# Placeholder: DIY LED fixture (oh ya, I am still at it!)



## Gomer (Feb 2, 2004)

I have parts on order so it will be a bit before I can show anything in hand, but I thought I would post this to let the small LED followings know of a thread they may want to subscribe to 

So, I have been doing this thing for a while and LEDs are about at the point where it isn't bloody painful to use on something larger then a nano. I started this out way back showing that a 7x1watt Luxeon array could grow plants as well as (arguably better) then a 7watt PC. My next substantial project used 12x Luxeon K2 @ 700mA over a finex 4g. This project worked really well. Plants THRIVED in that tank. Algae was extremely trivial and I had a TON of light in there (where stem plants would grow somewhat horizontal over vertical). So now I am stepping this up to a more ambitious project, but we first should put this into perspective.

The K2 project used 12x Luxeon K2s driven at 700mA WITHOUT any optics. Since the LEDs were about 4" from the water surface, I didn't loose tons of light, but I did lose a fair bit. I probably lost maybe 40% of my light due to spill and total internal reflection. For a base, those LEDs put out about 70 Lumens at 700mA, so the total output was about 12x70=840 Lumens. Figuring in losses, I got around 500 lumens into the tank.

The new project still uses 12 LEDs but times have changed. I'll be using 12x Q-bin XR-Es which put out, oh, about 190 Lumens @700mA. They will be driven with a pair of 700mA Xitanium constant current drivers. This puts their total output of light at 12x190=2280 Lumens. The plan is to use a pendent sort of system for an open top tank. To avoid a lot of loss, I'll be using Ledil 30deg (1/2 angle) CRS-W optics which are about 90% efficient. given the angle and focusing, about 85% of the total light should make it into the tank resulting in an estimated 1940 Lumens of usable light. Compare that to a 70watt 6500k bulb which puts out about 4100 lumens which maybe 50-60% (figure in spill + restrike + total internal reflection) actually makes it to your carpet plants.

So there is the teaser. Lets see how this unfolds over the coming weeks


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## TNguyen (Mar 20, 2005)

subscribed!


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## JensR (Sep 21, 2006)

Looking forward to your tests.


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## treefish (Oct 10, 2007)

Godspeed


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## spypet (Jul 27, 2007)

Gomer, I played with LED's a while back,
and found their light lacks much red spectrum.
what type of LED's compensate for this?

*normal lighting*








*LED lighting*


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## Gomer (Feb 2, 2004)

Not all LEDs have the same spectral curve
Not all popular aquarium lights have good color rendition 

What LEDs did you play with? If high powered ones, what color bin?


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## evitagen22 (May 1, 2007)

As an EE, this stuff is really interesting. These are definitely not the LEDs I'm used to seeing on circuit boards. Could you post a link to the data sheet of the LEDs your planning on using. Thanks.


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## ColdServings (Oct 8, 2007)

subscribed


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## slickwillislim (Oct 11, 2005)

I remember seeing pics of your last set up. I can't wait to see what you come up with here. I am using 36w cf pendant style light on my 5g and I would love to trade that for a more focused light source.


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## Gomer (Feb 2, 2004)

These are the LEDs I will be using. I recieved my 12 in the mail the other day. They are Q bin, but i forget the color bin. Might be WG.

http://www.cree.com/products/pdf/XLamp7090XR-E.pdf

Depending on the intensity, I'll either be making a "low light" dual pendant for my 40g, or a single high power light for a tank I don't own yet LOL.


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## mhoy (Jun 12, 2007)

Interesting project. 
Any worries about heat dissipation?
Would you mind posting expected costs of the various components?


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## Gomer (Feb 2, 2004)

Now worries at all. Pulling away the heat is engineered into the plans  I'll post costs up later. I am still waiting for the optics to get here (being shipped in from Europe.)


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## Gomer (Feb 2, 2004)

well, I got my optics and LEDs...now I just need to get the heatsink.

Here is where I am stalled. Do I keep it as a 12LED system and see how it does for a duel mini pendent system, or do I expand it to a 25 LED system and start up a reef tank. I guess I need to run the numbers to see what I can afford since it would be all custom in the end LOL.

And as for cost, the LEDs are 7.75 each, the optics are 3.50 each and the 2 drivers I'll use to power them, I THINK I got them for $20 each a while back. The heatsink will probably run me another $20, $10 for the thermal epoxy and probably $30 in other misc stuff (fan, enclosure materials, power cord etc).

Estimated total=$235 for an LED hanging pendent. As for what equiv MH this would be, time will tell. If it works out to a 70watt DE system, consider that the e-cheapo viper runs $150 plus $50 a pop on bulbs.


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## Gomer (Feb 2, 2004)

*It took a bit of time, but ehre is SOME info. This is a cut and paste from a reef site. I hope to have a FW tank shot also for comparison. This will likely be used for a 30cm ADA cube once I can save up enough. The light is in the 7000k area (guess). WHite with a tint of blue. In the photos below, it will look yellow, but that is how it ends up with reef inhabitants (ever see a 6.7k over a reef? )*

*IMPORTANT INFO!!!*
This tank almost crashed recently. The corals look bleached cause they are. Fortunately, they are all still alive and I hope will all recover in time.

That said, here is the info!

