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Super cheap Dimmable LED Driver (cost under $3)

Printed From: Utah Reefs
Category: Specialized Discussion
Forum Name: DIY
Forum Description: Do it Yourself
URL: http://www.utahreefs.com/forum/forum_posts.asp?TID=47456
Printed Date: October 16 2018 at 2:42pm


Topic: Super cheap Dimmable LED Driver (cost under $3)
Posted By: seti007
Subject: Super cheap Dimmable LED Driver (cost under $3)
Date Posted: March 11 2011 at 10:05pm

LEDs are all the rage these days and a lot of peopel are doing DIY projects withe them. I thought I'd post a simple and very easy to build DIY driver that Im using on my tank. I originally went with a design based on cat4101 chip that could drive 6-7 3watt LEDs depengin in the forward voltage. But I found some issuees with the CAT4101 chip that forced me to look elsewhere. 

The design is based on the LM317 chip and can be made simply using one single resistor. The LM317 I used is a TO-220 package and has 3 pins. It can be operated in a constant current mode to drive LEDs like the one's most people use on their tanks i.e. Cree, Luxeon or Steve's LEDs. Here is a pic of the chip I found online.
 
Here is a pic of the The design works flawlessly and drives  6 + LEDs in series per chip based on the forward viltage of the LED chip and the supply voltage.
 
The way to calculate the size of the resistor to use is super simple Ohm's law
R=1.25/I   where I would be the desired current through the LEDs. Although the part is rated at 1.5A,  I would not recommed anything over 1A to keep the heat factor down ( I suppose you could go higher but use a higher wattage resistor and a larger heat sink). I would also recommend a heat sink on the chip to keep things cool. It is also receommended that you use a .01uF cap at the input if the power supply is noisy but I did not bother since I have a good quality Mean well switching supply that puts out a pretty good DC signal. Keep in mind that the Heat sink I used is a huge over kill. I just had a bunch laying around and used them. An aluminum U channel would work just as good. I am driving 7x 3watt Steve's LEDs based on an input voltage of ~24v with each one of the LM317 chips. The chips cost ~$.50 online and $1.50 locally at RaElco. The resistors are about $.70 each so the total cost to drive each string of 7LEDs for me was $2.20 Smilenot including heat sinks since I already had those. The dimmable ones would be a few dollars more but still way less that anyting else out there. I've been using these to drive about 100 LEDs over my 150 gal cube and the colors are just amazing.
 
 If anyone is thinking about building a DIY LED setup, Ill be happy to help you out. You are welcome to come check out my setup as well.
 
Here is a pic of the assembled driver. Im driving my LEDs at 850mA.
 
 


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke



Replies:
Posted By: Crazy Tarzan
Date Posted: March 11 2011 at 11:29pm
I'm interested in this.  How would you wire a dimmable set up?  What type of power supply would you use?  I am currently running 2 meanwells with 12 cree XR-E on each.  I'm looking to up it to 48 cree's and wouldn't mind a less bulky, less expensive dimmable set up.




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Was that in there yesterday? Casper--WY windier than ?

Down to a 20, soon to double or nothing


Posted By: Mark Peterson
Date Posted: March 12 2011 at 8:45am
Asad, that's awesome. Your new LED lights are awesome. I'm so happy that you are going to be on the RT. Your tank is AWESOME.

I've been meaning to ask you to help me put together an LED light bar for my Dentist's hang on the wall tank. Those aluminum T-bar heat sink mounting strips are just perfect for the 40x4.5x21 tank. I'll call you.

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Reefkeeping Tips, & quick, easy setup tricks:
www.utahreefs.com/forum/forum_posts.asp?TID=9244
Pay it forward - become a paid WMAS member


Posted By: Davidwillis
Date Posted: March 12 2011 at 9:40am
Wow!!! this is exactly what I am looking for.  I have my LED's on order, and have my 24v power supply, but did not know how to do this, and I don't want to buy them for $15 each.

I want to run two series of 8-12 LED's (I may have to break it up into 3 with only 24 volts), and I want them dimmable.  

Where did you find these online?  

Thanks again, this is perfect.



Posted By: seti007
Date Posted: March 12 2011 at 10:00am
Originally posted by Crazy Tarzan Crazy Tarzan wrote:

I'm interested in this.  How would you wire a dimmable set up?  What type of power supply would you use?  I am currently running 2 meanwells with 12 cree XR-E on each.  I'm looking to up it to 48 cree's and wouldn't mind a less bulky, less expensive dimmable set up.


I am using one meanwell power supply model number SP-320-24. I got it off ebay for about $42 shipped. It puts out 24V at 13A max. My recommendation would be to drive this or any power supply to a max of 80% of its rated power that owuld mean that you should drive it at a max of 10.4 A which would equate to about 250 Watts. The LEDs im using have a Vf of 3.2-3.3 V so I can drive 24/3.2=~7.5 ( or 7 in my case) LEDs in series. My desired current was ~850mA that means I could drive 10.4/.850=~12.2 rows(or 12 rows) of 7 LEDs each driven by an LM317 off just this one power supply. That would make 12x7= 84 LEDs driven off the meanwell SP-320-24. Hope that makes sense. If not, LMK and I can explain in more detail or over the phone.
 I also have a smaller 24V power supply to drive the rest of the LEDs in a similar fashion. The neat thing is that I can add more rows if needed at any time to the other power supply. Another thing to consider is that imho its better to have a few smaller power supplys and turn them on one at a time rather than have a large power suplpy and have t turn a bunch of LEDs on at the same timme. Remmber that the inrush current of the SP-320-24 is 20A at 120VShocked so a couple of these turning on at the same time could trip the circuit breaker.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: seti007
Date Posted: March 12 2011 at 10:04am
Originally posted by Davidwillis Davidwillis wrote:

Wow!!! this is exactly what I am looking for.  I have my LED's on order, and have my 24v power supply, but did not know how to do this, and I don't want to buy them for $15 each.

I want to run two series of 8-12 LED's (I may have to break it up into 3 with only 24 volts), and I want them dimmable.  

Where did you find these online?  

Thanks again, this is perfect.

Dave that would depend on the voltage drop across the LEDs you are using. In My case, if I had to drive the same number of LEDs you are wanting to, I would have to have 7 LEDS x3 rows. The meanwell power supply I mentioned above has a trim pot that can be adjusted to vary the voltage slightly above or below 24v which comes in real handy while fine tuning the system to make it run as efficeiently and cool (temp wise) as possible.
Mark, thanks for the kind words. Im looking forward to be in the Reef tour.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: saltlaketank
Date Posted: March 12 2011 at 1:48pm
well that looks like a sinch. Clown

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JayDee 8016042780
90 Gallon
30 Gallon sump
G3 Skimmer


Posted By: Davidwillis
Date Posted: March 12 2011 at 8:59pm
Originally posted by seti007 seti007 wrote:

Originally posted by Davidwillis Davidwillis wrote:

Wow!!! this is exactly what I am looking for.  I have my LED's on order, and have my 24v power supply, but did not know how to do this, and I don't want to buy them for $15 each.

I want to run two series of 8-12 LED's (I may have to break it up into 3 with only 24 volts), and I want them dimmable.  

Where did you find these online?  

Thanks again, this is perfect.

Dave that would depend on the voltage drop across the LEDs you are using. In My case, if I had to drive the same number of LEDs you are wanting to, I would have to have 7 LEDS x3 rows. The meanwell power supply I mentioned above has a trim pot that can be adjusted to vary the voltage slightly above or below 24v which comes in real handy while fine tuning the system to make it run as efficeiently and cool (temp wise) as possible.
Mark, thanks for the kind words. Im looking forward to be in the Reef tour.

