Diy led

[cabezon]

I used an old marineland 48" T5 fixture to make an actinic fixture for my 75 gallon.

I got a supply of LED and a power supply from afriend that orders from china. I gota great price and the total was $80 for the PS and 20 royal blue LEDs. he gave me 4 whites to bring the total to 4 rows of 6. the glue is $10 for enough to do 30.

on. it's insanely bright

you will notice that I blew a couple of LEDs and one group of 6 is not lit. I should have diagrammed out or thought more before i hooked up the parallel part. i had hooked up one too many wires.

Still just 15 blues and 3 whites. 54w, the power of just one of the T5HO

All my lights on, 2 white 54w 2 actinic 54w and then a 2x96 watt PC one white one actinic.

now all the lights with the blue

the picture does not do justice to the amount of POP. Tomorrow I will mess with optics to see if they help. I also bought some computer CPU heat sinks. they were bargain bin $1.99, so i got 7. they have fans too, I might put those on a separate wall wart. this thing gets hott.

 

[BigJim]

Nice work. How well does the light fixture work as a heat sink?

 

[cabezon]

Unfortunately the metal is too thin and gets too hot. I placed some heat sinks on the lamp and they got warm. Tomorrow I will attach them properly and wire up the fans.

My buddy uses L shaped aluminum on his at$2 a foot. Some have used box al beams too. LEDs get hot.

 

[BigJim]

Yeah, I'm aware that LEDs get pretty toasty. I've got some Cree XR-Es sitting at home that I'm going to use for a planted tank. I've been looking at heat sink options, but they're all so blasted expensive. $15 a foot was what I found. I was toying with the idea of using a square aluminum tube and liquid cooling it with tank water, but I've read that aluminum in aquariums can be toxic, so that was the end of that.

Where does your friend get angled aluminum for $2 a foot? What thickness does he use and how well does it work?

 

[cabezon]

I dont know the thickness, but it is probably about 3mm. it gets warm to the touch, but not hot. He gets it from a local metal supplier.

good idea about the tank water, i wonder if you can find the plastic tubing that is used in underfloor heating.

 

[BigJim]

I may have to try going to my local metal recycler. I don't know if plastic tubing will transfer heat well enough to work for LEDs, but I like where you're going with that. If no good heat sink option presents itself, I may try the water cooling with a remote reservoir or possibly an in-tank heat exchanger.

 

[Jnam]

heatsinkusa.com

they are pretty good. or for the Lchannel stevesleds.com has some by the foot that he pre taps for the star PCBS pretty inexpensive.

 

[BigJim]

I've looked at heatsinkusa.com. For a 20H, I'm looking at about $60 for the heat sinks to build the fixture the way I want it. Little rich for my blood. I think I can do better. stevesleds.com is interesting. I'm glad to see that he just uses some square tubing. I'll probably go that route if I can find it for the right price.

 

[Jnam]

square tubing with a pressure fan the concept is quite nice, but dont skimp on the heat sink LEDs are expensive and shortening there lives by running them hot realy defeats the cost savings over time the LEDs present over bulbs. FWIW