DIY LED Fixture

[sudz]

Update: so all the mini drawings i've been doing for LED patterns and optics... Out the window.

I ordered 80 Degree Optics, and its WAY to focused. I can clearly see that no light is reaching the back of the tank. I'm going to go Optic-less. I think if I get a very high light carpet plant, I'll install one or two lens's overtop of them to focus, But on the whole, Optics = Too focused. Maybe if I got 120 degree optics it would have been better.

What gets me, is that with 80 Degree Optics, I expected the beam to get nearly as wide as the tank is tall. (about 80-85% ratio, at least) Its not close. The lights are 20 inches off the substrate, and the spotlight is about 12 inches across.

Also, the Fixture has been cranked for about 15 minutes, and First, my discus Hid, but after a while they came out and I fed them. (they wouldn't take it by hand this time though, Clearly not adjusted to the change yet)

The heatsync is warm. Maybe about 100*f.

 

[sudz]

Alright, its been cranked for 45 minutes now, The heatsync is still Warm but definately not hot. I think I can safely stay fan-less. I know that the LED's pump out significantly more heat when running at max current (1500mah) so if I ever want to crank it to 1300mah I'll have to revisit.

Also, These things are BRIGHT! Much brighter than my 108 watt T5H0, but that's just subjective. I don't know what the XP-G R5's put out in usable Plant friendly light, but I'd be tempted to run these babies at 1300mah and just forget about my T5's. It'd make for a much cleaner installation.

Also, My T5HO's are just a T5 kit in which I've put a T5HO ballast (and new bulbs) Turns out, Thermally, it was never meant for it, as the Plexiglass in front of the bulbs was melting slowly (Drooping, twisting, yellowing etc) It's been running for about a year, I'm lucky nothing worse happened. I've taken the plexiglass off, But am worried what else is going on behind the scenes. The ballast is mounted away from the lights, so I know that what melted the plexi is strictly the heat from the bulbs. I think I should be ok now, but worry about the wiring stashed behind the reflector (doesn't look melted... yet?)

Ohhhh Can of worms.

 

[angelvelez87]

Yeah i know what you're talking about!! But when you put the leds without optics the par readings go low! How many strings of leds you putted??

 

[sudz]

Just one string, About 3.5 inches apart from eachother.

After mounting it in my cabinet, its gotten to the point where its at my comfort level to touch - I think I'm going to have to get a fan on it. I wonder if I can use the 10 volt wall wort to power it as well as the dimmer. I'd hate to have to run another power line to it. Right now, all the power comes from one plug!

 

[sudz]

Definately too hot. I'm running them at about 600 mah now until I get a fan

 

[sudz]

My Crypts and Anubias are growing much faster. So is my algae. I think I need to get to CO2.

I have the driver set to 1000mah max, even though the lights can handle 1300. I did this for thermal reasons, and also the fact that i'm not running CO2.

It is subjectively 2-3 times brighter than 108 watts of T5HO @ 1000mah. Wish I had a Par Meter!

The Heatsync is inadequate. This is sad, because the LED's are permanently attached to it. I've added 3 40mm fans and a 12 volt wall wort. Because the box isn't vented, its still quite quiet. It's allowed me to run the lights at 800-900mah sustained, and the heatsync is just hot to the touch (barely uncomfortable to hold it for prolonged periods)

I'll need to jury rig something, or maybe vent/actively cool the entire enclosure to get the temperature lower if I want to crank it up to 1300mah. In the mean time, I'm VERY pleased with the light output from these babies @ 700-800mah. Just need some carpeting forground plants now!

 

[angelvelez87]

So even with the fans is too hot??

 

[sudz]

I think so. There are two "channels" which are closed in on the piece of aluminium. I might try and affix another fan to one side of it to get air flowing through the entire thing.

I'll take pictures of what I've done so far sometime today or tomorrow.

 

[sudz]

Some Photo's of the "finished"

Product

As an experiment, I have it upside down (facing up) with no fans on. The heatsync is warm after 15 minutes, but not as hot as it is with the fans on, while ontop of the tank. Definately going to have to vent it if I want to keep it cool.

FYI - My handywork is horrible. I mean, everything in here is from scratch, Limited to what I can do inside my apartment, etc... but yeah.

Also, I know its not mositure-proof wiring, however, there is glass infront of this and my fishtank. It's never gotten above 75% moisture, and its never consdensed. I used butt connectors for everything.


Off:

On:

fans:

Close up of LED's (off)

I'll take some better shots with my SLR, with set exposure to get you guys an impression of how bright these suckers are.

 

[scottayy]

Looking pretty good! You can tell that they are much brighter than the t5 bulbs. Those fans are pretty small and there's no place for the hot air to go.

Is this a 4 foot fixture? If you could, I think 2 120mm fans would work good (in addition to your 3 small fans, those are pulling heat away from the fixture (assuming the air flow is going the right direction) - but could remove these if you want). You could have one sucking air in on the left and another blowing air out on the right.

120mm fans can get pretty noisy but there are magnetic ones that make less noise than the traditional ones.

Either way, just get some venting in there and you'll notice a huge difference.

Nice craftsmanship!

 

[sudz]

Yeah, 4 foot fixture. They are 40mm ball bearing fans, 12 volt.

I have a few 120mm case fans laying around. Problem is I don't have a way to cut a hole in the enclosure for them. I'll have to figure something out. maybe I can buy a hole saw for my drill and do it that way. (8cm fan?)