Remember, this light is NOT setup for a reef (ie, I didn't include ANY blue LEDs. They are all "white".)

Photo set 1: 
All photos have the same color correction. The color shown is representative of the actual color in the tank
All photos are shot with the SAME shutter speed, SAME iso, SAME balance, SAME 1/f. ie, you can DIRECTLY COMPARE.
Image guide:
Stock (1x10k, 1x50/50, 1xactinic) //// 1x10k only 
1x 50/50 & 1x actinic //// no image
12x 700mA Cree XR-E Qbin @ 1" height //// @ 6" height










Photoset2:
 All photos have the same color correction. The color shown is representative of the actual color in the tank
All photos are shot with the SAME iso, SAME balance, SAME 1/f but NOT the same shutter speed,. ie, you can *NOT DIRECTLY COMPARE*. You can however use shutter speeds to indirectly compare.
The base image (1x18watt 10K bulb) is shot at 1/30sec.
Image Guide:
Stock (1x18watt 10k) 1/30sec //// 1/30 LED //// 1/40 LED
1/50 LED //// 1/60 LED //// 1/80 LED
1/100 LED //// 1/125 LED /// 1/160 LED









each LED is about 2.5watts for a total of 30watts

1/60=effective 1/2 LEDpower
1/120= effective 1/4 LED power

To my eyes, the intensity of the PC stock (1x18watt 10K) is about the same as the LED at 1/125sec. This is the same as saying, the LED light puts out about the same effective amount of light as 4x18watt 10K PC* By effective, I mean the amount of light that actually makes it TO the coral.

*Keep in mind that the LED is more like a MH and acts more like a point source, so the edges are darker and the center is brighter to that of the PC comparison.


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## Gomer (Feb 2, 2004)

TOmorrow, I'll try and get a photo comparison of the 30watt LED setup vs a 36watt AH supply 6.7k setup. It doesn't get much better than that. I wish I had a good scape to test it out in though  Instead, you get a half-assed tank with algae


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## spypet (Jul 27, 2007)

Gomer, can you throw anything RED into that tank before your next series of LED lit photos. thanx.


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## Gomer (Feb 2, 2004)

I do not own a single red plant. I can see about some red object though


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## Freshwater (Oct 22, 2007)

Hey Gomer, 

Great post, I was reading the specs on the link you provided to Cree. Now I know just about enough to be dangerous (9 years Biomed Eng.), but am I understanding that by varying the voltage you can control the "temp." of the bulb? Say per the cool white led from 5,000k to 10,000k? 

If that where the case, you could get into more realistic photo periods, gradually raising the light output and temp. of the light to better mimic nature. Just a thought, I might be off base.


Todd


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## slickwillislim (Oct 11, 2005)

I would be interested to see the led's over a color chart or something, then compared to a regular cf light. 

That would seem more effective to me, especially since I don't really know what color that reef's supposed to have.


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## Gomer (Feb 2, 2004)

Todd, sorry, but you are missunderstanding how LEDs work. There is a different voltage drop across an LED depending on the driving current (LEDs are current devices, unlike most things you are used to which are voltage). The color change is by changing the phosphore on the blue LED (which all white LEDs are).

Will, in about 10 minutes, I will have what you are looking for!


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## slickwillislim (Oct 11, 2005)

From the pictures the red looks a little dark, but that could be the position of the lighting. The LED also looks a little yellow to me. 

This is all nitpicking compared to how it grows plants though, at least for me.


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## Gomer (Feb 2, 2004)

I'll try and repeat this again tonight without outside light


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## Gomer (Feb 2, 2004)

ok, new pictures taken at night.

Again, all images are directly comparable. Exact same settings for all images

2x39 T5HO GE Starcoats
1x36watt AH Supply 6700k CoraLife
12x Cree XR-E (~30watts)


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## epicfish (Sep 11, 2006)

Good setup so far Tony. Still posting on this over at NR?


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## Gomer (Feb 2, 2004)

sure am  I am debating right now if I want to sqeeze in some blues/royal blues and retro my biocube.


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## epicfish (Sep 11, 2006)

I've been following too many LED threads and have gotten myself confused, but are you using a PWM driver to drive the LEDs?

I have a similar setup but with various colors being driven by a PWM driver so that I can alter the color temperature as I see fit...still in the tinkering stages of this though.


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## Gomer (Feb 2, 2004)

I am using a pair of 700mA constant current Xitanium (Advanced Transformers) drivers.

The only way you can change the color on a white LED is if it is multi diode (like an RBG), or if you under/over drive it.


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## Gomer (Feb 2, 2004)

Right now I am going through a few thermal checks. I did the 5min runtime and the heatsink was cool. on the 30min one right now (with all lights on)

what I did:
1) cut my cree light in half
2) removed my third light (nanotunners upgrade)
3) cut the reflector
4) installed 2 1" vents above the heatsink (i'll get photos later)
5) spliced in the driver to one of the PC power lines
6) sealed up most of the air flow by the fans and made both fans blow outward (this forces cool air in through the vents above the heatsink
7) test to make sure nothing catches on fire
8) bask in the glory of this wonderful little lighting upgrade.

Tank shots to come (albeit over a "sleeping tank with bleached corals) in an hour or so after it passes a longer term heat check.


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