# DIY cheapest CREE XPG LED fixture for 55 g



## Min (Dec 23, 2010)

there is a lot of talk and debate about LED for freshwater and there is not enough posts or information yet, so here is my 2cents. 

I do not want to prove anything or argue how many watts per gallon there should be because it all too much calculation and guessing. 
I bought a used 55 gal tank with stand and canopy and the lights were regular 2x 15w flourensic bulbs. obviously was not enough to grow anything. 
after looking at some possible light options i could not come up with anything less than $120 for 4xT5 used fixture at my LFS. the thing even did not fit in my canopy, so i decided to see what happens with DIY led. 

to keep this short this is what i have: 
*Mean Well LPC-60-1050 constant current driver* $26+ship 6 = 32$ from rapidled.com
8 x 
CREE XP-G R51B 7000K 350LM Emitter with 16mm Base $5.71 x8= $45.68
from dealextreme.com (free shipping but takes forever)

later i found a better source than above for LED it is http://www.ledgroupbuy.com/ the site is legit and i currently bought LED's there 2 times. Original factory and at even better price. cost of shipping is more, but if you can "pool" with someone or consider its definetely comes out of factory its well worth it. 

picked up 36 in. x 1-1/2 in. x 1/8 in. Aluminum Flat Bar at local Home depot for another $8 for heatsink. 

soldering kit at local Radio shack was another 9.99$ 
Having fun soldering -FREE
wires, plug and connectors from various house hold items -FREE
so roughly $96 total.

i just spread LED "evenly" on the aliuminum rod 4-5 inches apart. oh i forgot to put in some thermal glue for $2 that i got from dealextreme also. 

now as far as light goes. you can see for yourself

https://picasaweb.google.com/mindei/Akvariumas#

it tried to see how it will progress and if thats going to be enought light and so far i do not see any need for additional LED at all. 
I had to start using excel since there was algea burst once i start using the lights. 
now water wisteria seems to be taking over the tank. 
My personal thought is that going with lots of LED and running them half power is fine also, but why should i invest money in something im only gonna use half of it.

More pictures added Mar 8th


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## IWANNAGOFAST (Jan 14, 2008)

Hey that looks pretty good! 

I think the reasoning for getting more LEDs vs only using 8 is to reduce the spot lighting effect and to get a better spread of light.


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## Wicket_lfe (Aug 21, 2008)

nice for just one row of lights. Did you ever put the lenses on?

I have a 20X 18 "cube" tank that's tall, and I thought i was going to need like 30 LEDS. Maybe i should look into less LEDs

Anyway good work!


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## trackhazard (Aug 24, 2006)

Coverage for people that want it as IWANNAGOFAST mentioned.

If you double the LEDs for coverage and then work them each at full power, well you can see where that can lead you. If you get higher wattage LEDs and run them at lower watts, you get your coverage and energy savings as well as increased longevity.

That said, I think your tank looks fine Min. Great job. If your plants are growing with what you have, then i don't see the need to add any additional LEDs either.

-Charlie


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## Min (Dec 23, 2010)

my tank is 48"L 12"W 18"Tall, i truly dont think i need a second strip. the light itself is about 5"-6" above water level right under canopy cover. i do have 60degree optics, but i can not tell the difference between with and without them. 
the bar is free hanging on some holders so i can move it if i need to get into the tank. i can not see any coverage issues unless i target the light to the very back of the tank, then the front side get darker. otherwise i think its fine. i do have darker corner because the driftwood shadows and the the strip is only 36" long, the end LED are most likely 6"+ away from sideglass.


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## Hoppy (Dec 24, 2005)

That looks great! You weren't trying to prove anything, but you did prove that a single row of LEDs can light up a tank so that the light looks very even to the eyes. If you can get a PAR reading at the substrate I would be very interested in it.

This is definitely a cheaper approach than mine. I'm a bit concerned with mine that I will have more light striking the glass inside than I would like. A single row reduces that, especially with the right optics.