How much can you adjust your meanwell power supply?  It would be really nice to have a power supply that would be able to adjust from 20-35 V.

Also, where can you find a 5 ohm Pot?  They don't seem that common.


Posted By: seti007
Date Posted: March 13 2011 at 8:09pm
Originally posted by Davidwillis Davidwillis wrote:


How much can you adjust your meanwell power supply?  It would be really nice to have a power supply that would be able to adjust from 20-35 V.

Also, where can you find a 5 ohm Pot?  They don't seem that common.
The meanwell can be adjusted from about 22-26v IIRC . I have found that to be perfect if im driving 6-8 3W LEDs in series. The 5Ohm Pots can be found on ebay. You are right they are not very common. Try looking for a 5Ohm Rheostat as well but they are higher wattage and usually more $$. Check out this auction with 4 pieces( POTs) for $11 delivered
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300535769006 - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300535769006


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 13 2011 at 8:30pm
That is interesting.  Could you use an adjustable voltage regulator before the LM317 to do the dimming?  Or would that cause problems?  It looks like the efficiency of these will really go down if you dimm them (you will still use as much power as when on full, but you will be just wasting some to dimm the light).   


Posted By: seti007
Date Posted: March 13 2011 at 8:35pm

I have been running the LEDS on my tanks for about a month or so and initially i was worried about the corals losing color. However, so far Im pretty happy with the results. Most corals have colored but a bit more than before on T5 lights. Here are some pics of the actual LED fixture. It looks dim but trust me, its super bright.

First the Aluminum T channel heat sinks. The LEDs are attached using Heat conducting double sided tape.
 
LEDs with 30 degree optics
 
Now for some tank and coral shots under the LEDs
 
 
 
 
 


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: seti007
Date Posted: March 13 2011 at 8:42pm
Originally posted by Davidwillis Davidwillis wrote:

That is interesting.  Could you use an adjustable voltage regulator before the LM317 to do the dimming?  Or would that cause problems?  It looks like the efficiency of these will really go down if you dimm them (you will still use as much power as when on full, but you will be just wasting some to dimm the light).   
No, you dont want to dim by varying the voltage through the Meanwell. You want to use the adj Resistor. The efficiency does not really drop as you drop the current because the powersupply varies the current as needed by the lm317 circuit. So power being voltagexCurrent, the output power varies depending on the current the LEDs are being driven at. Hope that makes sense.

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 14 2011 at 2:04am
Maybe I don't understand correctly...  I am looking here: http://users.telenet.be/davshomepage/current-source.htm

  • P=power loss
  • U=supply voltage
  • Uf=voltage drop device
  • I=current
     P = ( U - Uf ) * I

My understanding from that is that if you have (just as an example) 40v supply, but your LED's only need 20 to maintain your current (of say 1000ma to keep the math easy).  Your power loss is (40-20)*1 = 20W.  But if you supply with 24v and need 20, then you end up with (24-20)*1=4W.  Or am I not doing that correctly?

Also, I was wondering if you have tried any chips like the LM3401 or ZXLD1360?  From what I understand they would be more efficient...???

Thanks



Posted By: seti007
Date Posted: March 14 2011 at 11:49am
Originally posted by Davidwillis Davidwillis wrote:

Maybe I don't understand correctly...  I am looking here: http://users.telenet.be/davshomepage/current-source.htm

  • P=power loss
  • U=supply voltage
  • Uf=voltage drop device
  • I=current
     P = ( U - Uf ) * I

My understanding from that is that if you have (just as an example) 40v supply, but your LED's only need 20 to maintain your current (of say 1000ma to keep the math easy).  Your power loss is (40-20)*1 = 20W.  But if you supply with 24v and need 20, then you end up with (24-20)*1=4W.  Or am I not doing that correctly?

Also, I was wondering if you have tried any chips like the LM3401 or ZXLD1360?  From what I understand they would be more efficient...???

Thanks

What you state would be true for a linear power supply that would wate the "unused" portion of the power it is supplying thta is why you want to use a switching power supply that can regulate by varying the current at a given voltage. Think of your laptop power supply (also a switchign power supply) when the battery is fully charged and the computer is not doing anything cpu intensive, the power supply, even though it maybe rated at 19v @ 3A does not "burn off" the excess power but rather varys the only supplies whats needed. Try it out by putting a power meter like the kill-a-watt meter in front of a computer. You'll see the power consumed change as you do less or more cpu intensive things on the computer. Same exact principal applies to the LEDs.
That said, there is a way that power can be wasted in the circuit and that would be if the supplied voltage does not match the total voltage drop. In one of my posts above, i mentioned tweaking the trim pot to just the right voltage. I can explain this with the help of an example:
Lets assume that i have a 7 LED array (in series) and the voltage drop is 3.2V across each LED. I'm driving these with an LM317 with a voltage drop of 1.25. So the toal voltage drop is (3.2x7)=1.25=23.65v.   I will then turn the trim pot until i get as close to this voltage as I can. Let assume that Im driving this LED array with 850mA. If I were to supply say 24.65v from the power supply instead of 23.65v then the 1v difference would result in a 1v x 800mA =.8Watts of wasted power. that is the equation you mentiuoned above P = ( U - Uf ) * I
So what you say above is very true in this scenario. That is why you want to match the voltages as close as possible.
 In real life you will have to physically measure the voltage drops with a volt meter and that would be different for LEDS of even the same bin #s. The total voltage drops across each one of the multiple LED array would undoubtedly differ slightly so you will for sure have a bit of wasted power but the overall design will still be a lot more efficient than say Metal Hlides.
As for using other chips, as I mentioned, i have tried the cat4101 ( see the huge reefcentral thread) but i had some bad luck with that design. Even though the CAT4101 is a lot more efficient, i decided to go with the LM317 because of the simplicity, availability and cost. It works well for me. That is not to say that other designs would not work.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Crazy Tarzan
Date Posted: March 14 2011 at 1:48pm
Asad--using this method, can I use the 24v 1A wall warts I find on ebay to run separate strings of 6-7 led?  I'm thinking about using 3-4 colors of LED on my next fixture.  Also, can you please put the second diagram into layman's terms?  I'm interested in doing dimmable fixtures to adjust the color of the lighting.

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Was that in there yesterday? Casper--WY windier than ?

Down to a 20, soon to double or nothing


Posted By: seti007
Date Posted: March 14 2011 at 3:04pm
Originally posted by Crazy Tarzan Crazy Tarzan wrote:

Asad--using this method, can I use the 24v 1A wall warts I find on ebay to run separate strings of 6-7 led?  I'm thinking about using 3-4 colors of LED on my next fixture.  Also, can you please put the second diagram into layman's terms?  I'm interested in doing dimmable fixtures to adjust the color of the lighting.
If they are a linear powers supply, i would stay away. Most walwarts are simple ac to dc transformer with a rectifier circuit ane not suitable for this project. Besides, if you want to drive them at 80% you are looking at one of these per string of LEDs and depending on how many LEDs yo have you may need a whole lot of them. Another thing these probably wont have is a trim pot to adjust the output voltage by a small amount. As i mentioned earlier, this adjustment is super helpful to make sure the whoile thing runs as efficiently as possible.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 14 2011 at 7:19pm
Originally posted by seti007 seti007 wrote:

Originally posted by Davidwillis Davidwillis wrote:

Maybe I don't understand correctly...  I am looking here: http://users.telenet.be/davshomepage/current-source.htm

  • P=power loss
  • U=supply voltage
  • Uf=voltage drop device
  • I=current
     P = ( U - Uf ) * I

My understanding from that is that if you have (just as an example) 40v supply, but your LED's only need 20 to maintain your current (of say 1000ma to keep the math easy).  Your power loss is (40-20)*1 = 20W.  But if you supply with 24v and need 20, then you end up with (24-20)*1=4W.  Or am I not doing that correctly?

