DIY LED Using 10 Watt Arrays

[chewie]

Very informative read. I am in the process of trying to figure out how to do a build myself, following along this thread to see how it is done.

Here is a list of parts I am thinking of using:

Dimmer. ( may have a few to run different led temps, blue, daylight 12000k etc...)
http://www.dealextreme.com/p/dimming...s-dc-12v-73618

Daylight 12000k
http://www.dealextreme.com/p/t10-sv8...-dc-12v-112583

Blue light
http://www.dealextreme.com/p/10w-180...r-9-11v-100875
OR
http://www.dealextreme.com/p/31-44mm...-dc-12v-100622

Power supply ( once again a few to run different lights on timer. Not sure if this will work or if I need an actually LED driver supply. )
http://www.dealextreme.com/p/120w-un...-240v-ac-37110

or if I need a proper led driver
http://s.dealextreme.com/search/led%20driver%2012v

any suggestions?

[mike31154]

Originally Posted by Elias@caco3reef.com

I skimmed through this tread a little fast excuse me if this question already have an answer
As I am planning to do a 20W led setup for a couple of my tanks similar to what you are doing but 1st I would like to know how good are these fans at keeping these LED cool as I am planing on running then at full power.
By the way good thread on this build.

Sorry for the delay in answering your question, I've just returned from a week long backcountry ski trip!

The fans in combination with the heatsink do a great job of cooling the 10 watt arrays since they are more or less designed for them. There are alternative options without fans in the form of larger heatsinks, but I'd like to keep the aluminum mass to a minimum. If you do any searching on eBay for similar items, you will find plenty of sellers offering heatsinks with fans suited for the larger 20 watt LED arrays, as well as the big honking 50, 100 & even larger ones. Needless to say, as you go higher with the wattage, the corresponding heatsink & fan will also have to be much larger to cool the LEDs.

The fans on the heatsink for my 10 watt arrays are designed to run at full speed with 12 Volts DC. I decided to wire the fan leads to the LEDs so that my fans will run at a lower speed, since the LEDs will be run at anywhere from 9 to 10 Volts DC, depending on the size of resistor I put in series with each LED array. I've done some initial short runs to test the rail & it looks like this approach will be fine. If I need more cooling, I may simply add another piece of angle aluminum facing up to give the assembly additional mass for drawing away heat.

[mike31154]

Originally Posted by chewie

Very informative read. I am in the process of trying to figure out how to do a build myself, following along this thread to see how it is done.

Here is a list of parts I am thinking of using:

Dimmer. ( may have a few to run different led temps, blue, daylight 12000k etc...)
http://www.dealextreme.com/p/dimming...s-dc-12v-73618

Daylight 12000k
http://www.dealextreme.com/p/t10-sv8...-dc-12v-112583

Blue light
http://www.dealextreme.com/p/10w-180...r-9-11v-100875
OR
http://www.dealextreme.com/p/31-44mm...-dc-12v-100622

Power supply ( once again a few to run different lights on timer. Not sure if this will work or if I need an actually LED driver supply. )
http://www.dealextreme.com/p/120w-un...-240v-ac-37110

or if I need a proper led driver
http://s.dealextreme.com/search/led%20driver%2012v

any suggestions?

The dimmer is something I've also been looking at to control the current my 12 Volt power supply delivers to the LEDs.

The daylight 12000K 5630 SMD LEDs are generally considered insufficient for our purposes, since the LEDs are not large enough to penetrate the water properly. Yes, there are 32 of them on the board for 16 watts, but I'd still advise against trying to use these since they just don't have enough punch per individual LED. About the only advantage to them is that since they're designed to replace automobile lighting, any 12 Volt DC power supply may be used to run them, no driver to worry about.

Your first link for the blue light is the same 10 watt LED form factor that I'm using in different colour temperatures. You will need either large heatsinks, or the fan/heatsink combination I'm using for my build. You will also need either individual drivers for each 10 watt LED, or a power supply in the 12 Volt DC range of sufficient rating to run multiple 10 watters in addition to a current limiting resistor for each 10 watt LED.
The second link for blue light is again, a board with low wattage 5050 SMD LEDs really unsuitable for anything except maybe a night light.

With respect to power supplies/drivers, the preceding paragraph should pretty much answer that. Your choice really. You can either get a separate driver for each 10 watt LED, or a larger 12 Volt DC power supply to drive a bunch of them with current limiting resistors for each 10 watt LED. If you decide to use the SMD LEDs for sunrise/sunset or night lighting, all you need is the 12 Volt DC power supply on a timer.

[chewie]

I would love to do a build like yours or Grizzs using leds from Modular Led but just cannot justify the cost a.t.m . I am trying to go cheap and thought going 12v would simplify things. My tank is only 18" deep so was hoping to get away with it...well maybe I should stop being cheap and use proven led's from Modular.

[mike31154]

Originally Posted by chewie

I would love to do a build like yours or Grizzs using leds from Modular Led but just cannot justify the cost a.t.m . I am trying to go cheap and thought going 12v would simplify things. My tank is only 18" deep so was hoping to get away with it...well maybe I should stop being cheap and use proven led's from Modular.

