- Joined
- Jun 7, 2007
- Messages
- 6,381
- Reaction score
- 4,853
- Location
- Waukesha, Wi
- What state or country do you live in
- Wisconsin
But that wasn't his question.. it was:
So does LED PAR Really Drop Dramatically over the course of a Year?
Does LED PAR Really Drop Dramatically over the course of a Year?
- Thread starter that Reef Guy
- Start date
- Tagged users None
But that wasn't his question.. it was:
So does LED PAR Really Drop Dramatically over the course of a Year?
jedimasterben
Bubble coral sting good
The answer to that was no, but the reason the OP posted this thread was because of that.
- Joined
- Jun 7, 2007
- Messages
- 6,381
- Reaction score
- 4,853
- Location
- Waukesha, Wi
- What state or country do you live in
- Wisconsin
Well I did a little research and came up with this chart..
That chart or ones similar to it show up all over..
Below is a link to crees study in pdf and pretty much mimics the curve above for led... Cree will obviously use the best conditions..
So at about 50,000 hours a led will be at around 60 percent of output or around 40 percent drop .. Again allot will be what leds, and how good of fixture you have.. Now that was a real fast look up and I am not even sure what leds those are...
http://www.google.com/url?sa=t&rct=...v6y7ZUB4bNJEv-g&bvm=bv.68235269,d.aWw&cad=rja
Again this is just to show they do drop.. I am not sure since I did not have time to research fully what leds were even used.. But it does show a drop...
That chart or ones similar to it show up all over..
Below is a link to crees study in pdf and pretty much mimics the curve above for led... Cree will obviously use the best conditions..
So at about 50,000 hours a led will be at around 60 percent of output or around 40 percent drop .. Again allot will be what leds, and how good of fixture you have.. Now that was a real fast look up and I am not even sure what leds those are...
http://www.google.com/url?sa=t&rct=...v6y7ZUB4bNJEv-g&bvm=bv.68235269,d.aWw&cad=rja
Again this is just to show they do drop.. I am not sure since I did not have time to research fully what leds were even used.. But it does show a drop...
Last edited:
jedimasterben
Bubble coral sting good
LM80 specifications (which determine the basics for testing lumen maintenance) are not really 'lab conditions' by any means, they're done at very high temperatures that will realistically never be seen by any of the fixtures we use since almost all are actively cooled. I would say that that chart is pretty accurate as far as generic/Chinese diodes, though, but I would probably expect the drop to happen sooner.
- Joined
- Jun 7, 2007
- Messages
- 6,381
- Reaction score
- 4,853
- Location
- Waukesha, Wi
- What state or country do you live in
- Wisconsin
Well the top chart also is for induction lamps and they will pick the worst case of other lamps to make their lamps look better too....
I think I am going to ask tomorrow what the maintenance factor we put into for leds when doing our lighting calcs... I have not done one myself in a while....
I think its really not output its spectral shift in color.. Halides and t-5 do that at a pretty fast rate where leds do but at a much much slower pace.
Last edited:
TJ's Reef
Valuable Member
- Joined
- Oct 26, 2013
- Messages
- 2,454
- Reaction score
- 289
- Location
- Everett, WA
- What state or country do you live in
- Washington
My educated guess would be that the overall luminous intensity would drop over time as the chart shows but think that the overall spectral output would remain fairly similar/stable with LED's. Possible exception could be Whites if the Phosphorous coating degrades, but that would most likely shift more towards Blue then. The inherent problem with Incandescent style lamps is that there spectral quality declines quite rapidly and usually towards a non preferential part of the spectrum ie; Yellow to Green. Time will tell for sure on these questions though as there are certainly a multitude of different LED fixtures out there over many thousands of Reeftanks now. For me, still a very sound choice and not that difficult or expensive to repair/replace emitters when the time comes. ReefBreeders sells lose emitters in most all wanted colors for $1.50 that make it quite easy to upgrade/repair most any of the Chinese imported fixtures out there. So if you are just a little bit handy you could probably get away with a $20-30 fix every 3-5 years and keep more than adequate lighting above your Reeftank.
Cheers, Todd
Color will also shift based upon temperature and current. You will not see that on the manufacturers data sheet. This is important to know if you are doing a DIY setup. I have seen a neutral white turn blue from being overdriven and not properly cooled. While the color may be preferred in reef applications, the output was severely diminished at that point. Certain LED's will be affected more than others. As far as different fixtures, as it has been said, cooling is the most important in maintaining the life and consistency of the LED's. There is also quite the difference in the manufactured quality of LED's. There is no question about that. There are cheap ones, and better grades. We test individual LED's all the time, as the spectral output is very important to the work we are doing.
Agree completely
It is so easy to replace an emitter in a Chinese fixture.
Mine is so bright on my 20 gal I had to put tinted glass on the tank to keep from burning corals. Current goes up when you turn down the leds, so they can burn out when underdriven. Couldn't reliably turn mine down low enough to please my corals. Hence the tinted glass. I have lost a few emitters but they were easily replaced and allowed me to alter the spectrum a bit.
120$ entry price is nothing. A few dollars for leds or 10s and 20 for t5.
Sps and lps
It is so easy to replace an emitter in a Chinese fixture.
Mine is so bright on my 20 gal I had to put tinted glass on the tank to keep from burning corals. Current goes up when you turn down the leds, so they can burn out when underdriven. Couldn't reliably turn mine down low enough to please my corals. Hence the tinted glass. I have lost a few emitters but they were easily replaced and allowed me to alter the spectrum a bit.
120$ entry price is nothing. A few dollars for leds or 10s and 20 for t5.
Sps and lps
jedimasterben
Bubble coral sting good
Uh, what? That's not how it works. Current determines intensity, more current means more light, and vice versa.
jedimasterben
Bubble coral sting good
LEDs are current driven. Their voltage is determined by the current that they are given. Dimming depends on the driver that you use, either PWM or analog.
jedimasterben
Bubble coral sting good
Crappy power delivery will do it every time.
jedimasterben
Bubble coral sting good
Pretty much. I spent right around $300 on drivers, ballasts, and power supplies for my LED/T5 build, but I got the highest quality parts that I could feasibly source, and I can be sure that they will continue to last right alongside the LEDs.
jedimasterben
Bubble coral sting good
I use Meanwell LDD drivers mounted to a custom PCB and power them using a Meanwell HLG power supply.