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## redfishsc (Aug 29, 2010)

Looks good. I think you're on the border as far as PAR is concerned. You're probably getting around 35-40 ppfd, max, on the substrate. 


I got 55-60 ppfd from a single row of Crees at 1,000mA over a 25g, but I had 8 LEDs over a 24" space, not 48. No optics, sitting about 4" over the water. 


I'd also like to caution you that I think your heatsink strip is undersized. 

At 1,050mA, those XPG's get VERY hot. 


I suspect you will be getting reduced life out of them using a single strip of 1/8" aluminum. That's about 1/3 the size I'd personally recommend. 


In your case I'd feel much safer using some aluminum C channel that's 3/16" or 1/4" thick, 2" wide. Not as cheap as $8 but much more effective.


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## IWANNAGOFAST (Jan 14, 2008)

Since your light is in a hood, you could add fans to it to help cool it down


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## Min (Dec 23, 2010)

if someone has a PAR reader i would be happy to volunteer.  
as far as aluminum goes, i would probably use a thicker/ wider one, but i think its fine. it seem to get to certain temp and stay that way. my guess would be around 38-39 celsius. hot to touch but not hot enough to burn you. there is definetely no need for fans.


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## Wicket_lfe (Aug 21, 2008)

man intriguing, maybe ill only do 2 strips of 6 leds. That would save me a bunch of money.

Thanks!


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## Min (Dec 23, 2010)

i say you can always add more if you need. 

im helping my friend to build a LED light for 200g tank. the work is in progress since soldering 100 Crees takes a while, but its a huge overkill even for reefers.


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## Min (Dec 23, 2010)

Last semester I took my first stab at a formal research paper as a part of my measurements and instrumentation class for mechanical engineering. I ran a thermal torcher test on a cree xp-g (IIRC). Recorded temp from the back of a 20mm star MCPCB (note: No extraneous heat sink) using a DS18B20 sensor and an Arduino. Used some math (from themal resistance, power dissapated, and ambient temps) to convert the MCPCB temp to junction temp. The power dissapated in the LED was controlled and varied with the Arduino via PWM.

At room temp and no airflow I was supprised to find that the junction temp just barely eclipsed the critical maximum recommened value of 150 Celsius at the maximum current of 1A. Meaning that, for all powers tested less than full power, the LED would not overheat. Yes it would get very hot which presents its own issues, but not to the point of damaging the junction. I did record junction temperatures greater than the maximum allowable duing the full 1 Amp test, but just barely, possibely within the resolution of my equipment at that temp. I bought 4 LEDs thinking I would need to burn at least one out to find the failure power (with no heatsink), but I was infact unable to destroy even one LED.

Comments: 
A heat sink should be thought of as a way to keep the casing temperature down (so you won't burn yourself or your house).

quote from somewhere


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## Dave-H (Jul 29, 2010)

I am trying to plan an LED setup myself - did you ever get any PAR readings on this fixture? 

Also, did you say what the distance was from the LED emitters to the substrate??

thanks!


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## Min (Dec 23, 2010)

im trying to find someone in my area with par reader. 

LED are about 22"-23" from substrate, that is including 5" above water lvl.


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## wootlaws (Feb 25, 2011)

as a newcomer to this hobby this is certainly a cheap route to start. however how do you prevent water getting onto your led leads?


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## Min (Dec 23, 2010)

on my 55g tank the lights are actually about 5 inches above water level, they are hanging by the top of the canopy. also the lights have optics. so there is no problem there. previously, i had my lights sitting on top of original tank covers, where the regular lights go, but then i decided to move them up. 
the big lights on 200g tank have couple of LED burned out due to bubbles poping too close and being right on waters edge. we solved it by putting plexi glass (not sure how to spell it). LED do not emit much heat and it is fine as long as it is not touching the glass.


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## Min (Dec 23, 2010)

3+ months with lights, still no CO2 some excel.


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## Min (Dec 23, 2010)




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## zenche (Feb 9, 2011)

looking very good.

i wish i was better at DIY.

do your tigers get a long well with the cardinals?


