BSOD LED Build

[DarinSchmidt]

This is a single LED unit that i build. It is a 48v 5A system containing 28 CREE LEDs. 14 Cool White XPG and 14 Royal Blue XPE.

This is the parts list:

48v PSU   
14 Cool White XPG
14 Royal Blue XPE
1A quick burn fuse
80 degree optics (these fit on WPG and XPE)
18 x 8.5 heatsink
and of course a soldering iron, solder, 20g wire
I used black acrylic from USPlastics for the casing and clear acrylic from Lowes for the base
1/4 threaded rod - Lowes
1/4 Acorn Nuts - Lowes
1/4 plastic nuts and washers
Power cable from an old PSU (same style/rating)
2 24v Fans (dont remember off hand where i bought them, i think maybe newegg)

all technical electrical questions most likely can be solved here

When i first jumped into this, i wanted to figure out which LEDs were the best to get, i didnt care about how much light it put out, but i wanted efficiency, in other words, lumens per watt.

XPG fit the bill at 139 lumens per watt. But they dont make Royal Blues in XPG so the next best were the XPE series, not much less efficient.

If you look at the XPG data sheet you can see on the second page that XPG (R5) produces 139 lumens at 350mA(0.35A).  If you scroll down to the characteristics chart, at the bottom, it labels what current is consumed at what voltage (Forward Voltage). And if you scroll down further through the document, it tells you the spectrum's, an exponential chart of the voltage and mA (milli amp) relation, etc.

So, now that i have the LEDs picked out it was time for the PSU. I chose the above PSU because i wanted all the whites on one array and all the blues on another. Turns out that 14 was perfect. 48v/14leds = 3.43v for each LED which was the MAX you want to run the XPE's. Though, now that i played a bit, i would recommend the 24v 10A psu they sell, 7 leds per array still gives you 3.43v on a 24v system. These types of PSU's (power supplies) have a POT (potentiometer) build in so you can adjust the voltage as needed. IF the PSU you get doesnt, then you will need to get a variable resistor as described in the referenced article.

Anyways, then you need a fuse because you dont want to blow your LEDs since we are relying on the PSU to supply a fairly descent constant voltage. Protection from accidents. I tested it by cranking the voltage up while i had a multimeter connected to ensure it blew at 1A, and it did, so it seems these fuses are pretty reliable.

All that was left was to get the heatsink and mount the LEDs to it. I marked out where to place them, put a drop of thermal paste on and pressed the LED down till i saw a little ooze out the side. Then i used some Krazy Glue along the outer edge to secure it to the heatsink. I would recommend using some thermal epoxy, i only did it this way because i was testing out placements, etc.



as you can see I alternated the leds (I took off the resistors that you see, i was doing some other testing), the black cable runs to the blues and the red runs to the whites. Under the electrical tape are the fuses.  You can see the power rails (barrriers), one is for positive, the other for negative to the power supply. Connect the + to the + of the LED then from the - of that LED to the + of the next LED and so on.



here you can see how i wired everything to the PSU.
On the FAR left are the + and - leads from the LEDs. The green is the +, i ran out of red..... Next is the power cable. i cut off the end of the power cable and connected it. The 4 screws on the right are the DC output lines where your LEDs and Fans get connected. The Fans i used are 24v fans. When you connect them in series, it takes 48v to operate them as the voltage is divided between them. Then i took the optics and they kind of snap on, but i put a drop of glue on them to ensure they werent going anywhere.

Now that we have everything wired, solderes, and glued together, it's time ti test and set the LEDs brightness. I turned my PSU all the way down (41v). With my multimeter inline, i watched the amps climb to 900mA which was about 46.5V. Left it running for a while to make sure nothing was smoking, burned out, etc. Then i turned it down to 700mA. At this power level i get 300PAR.

and this is the final product after the casing was built.







Sorry if this is a bit dry, i'm pretty tired right now so if you have any questions, feel free to ask. There are no stupid questions.

[Wall_Tank]

Okay, I give, what does BSOD stand for......Blue Screen Of Death ?

[Boonjob]

Okay, I give, what does BSOD stand for......Blue Screen Of Death ?

