DIY LED Using 10 Watt Arrays

[mike31154]

Decided to document what I'd like to do with respect to LED lighting for my 77 gal tank. I've been fence sitting for some time watching various builds etc & finally decided to do a bit more than experiment, although this is really still just that, an experiment. While I'd love to get my hands on something like an EcoTech Radion, they're just a bit too rich for my budget at the moment. I have some knowledge as far as electrical gear goes, so a DIY lighting fixture should not be a problem & save me a few $$ in the process.

I'm not a fan of builds with massive heatsinks and have been looking for a somewhat lighter & more elegant solution. Some of the more costly commercial fixtures like Radion, Orphek, Kessil have caught my fancy since they seem to be able to get the job done without a 50lb piece of aluminum to draw heat from their LEDs. A reasonably sized heatsink with a fan or two is more to my liking.

Inititally I'd been looking at an MR16 two pin bulb solution. They're designed to run off 12VDC, so with a 12 Volt power supply, some MR16 LEDs & sockets to plug them into, I figured that would be a good way to go. Have a few 4 watt (4 x 1 watt) MR16s in cool white as samples that I'm using above the kitchen sink as task lighting.



These are great little lamps with heatsink & current limiting circuitry incorporated, but they do seem to run a little hot after being on for a while, so not sure whether they'll last the advertised number of hours before giving up the ghost. So far so good, perhaps the heatsinks are doing their job & my fears are unfounded. There are few to no threads on anyone using these over their tank, FOWLR, softie, LPS or SPS. Nevertheless, I'll keep my options open, since once the sockets are wired up to a 12 VDC supply, they're plug & play, easily replaced. Worst case, I can even disassemble them & replace the individual LEDs.

Since I'm on a 12 VDC kick as far as power supplies go, I've decided to pursue the 10 watt LED array route. Several manufacturers are now using similar arrays as a LED option for aquariums. Arrays can be had that run at over 100 watts. They're now available in many different colours, including UV & combo colours on the same chip. The combo chips are an interesting development since they should minimize the disco ball effect reported from many builders using individual 3 watt LEDs of different colours. They all use between 9 & 12 VDC running at 900 to 1000 mA. So close to 10 watts each at the rated voltage. I already have 4 cool white (6,000 to 7,000K) versions of these. 10 Royal Blues came in the mail yesterday & ten 10,000K arrays are enroute. Should be plenty for my 77 including spares.



Now to the heatsink issue. I already have two small heatsinks with fans designed specifically for these arrays & 10 more on the way. What I'm thinking is to use two aluminum rails in parallel & screwing these heatsinks into them. The heatsinks will span the two rails & serve to hold them together. I'd like to tap the heatsinks & mount each array with two screws in addition to using heatsink compound. Even with the tiny fan, these are very light, so the fixture should be light & open for air circulation as well.



Last but not least, there are optics available to fit over these. I'm thinking of trying without to start & go from there. Here's a pic with all the goods(except the power supply).



Stay tuned.

[wingedfish]

Going to follow along on this build.
What is your projected cost, finished?

[mike31154]

Originally Posted by wingedfish

What is your projected cost, finished?

Components I have (& on order) so far cost roughly $260. That includes 4 cool white arrays (6,000-7,000K), 10 Royal Blue arrays (452-455NM), 10 10,000K arrays, 12 heatsinks with built in fans, one 250 watt 12 VDC power supply & 2 sets of optics with holders. Probably won't use all 10 Royal Blues & may order some regular blues and/or the odd red, green, UV, combo array. Should be able to keep it between $300 & $400 I reckon. These are not Cree emitters & I don't care to get into the lumens for your buck debate here. I don't have much in the way of SPS coral and am confident that these generic arrays will do the job nicely for my LPS, softies & couple of SPS frags. I'm not in the coral farming business & provided there's moderate growth & the tank is pleasing to the eye, I'm good.

Still need to get the aluminum rails/supports, additional heat sinks and perhaps more power supplies & optics. Depending on how the power supply I ordered works, I may need to add current limiting drivers so as not to overdrive the LEDs. A couple of variable resistors are an option for dimming & limiting current, but those don't cost that much. Other miscellaneous hardware & wiring.

The optics & holders I have at the moment are actually the wrong size for the 10 watt arrays, the lens is probably ok, but the opening in the plastic holder looks to be designed for the higher wattage arrays, from 20 watts up. So I might just order a higher wattage array & see how that looks.

[mseepman]

If you're looking to keep costs down...look to Donald's machine for the rails. One of the owners has a reef tank and they are priced much better than the big box stores.

[Ryan]

Tagging along.

[mike31154]

Originally Posted by mseepman

If you're looking to keep costs down...look to Donald's machine for the rails. One of the owners has a reef tank and they are priced much better than the big box stores.

