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DIY LED Questions Answered Here

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Do I really need a heatsink? Suppose I was to take the stars and mount them to another piece of metal with a delrin or other heat resistant plastic spacer about 1/2" thick. Then I could blow air around the stars for cooling. Will this work?

 

 

Why you are risking it? Here something for reading from Cree about heat management

 

http://www.cree.com/products/pdf/XLampThermalManagement.pdf

 

You could get away with smaller heatsink or those L channel or even 2" aluminum tubing but you must rely fans to dissipate the heat.

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I see you have built some of the cat4101 drivers.A little guidance would be appreciated was going to use some meanwells but with the amount of LEDS I want for my build I don't think it possible.Starting with two 120 LED builds for now and may add more if its not the lighting we are looking for.Also who are you getting your boards made by and parts.

If you dont mind me asking.

Thanks

Jim

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Guest thefishman65

I designed my own board. There is a thread over on reef central that discussed a DIY driver. This was the chip that most settled (at that is my opinion). My board will drive 49 LEDs, but you need a separate 24 volt power supply. I got the parts from Future Electronics. IIRC a board cost less than $25. Don't have the numbers in front of me.

 

You might hand on Meanwell is coming out with a driver that would pwer 7 string of 12 LED, I think. It is the HLN (maybe) series.

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An update for your section on mounting LEDs. There are two additional non-solder options of which I am aware:

 

http://www.rapidled.com/servlet/the-121/Solderless-Connector-for-CREE/Detail

 

http://www.shapeways.com/shops/awesome_stuff

 

I have not yet used the one in the top link, but full disclosure: I designed the one in the later link. I actually came up with it before I knew about the RapidLED model, and I'll be comparing the two for my upcoming build 'cuz I hate soldering these things. :-)

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What sort of dimming circuit do the meanwells use? Is it something that can be DIYed on the output using a transistor circuit and a microcomputer? In other words (understanding the limitations of running multiple strings off of one driver), how could you go about dimming individual strings run off of one driver?

 

 

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^or would the constant current circuit within the drivers attempt to compensate a lower current (dimming) on one string by raising the current on the other?

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Guest thefishman65

Depends on the type. Pulse Width Modulation all dimmers would behave the same

Voltage they also would behave the same if they get the same dim voltage.

The Current and Voltage are lowered as the request for more dimming happens.

 

I am not sure of your question. Are you talking one string per driver? What driver?

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I sent you a PM... my thoughts are a bit scattered about what I am actually working on... still trying to drive some resolution to them.

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Reviving this thread a bit ....

 

I see the recommendation is for the XP-G Cool Whites and XR-E Royal Blues. Cool White also comes in XR-E. Is this only a form-factor difference (XP-G being smaller) or are there other fundamental differences? I'm having a very hard time deciphering the spec sheets.

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Reviving this thread a bit ....

 

I see the recommendation is for the XP-G Cool Whites and XR-E Royal Blues. Cool White also comes in XR-E. Is this only a form-factor difference (XP-G being smaller) or are there other fundamental differences? I'm having a very hard time deciphering the spec sheets.

 

 

The XP-G's are more efficient. I think it is a 30% difference in efficiency. Therefore they are 30% more efficient (since they are both 3watts) they are 30% brighter using the same driver. They can also be driven harder so they are brighter in that aspect as well. Fisherman might have more technical info.

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The XP-G's are more efficient. I think it is a 30% difference in efficiency. Therefore they are 30% more efficient (since they are both 3watts) they are 30% brighter using the same driver. They can also be driven harder so they are brighter in that aspect as well. Fisherman might have more technical info.

 

If that's accurate, it's technical enough for me.

 

One thing many may find interesting is that the rapidled kit is $95 and (what seems to be) the same thing pre-assembled from ecoxotic is $99:

http://www.ecoxotic.com/products/modular-led-lighting/panorama-led-modules.html

 

Anyone know if there is a significant difference in performance between the rapidled kit and the ecoxotic module?

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If that's accurate, it's technical enough for me.

