DIY LEDs - The write-up

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<a href=showthread.php?s=&postid=15130891#post15130891 target=_blank>Originally posted</a> by Soundwave

2. I've killed a few corals but bleaching has never been the case.
What caused the coral died? Thanks.
 
<a href=showthread.php?s=&postid=15128665#post15128665 target=_blank>Originally posted</a> by lilmonster
What are the 2 UV lights for?
are they for the shimmer effect?

I read on this nano related site that some say sps and clams need close to this spectrum, they suggested using these LEDs to provide it. I would imagine that they also help with fluoresce.

Jerome
 
<a href=showthread.php?s=&postid=15127220#post15127220 target=_blank>Originally posted</a> by jimnrose
heat sink design - I'm designing a 16" x 60" LED fixture for a 24" x 72" (x 17") tank. Initially I looked at the solid heat sinks but the weight& price were prohibitive, plus the heat sink is mounted horizontally which isn't ideal for convection flow. So, I'm going with 5 aluminum channels (1.5 x 1.75") on 3.5 centers with cross straps (physical & thermal use) as well as aluminum vanes to enhance convection flow. [The vanes will also behave as light shields to avoid viewers looking at the leds]There are 6, 3" diameter fans (3/side) to blow air across the fixture. The LED's are on 5" centers with a 50% mix of white & blue. The fixture is in a wooden enclosure with slots along the horizonal panel for heated air exhaust. I'll also use optics to control the light beams. Jim

Do you have drawings or photos? I'm interested in your use of the aluminium channel instead of heat sinks. Have you been able to take any temp readings to see how that compares to using the gigantic extruded heat sinks others have used?
 
Hmmm thanks.

Hmmm thanks.

I thought that the more points of light, the more muddled it would look but perhaps it is more dependent on the size of the light source that makes it look defuse. I was looking for the brightest LEDs on the market and it looked like the Luxeon K2 for white light and the Luxeon V for blue light put out the most. Is that not true? Is the Cree just a better quality LED?
 
Hi all -

I've started my own project making LED spotlights for T5 supplementation (shimmer). I've been taking pictures along the way and plan to post them when I'm done.

I'm having some trouble though, and I think it might be related to some shorting happening while the LEDs are screwed onto the heatsink. I am using an aluminum CPU heatsink, #6-32 stainless steel machine screws, and #6 vinyl (or was it nylon?) washers under the screwheads. I thought I had sufficiently isolated everything to avoid shorting, but the lights still won't come on. They work when taken off the heatsink.

I'm thinking of using nylon screws (if I can find them) to see if that helps.

Is there anything else I can check, something I'm not thinking of?

Thanks!
 
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qfrisco; On your turned off system use an ohm meter to hunt down your problem. Measure from a bare un-anodized place on the heat sink to the power pads of the star to see where your problem is. Then you can properly address the issue.
 
Okay!

After taking a week to read this thread I am 90% of the way there before buying.

There is just one thing I can't figure out.

I am going to use the medium ripple optics as some have had success with them. http://www.ledsupply.com/10210.php

Since the spread will be less, I can't figure out how many led's I should add to a 24''x 5'' heatsink to get even coverage without a spot light effect between the leds. Any thoughts?



Tank is a 36 gallon corner tank. It looks identical to this one
http://op5.triadinet.com/elmers/nlcatalog.asp?rt=1&loc=nlsearch.asp&args=action|search|searchfor|36b|searchby|bydesc
 
Re: Hmmm thanks.

Re: Hmmm thanks.

<a href=showthread.php?s=&postid=15132831#post15132831 target=_blank>Originally posted</a> by herring_fish
I was looking for the brightest LEDs on the market

It really depends on what you mean by "brightest." Do you literally mean the highest output?

Or, do you mean the most efficient?

For instance, you may have LED brand A that puts out 250 lumens @ 700mAh, and brand B puts out only 100 lumens @ 700mAh. Brand A looks like the clear winner. But, if you look at voltage drops, you may find that brand A is 12v, but brand B is at only 4v. Suddenly, brand B is the better choice, even though it's not as "bright." You could run 3 of them off the same power supply it took to run one of brand A, and you'd get 300 lumens for the same power consumption, instead of just 250.

As I've been planning my system, I've looked at lumen output per watt (at the current I'd most likely run an LED), since IME this is the best measure of "brightness," since it takes into account efficiency, and not just absolute output. Most of the white LEDs people are using on these projects are around 80 - 100 lumens/watt, so there is some significant difference even among the "best" out there.
 
You’re giving me a lot to think about. When I was doing my research, I was looking at maximum light output, regardless of consumption. I found that Luxeon K2 and V put out 200 lumens for 6500K and 700mW for 455nM respectively. This was because of the minimal point shimmer theory. Since you guys have debunked that, I have some rethinking to do. Thanks
 
Oh boy, I just thought of something. Because of the weird shape of my tank and the limited spread of LED's, I might have to change how I arrange my lights in the heat sink.

Looks like I will have to make somewhat of a triangular heatsink.

Looking at the photo in the link I gave, anyone have suggestions for me? I've got all the equipment picked out, I'm just struggling with the light setup.

http://www.aqueonproducts.com/assets/011/17999_400wh.jpg

Edit: Added a pic of the tank
 
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I'm not sure if I got size of the tank right, but here is two options you can use:

First one is just put 24"x5" heatsync as is.
Second is to cut it into 3 parts: 10", 6" and 6"

81917corner.jpg


Hope this will help you.

I like second option because it should reach into corner unlike single 24" heatsync. Also, you will have freedom to move those around if needed.
 
Channel sink question: I haven't started on the build and just locked into a channel available in a mill finish. The 1.5" x 1.75" channel (5, 60" pieces) cost $80. The design is on paper & I don't have the software/hardware to digitize it. The concept is to use light bars instead of a solid block. My tank is only 17" deep therefore I'll only need 60 LED's (12/channel) on 5" center and offset the LED's on adjacent channels 2.5". If I had a 24" depth then I'd use 72 LED's on 6 channels. Sorry for not providing drawings. Jim
 
Looks like I will be doing a big set of LEDs, one of the locals sold me his 125G tank today with everything live stock and all, there is a tone of coral and 300lbs of live rock and 14 fish, a really nice 8" purple tang. Here's the killer everything is just almost year old and he sold all of it for $100 bucks. I'm going to ditch all the lighting I got and go with LEDs. I also need to add pictures of my 30G tank with the LEDs on them.
 
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<a href=showthread.php?s=&postid=15144400#post15144400 target=_blank>Originally posted</a> by webbrage
I also need to add pictures of my 30G tanks with the LEDs on them.
Yes please :) .
 
jimnrose; I don't think you need milled.. Just any old extrusion should work. Probably cost 1/3 too.

Nice score webbrage.
 
<a href=showthread.php?s=&postid=15133898#post15133898 target=_blank>Originally posted</a> by kcress
qfrisco; On your turned off system use an ohm meter to hunt down your problem. Measure from a bare un-anodized place on the heat sink to the power pads of the star to see where your problem is. Then you can properly address the issue.

Thanks, kcress. Great suggestion - I did just that and found exactly where it was. I'm wrapping up my project now - will post pics soon!
 
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