Also, I was wondering if you have tried any chips like the LM3401 or ZXLD1360?  From what I understand they would be more efficient...???

Thanks

What you state would be true for a linear power supply that would wate the "unused" portion of the power it is supplying thta is why you want to use a switching power supply that can regulate by varying the current at a given voltage. Think of your laptop power supply (also a switchign power supply) when the battery is fully charged and the computer is not doing anything cpu intensive, the power supply, even though it maybe rated at 19v @ 3A does not "burn off" the excess power but rather varys the only supplies whats needed. Try it out by putting a power meter like the kill-a-watt meter in front of a computer. You'll see the power consumed change as you do less or more cpu intensive things on the computer. Same exact principal applies to the LEDs.
That said, there is a way that power can be wasted in the circuit and that would be if the supplied voltage does not match the total voltage drop. In one of my posts above, i mentioned tweaking the trim pot to just the right voltage. I can explain this with the help of an example:
Lets assume that i have a 7 LED array (in series) and the voltage drop is 3.2V across each LED. I'm driving these with an LM317 with a voltage drop of 1.25. So the toal voltage drop is (3.2x7)=1.25=23.65v.   I will then turn the trim pot until i get as close to this voltage as I can. Let assume that Im driving this LED array with 850mA. If I were to supply say 24.65v from the power supply instead of 23.65v then the 1v difference would result in a 1v x 800mA =.8Watts of wasted power. that is the equation you mentiuoned above P = ( U - Uf ) * I
So what you say above is very true in this scenario. That is why you want to match the voltages as close as possible.
 In real life you will have to physically measure the voltage drops with a volt meter and that would be different for LEDS of even the same bin #s. The total voltage drops across each one of the multiple LED array would undoubtedly differ slightly so you will for sure have a bit of wasted power but the overall design will still be a lot more efficient than say Metal Hlides.
As for using other chips, as I mentioned, i have tried the cat4101 ( see the huge reefcentral thread) but i had some bad luck with that design. Even though the CAT4101 is a lot more efficient, i decided to go with the LM317 because of the simplicity, availability and cost. It works well for me. That is not to say that other designs would not work.


Thank you so much for your explanation, it makes perfect sense.  The only problem I see is when dimming, and using more than one array of different sizes off the same power supply.  If I dimm an array, I would change the voltage drop, and would also need to change the power in to keep it efficient.  And If I had two or more arrays, I would need to keep the voltage at the highest voltage drop, making the lower voltage drop arrays less efficient.

I guess I could put something like this on each array:  http://cgi.ebay.com/LM2596-DC-DC-Step-Down-Adjustable-Power-Supply-Module-/270712776755?pt=LH_DefaultDomain_0&hash=item3f07bd2833

But that would add some cost, and would still have to be lowered when dimming to keep it efficient.


Posted By: Davidwillis
Date Posted: March 14 2011 at 7:38pm
by the way, can you give me a link to your thread using the CAT4101?

Thanks


Posted By: seti007
Date Posted: March 14 2011 at 9:57pm
Originally posted by Davidwillis Davidwillis wrote:



Thank you so much for your explanation, it makes perfect sense.  The only problem I see is when dimming, and using more than one array of different sizes off the same power supply.  If I dimm an array, I would change the voltage drop, and would also need to change the power in to keep it efficient.  And If I had two or more arrays, I would need to keep the voltage at the highest voltage drop, making the lower voltage drop arrays less efficient.

I guess I could put something like this on each array:  http://cgi.ebay.com/LM2596-DC-DC-Step-Down-Adjustable-Power-Supply-Module-/270712776755?pt=LH_DefaultDomain_0&hash=item3f07bd2833

But that would add some cost, and would still have to be lowered when dimming to keep it efficient.
Thats not entirely true, although there would be differences in the voltage drops of the arrays. but when you dim, you are not changing the voltage but rather the current that is becasue the lm317 chip is acting as a constant current driver. 
here is the link to the cat4101 thread. They dont start talking about the cat4101 design until much later in the thread. I built these and they worked well until I had some issues with the cat 4101 chips. The manufacturer seems to think its a quality control issue and I currently have these in RMA. Hence, i went with  amuch easier and simpler solution that has worked well fo rme.
http://reefcentral.com/forums/showthread.php?t=1759758&highlight=driver - http://reefcentral.com/forums/showthread.php?t=1759758&highlight=driver


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: seti007
Date Posted: March 14 2011 at 10:01pm

BTW, that ebay link is a voltage regulator NOT a constant current driver. You would need the latter if you want to not fry your led array. I guess you could use that voltage regulator but then you would have to have a beefy resistor to regulate the current through the array. So to recap you want to drive the led array with a current regulator  (AKA a constatnt current driver) and not a voltage driver. The LM317 can be used both ways depending on the circuit design. Im using it in a constant current mode.



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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 14 2011 at 10:20pm
Thanks.... I don't think I explained my thought very well.  I meant to run the voltage regulater into the lm317 to give the correct voltage into the lm317.  Then the lm317 would regulate the current.  I would have to have one for each array (along with the lm317)  It is probably not worth the extra expense though.  Is there a good 24v 1-1.5a power supply for cheap?  Then I could just use a sepearte power supply for each array.






Posted By: BnK
Date Posted: March 14 2011 at 10:45pm
sorry this is off topic but what is that coral in the fifth picture that looks like purple flames

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Brett and Kristine | Layton, UT | Brett's e-mail: bruno21447@yahoo.com | Kristine's e-mail: oocherryo0@yahoo.com


Posted By: seti007
Date Posted: March 14 2011 at 11:11pm
Originally posted by Davidwillis Davidwillis wrote:

Thanks.... I don't think I explained my thought very well.  I meant to run the voltage regulater into the lm317 to give the correct voltage into the lm317.  Then the lm317 would regulate the current.  I would have to have one for each array (along with the lm317)  It is probably not worth the extra expense though.  Is there a good 24v 1-1.5a power supply for cheap?  Then I could just use a sepearte power supply for each array.




You'll be just fine with 2 to 3 24v power supplies. If you want to do seperate power supplies for each array, you might consider the meanwell eln-60-48d dimmable driver. Although its considerably more $$ it will give you the peace of mind that you have one of the best drivers out there. I seriously considered using it but then in the end the $3 won out over the $35. THere are definately advantages of going with the meanwell but to me the price was a bigger factor.
Someone at RC named spacedcowboy suggested this power supply. Its a great PS for the money but is currently sold out. If you can find something comprable, you can use 2-3 of these to drive all you leds.
http://www.mpja.com/prodinfo.asp?number=16855+PS - http://www.mpja.com/prodinfo.asp?number=16855+PS
 
 
You might also consider the smaller 4.2A supply
http://www.mpja.com/prodinfo.asp?number=16853+PS - http://www.mpja.com/prodinfo.asp?number=16853+PS
 
EDIT:
Just found this powers supply. its a 24v 1.8A with a trim pot for $10.
http://www.mpja.com/prodinfo.asp?number=17426+PS - http://www.mpja.com/prodinfo.asp?number=17426+PS
 
BnK that's a pink/purple birds nest. It was more pink before but has turned a slight purple under the LEDs. I kinda like teh color and growth pattern.
 