 

One thing many may find interesting is that the rapidled kit is $95 and (what seems to be) the same thing pre-assembled from ecoxotic is $99:

http://www.ecoxotic....ed-modules.html

 

Anyone know if there is a significant difference in performance between the rapidled kit and the ecoxotic module?

 

 

That kit uses 1 watt led's that are not produced by CREE. They are not as powerful, and probably not even close to as powerful as the CREE XR-E and XP-G's. I guess it depeneds what your goals are for your system on what would be a better value. Two of those would likely not be powerful enough for SPS, while 24 CREE led's have to be turned down so they don't bleach your sps.

 

I am basing this opinion on having personally bleached some corals in my tank under CREE led's at full power without any optics. wacko.gif

 

Forrealb has those lights, and I THINK he is using 6 of them over his tank. Here is his build http://www.wamas.org/forums/topic/39038-forrealb50s-60-gallon-led-cube-build/page__p__333181__fromsearch__1&?do=findComment&comment=333181

Edited by BowieReefer84

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Guest thefishman65

Sorry I am late to the party :). Actually for Royal blue I would recommend XP-E. Although they overlap for efficiency the XP-E are easier to get the brighter bins. They also use the same lenses as the XP-G. Cree has also released the XM-L which are about 30% brighter than the XP-G and can be driven even harder (higher current).

 

I have read numerous places that about 72 watts of LEDs is the same as a 250 watt MH. This is rough as lenses, height, reflectors all play an impact.

 

I also read once that 3 watts of T5 is 1 watt of LEDs.

 

Personally, 48 XR-E at about half current (.5 amps) bleached my SPS about 8 inches down in a 75. The fixture was 18 inches above the tank and a mixture of no, 40, and 60 degree optics. Not knowing enough I lowered the fixture and added more lenses. Oops.

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Sorry I am late to the party :). Actually for Royal blue I would recommend XP-E. Although they overlap for efficiency the XP-E are easier to get the brighter bins. They also use the same lenses as the XP-G. Cree has also released the XM-L which are about 30% brighter than the XP-G and can be driven even harder (higher current).

 

I have read numerous places that about 72 watts of LEDs is the same as a 250 watt MH. This is rough as lenses, height, reflectors all play an impact.

 

I also read once that 3 watts of T5 is 1 watt of LEDs.

 

Personally, 48 XR-E at about half current (.5 amps) bleached my SPS about 8 inches down in a 75. The fixture was 18 inches above the tank and a mixture of no, 40, and 60 degree optics. Not knowing enough I lowered the fixture and added more lenses. Oops.

 

Any chance you took some PAR readings? I'm trying to figure out what density would be ideal. The heat in my basement is starting to crank up so I'm thinking about replacing a couple of my lights this summer :)

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I took some par readings on mine. Here ya go http://www.wamas.org..._1entry356014

 

Edit - I have since swaped the driver on the whites to make them dimmable... I have a thread with the different "colors" http://www.wamas.org/forums/topic/39572-mikes-29gal-biocube/page__st__50

Edited by BowieReefer84

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awesome. If you get a chance, can you share the dimensions of the board you used? 1900 is really high, so I'm betting you could have taken the same number of bulbs and spread them out more to get more even lighting and still have acceptable PAR?

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awesome. If you get a chance, can you share the dimensions of the board you used? 1900 is really high, so I'm betting you could have taken the same number of bulbs and spread them out more to get more even lighting and still have acceptable PAR?

 

 

1900 is at the fixture out of the water. The board I used is small and the led's are close together. I have read you want to spread them 2"-3" apart from each other to avoid any spotlighting. Can't give any personal experience, but mine are closer than this. If you use optics you want to raise the fixture up more. Being that I have a biocube retro fitted my lights are only like 4" over the water. Hope this helps. Also, at full power my fixture gets very warm (borderline hot). The heatsink is sort of small for 24 led's. I never crank the white even close to all the way up, and the temps are fine.

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Guest thefishman65

I had 300 at the surface. I need to measure below that. You will not that his dropped quickly to 400-600 as he went down and out. I am guessing that I don't loose the light that fast because of the optics.

