DIY LED Using 10 Watt Arrays

[mseepman]

I've been following the build on RC...he's done an amazing job. His light only requires a basic heat sink (VGA, not CPU) but it just looks huge. The Heat pipes don't use liquid...but some others suggested he try liquid cooling. I think that would be too much effort.
I'm not done my cree build yet and I wouldn't change anything right now, but the large multi-chip builds interest me a lot.

[mike31154]

Still a bit of work ahead, but I now have the components for assembly & testing. The wiring needs some serious cleaning up, but I'm still experimenting with different options to drive the LEDs. The 3 dimmers work very well so I'll order a few more of them for added flexibility in controlling the intensity of each colour. I'm close to their current limit of 8 amps each, so there's a safety factor to consider. The 12VDC constant current drivers I ordered should arrive within a week, so I'll be able to see how they might fit into the scenario.

A summary of the fixture's current config:
-Three rails of nine 10watt LED arrays each for a total of 27 LEDs,
-Two outer rails each have five 10000K White & four 452-455NM Royal Blue,
-Center rail has five 460-470NM Blue & four 6000-7000K White,
-Three 8 amp Dimmers, one controlling all the Whites & one each for the Blues & Royal Blues,
-One heatsink with fan per LED,
-One 250watt 12VDC power supply,
-Terminal boards, wiring, stainless steel hardware & aluminum angle stock,
-Mahogany veneer wood frame (I scored the wood real cheap in the clearance pile at Windsor Plywood).

The fixture weighs just over 12 lbs, or approx 5.5 kg. I ran it last night trying each colour on it's own & in various combos, including full on. Although the calculated wattage with 27 ten watt LEDs is 270 watts (more than the power supply max wattage), the energy monitor showed around 230 watts with all LEDs & fans running. I attribute this to the fact that I didn't run them at their full voltage/current. I dialed the voltage on the power supply down to 9.9 VDC & using each dimmer, further lowered the voltage delivered to each colour to < max rated forward voltage. When time permits, I'll perform current measurements on each LED to confirm they're operating at or below max rating.

One of 3 dimmers I used during the initial test. These are actually sold to dim 12 volt SMD LED strips, but they work fine with the 10 watters, provided you mind the current rating:


The entire assembly. Wiring will be cleaned up, shortened, more terminal boards added & dimmers mounted remotely near the power supply:


The 'bright' side:


Side view showing the Mahogany veneer frame. This should look pretty good with some finish & trimmed with moldings:


As far as the test run goes, I very much like what I saw last night & don't think I need to modify anything with respect to colour blending & spacing between the LEDs. I used a couple of 2x4s to rest the fixture on the rim of the tank, much closer to the surface than it will eventually hang. Quite anxious to get it completed now & start experimenting with height above water. The Royal Blues in particular bring out a flourescence in my LPS & soft coral that I've never seen with my current MH/T5HO set up.

Some pros & cons having reached this point:

Pros (as I see them anyhow);
-DIY, so I can repair or modify any part of the fixture myself with parts readily available & relatively inexpensive,
-Fewer LEDs required than with the more common 3 watt builds,
-Not as heavy as builds with massive heatsinks,
-10 watt LED forward voltage is in the 9-12 VDC range, more flexibility in choice of drivers, power supplies etc. Easier to adapt to off grid power, solar, wind, battery etc.

Cons;
-DIY, not everyone's cup of tea,
-Noise from fans (didn't seem bad at all during test run),
-Limited controllability compared to the fancier manufactured fixtures, i.e. dimming is manual at this point,
-I have no measurements as far as light output etc, so experimentation & time will be needed to confirm suitability. Manufactured fixtures have all the testing done & data available. My build is a best guess as to what I require.

More to follow as additional components arrive & I finalize assembly. I plan on ordering a couple more power supplies so that I can run each colour on a separate timer to get some form of sunset, sunrise effect. I also need them to keep from overworking the single 250 watt supply. Still pondering whether soldering the heatsink fans directly to the LED contacts is a good idea or whether I should cut the leads & run them at the full 12 volts all the time. Stay tuned.

[bkelly]

HI Mike Thanks for bringing your LED to the swap and showing us, sorry i didnt get time to see it more. Unreal how bright they are.
brent

[mike31154]

Originally Posted by bkelly

HI Mike Thanks for bringing your LED to the swap and showing us, sorry i didnt get time to see it more. Unreal how bright they are.
brent

No trouble at all Brent, there wasn't much more to show. All I was able to do was get a couple of them fired up at your place, one blue & one white. It was a busy venue!

