DIY LED Using 10 Watt Arrays

[mike31154]

Originally Posted by emerald crab

Here are the pics of the optic system used with VGA heatsinks. 1.5" ABS coupling, 2 rings cut out of a 1.5" ABS pipe, one 44mm glass lens and two #4 screws (stainless) to attach the heatsink to the optics.

Thanks for the pics, good info. Price I paid for the heatsinks is about what you paid as well, I don't think I've overpaid. Good to know what else they are used for. I assumed they were specifically designed for the 10 watt LEDs since the eBay sellers I've purchased the LEDs from often list the heatsinks as well and the item description says they're designed for them. I reckon in the interest of economy in manufacturing, many heatsinks are used for different applications, provided the specs meet the required cooling capability and have the necessary footprint & mounting options.

[mike31154]

Not much in the way of progress with the build, but I have been scoring a few more parts that I need. While in Kelowna the other day getting more wire at Princess Auto, I found out about a great electronics outlet not far from there, Interior Electronics. Eureka, a shop full of resistors, capacitors, voltage regulators, hard to find connectors, it was like being in a candy store as a kid. I picked up a few 5watt & 2 watt resistors ranging from 1.5 to 3.3 ohms and a breadboard. This will allow me to run each LED chip with the different resistances to determine what value of resistor I'll need to limit the current to the rated spec. Might be a tedious process & I'll need a resistor in series with the power supply for each LED. Also not the most elegant solution by today's standards with LEDs, but simple & effective. A good thing about doing it this way is that failure of one resistor isn't going to take out any other LEDs. About the only thing that will take out multiple LEDs would be an overvoltage fault of the 12 VDC power supply & I'm banking on that being very unlikely.

I used the breadboard with resistors yesterday to run 2 whites & 3 blues at once. Worked very well & the fans were nowhere near as audible as the four I'm using on my overdriven T5 tubes. In theory the 5 LEDs should have been using 50 watts, but if I recall correctly the wattmeter was showing less than that, so I assume they were being underdriven. Still very bright though & I think the 4 & 1/2 inch spacing between them should work fine without optics if I hang them at the proper height.

[mike31154]

For the benefit of those wondering what the H a breadboard has to do with electronics....



Interior Electronics also had some fine little project boxes. What I'm thinking of doing is mounting several of these on each rail with a terminal block & resistors inside to keep things tidy & relatively moisture proof.

[eli@fijireefrock.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.

[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 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.