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 14 2011 at 11:25pm
I have a couple of power supplies.  But I am not sure if they will work for this.

This one:  http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p4340.l2557&rt=nc&nma=true&item=320655016335&si=Qq8MVSJUqwOyvBJMaN5ZVTXtVmM%253D&viewitem=&sspagename=STRK%3AMEWNX%3AIT

And this one: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170604177333&ssPageName=STRK:MEWNX:IT




Posted By: seti007
Date Posted: March 14 2011 at 11:48pm
you could use either to drive leds as long as you have a constant current driver. Looks like the first one may have a trim pot, although i dont see any pics of the front. that would help you tweak the voltage to where you need to be. With the leds i have you could drive 2 arrays of 7 LEDs each at 750-800mA. The second one would be tricky because you'll have to pick the number of leds in the array to have the forward voltage exactly match the voltage supplied by the power supply since its not adjustable.

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 15 2011 at 8:32am
The first one I got does have a trim pot.  So I think it will work well.  I also like that $10 one you found.  At that price I could have a power supply for each array (connected to the constant current driver).  Total cost would only be less than $15/ array 


Posted By: seti007
Date Posted: March 15 2011 at 1:41pm
Originally posted by Davidwillis Davidwillis wrote:

The first one I got does have a trim pot.  So I think it will work well.  I also like that $10 one you found.  At that price I could have a power supply for each array (connected to the constant current driver).  Total cost would only be less than $15/ array 
That sounds good. You would have good control over the color and do a great dusk to dawn effect with each array driven off its own PS.
One thing i just realized is that the voltage drop across the lm317 is 3v and not 1.25 as i stated earlier. I was going off memory but checked my notes and realized the mistake. the 1.25 is the voltage drop across the adj and vout pins:)

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 15 2011 at 10:01pm
So the voltage from adj and vout is always 1.25 v no matter what the resistor is?  And the drop across the lm317 is 3 volts (is this the minimum voltage drop?).


Posted By: seti007
Date Posted: March 15 2011 at 11:26pm
yes and yes. The LM317 keeps the voltage diff between the adj and vout pin at 1.25v that is what allows you to pick a constant current based on the resistor value. The voltage drop across the lm317 is usually 1.7v ( in voltage regulator mode)  but in constant current mode you add the Vref of 1.25v to it which equals about 3v. This woud probably change a bit as the temp goes up. However, in my application since the volatages are matched quite well,  and i have an overkill of a heat sink, mine dont even get mildly warm. So dont worry about the change in temp. BTW. the lm317 has an over temperature and over curernt shutdown. Check out the Pdf for more info.
http://www.fairchildsemi.com/ds/LM/LM317.pdf - http://www.fairchildsemi.com/ds/LM/LM317.pdf


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 16 2011 at 8:51pm
In my searching, I ran into this:
http://cgi.ebay.com/DC-24V-1A-24W-Switching-Power-Supply-CCTV-LED-Driver-/290498474807?pt=LH_DefaultDomain_0&hash=item43a30ef337

It looks very interesting because it says you can set the current with it.  Would this work?


Posted By: seti007
Date Posted: March 17 2011 at 12:12am
looks pretty good based on the description. It seems to be a regulated current and regulated voltage driver. also looks like you can vary the current and the voltage which is good. The only thing is that its not dimmable without messing with the (probably) a trim pot on the device itself. I wonder if they make a 48v version of it. You could drive twice as many LEDs per array with a 48v version.

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 17 2011 at 8:44am
I couldn't find a 48v version, just 12, and 24.  If you wanted a dimmer, could you just remove the trim pot, and replace it with a different pot wired to a remote location?

You can't beat that price though.  $10.88 with free shipping, and you have your power supply, and current control for one array.


Posted By: seti007
Date Posted: March 17 2011 at 10:55am
You could remote mount the pot but I would keep the wire length Short because it will introduce Some resistance. Looks like it would be worthwhile to try one and see. You c can make an offer @ $8 or so and see If they take it. I probably won't drive anything above 800mA which would be 80% of its rated Value. Depending on the LED used you may want to drive at a higher current than that so  something to think about. If you do try it keep us posted-

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 18 2011 at 9:03am

I put in an offer of $8 for it, we will see.

my leds are: CREE XP-G Cool White, and CREE XP-E Royal Blue

Royal blue:
Wattage:3w
Max Drive Current:1000mA
Forward voltage (@ 700 mA):3.4
Light Intensity: 500mW flux @ 350mA
Dominant Wave Length (max):450nm-465nm
Viewing angle:115°-130°
Color:Royal Blue
Star Size:20mm
Specification: http://www.cree.com/products/pdf/XLampXP-E.pdf - http://www.cree.com/products/pdf/XLampXP-E.pdf
http://www.cree.com/products/pdf/XLampXP-E.pdf - Version:XPEROY-L1-0000-00B01  
cool white:
Wattage:3w
Max Drive Current:1500mA
Forward voltage (@ 700 mA):3.0
Light Intensity:139lm flux @ 350ma
CCT:5000K-8300K
Viewing angle:125°
Color:Cool White
Star Size:20mm
Specification: http://www.cree.com/products/pdf/XLampXP-G.pdf - http://www.cree.com/products/pdf/XLampXP-G.pdf
http://www.cree.com/products/pdf/XLampXP-G.pdf - Version:XPGWHT-L1-0000-00H51  

It looks like the royal blues could be run with the 800ma, since its max is 1000ma.  But the cool white may need more..??


Posted By: thefu
Date Posted: March 18 2011 at 10:45am
curious as to why a pre-packaged version of this approach has not been made commercially available by the likes of nano-tuners, rapid-led, etc. This intrigues me.

Also, could this solution be easily adaptable to make the dimming happen via a standard 0-10V circuit like used on the Apex Controller?


Posted By: seti007
Date Posted: March 18 2011 at 1:56pm
Originally posted by Davidwillis Davidwillis wrote:


I put in an offer of $8 for it, we will see.

my leds are: CREE XP-G Cool White, and CREE XP-E Royal Blue

Royal blue:
Wattage:3w
Max Drive Current:1000mA
Forward voltage (@ 700 mA):3.4
Light Intensity: 500mW flux @ 350mA
Dominant Wave Length (max):450nm-465nm
Viewing angle:115°-130°
Color:Royal Blue
Star Size:20mm
Specification: http://www.cree.com/products/pdf/XLampXP-E.pdf - http://www.cree.com/products/pdf/XLampXP-E.pdf
http://www.cree.com/products/pdf/XLampXP-E.pdf - Version:XPEROY-L1-0000-00B01  
cool white:
Wattage:3w
Max Drive Current:1500mA
Forward voltage (@ 700 mA):3.0
Light Intensity:139lm flux @ 350ma
CCT:5000K-8300K
Viewing angle:125°
Color:Cool White
Star Size:20mm
Specification: http://www.cree.com/products/pdf/XLampXP-G.pdf - http://www.cree.com/products/pdf/XLampXP-G.pdf
http://www.cree.com/products/pdf/XLampXP-G.pdf - Version:XPGWHT-L1-0000-00H51  

It looks like the royal blues could be run with the 800ma, since its max is 1000ma.  But the cool white may need more..??
Yeah, i would think you'd want to drive the white LEDs over 800mA for sure. You could do what I did in my design for the White LEDs and have a large power suply driving multiple lm317s.
Thefu, i dont know what type of drivers are used in some of the commercially available lights since i dont own one. My guess is that the lm317 is not as efficient as say a cat4101 based design. However, as i mentioned earlier, for me losing a slight but of efficiency is fine if it saves me a bunch of $$. Right now I have a bunch of blank PCBs for the tripple cat4101 design that are ready to go but I dont think ill be using those since im very happy with this simple design. You dont need an external 0-10v source like with some drivers. the LM317 can be dimmed most simply by varying the resistor. A POT or rheostat of appropriate power rating would work just fine. So, unfortunately, diming usig teh 0-10v out of the Apex might not be an option with this design :(


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: thefu
Date Posted: March 18 2011 at 2:09pm
No, my question was that if there was a way to take a single MeanWell power supply and power 42 LED instead of just 12 by adding $10 in extra hardware, why have they not made such a box available? I was not speaking about commercial fixtures...nano-tuners and rapid-led both sell parts to DIYers.