For what it's worth, I made a few photos of the set up over my tank this afternoon/evening. I'll try to get several more tomorrow with the T5HO & Halides for comparison, but just looking at the photos compared to real life, I must admit the photos don't really tell the story. Seeing the LEDs over the tank has given me more incentive to finish up the build & replace the old lights. Anyhow, here they are:

All LEDs running with the fixture 7 inches above water surface. Blues & Royal Blues set at 8 VDC, Cool White & 10000K White set at 9 VDC. So in effect they are all being driven at somewhat below their maximum forward voltage. Still very bright & the colours are blending nicely. Did not perceive any disco ball effect.



This one is only the 5 Blues on the center rail dialed down low, set at only a few volts with the heatsink fans barely turning.

[bkelly]

that looks great , should be cool if you get into programming/controlling the diff lightings.

[mike31154]

Originally Posted by bkelly

that looks great , should be cool if you get into programming/controlling the diff lightings.

Yeah, I don't have a controller at the moment, not sure I want one either. Current lighting is on digital timers & I was thinking the same with the LEDs. This is one reason (aside from the wattage requirements) I need more power supplies, so I can run each colour with it's own power supply on separate timers. But now that I've started toying with the dimmers, a more sophisticated/automated method of controlling & dimming the LEDs is certainly tempting. On/Off with just a timer might not cut it anymore! Not that the livestock will care, since it's all been doing fine without sophisticated controlling.... more for the hobbyist I guess! I simply can't get that excited over fixtures that offer overkill features like cloud effect & lightning etc. I love my EcoTech VorTech pumps, but could care less that the Radion lights can communicate with them. What the hell for? Dawn/dusk dimming would make me a happy camper, don't need any more than that. 'Want' & 'Need' are different animals, often associated with large variations in $$$$$.

[mike31154]

Decided to forge ahead & start using this fixture even though there's still a fair bit of work & experimentation ahead. A major part of the experimentation is of course how my critters react to the lighting change. Burned the midnight oil last night, pulled the old MH/T5HO monstrosity & hung the LEDs. Running them as is, with loose wires all over on only one power supply & 3 dimmers has it's limitations, but I figured the sooner I get started, the sooner I'll see how the livestock fares. The LED configuration with respect to numbers & colours is where I intended for the initial trial, so damn the torpedoes.

I started with the fixture approx. 12 inches above water surface this morning. The 12 volt power supply, set at just under 10 volts is on a single timer & changes in intensity are done manually, either with the 3 dimmers or raising/lowering the fixture. I cut some wooden wedges to mount the outer rails, giving them a 10 degree inward tilt. I'm hoping the increase in focus to center, away from the sides translates into less glass cleaning! I'll probably be moving the outer rails a fraction closer to the center to further tighten light spread & minimize spill over the sides where it's neither needed nor wanted. The Hagen 77 gallon is relatively narrow & my rock scape with corals runs pretty much down the center longitudinally. It will take some tweaking to find the sweet spot of LED spacing in conjunction with height above tank, but I don't think I did too bad with my initial guess in that regard.

The fans are definitely audible & although lower in noise level than those I had cooling the ends of my overdriven T5HOs, some of them have a mildly irritating high pitched whine. This may be due to the fact that they're running below rated voltage or simply because they're cheap, dunno. The more I bump up the voltage on the LEDs, the faster they run & actually quiet down a little. Might try cutting all the fan leads & running them full speed at the rated 12 volts to see how that works out.

I like the look, plenty of shimmer & great colours on the coral. The tank is more accessible since the fixture is mounted higher than the old set up. The fishes certainly noticed something was different this morning and were a bit shy, but in less than an hour they were behaving pretty well as usual. I have a spawning Maroon clownfish pair so it will be interesting if the lighting change has any impact on their schedule. It's been about 4 days since their last clutch hatched and the female should be about ready to put down another.

After a couple of hours, I lowered the fixture by 2 inches to 10 above surface & bumped up the voltage on all 3 colours of LED. That'll be my sophisticated, high tech dawn/dusk program until I get more power supplies & timers. Numbers are now as follows, measured at the input & output of each dimmer:

LED colour, Dimmer input VDC, Dimmer output VDC

10000K & 6000K White, 9.63, 7.98
Royal Blue, 9.73, 5.51
Blue, 9.83, 5.51

Not entirely sure why the difference in input voltage values, since a single power supply is driving all the dimmers & lights. I assume it's due to slight variations in wire lengths feeding the dimmers & probably the different number of LEDs being run by each dimmer. The dimmer running the Blues is driving only 5 LEDs, Royal Blues number 8 for that dimmer & the one working hardest is the dimmer running both the 10000K White & 60000K White which total 14. I'll have to keep an eye on that one since it's probably close if not over it's 8 amp limit. Haven't made any current measurements, but by underdriving the LEDs with the low forward voltages, they won't be drawing anywhere near their maximum of 1 amp, so should be fine.

Inserted my power monitor into the circuit & the fixture with voltages as set now is drawing 140-146 watts. Should equate to some useful energy savings over the long term, although it seems that my heaters will be running a little longer without the Halides doing their thing during the midday lighting period.