# Attempting a DIY LED fixture - Part 2. New pics 9/27 (56k)



## malaybiswas

I am planning to make a LED light fixture (actually 2 of them) to replace my T5s for my 22 gallon tanks. This is a challenging project for me since my skills and knowledge with electrical equipments and circuits is very limited. So much of it is still very much is planning and design stage now.

I will need a lot of help with it to make it a success so every feedback and suggestion is very welcome and appreciated. I need HELP!!

I am planning to use Luxeon Star LEDs. Here is basic circuit diagram I am planning to use. *My first question is with parallel circuits. Below the circuit diagram are 2 wiring diagrams. Which one is the right way to do parallel circuit to evenly distribute 1050 mA into 3 legs of the circuit?*
Note that the circuit diagrams are based of sample circuits provided at luxeonstar.com










*Next question. I am planning to use either
**LED120A0024V10F (Xitanium 120VAC 25W 1050mA driver)*

Datasheet - http://www.luxeonstar.com/xitanium-120v-drivers.pdf

Or 
*LED120A0024V10D (Xitanium 120VAC 25W 1050mA dimming driver)*

Datasheet - http://britelite.com/pdf/a_25w_dimming.pdf

I am considering the second one in hope to build a circuit off it to automatically dim the lights over a 1-2 hr period for dawn/dusk effect. However I am completely clueless how to do it. Can anybody suggest a circuit (with diagram and components) to make such a circuit off any of these drivers? I am planning to use 15 LEDs (7 blue, 8 white) as in the circuit (350mA/3.42Vf each)

Below are a couple of diagrams I put together to plan the layout of the lights over the tank to cover most of the area. The light intensity at the bottom of the tank is in progress to be calculated. I plan to use 25 degree Fraen lenses.
image 1








Light coverage
image 2
If these links don't work for you, the images are attached to one of my posts on page 2 as well.

More questions on heat sinking and other aspects coming soon.


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## epicfish

Check out a guy named evilc66 (evilc666?) on the nano-reef.com forums. Read his posts.


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## kid creole

It's all the same circuit. Whatever would look the neatest. I would guess that would be wiring diagram #1.


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## coolnick

Yeah those are both paralell. And I'm pretty sure DIY HIDs would be cheaper.


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## malaybiswas

Thank you all so far. I have been checking various forums for circuit ideas for dawn/dusk. While I get some parts of it, my biggest confusion is how (and which parts) of those circuits can be integrated with Xitanium drivers since I am not clear how the internal circuit of the drivers look like.

As such any specifics on automatic dimmer circuits involving Xitanium drivers would be a great help.


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## malaybiswas

coolnick said:


> Yeah those are both paralell. And I'm pretty sure DIY HIDs would be cheaper.


The ready made product that closely resembles what I want to do costs $800 for the specs I need. Although I am going to use the Luxeon products which makes it a little expensive I still think it will cost me anything between $300-$400 (including the tools I need to buy) so yes it is a bargain if I can do it. :thumbsup:


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## malaybiswas

epicfish said:


> Check out a guy named evilc66 (evilc666?) on the nano-reef.com forums. Read his posts.


Thank you epicfish. I'll check that out.


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## evilc66

Can I ask what your goals are for the tank? This will help decide if the array will fit your needs. You have a good start, but it may need a little tweaking.

You mentioned that you are looking to replace 2 T5s, but don't state wattage. Also you haven't stated your tank dimentions. This info will help shape things.

Epic, thanks for the plug


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## epicfish

Ahh, speaking of the devil.


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## malaybiswas

evilc66 said:


> Can I ask what your goals are for the tank? This will help decide if the array will fit your needs. You have a good start, but it may need a little tweaking.
> 
> You mentioned that you are looking to replace 2 T5s, but don't state wattage. Also you haven't stated your tank dimentions. This info will help shape things.
> 
> Epic, thanks for the plug


Currently I have 1 65W 10000K T5 per 22 gallon tank. It is about 3 WPG but not sure if that is the right way to measure. My tanks are 24" L X 15" W X 18" deep. 

The light bars are 8" inches above the tank surface and the average depth of substrate is about 2.5 to 3 inches". So I did my calculations of the light spread at the substrate for a depth of 8" + (18" - 3") = 23". I actually calculated for 22" just to account for slopes.

I am doing my own calculations to determine PAR at the bottom but they will be highly approximated. Please suggest liberally 

Let me know if I am missing any other information.


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## malaybiswas

evilc66 said:


> Can I ask what your goals are for the tank? This will help decide if the array will fit your needs. You have a good start, but it may need a little tweaking.
> 
> You mentioned that you are looking to replace 2 T5s, but don't state wattage. Also you haven't stated your tank dimentions. This info will help shape things.
> 
> Epic, thanks for the plug


Forgot about the goal. Not sure if I understand the question totally but as I mentioned earlier I want to replace the T5s. The lED should be able to support plant growth so I am looking at the combination of blue and white (no red...but let me know). I currently have about 3 WPG but as I read in multiple places they are not a good measure. I am not really sure what is a good measure for lights for plants. 

I got the references of 100 PAR and 4 lumen/sq inch. Not sure which is better target but trying to calculate on the setup I sketched and see how close it can produce with these targets.

If I am correct lumen/sq in is probably not a good measure for light intensity helping photosynthesis so I tried to place the blue lights such that they cover maximum ground surface. That way along with intensity I am also ensuring that the right wavelenghts are hitting the surface. The rest of the places in the grid were filled up with white for visual impact only.

