DIY LED Lighting Fixture

[keno]

DoctaQ;

i am doing a similar build for a friend of mine, i plan on using 16 leds to get the better coverage on the ends of the tank. i also plan on using that driver i linked to. what do you think?

I am very interested in knowing how the AC driver's work out. Get some current readings when you are done.

What's the overall length of your finished fixture? How many heatsinks are you planning on using?
When I build my next fixture, I am going to use 3 heatsinks to get better coverage on the ends.

what is your distance between leds back to front? i see you used a 5.5 inch heatsink so im thinkin 3-4 inches between them?

Yes, it is roughly 3-4 inches. (see image)

 

[PAL]

As great as this thread and the DIY has been, I think I'm still gonna go with the Marineland LEDs because of their simplicity.

 

[keno]

PAL;

I was looking at the Marineland LED fixture and it states the following:
Appropriate for fish-only tanks as the main light or for reef tanks or planted tanks as a night light
So am I reading this correctly, is it only good as a night light?

 

[DoctaQ]

the marineland fixture puts out roughly as much light as one or two of your leds keno i beleive

i have a 3 ft metal plate roughly width of your heatsinks and i might spread the leds as much as possible and then strap a heatsink to the back, cut the plate in half which will give me a little more spread than you had here, like i said, your heatsinking is super overkill, i can see it for a reef since the lighting density is so much higher but at the levels we are trying to light here for a planted are much lower. on my build i used a 29 inch plate with a couple of 2x2 heatsinks and a couple 1 inch heatsinks, i had 6 leds on this and the plate and leds are only slightly warmer than my super overkill 2 ft heatsink (18 leds) on my reef 8 leds on a 1.5 ft plate, should be fine provided that there is good ventilation. plus i will be slightly underdriving them to 700ma, but with the increased coverage and overlap i think it will have comparable light levels.

when the led is driven to 700ma, the voltage also drops a little further saving a little energy and producing less heat as well. the output is about 170ish lumens vs 220, its actually fairly linear. i could also possibly compensate by using the new xp-g which will have an even higher output at 700ma than an xr-e at 1000ma and even lower voltage, saving over a 3rd of the power, they are pretty hard to get though at the moment

im also thinking of another driver(when arent i?)
http://www.bestofferbuy.com/700ma-40v68v-constant-current-led-driver-110v240v-ac-input-p-7626.html

it can drive from 13-18 leds, right in the range im looking for.

i could be completeley making this up, but i think that these kinds of drivers tend to be more effecient at thier higher voltage limits because they use either transistor or linear regulator based drivers. 16 leds should put me in to relativeley high effeciency without the risk of over voltage drawing.

 

[keno]

DoctaQ;

Interesting AC driver and a good price at that.

For your heatsink. I have been wanting to build my own heatsink using flat aluminum stock and aluminum angle brackets. The aluminum angle brackets would act as "fins". I was thinking of using a thermal epoxy to bond the angle brackets to the flat stock. The thermal epoxy should help in transferring the heat to the angle brackets. A fan blowing across the angle bracket fins would help to remove the heat. This might work for what you are trying to do.

 

[PAL]

Oh, Keno, thanks for that, I didn't see that the first time. Any good LED's out there. I'm not very good at DIY electical stuff.

 

[keno]

PAL;

American Aquarium Products has an LED unit that has 5 LED's / 12 Watt total using CREE XR-E LED's. I spoke with them several months back they seemed pretty happy with the units. Here is a link to their LED aquarium lights.

 

[DoctaQ]

as long as you are totally working with parts like that you might as well use thermal paste and bolt them together i guess, but i like having a few high quality heatsinks, even if everything is a ghetto mess, id like to say that the heatsink can cool from this temp to this temp with this much capacity blah blah blah, ya know

 

[keno]

DoctaQ;

Did you see that LEDsupply has the CREE xp-g LEDs. Not cheap, but they do sound great. I have been thinking about using them on my two new DIY LED fixtures I am going to build for my 200 gallon. I was able to get a used 48" 4x65W Orbit PC Fixture by Current USA that I am going to convert. I was also able to get a wooden light fixture that doesn't have any electrical components in it. I am going to use that as my second fixture.

I also found a place that has the meanwell eln-60-48 power supplies at a good price. Still more expensive than the AC drivers you have found, but still not bad. I am going to need 5 so the price is $31.95 each. Since they have the current drivers built in I don't need any buckpucks.

 

[DoctaQ]

so i looked at my order today and it hasent even been shipped yet, what a bummer, im about to cancel it and just build a lm317 based or a true buck regulator, ive already assembled a few and only one of them works, i have no idea why though.

looks like the link you are trying to get your meanwells from is out of stock, id be interested , i wonder if its the D or P models, although it seems like they are somewhat interchangable, anecdotally at least