ROFL, it has been bugging me as what it stands for the last hour or so since he said he was gonna make it this name...

[DarinSchmidt]

yeah, its the nick i go by on many other sites. Started when i played on the XBOX360, that was my nick on there and it just kind of stuck with me. You get a star Wall lol

[DarinSchmidt]

sorry guys, i messed up the links, delete the " in the address and they will work

[Boonjob]

Just curious how much this project ran you in total... and did it replace all your other lighting aswell or are you running some other bulbs with it?

[DarinSchmidt]

it was around 400 and i run nothing else but these lights, 4 of them.

[Boonjob]

You think one or two of these would be good for a 55gal(4 long and 21inch deep?)

[DarinSchmidt]

yeah but i dont think that you would need as many LEDs because odds are you would have to turn them down or raise them pretty high above your tank. Around 1-1.5' maybe

[DarinSchmidt]

just an update on my LEDs. Finished them all today. Now i just need to get some turn nob POTs to have a little bit better control.











now i just got to make the canopy so i can get rid of the 2x4's holding them up.

[DarinSchmidt]

i made my own thermal epoxy also. Arctic silver paste and some 2ton epoxy. AS:EP1:EP2 ratio 1:2:2

its been keeping them cool, so FWIW, it works, saves money and can do hundreds of LEDs this way.

[Reefpete]

So what would you say that the overall color temperature ended up looking like to you? Would you suggest this project be attempted by someone with (lets say) less knowledge?

[DarinSchmidt]

So what would you say that the overall color temperature ended up looking like to you? Would you suggest this project be attempted by someone with (lets say) less knowledge?

i would suggest it to those who have the ability to understand and if they dont understand, have the ability to ask before doing. Wiring LEDs isnt complex, but you should have a basic understanding of how it works and BE SAFE.

I dont know what the Kelvin rating would  be, i'd have to look it up. But i think it has to be around the 10-12000k

[Reefpete]

Would it be possible to control the two different color leds independently? Would you care to help me plan for a future lighting build, and once I purchased the necessary pieces could you help in its assembly?

[DarinSchmidt]

sure i can help. with the method i used, you will need a couple 5ohm 5watt POTs to control them independently which is what i'll be working on here shortly.

[Reefpete]

So to put the xpg leds on a timer separate from the xpe leds would you need a psu

[DarinSchmidt]

The POTs are after the PSU. So what you will need is a PSU, POTs for how ever many arrays of LEDs you have and a fuse. If you wanted to use a timer, which i thought about doing, is get a DC timer to put inline before the POTs. But I'm using 48v PSU's which is hard to find stuff to go with it. So I would highly suggest getting a 24v PSU.

[Reefpete]

Something tells me that you have background in engineering?

[DarinSchmidt]

lol, well I'm going to school for computer engineering, but i havent made it to my electronics courses. All this electrical stuff has been self taught.

[Reefpete]

Kudos! I will see about getting the required computer related items from my father. He has spare computer parts filling most of his workshop. Thank you for posting all you hard work and efforts. I'm wondering what size heatsink/number of leds to use for my upcoming project tank. 36x18x21, any ideas? I'm ready to ditch the mh

[DarinSchmidt]

Hmm, well, i prob would say that one of my units would do well. If you want, some weekend i could bring one buy and we can throw it up there and see how it looks so you can get an idea of what you want before you build.

Not so sure what computer parts that you would use. Odds are they are 12v electronics, which is too small voltage to play with. I highly recommend the PSUs from Circuit Specialists. http://www.circuitspecialists.com/prod.itml/icOid/9623 thats a 24v 10A PSU. I would recommend getting that one because, yes its overkill, but it allows you to expand your setup if you so choose so and should last longer and it can well over handle the demand.

I work at WPAFB so i could swing by any time after work, after 3pm.

[Reefpete]

Ah yes, that would make sense. I too work on base. Which area do you work in?  Its going to be a little while before I'm ready, but thank you for the help. Right now I'm using a temporary enclosure (What used to be an acrylic sump) I'm waiting until I get settled in a house with a more secure flooring. I currently live on the third floor of a old apartment building.

[DarinSchmidt]

Area A building 271