Hey thanks Mark. Last bunch I used to fabricate my current MH/T5 setup I got at Princess Auto in Kelowna. I assume Donald's machine is in Vernon?? NM, found it in the Vernon phone book.

[mike31154]

Time for an update. I've got a little more work done on this. SeaHorse Fanatic has a similar project going built by a friend of his. This is what provided the motivation for me to finally get started on a LED fixture for my system.

http://www.canreef.com/vbulletin/showthread.php?t=81619

I checked out the local machine shop for aluminum stock that mseepman recommended, but they only had larger, thick material & I'm looking to keep the mass & weight of my build to a minimum. They recommended I try another local machine shop, but I was on my way to Kelowna that day anyhow, so went to Princess Auto where I had scored some reasonably priced square & angle stock before. Ended up getting some thin 8 foot lengths of 3/4 aluminum angle for about $15 ea incl taxes.

I haven't made up any kind of plan on paper or otherwise, kind of doing it on the fly. Still waiting for heatsinks, power supply & additional LEDs I've ordered, customs is taking their time in processing the shipments. grr. Since I have the aluminum & hardware to get started, I put together one 4 foot rack with two heatsinks.



Had some thicker angle stock left over from building my MH/T5 rack, so used those pieces at each end of the lighter stock. Threaded with 8-32 tap & used stainless bolts to fasten.

Here's a detail view of the business side of the heatsinks with 10 watt LED arrays loosely positioned. Will endeavour to keep the wiring neat & tidy, using small terminals or soldering wires together & covering with heatshrink tubing. I'm thinking heatshrink will provide protection from moisture, but we'll see.



Here's the flip side of the rack, showing the fans on the heatsinks. This will be facing away from the water surface. I threaded the heatsinks to allow use of stainless bolts for fastening. Tried 6-32, but one didn't hold, so went with 8-32 here as well. Mounted the heatsinks diagonally since this provides the best clearance for the fans to do their job of cooling. They're plenty secure with two 8-32 ss bolts.



Spacing from center of one heatsink to the next is approx. 6 & 1/2 inches. This will allow installation of at least 6 arrays equally spaced along the 4 foot rail. I'll start with that, or maybe 5, & see how that goes. The thing I like about using this material & fastening with bolts, is that if I need to modify the set up, it's as simple as drilling additional holes. Electrical hookup should also be easy to modify, with a minimum of soldering. Also still thinking I might add a few MR16 bulbs to the rail as needed. This will allow me to spotlight a certain coral or area of live rock with a custom LED colour of whatever works for that area. Just need to figure out a way to fasten the MR16 bulb socket to the rail. Shouldn't be too difficult.

I'm thinking 3 of these rails for my 4 foot tank. One down the center & two along the outside. Not quite sure whether I'll hang them or make up something to set them on the tank rim. Either way, I plan to install the outside rails so that they can be swiveled to point slightly inwards. A single bolt through the end brackets with a wing nut to allow friction fit with quick adjustment should do the trick.

[mseepman]

Looking good so far. Anxious to see how this turns out.

[mike31154]

A little more progress on the project since the 12VDC 240Watt power supply & 10 additional heatsinks finally arrived yesterday. Still waiting for 10 10Watt 10,000K LED chips. Chuckle, all those 10s make my eyes go buggy.

Power Supply. Adjustable from 10.07 to 13.58 VDC with the variable resistor. I will probably set it at close to 12 VDC & use separate variable resistors or drivers on each output line to control current & brightness of LEDs. With a potentiometer on each output line, I'll be able to control 3 colours of LEDs individually. This is pretty much mandatory, since different colours of these LED arrays tend to have slightly different maximum voltages, anywhere from 9 to 12. For example, the Royal Blues' rated forward voltage is 9-10 volts, so running them at 12 will sure as hell make them brighter, but I reckon they wouldn't last too long.



I've now mounted 6 heatsinks on to the first rail with 3 each of the cool white 6,000-7,000K LEDs & 452-455NM Royal Blues. The LED chips are only held on with heatsink compound at the moment. I'll see how secure that is once the compound cures & may leave it at that instead of securing additionally with screws. The tiny screws required are hard to source.



Original idea was 3 of these rails, but having assembled the one, I think I may reconfigure to have 2 rails only, but with 8 LEDs per rail vice 6. My 77 gal is just under 16 inches inside dimension front to back & 3 rails would be too much hardware with these 10 Watt arrays.

Now it's wait for the remaining LEDs, shop for additional hardware - potentiometers & wiring for hookup. Have a couple more heatsinks on hand, so I can get to work building the second rail.

[hillegom]

Great build, following along.
I have been wanting to build one as well, still just learning.
Where are you getting all the components, if you don't mind me asking.
Thanks