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## redfishsc (Aug 29, 2010)

Beautiful plants, no algae. Wonderful!


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## chrisnif (Aug 20, 2010)

I like it.

There is a reef guy in my local club, he is running 250 Cree XP-Gs at 1 amp each. 150 white, 40 royal blue and 40 purple and 20 cyan. He has them set up on single rails in concentric squares 48, 40, 32, and 24 inches, very similar to the single strip on a long tank. Only "spot lighting" he gets is from the inner ring that he uses white/blue/white/blue on 15 degree optics, but he meant for it to highlight certain things and make them "pop." It cost him "wat too much" as he says, but the power bill is cut significantly from the 2000w of halide he was using before, not to mention $800 in bulbs every 8-10 months.


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## Min (Dec 23, 2010)

more pictures added here 
https://picasaweb.google.com/mindei/Akvariumas#


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## ktm4us6 (Aug 18, 2009)

great job on the led lighting, i just bought a 8000k 30w led strip light from aquacave for $180 plus $40 for the power supply, hope it works good. In the future when i get settled in a permanet house i have a 450 gallon acrylic tank that i will have to light, thinking your way will be alot cheaper in the end. thanks for the info


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## Min (Dec 23, 2010)

had lots of thig happen lately. 
mostly my kid messing with wires and shortening the light out. 

on bright side, bought 10 cree afterwards. new aluminum corner mounted and much brighter light! 

will post some pics soon. tank is somewhat recovery since was out of lights for almost 2 weeks and plants did not take it well.


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## FDNY911 (Dec 6, 2009)

Wow, really nice project! How is the 200G tank coming? Is it for a reefer? I'm building a fixture for my 4x2x2 120 gallon planted tank. Any info on that big tank would be great! Maybe you should start a thread on it.


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## audioaficionado (Apr 19, 2011)

Marineland LED Double Bright Lights
$169.99 Sale $118.49 (Save 30% ) 

How would these compare to your DIY lights on my 40gal 36" tank?

Nice job on your project roud:


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## Min (Dec 23, 2010)

the 200g lights are done, but seems like we going to convert it to reef. we just got additional blue cree's to add and about to set it all up on the tank. just for color right now. tank is really bright with white if powered up. going high tech, with morning day evening setups. just to get 200gal started as reef cost some $$$. 
since never had a salt water we started a 5 gal nano tester.


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## Min (Dec 23, 2010)

under canopy


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## Min (Dec 23, 2010)

you cant tell the moonlights are on since Crees are so much more powerfull 
only when turned off you can see them.


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## Min (Dec 23, 2010)

same front shot just adjusted camera for less sensitive to light


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## FDNY911 (Dec 6, 2009)

Out of curiosity would you happen to have any more info about the 200g set up? As far as drivers, specific leds, the heatsink. If you have it I can PM you for details.

You're 55 is looking pretty nice. The moonlights really do a good job of lighting up that tank!


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## zenche (Feb 9, 2011)

very nice!

man...200G SW...holy


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## Min (Dec 23, 2010)

this video is for small 5g reef light
http://www.youtube.com/watch?v=Y8xYzg92lpk&NR=1
https://picasaweb.google.com/109154552118341257069/Apr82011?authkey=Gv1sRgCMnzhbTx95_4uQE#5600243169803295490

shows the process and finished product


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## Min (Dec 23, 2010)

FDNY911 said:


> Out of curiosity would you happen to have any more info about the 200g set up? As far as drivers, specific leds, the heatsink. If you have it I can PM you for details.
> 
> You're 55 is looking pretty nice. The moonlights really do a good job of lighting up that tank!


we had a set up 4 rows of 28 cree xpg, with 14 crees on 1 Meanwell ELN-60-48D driver. so total of 8 driver. 
The tank is 78x24x24 (200x60x60cm). for heatsinks we used the aluminum showed in pics before added PC fan on the end to cool it off. so its blowing inside the tube. the 112 crees was an little over kill


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