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1900 is at the fixture out of the water. The board I used is small and the led's are close together. I have read you want to spread them 2"-3" apart from each other to avoid any spotlighting. Can't give any personal experience, but mine are closer than this. If you use optics you want to raise the fixture up more. Being that I have a biocube retro fitted my lights are only like 4" over the water. Hope this helps. Also, at full power my fixture gets very warm (borderline hot). The heatsink is sort of small for 24 led's. I never crank the white even close to all the way up, and the temps are fine.

 

Thanks. I'm going to have to spend some time with the other linked threads to avoid asking redundant questions, but I'm trying to get an estimate so I can get budget approved wink.gif

 

So to replace 1 of my lumenarc pendants, I'll need to cover a 15" x 15" space. I think with no optics I should be OK and I'll keep my existing actinic supplementation. If I do a 5:2 white:blue ratio that should give me about a 14k color. If I do 6 on a side spread across 15" that would be a total of 36 diodes. At 3W each, that's a total of 108W of LED light which is way more than the 72W that are estimated as needed to replace the 250W halide. Do you think this would be OK?

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Thanks. I'm going to have to spend some time with the other linked threads to avoid asking redundant questions, but I'm trying to get an estimate so I can get budget approved wink.gif

 

So to replace 1 of my lumenarc pendants, I'll need to cover a 15" x 15" space. I think with no optics I should be OK and I'll keep my existing actinic supplementation. If I do a 5:2 white:blue ratio that should give me about a 14k color. If I do 6 on a side spread across 15" that would be a total of 36 diodes. At 3W each, that's a total of 108W of LED light which is way more than the 72W that are estimated as needed to replace the 250W halide. Do you think this would be OK?

 

I would not do 5 whites to 2 blues. I did 1 to 1 and wish I would have done 2 blues to 1 white looking back. You should go look at people's setups. I think for 14k 1 to 1 ratio or maybe 2 blue XR-E to 1 white XP-G... Again, I would find someone's tank to look at. You are more than welcome to check mine out in Elkridge, but you prob can find someone closer with led's (and nicer setup).

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I would not do 5 whites to 2 blues. I did 1 to 1 and wish I would have done 2 blues to 1 white looking back. You should go look at people's setups. I think for 14k 1 to 1 ratio or maybe 2 blue XR-E to 1 white XP-G... Again, I would find someone's tank to look at. You are more than welcome to check mine out in Elkridge, but you prob can find someone closer with led's (and nicer setup).

 

OK. What's your opinion on density? Do you think 36 is too many in that space?

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Guest thefishman65

I agree you probably don't want 5:2. You can visit me too if you like. What is in your tank (LPS, SPS)? According to the common math LED estimation 15x15 would require at most 22. Too many is alright if you have dimmable drivers.

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I agree you probably don't want 5:2. You can visit me too if you like. What is in your tank (LPS, SPS)? According to the common math LED estimation 15x15 would require at most 22. Too many is alright if you have dimmable drivers.

 

 

I would do 24 in that area MAX, and that would be a LOT. You would need a dimmer to turn them down for sure. If you decide on 24 I would do like 14 blue and 10 white maybe. You would really want to look at someones setup imo.

 

 

 

 

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I would do 24 in that area MAX, and that would be a LOT. You would need a dimmer to turn them down for sure. If you decide on 24 I would do like 14 blue and 10 white maybe. You would really want to look at someones setup imo.

 

 

 

 

 

OK. If I decide to go ahead, I'll definitely look at someone's setup. I got to that number based on the 2-3" spacing that was recommended to avoid spotlighting. Any fewer and the spacing is greater than 3". See the following 6x6 array resulting in a total of 36 diodes:

 

x--3"--x--3"--x--3"--x--3"--x--3"--x

|

3"

|

x

|

3"

|

x

|

3"

|

x

|

3"

|

x

|

3"

|

x

 

Does this make sense or do I just need to look at some people's setups?

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Guest thefishman65

I think that spacing go carries away early on. It can happen, but the LEDs have a wide spread about 110 degrees. They should mix fairly quickly. No I will also say that I have piece of egg crate in my tank. Below it is a flat but tipped rock. In certain locations you can clearly see blue and white spots.

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