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 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.