Also, I know that you don't NEED a 0-10V source, but what if you DO want to control these with a controller like and Apex? How could you adapt it for that.

Also, comparing $3 to a $30 meanwell ELN-60-48D is not apples to apples because with the $3 you still have to buy some pwer supply, right? The savings really comes in when you are doing very large arrays, where you have one power supply and three or four of your circuits powering 7 LED, right? Then, instead of three meanwells to do 36 LED, you use one meanwell and 5 of your circuits to do 35 LED. That would be $90 vs. $45, right? With the main difference being that I could not dim them with a controller.

Just trying to understand the application, the numbers, and the differences when you do it this way.


Posted By: seti007
Date Posted: March 18 2011 at 2:35pm
Originally posted by thefu thefu wrote:

No, my question was that if there was a way to take a single MeanWell power supply and power 42 LED instead of just 12 by adding $10 in extra hardware, why have they not made such a box available? I was not speaking about commercial fixtures...nano-tuners and rapid-led both sell parts to DIYers.

Also, I know that you don't NEED a 0-10V source, but what if you DO want to control these with a controller like and Apex? How could you adapt it for that.

Also, comparing $3 to a $30 meanwell ELN-60-48D is not apples to apples because with the $3 you still have to buy some pwer supply, right? The savings really comes in when you are doing very large arrays, where you have one power supply and three or four of your circuits powering 7 LED, right? Then, instead of three meanwells to do 36 LED, you use one meanwell and 5 of your circuits to do 35 LED. That would be $90 vs. $45, right? With the main difference being that I could not dim them with a controller.

Just trying to understand the application, the numbers, and the differences when you do it this way.
That is very true Thefu, maybe another reason why most commercial applications as wella s most DIY designs dont use this design. Im my case, My initial design using the cat4101 had dimming pots but I always had it running at max current so i decided not to incorporate dimming with this design. I guess if i had an Apex, i would have chosen a different design to do dimming. It really makes it slick to be able to do dimming with a neat controller like the Apex. You could do some neat cloud and lightnign effects that way.
You are also the savings from this design. the bigger the build the more you would end up saving. You would still need a power supply to drive the lm317. But a $40 power supply can drive quite a lot of LEDs. eg, you can drive 100 LEDs with a couple of the power supplies I used.
BTW, if you are interested in a cost effective way to use the 0-10v from the Apex, look at the cat4101 design. You may have better luck than I did. There is a huge thread about it on RC. I can help you if you need it.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 19 2011 at 9:34am
I am just waiting for my LED's to show up.  It looks like they are delayed.  But I was wondering, what size, and where did you get the Aluminum T material to mount your LED's on.




Posted By: seti007
Date Posted: March 19 2011 at 11:31am
I found those particular ones at NPS market square store. They have since sold out of that particular type but have others like aluminum U channels that would work just as well. You can often find some pieces that are sold by weight so that would make for a real cheap heat sink. The ones i got came in lengths of 8' that I cut down to 36" length.
The double sided thermal tape is this one from ebay. It makes the job of attaching or detaching LEDs real easy:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180592168677&ssPageName=STRK:MEWNX:IT - http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180592168677&ssPageName=STRK:MEWNX:IT


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 19 2011 at 11:45am
Thanks.  How wide are those aluminum T, or U channels?  I see you ran two rows on one.  NPS is a ways to drive for me, so I am going to see if I can find any closer to me.  They cost too much at Lowes, but I may be able to find them at ipaco (except they will probably make me buy 20 feet or charge for cutting).


Posted By: seti007
Date Posted: March 19 2011 at 12:38pm

I used 2 types of Aluminum channels tht T channels with two staggered rows of LEDs (14 total) are 2" wide and have a fin thats 1" high. I also used another type of AL channel with 1 row of LEDs (7 total) that is 1.5" wide and is sort of a distorted U. I partially removed one from the canopy to take a shot of it. The nice thing is that I can easily add this U channel to the canpopy to add more light as needed.

Both these were very light weight, super cheap and work awesome. Here is a pic i just took:


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: jcom
Date Posted: March 19 2011 at 6:08pm
Just saw this setup in person today...amazing! 


Posted By: seti007
Date Posted: March 19 2011 at 8:05pm
Originally posted by jcom jcom wrote:

Just saw this setup in person today...amazing! 
]
Thanks for the fragThumbs Up LMK when you wanna come by and get some from me.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: jcoulter17
Date Posted: March 19 2011 at 11:56pm
Saw it today too and it is one of the best setups I seen here in Utah. Even better than the LFS.


Posted By: seti007
Date Posted: March 20 2011 at 9:55am
Originally posted by jcoulter17 jcoulter17 wrote:

Saw it today too and it is one of the best setups I seen here in Utah. Even better than the LFS.
Thanks, it was great having you guys over.

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: March 20 2011 at 2:41pm
Thanks for the picture.  I went to lowe's, and home depot yesterday, but couldn't find anything like that.  They just had flat aluminum, or L aluminum.  They did have small U shaped aluminum, but it was only 3/4 inch wide.  Do you know what that distorted U is used for?  Hopefully I can find something without driving all the way to NPS.

Originally posted by seti007 seti007 wrote:

I used 2 types of Aluminum channels tht T channels with two staggered rows of LEDs (14 total) are 2" wide and have a fin thats 1" high. I also used another type of AL channel with 1 row of LEDs (7 total) that is 1.5" wide and is sort of a distorted U. I partially removed one from the canopy to take a shot of it. The nice thing is that I can easily add this U channel to the canpopy to add more light as needed.

Both these were very light weight, super cheap and work awesome. Here is a pic i just took:


Posted By: seti007
Date Posted: March 20 2011 at 2:52pm
You can find some really cool pieces at Utah metal works on 805 Everett Ave in SLC. You will for sure find something close to if not better than what I have. The U channel piece, I got was from them. You'll have to rummage through toms of junk metal to get to the good stuff but its well worth it for the price. They sell everything by weight so its cheap as it gets.

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: BnK
Date Posted: March 20 2011 at 7:41pm
Yes thank you for those frags i love them. And your tank is real nice, love the light set up.

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Brett and Kristine | Layton, UT | Brett's e-mail: bruno21447@yahoo.com | Kristine's e-mail: oocherryo0@yahoo.com


Posted By: chris.rogers
Date Posted: April 24 2011 at 12:48pm
awesome info, asad. 

couple q's...

have you noticed a power bill drop?

and what're the specs on the LEDs?


