting the right spectrum and intensity. One fixture I purchased (was NOT a BuildMyLED) had only cool white and royal blue and I was very disappointed by it. Coloration of corals is strongly influenced by spectrum and intensity. Here's an example of coloration influenced by intensity: http://www.austinreefclub.com/topic/24054-the-difference-a-12-inch-makes . With only two BuildMyLED fixtures there are going to be areas up high where light loving species will show good colors but personally on a 120 I would be inclined to go with three or four fixtures.

[+JoseZ]

Thanks for the info tim. It's a 4' 120g if that matters any. I'm pretty happy with my t5s my biggest dilemma is the fact that ill have to keep replacing bulbs. I have considered getting another t5 or halide fixture though the life expectancy and efficiency is what is swaying me towards LEDs and I've heard pretty good things about the build my LEDs which is why I'm leaning towards these.

[JamesL]

What kind of corals are you keeping under these lights? I've also been thinking of getting 2 bml fixtures for my 120g. How have your corals been doing?

My tank is mostly zoas, softies, a few photo gorgonians, but some candy canes at various levels, and a plat and brain in the sand. The big experiment is a small squamosa clam I have in the sand. The two BML strips are quite a bit brighter than my old 150 MH, so I think I should be good.

And the corals have been fine, in fact one leather seems to be doing better. Some teal paly's are starting to shift color I think, at least the ones a bit lower in the tank to a bit more brownish ... which is something a guy mentioned (his name espaces me right now, but he is Mr. Santa ) at C4 happened to him also with LEDs. Will be interesting to see what happens long term.

[+JoseZ]

Sounds pretty similar to what I have in my tank. Which fixtures do you have? After the lecture at c4 I've been kind of hooked on clams as well lol so ill probably end up buying one in the near future

[JamesL]

Sounds pretty similar to what I have in my tank. Which fixtures do you have? After the lecture at c4 I've been kind of hooked on clams as well lol so ill probably end up buying one in the near future

I bought two pre-made 48" reef spectrum ones from Aqua-Dome... I was in a pinch as my MH light konked out on me... but I have been very happy with them, not sure how I would have customized them any differently.

[+JoseZ]

Thanks for the input James. I'm thinking of doing the same then maybe adding a super actinic down the road. It's time for some new bulbs so I'd rather invest on some new lights.