LED Intensity
 

A question came up in a different thread, asking why almost everyone runs their LEDs at less than 100%, often much less. Why is that?

Does it not make sense, mathematically, that if I run 4 lights at 50%, I can get the same results with 2 lights at 100% ? Sure, coverage is a different, but lets say 3 lights, higher up but brighter, doesn't that do more than 4 lights at 60%??

So what do you run your LEDs at, and why?

I have my AI Sol, running at about 35% over my cube, I find anything higher is too bright, and ticks off the coral. From what I am seeing online and first hand, LEDs are right up there with MH in terms of brightness, but are not as prone to browning out corals.
I think that if you dont mind minor dark areas, you can definitely run them higher hang them higher and get the same results, also as we know many leds have options on optics that you can choose from, I believe AI has 70 or 90 degree, I cant remember which, but with a wider lens I see no reason that you couldnt run less lights at higher intensity. after all, to me 4 sols on a 4' tank seems like a waste, 2-3 would be more then adequate. provided they are suspended just right. It may limit what you can keep on the sand bed once you get to a certain height, as we know light gets less intense the deeper it has to penetrate, but for me, my softies on the sand bed and sps high, lps low to middle, it seems to be perfect! thats just my opinion though:lol:

When I first installed my Radions, I started them at 30%, and they were still brighter than my old T5's. I then raised it to 40%, but noticed that my corals were shrinking a bit, so I dialed them back to 30%. Since I don't have any SPS (only softies and LPS), I thought I would go even lower and see how they do. I am currently running them at 20%, and corals are doing better than ever now. Seems like my softies just don't like bright light.

I have a 6ft tank, 18" deep, with 3 Radions 8" above the water. I use the natural mode setting, so it gradually ramps up and peaks at mid day, and then down again to dusk. Then a low blue for moonlight thru most (totally off for about 3 hours) of the night.

From a mathematical perspective, you will have more uniform par if the lights are higher up, assuming you have lights strong enough. There will be a drastic difference between par at the surface and at the sand bed if the lights are in the rim. If you can raise the light up a few feet the difference in par will be less.

there is also the factor that constantly running an LED at 100% will cut its lifespan almost in half.

if you get the hights proper so PAR is the same yes you can do the same if not better with two as you will have better color blending and such. you will still get good life off the LEDs as they are rated to be run at there max power, and if you can keep them cool that will not be an issue anyways.

the issue you will have is less ability to customize colors as you already are at 100%, you will have more light spillage, and you will have a stupid fixture hanging 4 feet above the tank.

Steve

That makes sense, but when the industry is stating X number of years worth of life, at what intensity are they rating them?

That makes sense for color blending. I'm thinking run white at 100% then tweak the blue. Not actually having one makes for lots of guessing and assumptions :)
not thinking 4' off the tank, but maybe 14" or so.

its lifespan is determined by running at 100%.
what i think you mean running them at a lower percent will increase life.



I'm curious as how long till the spectrum starts to change, if at all.

I "Heard" once 5% per year at 100% but I am sure that not accurate, and could be more. also depending on the types of features you use (I.E) thunderstorms etc, it could cause varied results IMO.

The way I approached buying my SOL's was sort of trial basis. I only ordered one the first time, I was 90% certain I would need a second with a 48" tank but with shipping being free for one or two I decided to see what one unit looked like. It took about five minutes to decide one was not enough and ordered the second. This same principal will work for anyone even if you had to start with say 3 or 4 and add units if needed.

kinda my plan as well. I"ll start with 3 and see how that goes. Problem I have is that the tank may suffer before I can afford to buy more.:razz:

Ask sbux for a V.I.P. discount card... :lol:

Just wondering what is the difference between one 3w LED and the other?
Other then dimming and fancy controls what is the difference between AI sols and these
http://www.aquatraders.com/EVO-48-LE...ht-p/56234.htm
?
They have single fixtures 5" wide and double fixtures 9.25" wide. If everyone is running their "fancy" LED's at 35%-50% anyway?
Really want to know what is the difference. thx

Just leave your existing lights in place, when the new ones arrive just get a bunch of people together to do a mock up and hold the lights over the tank for you as you sit back say "okay a little to the left, now up..no no the other up, you know down" All the time adjusting intensity to see how you like it. If you decide you need more units the original light is still there until the other unit arrives and swap out then. :biggrin:

shut.up!