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Ils sont fous, ces Romains!


Posted By: seti007
Date Posted: April 27 2011 at 3:19pm
Quite frankly, I havent looked at my electric bill for years Shocked i just have it on auto pay and it just gets paid without any bother to me. But, I guess I can look at the record and let you know. I do however, remember putting a kill-a-watt meter on the old lights and then on the LEDs and noticed a lower wattage draw ( cant remember the exact figures). So, hopefully the power bill will go down a bit. I was using T5s before and they are quite a bit more efficient compared to MH lights already. So, I expected only a small drop in power consumption. One thing I am counting on is that I would not have to replace the bulbs any time soon. That is where the real savings would be IMO.
The lights I used were from Steve's LEDs. They are a generic Chinese 3W LEDs that are quite cheap (about half the price of CREE) but not quite as efficient as Cree. You can go to his website and check them out.
 
Originally posted by chris.rogers chris.rogers wrote:

awesome info, asad. 

couple q's...

have you noticed a power bill drop?

and what're the specs on the LEDs?


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: chris.rogers
Date Posted: April 29 2011 at 1:51pm
Nice.

I'm really impressed, Asad.  Well done.  And high five for using the LM317.  Thumbs Up


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Ils sont fous, ces Romains!


Posted By: seti007
Date Posted: April 30 2011 at 1:04am
Originally posted by chris.rogers chris.rogers wrote:

Nice.

I'm really impressed, Asad.  Well done.  And high five for using the LM317.  Thumbs Up
Thanks Chris :)

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: rbtron
Date Posted: April 30 2011 at 9:39am
[QUOTE=seti007]

LEDs are all the rage these days and a lot of peopel are doing DIY projects withe them. I thought I'd post a simple and very easy to build DIY driver that Im using on my tank. I originally went with a design based on cat4101 chip that could drive 6-7 3watt LEDs depengin in the forward voltage. But I found some issuees with the CAT4101 chip that forced me to look elsewhere. 



Posted By: rbtron
Date Posted: April 30 2011 at 9:41am
What kind of problem did you see with the CAT4101? Thermal shutoff?
Thanks, Tron


Posted By: seti007
Date Posted: April 30 2011 at 6:27pm
Originally posted by rbtron rbtron wrote:

What kind of problem did you see with the CAT4101? Thermal shutoff?
Thanks, Tron
Dont know exactly, but my guess is that I got a bad batch from the manufacturer. Some worked but most did not work or overheated. I have sent samples back to the manufacturer in order to check whats wrong but have not heard back yet. So i switched to the lm317.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Jeffatpm
Date Posted: May 04 2011 at 11:00pm
Thought I would share a link for awesome LED drivers similar to thomas research - http://www.inventronics-co.com/ - http://www.inventronics-co.com/
These are what I'm using on my 210 setup I'm building led's should be in soon, I should have it up and pics up soon!


Posted By: Jerrick
Date Posted: May 05 2011 at 3:12pm
Okay So Since I just read the entire thread and still have no clue! how much would someone charge me to put a setup together for a 36 Gallon bow front frag tank? ANYONE?  


Posted By: Jeffatpm
Date Posted: May 05 2011 at 5:18pm
I am going to start doing just that - I'm just thrilled with LED's and I want to help/build fixtures for people.
PM Me and we can talk more.


Posted By: sanddune600
Date Posted: May 07 2011 at 11:40am
I just built 4 drivers to run 5 leds each from cat4104 I am very happy with the simplicity of them and sunrise/sunset effects controlled with a hydra controller (diy arduino based reef controller)

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Andy Jorgensen
My number is four three 5 7 six four 8 0 three four


Posted By: seti007
Date Posted: May 07 2011 at 9:47pm
Originally posted by Jerrick Jerrick wrote:

Okay So Since I just read the entire thread and still have no clue! how much would someone charge me to put a setup together for a 36 Gallon bow front frag tank? ANYONE?  
 
You can get a hold of me and I can help you out with your design free of chargeSmile. Pm me and we can talk. Im sure there are plenty of other ppl on this forum who would like to help.
Sanddune, that's great to hear. Post some pics of your LEDs.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: May 08 2011 at 9:51pm
Originally posted by Jerrick Jerrick wrote:

Okay So Since I just read the entire thread and still have no clue! how much would someone charge me to put a setup together for a 36 Gallon bow front frag tank? ANYONE?  


I have all the stuff to put together mine on my 29 gal.  I have been busy lately, but hopefully I will have some time soon.  I know you are close by, so when I do put it together you can come look at it.  It really is not that complicated, I am sure once you see it, it will make sense.


Posted By: BnK
Date Posted: May 08 2011 at 10:04pm
I tried sottering (to lazy to see how to spell that lol) for the first time and did not do so good. So guess I will have to find someone that can make one for me if I buy all the materials and give me a good deal :).

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Brett and Kristine | Layton, UT | Brett's e-mail: bruno21447@yahoo.com | Kristine's e-mail: oocherryo0@yahoo.com


Posted By: sanddune600
Date Posted: May 09 2011 at 10:49pm
Originally posted by Jerrick Jerrick wrote:

Okay So Since I just read the entire thread and still have no clue! how much would someone charge me to put a setup together for a 36 Gallon bow front frag tank? ANYONE?  


your welcome to stop by and look at my nano that with LEDs I can try and teach you some while your here or I may be interested in setting it up for you I am also in Logan

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Andy Jorgensen
My number is four three 5 7 six four 8 0 three four


Posted By: Jerrick
Date Posted: May 10 2011 at 1:16pm
Originally posted by sanddune600 sanddune600 wrote:

Originally posted by Jerrick Jerrick wrote:

Okay So Since I just read the entire thread and still have no clue! how much would someone charge me to put a setup together for a 36 Gallon bow front frag tank? ANYONE?  


your welcome to stop by and look at my nano that with LEDs I can try and teach you some while your here or I may be interested in setting it up for you I am also in Logan

I might take you up on that when I get some free time! thanks


Posted By: chris.rogers
Date Posted: July 07 2011 at 1:03pm
Asad,

I started reading some of the ReefCentral mega-threads on LED lighting and noticed that some aquarists have opted for the switched mode power supply to increase efficiency.  Did you consider that route?


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Ils sont fous, ces Romains!


Posted By: seti007
Date Posted: July 07 2011 at 3:10pm
Originally posted by chris.rogers chris.rogers wrote:

Asad,

I started reading some of the ReefCentral mega-threads on LED lighting and noticed that some aquarists have opted for the switched mode power supply to increase efficiency.  Did you consider that route?


 I'm using the SP-320-24  which is a Switching power Supply from Meanwell.  Its really well designed and fairly efficient. The main inefficiancy in my design is the LED itself. Cree LEDs are more efficient but I would have sent more than double what I ended up  spending.  I added a couple more computer  case fans  for summer and the whole thing is running really cool.  The temperature swings are minor Compared to what I was getting with T5 and MH Combo.  So far I couldn't be happier with the light Setup.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: chris.rogers
Date Posted: July 07 2011 at 4:12pm
That's right, I even went and googled it after I read it the first time.

So you have 110AC on the wall side, and up to 42V on the output of your Meanwell, and so you use the LM317 to match the sum-total of all v-drops across all the LEDs on your array?

So if you are running 3A down a string of LEDs, and each LED has a v-drop of 1V, you could put 13 of those (13 LEDs = 39W from 13V at 3A) on an array?  Am I understanding correctly?


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Ils sont fous, ces Romains!


