DIY LED Using 10 Watt Arrays

[mike31154]

Tomorrow will be the 1 year mark running this DIY 10 watt multi-chip fixture. It's been working great, no LED burnouts despite the fact that a few of the fans failed and the LEDs are basically no name cheapies. I have replacement fans so not a problem there, but I would probably build it a little differently next time around. There are now slightly larger heatsinks available for 10 watt multi chips that supposedly cool sufficiently without a fan directly attached. I'll probably order a few of them to check it out. I think if I built a top on the fixture and added a couple of larger fans to move air through that, it may work without all the individual mini fans. I have something in mind along the lines of a semicircular piece of wood at each end, then adding thin slats across the top with a slight space between each. This will cover the top nicely while allowing air circulation similar to the open top configuration at present.

Livestock is happy, coral growing & my BTAs have never looked better. In fact they are taking over the tank. I'm still slightly underdriving most of the LEDs, so they should continue to plug away for another year or two no problem. The fixture is likely nearing the point where it will have paid for itself in power savings & not having to buy replacement halides and T5HO lamps. Starting to get the itch for another build though, this time with larger, fewer multi chips. Anyone contemplating a DIY LED fixture should at least consider these multi chips rather than the more common builds using 3 watt Crees etc. They may not be quite as efficient as the Crees or other big name brands, but the price is right & they work fine. They also now come in multi colour arrays on the same chip. Fewer LEDs can be used meaning less wiring & soldering.

[daplatapus]

Hey Mike. I'm still wondering if I shouldn't have gone this way too. I chickened out and went with what I kinda knew already. I think if I get a frag tank running in my basement I might try and go this route and pick your brain again. If you get to making another, definitely log your progress, I'd love watch it get built.

[mike31154]

Originally Posted by daplatapus

Hey Mike. I'm still wondering if I shouldn't have gone this way too. I chickened out and went with what I kinda knew already. I think if I get a frag tank running in my basement I might try and go this route and pick your brain again. If you get to making another, definitely log your progress, I'd love watch it get built.

I would hardly call what you're doing with the 'Jarduino' build chickening out. More like going all out with controller, programming etc. I've come to appreciate the simpler things these days, without so much computing. It's great to have the many features a controller or controlled LED fixture provides, but the results I'm having with a a few timers running the lights is working for me at the moment.

I continue to watch builds like yours with interest & may embark on something similar down the road, with programmable features. Folks like you are paving the way!

[mike31154]

This coming April will be the 2 year mark since I've put this fixture into service. I'm finally preparing a proper top for the thing. All the LEDs are still going strong but the 27 heatsink fans are becoming a nuisance. They are cheap & I suppose I should have expected the odd failure but it's starting to get old with 5 or 6 failures & many of them are getting a tad noisy. Time for a redesign in that regard.

Larger heatsinks that are supposed to provide adequate cooling of the 10 watt multi chip LEDs without a fan have started showing up on eBay so I ordered a batch of 10. They came in recently & I've redone the center rail of 9 LEDs with them. They come drilled/tapped complete with screws to mount the 10 watt multi-chips. Instead of using angle aluminum I opted for a piece of U-channel I had laying around from my old MH/T5HO Frankenfixture. Drilled a single hole in the back of each heatsink, tapped it & screw mounted with a blob of heatsink compound, making the U-channel an efficient contributor to the cooling process.



Running for about a week now & so far so good. Vewy, vewy quiet! The U-channel gets quite warm but not hot enough to burn fingertips. I had to remount the SMD5050 strips used for supplemental lighting because they'd been attached to the aluminum angle of the original rail. No biggie, but they're a bit higher now, attached to the wood braces of the fixture frame. The new rail weighs only slightly more than the original.

For the cover, I've cut two arc-shaped end pieces out of the same material used for the frame & my idea is to span these with strips of wood, effectively hiding the mess of wiring. Spaces between the wood will allow warm air to vent and I plan to add a couple of larger fans to boost circulation. I have 20 more of the large heatsinks on order to replace the outer rails, so I'm thinking additional flow to keep things cooler will be required.

I've laid some thin pine slats left over from another project on to the end arcs, noting that they sag in the middle due to the 4 foot span. Might have to rethink that & go with very thin plywood that I can bend to shape over the end pieces. Will need to add slots or holes to ventilate. Or I could go with some corner molding, which might hold it's shape a bit better, but not sure I'd like the look of that. Whatever I decide, I'd like to keep it as lightweight as possible. If anyone has ideas, I'd be glad to hear them. I'd like to stick to wood as a material. A couple of coats of finish & the thing should look quite pleasing to the eye.

[mseepman]

Do have suggestions but would love to come see your setup sometime Mike. I also liked those heatsinks so much I bought three myself today. I have 3 10w chips sitting doing nothing so I figure I'll do something with them now.

[daplatapus]

Hey Mike, can you just cut 2 matching arc shaped pieces of 1/2" ply or something and just stick them in 1/3 of the way from each end, effectively cutting the span of those strips to 16"?

[SeaHorse_Fanatic]

My main display's DIY LED unit using 10w emitters has a big enough Al heatsink that it uses NO fans and stays barely warm to the touch. Should consider upping the heatsink size/mass to dissipate the heat.

[mike31154]

Originally Posted by daplatapus

Hey Mike, can you just cut 2 matching arc shaped pieces of 1/2" ply or something and just stick them in 1/3 of the way from each end, effectively cutting the span of those strips to 16"?

Thanks for the suggestion. I have considered an additional support near the center of the fixture, but there's just too much stuff in the way, wiring, terminal strips etc.

[mike31154]

Originally Posted by mseepman

Do have suggestions but would love to come see your setup sometime Mike. I also liked those heatsinks so much I bought three myself today. I have 3 10w chips sitting doing nothing so I figure I'll do something with them now.

Sure thing. My setup is pretty modest, but yeah, I'd be happy to let you have a look see some time. My schedule is pretty flexible, I'll shoot you my phone # by pm. I'm in the old part of town on Mission Hill, a few blocks southeast of the hospital. I've been planning an upgrade for years, room divider probably similar to what you've done, but not much progress due to other things in life keeping me busy & drawing on my finances.

[hillegom]

Mike instead of a center brace, a half moon, maybe a quarter moon shape in the middle will clear all the wiring, terminal blocks etc.