Oh, absolutely. I currently have a canopy that can just lift off. It will go to the side until I'm sure the new lights can maintain color. If not, they go back on until I can buy more units.

But I'll try to run closer to 80%+ on the whites to try and keep intensity while raising high enough to keep coverage.

My lights are hung under my canopy pretty much sitting on the tank brace, so mine are pretty close to the surface, which makes them super bright. This in turn has caused me to have the whites about 40% and the blues close to 90.

If I had a way to have them up higher, I'd probably run them higher just to get the same level of brightness.

Holy look like night time in there? What's your white to blue ratio?

the spectrum doesn't change on LED's only there intensity. and at there rated live they are usaly still at 85% of there new intensity. of course different brands/models will have different numbers.

as for the life span, running them at 50% or 100% will make no difference on life span if the junction temp is the same, so in other words if you can keep them below there max junction temp even at 100% the life will be longer. this is why it is very important to think out your cooling (heatsink/fan) setup when building your own LEDs. If you buying them you would assume the company did there home work to be able to allow them to be run at 100% while keeping the junction temp under the max.

Steve

You get what you pay for, with anything, AI has a proven track record as well as radions, sure the evo may have 3w LEDs but what do we actually know of the quality of the lights, etc. having features like dimming or sun rise sun set etc, is very ideal and healthy for the tank stimulating all aspects of a day/night cycle, something you can't do with out a controller. Honestly, and please dont take this the wrong way, but I have seen a couple of threads from you in regards to Evo Leds, and I just want to say that if you are considering jumping into LEDs that you make the right choice the first time, so as not to waste money (potentially) I would personally go with a light that has testimonial from people you are familiar with to back it up. it looks like it would be more suited for planted/refugiums or little frag tanks if anything, but for a main display tank I would put your money to good use on a good light :) just my opinion though :wink:

As far as ive heard, there isn't any spectrum change. I called up Cree and talked to a tech about it before I built my unit and he said as long as you don't over heat them, the spectrum will stay the same. Basically the shortened down explanation of what he said was that the compound that is used to give an led there specific spectrum is stable as long as it isn't over heated. So if you burn your leds to hot they can have a spectrum change because of the compound breaking down into something else Like the zinc based compound used in blue breaks down into something that makes it kinda purple when it gets really hot.

They aren't really line halides or t5 which actually burn a compound to create the spectrum.

Just what I've heard anyways!

Intensity guys, this thread is about intensity :)

for one they don't say what kind of LEDs there using, if they are using Cree (or another good brand) then no difference, if they are using some of the cheep ones that use a coating to get the color then the coating will break down eventually and these ones will give you a spectrum shift. there has even been reports of the coating pealing off in places. so it basically comes down to how the LED is made. you get the expensive high quality that use the actually metal of the diode to give off the color you want and you get the cheep and sometimes expensive ones that use a cheep metal to give a blueish color and then coat the dome with colored phosphorus to tune the color to what they want.

Also you want to check into the power supply and if it can be controlled. there are cheaper power supplies that are not regulated as much so this can lead to early failure, and controllability adds cost (although not much)

and finally what is there heat sink and how is the temp managed, you can get systems that use a aluminum heat sink that is enough on there own then add fans as a back up, and you can get systems that if the fans fail your system will be cooked. allot of the companies now are using a heat sink material as the circuit board and mounting the bare LEDs directly to it. nothing wrong with this as long as it is rated for proper thermal dissipation, some companies will do this but use the cheapest material they can find then over size fans. So you really have to looking to the construction and parts used in the system.