Posted By: seti007
Date Posted: July 07 2011 at 6:01pm
Originally posted by chris.rogers chris.rogers wrote:

That's right, I even went and googled it after I read it the first time.

So you have 110AC on the wall side, and up to 42V on the output of your Meanwell, and so you use the LM317 to match the sum-total of all v-drops across all the LEDs on your array?

So if you are running 3A down a string of LEDs, and each LED has a v-drop of 1V, you could put 13 of those (13 LEDs = 39W from 13V at 3A) on an array?  Am I understanding correctly?


Actually not quite. The meanwell puts out a 24V which is adjustable between 18.2 v - 27.5 v using the trim pot. The LM317 just regulates the current to a value based on the resistor I choose. The datasheet will give you the resistor values that you can choose for a desired current.  The LEDs im using have a Vf of 3.2-3.3 V so I can drive 24/3.2=~7.5. In my case, I adjust the trim pot on the meanwell to as close to the total voltage drop of 7 LEDs as possible. So in my case 3.2x7=22.4, I adjust it to be close to this value so that the least amount of power is lost as heat in the driver.
You don't want to drive 3A of current down a string since it will burn them up in a blink of an eye. I try to drive mine under 1A.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: chris.rogers
Date Posted: July 07 2011 at 6:22pm
Right, I went through your math before you posted and I think I'm square.  I was just trying to pick numbers that squared away rather than realistically what an LED would take - 3A definitely would burn things up.  I'm embarrassed I wrote that...  Embarrassed

Basically, my question was why you used the linear regulator setup as opposed to a PWM setup (like the LM3414).  I think the tradeoff between cost and simplicity (the LM317 route) and the high efficiency of the LM3414 is a good tradeoff because you can adjust the string of LEDs to keep the voltage/current demands through the LM317 within good limits.

I remember hearing that with the LM317 needs to have a 3V 'window,' so to speak, such that the v-drops across all your LEDs minus your output voltage of your Meanwel needs to be as close to 3V as possible?  Have you heard of that as well?

I am really itching to see this setup.  You're in, what, $400 total for this lighting setup?  $50 for the Meanwell, $300 for the LEDs, and $50 for various supplies?  For a 150 gallon tank?  That's awesome.


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Ils sont fous, ces Romains!


Posted By: seti007
Date Posted: July 07 2011 at 6:34pm
Yes forgot about that voltage drop across the lm317. Its 3V so you just add that to the total voltage drop. I talk about that on one of my posts on page 2.  In the above scenario you will adjust the trim pot to 22.4+3=25.4V. The  total cost but its considerably less than some other setups (probably better than mine) out there.  To me the efficiency hit I took by not going with the Cree and fancier drivers is well worth it for the $$ savings. 
BTW. PM me if you'd like to some check out the setup. Im in Holladay.


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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: chris.rogers
Date Posted: July 07 2011 at 9:22pm
I actually don't think you took much of an efficiency hit in terms of power usage.  Your components might heat up a bit more, but when it's all said and done, I'll take the simplicity and some extra heat sinks.

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Ils sont fous, ces Romains!


Posted By: chris.rogers
Date Posted: July 07 2011 at 9:25pm
I think I really need to swing by next time I'm in SLC.  I'd really like to see this in person.  The photos you took are really impressive. 

What did you do on the bench to test this all out to make sure you had your ducks in a row first?  Was it just a hookup job to ensure everything works before putting it in your hood?


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Ils sont fous, ces Romains!


Posted By: chris.rogers
Date Posted: July 08 2011 at 3:59pm
Oh, and another question

If you lose one LED in the string, doesn't that open up your circuit?  What happens in that case?  Would you source any current to the string at all without a return path?  It seems like you wouldn't, there'd just be an open circuit.  So what would happen?


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Ils sont fous, ces Romains!


Posted By: seti007
Date Posted: July 09 2011 at 12:41am
Originally posted by chris.rogers chris.rogers wrote:

Oh, and another question

If you lose one LED in the string, doesn't that open up your circuit?  What happens in that case?  Would you source any current to the string at all without a return path?  It seems like you wouldn't, there'd just be an open circuit.  So what would happen?
If you are using one sting with all LEDs in series, and one burns out into an open circuit, the whole string will turn off. In a parallel configuration, you will just drive more current through the remaining strings and possibly damage them if the current exceeds the LED's rating.

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: chris.rogers
Date Posted: July 09 2011 at 1:42pm
In parallel, yes, there's just a big current divider, so you just keep drawing current until they all burn out, but in series, wouldn't the power supply see the open/burned out LED as a super large load and try to source enough current to drive it?  Don't you burn something out there, too?


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Ils sont fous, ces Romains!


Posted By: Davidwillis
Date Posted: July 09 2011 at 10:02pm
I think it will just bump the voltage up to the maximum, but won't burn anything out. 


Posted By: Davidwillis
Date Posted: July 11 2011 at 6:25pm
Ok, I just started putting mine together, but I can't get the chip to work  I set it up like the dimmable diagram on the first page, but it does not dim.  In fact there is no difference even if I remove the resistor, and pot.  I am wondering what I am doing wrong.  I can dim them using the trim pot on the power supply though...  Also, the voltage between the out, and the adj is 0.


Posted By: chris.rogers
Date Posted: July 11 2011 at 11:04pm
Can you post a diagram of what your connections are?

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Ils sont fous, ces Romains!


Posted By: Davidwillis
Date Posted: July 12 2011 at 7:34pm
As far as I can tell it is the same as your dimmable diagram on your first post.  However after looking around a bit, I found that it should go out the adj pin, instead of the out pin.

Like this example....







Posted By: chris.rogers
Date Posted: July 13 2011 at 9:38am
It's Asad's diagram, not mine, but I'm flattered you think I'm as smart as Asad.  Smile

What are your numbers?  Input voltage from your supply?  What's your resistor?  What's your desired current?


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Ils sont fous, ces Romains!


Posted By: Davidwillis
Date Posted: July 13 2011 at 7:19pm
sorry.... I just read the post real quick, and thought you were Asad...

It seems to work with it hooked up the way I showed in my picture.  I have a 0-5 ohm pot for the resistor.  I adjusted my voltage differently for each array because they are different sizes, and colors.  But with it hooked up to the adj pin like in my picture, it adjusts from 200 to 1000ma.

I hope to get some time to put it together this weekend, and I will post pictures.


Posted By: chris.rogers
Date Posted: July 14 2011 at 8:50am
That's awesome.

Please do post some pics, I'd love to see them.  I'm convinced I'll be doing my lighting setup like this when the time comes.


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Ils sont fous, ces Romains!


Posted By: Laird
Date Posted: July 14 2011 at 4:41pm
Has anyone built any kind of housing for theirs? If so PICS PLEASE.



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Indefinite hiatus from sw aquariums.

Once I have my glorious return I'll set back up the following.
50 Gallon rimless cube.
180 Gallons mixed reef paradise


Posted By: Davidwillis
Date Posted: July 14 2011 at 7:32pm
I am using an aluminum housing with mine (I got it from e-bay for $5)... I will post when I get it put together



Posted By: Davidwillis
Date Posted: July 15 2011 at 4:08pm
Ok, I had some time today and got them put together.  First the pictures, then I will report on how they are working.


Inside the control box....



The control box assembled, and the light fixture.





Lights on the tank.




tipped up so you can see the lights...