If you wish to pursue the 12 V simple approach, you might want to look into the MR16 bulb form factor. They are designed to run off 12 VDC, even 12 VAC in some cases. Driver built into LED bulb, plug & play, sort of. Price is coming down on these bulbs & I understand there's a company about to launch more efficient/powerful MR16 LED bulbs. Initial customer base will be commercial, but shouldn't be long until they target the domestic consumer.

It's slowly getting to the point where it's more difficult to realize significant savings in a DIY LED build as long as you're not looking for all the bells & whistles such as an EcoTech Radion.

Below are some MR16 bulb pics. This bulb has four 1 watt LEDs in it & pretty good optics. You can even unscrew the bezel & remove the optics if you wish. This would expose the individual LEDs & provide more spread, but also expose them to water spray. They are very bright. Before embarking on the 10 watt LED chip build, I was seriously considering this option. I may still use some of them as supplemental lighting or to spotlight a particular coral/area of the tank. Of course if you have primarily low light corals etc. in your tank, those car lights might be enough, but I wouldn't count on it. For a FOWLR they'd probably be ok.

[mike31154]

Been a while, lots of skiing so not much work on the LED project, but I did manage to get a little more done. I've decided to go with a third rail down the center. Probably have some funky coloured night lights & one or two day supplement arrays on that. Maybe even a green or red. The two outer rails will do the bulk of the work. I've cobbled them together using two pieces of plywood to experiment with spacing & get an idea of what kind of spread the currently planned mix of LEDs will give.

I've ordered 10 more heatsinks with fans & 10 Blue arrays to see how they will work with the current bunch of Royal Blues & 10,000K. Still need a bunch of 5 to 10 watt resistors in the 1.5 to 3.3 ohm range to tune each LED array to the proper running voltage/current. As it sits right now with 17 LEDs, heatsinks, aluminum & plywood, the unit weighs in at 1.8 Kg, that's 4 lbs. Nice & light. Current plan will be to have 9 LED arrays on the two outer rails & maybe 4 to 6 on the center rail. Also need to add the weight of resistors, more wire, project boxes to wire the whole shebang etc. Might also add some plywood skirting to make some sort of open hood in order to minimize light spill & hide the aluminum. With any luck I'll be able to keep it under 10 lbs.

Here it is. Spacing between LEDs on each rail will be approx 4.5 inches. Spacing of LEDs between rails is around 5 inches. I plan to rotate the outer rails slightly inwards. No optics, I'll play with height above water to find a good compromise between spread & light output.



End view. The plywood will allow me to drill holes easily & reposition the rails if necessary. The wingnuts provide quick adjustment of the inward tilt of the outer rails.



Another view to better illustrate the tilt on the outer rails.

[mseepman]

Any new developments on this Mike?

[mike31154]

Originally Posted by mseepman

Any new developments on this Mike?

Well, sort of. Still waiting for more heatsink/fans as well as Blue LEDs as per my previous post. Somewhat rethinking the resistor method of controlling current to each LED so I've also ordered ten 12VDC constant current drivers to see how that will work. It may be more efficient than resistors but the downside is, they are somewhat larger than a 5 or 10 watt resistor & they also cost a bit more. These constant current drivers will accept an input of 12 to 24VDC and provide constant current of 800-1000mA at 8-12VDC out. As with the resistors, the plan is to use one per LED.

One idea I considered was to use 3 low resistance, high wattage resistors, one on each of the 12VDC power supply outputs feeding 3 different colours of LED. Not that keen on that idea since these resistors are physically quite large & if one goes bad, I risk frying all the LEDs downstream of that. So I'll probably stick with a resistor or driver for each LED. This will provide a safety factor & also allow me to tune each LED individually. However, not finished yet, & I've also ordered three 12VDC, 8A LED strip light brightness controllers. Might use them in combination with the resistor/drivers. I'll open one of these up to see what's inside when they arrive. Curious to see whether it's just a potentiometer or if there's some electronic wizardry going on in there. My 10watt LEDs are bulk ordered & not binned so production variations will require slight differences of current to each LED for the desired light output. I don't have a PAR meter to measure light output, but at least I can tune each LED to draw at or below the rated maximum.

Going shopping this afternoon for either plywood or thin pine planks to build some sort of enclosure to hold the rails. Would like to keep it open, so I'm thinking some wide side pieces as a frame & a few along the top to mount the terminal boards, resistors/drivers as well as keep the wiring neat. I'd really like to keep the weight of the whole thing down.

I've seen a few similar builds now on RC, one where the chap is using the larger 50watt LEDs. The build looks amazing but much more involved than mine since he needs to cool each LED chip with this monster heatsink with liquid cooling & huge fan. Since the higher wattage LEDs generally need higher voltage (36 VDC), your choice in power supplies gets limited & you end up having to buy the ready made drivers for whatever wattage LED you intend to use. One of the things I prefer about my build, is that 12VDC power supplies & drivers are more common. I can also diversify a bit easier with the colour spectrum & if a LED goes bad, I'm not out as many $$s as with the larger ones.

[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.