Steve

:lalala:

dude, get this out of my thread!! :razz:

what your against informational posts now :wink:.

simple answer. yes you can do it but you will never be able to increase the intensity unless you drop the lights. but you have several options. the higher you lift your lights the tighter of a vewing angle you can use which gives you more par/intensity as a specific distance and better blending as your farther away. if this is the way you are leaning I would sugest going with something like the 50 watt LED cannons you could have a blue and white right against each other for perfect blending and you could probably recess them into cealing fixtures using optice to controld how big the spread is. I think that would be the coolest setup. no visable lights, just pots mounted into the celing and yet a tank that is still customizable in light color and intensity. you could use electronic dimmers/controlers that mount into a light switch housing and are controled by your computer. now quite trying to drag out of me what I have been working on ;)

Steve

What you should do is try placing them in various different spots and seeing what you like best.

I have an illumina 260 and run the whites at about 45% and both blue at 100%. I prefer the colour at this intensity, and the light is ridiculously bright once you get much higher, even at blue at 100%. Once the UV add ons become available I may add some, and add more that at that time so the spectrum stays pleasing to the eye.

:lol: sorry Brad

I was on the fence about the AI's and Radions as well. What's the point of ordering 3 or 4 of them for a tank when it seems like everybody is only running them at less than 50 %. Also, they don't seem to have a very aesthetically pleasing hanging system, so I just ordered a pair of these from Jeff at J& L. Should be the first one in Canada to get them.

http://www.kessil.com/products/a350_led_aqua_light.php

I'm also very lazy and don't like playing around with programs. Set it and Forget it !

Well ya, but no. The question is rather than going with 4 or 5 or 6 lights at 50% intensity, why not go with less units, a little higher, at say, 80%? Most threads you read claim to run at much lower than full intensity. I'm sure visual coverage with three units in my case will be fine at 50 or 100, but what I'm concerned with is color of corals. I need to maintain that.

But more generally, just asking why most people run lower than 100. a single unit on a small tank is self explanatory, the lamp is clearly too powerful and you can't run less than one. But for 4' tanks, why run the lamp or multiple units at less than full, then buy additional lights to make up for it?

Pretty much my point exactly...

I run my AIs at 32% both white and blue (two on a 30x27x18" cubish). I cannot suspend them so if I ran at a higher % would blast everything as the tank is shallow. If you can suspend them up higher your idea of getting fewer should work and you should be able to maintain the colour of your corals. I don't have many SPS but the colour is pretty good on the frags that I have.

I know a lot of people were doubtful about leds when they first came into the hobby, so I hear, but after buying sps that had been under metal halides and putting them in my tank, they have 100% more color to them, and the rest of the corals seem to flourish under them as well.

What size tank are you thinking of for this Brad? for a 4' I cant see why you couldnt get away with 2 AI's as they cover a 24x24x24ish area with stock optics, with the wider ones I would imagine if hung at a respective height you could probably get close to 30x30x30 spread with a higher intensity. same thing for radions (aside from the optics part, I dont believe they have any):wink:

I have a DIY LED , it's a 72 led unit, 36 XPG white, 36 XPE blue and royal blue, spread out on a 4' x 1' heatsink 3 inches above the water on my 90 gal 48x18x24, no optics, my white drivers are set at 1.3 amp and my blue drivers are set at 1 amp, I run my whites at 85% and my blues at 100% it looks about 50% brighter than my 4 bulb t5 ho, I am LPS Zoa dominate and all growing well.
I think part of the problem with the AI and Radion units is the concentration of the LEDs

It's a 180, 72x24x24. Corals mostly cover a 60x18 area, so I'm going to try 3 SOLs, and blast them at near 100% and see what happens. (Not out of the box, but build up to it :))

I think you'll be fine, Martin would be able to confirm for sure, but if each light is capable of 24x24x24 area, there should be no problems. Personally, if I ordered one again I would get wider optics. I have a bit of dark on the top inch around the edge (no biggie) but its there, I can also eliminate that bu raising my light an inch or 2

For me it's because I only have LPS and softies and I don't want to torch anything. I think this is the case in the other thread. There didn't seem to be alot of feedback from SPS only tanks. I increased the white by 5% one day and there seemed to be alot of corals less than fully opened, could have been fine in a few days after an adjustment period but I have way too many corals to take the chance. There will always be a give and take regarding coral colors when switching lighting systems...some will look better some won't.

I guess that makes sense. Do you have multiple units? Or single fixture? If multiples, could you have gone less units at a higher intensity? Or would that still be too much, just more localized?