Posted By: Davidwillis
Date Posted: July 15 2011 at 4:30pm
I tried taking a picture of a before and after lighting.  My lights I was using before were 30 watts of t5 lighting.  The difference is incredible, but I can't show it on a camera.  I sold my leds I had on before, and have been using these t5's until I got these new ones put together, but I don't think the light was good enough, and all my sps corals have died, as well as my hammer coral.  So I don't have any corals to compare the lights with, but the fish look much more colorful under these lights, and they look 10X brighter than the t5s.

I am running 3 series of lights.  Two royal blues strings, and one white.  All are dimmable, so I can get a good range of blue or white.

I don't think I have a good enough heat sink to run them at full power though.  At 1000ma they start getting hot.  So I am currently running all the lights at 500ma, and they are still plenty bright, and the color mix looks great.

Power usage:
First I checked the power usage of my t5's.  Plugging in just my three power supplies (not connected) consumes 8W.  With the lights on full power I consume 83W... seems a bit high considering I am only running 19 3W LED's (19x3=57)  That might be why it was getting hot.  At 500ma per series my total power consumption is 40W.  Not bad considering they look 10X better than the t5's that used 33W.

p.s.  My kids love to look at the fish with just the blue lights on... they look like they glow...LOL


Posted By: chris.rogers
Date Posted: July 15 2011 at 5:01pm
I would expect that 1A of current would make an LED run hot - what is their current rating per the data sheet?

I'd love to see the pics, but they're blocked at work, and I'm going camping this weekend - d'oh!  Can't wait to see the pics though.

Weston's not far from Preston, right?  I might have to find the time to come up and see this.

Did you measure the power consumption using a kill-a-watt?


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Ils sont fous, ces Romains!


Posted By: chris.rogers
Date Posted: July 15 2011 at 5:10pm
Strange, on a refresh all the images show up.  Maybe I'm being watched by IT and they wanted to see the tank too...?   LOL

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Ils sont fous, ces Romains!


Posted By: Davidwillis
Date Posted: July 15 2011 at 5:16pm
The royal blues are rated for 1A max, and the whites are rated at 1.5A max.  So 500ma should be very safe.  But my heat sink is only a 3/4 inch wide strip of aluminum with an aluminum screen frame tube brazed to one side(it is all I had laying around, and I couldn't find anything locally).  Even at 500ma it is warm, and 1000ma it is hot (It will not burn, but it is to hot for my liking).  Although I don't think it is much hotter than my Exoxotic Panorama LED got even at 1000ma, and it is much cooler at 500ma.

Weston is about 15 min from Preston... but a long way from France...LOL

Yes, I measured the power consumption using a kill-a-watt meter, and the amperage using my multimeter.


Posted By: chris.rogers
Date Posted: July 15 2011 at 5:38pm
You're probably already know this, but I wouldn't push higher than 850mA on the blues or 1250mA on the whites.  So yeah, your 500mA is just peachy with a little room to grow, even.

France is my wishful thinking location.  LOL  I live in gorgeous Cache Valley.


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Ils sont fous, ces Romains!


Posted By: seti007
Date Posted: July 17 2011 at 7:41am
Looking good David. I like your control box with the Pots to control the dimming Thumbs Up As for teh heat issue. I would put a few small computer fans to cool it down. That would lenghten the life time of the lights. You can also get some aluminum U channels fairly cheap  from home depot ( or NPS) and use them as heat sinks.

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Davidwillis
Date Posted: July 17 2011 at 9:13am
Thanks, I may put up a couple fans.  How warm does yours get?


Posted By: Laird
Date Posted: July 17 2011 at 1:06pm
I'm thinking about adding some blue LED strips to my frag tank. I had a lot of help with my first LED build and I know that I wouldn't do a good enough job by myself on something like this.

So, I'm looking for someone who has built some strips to maybe put a couple together for me. I'm thinking two strips of 9 LEDs each on a 18' sink.    I'd pay for help, or give some frags, or I have store credit at a couple different places.

If anyone is at all interested in something like that send me a pm.



-------------
Indefinite hiatus from sw aquariums.

Once I have my glorious return I'll set back up the following.
50 Gallon rimless cube.
180 Gallons mixed reef paradise


Posted By: seti007
Date Posted: July 17 2011 at 10:27pm
Originally posted by Davidwillis Davidwillis wrote:

Thanks, I may put up a couple fans.  How warm does yours get?
I did the touch test after installing and found that in the winter time the heat sinks were  warm to the touch. For summer time, I only have a swamp cooler and the ambient room temps in the tank room can get in the high 70s so I added a few fans and now everything is running nice and cool.  I also added some fans under the tank to cool down the power supplys as well.  Sorry i didnt do any scientific measurements but the way i thought about it is that if the heat sink was warm, the LED junction temperatures were probably quite high so adding the fans would have lowerd the junction temps hopefully to within the safe operating range. Fans dont cost much and are easy to put in so why not :)

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Any sufficiently advanced technology is indistinguishable from magic--Arthur C. Clarke


Posted By: Sculpin
Date Posted: November 10 2011 at 6:54pm
I have a 225 (6 footer) tank and I'd love to build my own LED fixture like it. That said I have little background in electronics (at least this kind of electronics :) )

Would you be so kind as to, in a super simple way, show me how to build one of these fixtures? The frame work would be a breeze for me but all the electronic mumbo-jumbo is flying way over my head. I'm currently running 3 250W MH's and 2 55w T5HO's over my tank. 

For starters here are my questions-
How many LED's (if using the ones you have) would I need to replace the MH's and T5's?
What would be my electronic equipment list?
Could you show me how to assemble them?

I'm pretty good at following instructions and I'm sure I can build this thing but all the technical stuff is fairly intimidating to me. 

Thank you.

Micah


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225 Reef (not really mine but i act like it is)

29 Biocube

http://www.utahreefs.com/forum/forum_posts.asp?TID=45353" rel="nofollow - My Whole House System Build


Posted By: Davidwillis
Date Posted: November 11 2011 at 3:29pm
It sounds complicated, but it is really very easy.  To replace what you have, you would want an LED light every 1.5" side to side, and every 3 inches front to back.  I would suggest a 1/3 Royal Blue, 1/3 True violet, and 1/3 neutral white.   You will also need 3 24v power supplies (I like to have one for each color).  You could have one for each series if you want, but it will cost more.  The power supply has to be able to supply the amperage to run all the lights you put on it. 

Then if you need to decide which ones you want to be able to dimm (I like to have them all dimmable).  Dimming is easy, you just need to find some 0-5 ohm 5 W Potentiometers, and a project box.

Also, I have found there really is not even a need for the constant current chip (it may provide a larger range of dimming, but with the trimpot on the power supply, and the potentiometer I have plenty of range.


Posted By: wick246
Date Posted: November 13 2011 at 1:51pm
So for a 90 gallon tank I would need about 80 3 watt cree's, 10 or 12 of these drivers and power supplies to run the drivers. Does this sound right? How many and what type power supplies would be best?


Posted By: Rara
Date Posted: November 15 2011 at 10:22am
Has anyone every tried using a computer power supply to run LEDs? I believe they have multiple 12V outputs, but I don't know the amperage.


Posted By: Davidwillis
Date Posted: November 15 2011 at 5:31pm
The problem with a computer power supply is that it is only 12v, which makes your strings 1/2 the size, and it doesn't have a trimpot on it.  However you can get a 15a 24v (that is 360 watts of power) power supply for under $40, and run a bunch (probably about 15)of series off of it.  As long as each run is the same length, and same type of LED, you can adjust the trimpot to optimize all of them. 



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