Let me know if that helps explain what I am trying to achieve.


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## malaybiswas

Finally, this is optional, but if I can do it I want to add dawn/dusk effect such that when timer is ON

light intensity increases from 0 to 100% within 1-2 hr time frame
remains at maximum intensity for about 8 hours
dims gradually to 0% over 1-2 hr time frame.
Timer switches off

This is where I was considering the 2 types of Xitanium drivers but so far I am clueless how build a automatic dimmer cuircuit on top of those.

I already have moon lighting on a separate timer so that will remain as is.


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## evilc66

The dimmer portion of things might be difficult, but not impossible.

For your setup, I think 15 LEDs might be a little light. 24 might be a little better (8x3 grid). It will give better overall coverage with better overlap from LED to LED. Depending on how heavily you plan on planting the tank, very few LEDs will make it harder to get light to areas that are shaded by other plants.

In regards to your optics choice, what made you decide on 25 degree lenses? Something like that will give extremely high PAR numbers that would be the equivalent to over a 250W MH over the tank. For the power levels you are looking at, you can run the setup with a wide angle lense. Something in a 60-80 degree range. That will still get you very high light levels, almost to the point where you will have to dim it down to be more practical. The only reason to use the lenses is to increase perfomance on the substrate. If your tank was shallow (12" or less) you could easily get away without optics.

Color wise, no blue. Not necessary here. You can add a few reds, but they will tend to show up quite badly as red streaks in the tank. You can diffuse them, but you might just be better using a mix of cool white and a few warm white LEDs.

Have you thought about what you are going to use as a heatsink yet?

EDIT: the pictures you have for the tank layout at the bottom of your first post are not working.


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## malaybiswas

evilc66 said:


> The dimmer portion of things might be difficult, but not impossible.
> 
> For your setup, I think 15 LEDs might be a little light. 24 might be a little better (8x3 grid). It will give better overall coverage with better overlap from LED to LED. Depending on how heavily you plan on planting the tank, very few LEDs will make it harder to get light to areas that are shaded by other plants.
> 
> In regards to your optics choice, what made you decide on 25 degree lenses? Something like that will give extremely high PAR numbers that would be the equivalent to over a 250W MH over the tank. For the power levels you are looking at, you can run the setup with a wide angle lense. Something in a 60-80 degree range. That will still get you very high light levels, almost to the point where you will have to dim it down to be more practical. The only reason to use the lenses is to increase perfomance on the substrate. If your tank was shallow (12" or less) you could easily get away without optics.
> 
> Color wise, no blue. Not necessary here. You can add a few reds, but they will tend to show up quite badly as red streaks in the tank. You can diffuse them, but you might just be better using a mix of cool white and a few warm white LEDs.
> 
> Have you thought about what you are going to use as a heatsink yet?
> 
> EDIT: the pictures you have for the tank layout at the bottom of your first post are not working.


Thanks a lot for all the suggestions. This is great

I edited the first post for the pictures below. That would show why I decided on 15 bulbs and 25 degree optics. I found that to be optimum for coverage vs concentration. I originally thought of using 45 degree optics, but that led to too much light going outside the tank. Please have a look at the scheme in the first post and let me know if 15 with 25 degrees seems fine in terms of coverage (the drawings are in proper dimensions based on luxeon datasheets).

I will also check on the intensity. I am confused on one point. if I use 24 bulbs with 60-80 degree optics, wouldn't that waste a lot of light outside the tank? Also would be reduce the PAR or increase it.

Do you have any formula that I can use to measure the PAR for a given combination of lights for a given depth?

Last 2 questions
1. Why not blue?
2. Can you suggest any automatic dimmer circuits?

Thanks.


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## malaybiswas

evilc66 said:


> The dimmer portion of things might be difficult, but not impossible.
> 
> For your setup, I think 15 LEDs might be a little light. 24 might be a little better (8x3 grid). It will give better overall coverage with better overlap from LED to LED. Depending on how heavily you plan on planting the tank, very few LEDs will make it harder to get light to areas that are shaded by other plants.
> 
> In regards to your optics choice, what made you decide on 25 degree lenses? Something like that will give extremely high PAR numbers that would be the equivalent to over a 250W MH over the tank. For the power levels you are looking at, you can run the setup with a wide angle lense. Something in a 60-80 degree range. That will still get you very high light levels, almost to the point where you will have to dim it down to be more practical. The only reason to use the lenses is to increase perfomance on the substrate. If your tank was shallow (12" or less) you could easily get away without optics.
> 
> Color wise, no blue. Not necessary here. You can add a few reds, but they will tend to show up quite badly as red streaks in the tank. You can diffuse them, but you might just be better using a mix of cool white and a few warm white LEDs.
> 
> Have you thought about what you are going to use as a heatsink yet?
> 
> EDIT: the pictures you have for the tank layout at the bottom of your first post are not working.



Regarding the heatsink, I am checking on options but have not yet decided. Actually my tanks are open top. The lights will hang from light bars (link to my thread on the DIY cabinet + light bar will give you an idea of how the lights will be held).

As such I have to DIY the light fixture as well which should be light weight, hold all the stuff (bulbs, driver, heatsink etc.). As such I am looking for light weight boxes but have not found any yet. The fixture will probably dictate the heatsink options. I will post the design once I think of it and find the material for it. Need a cover too (thinking plexiglass) but not sure if I need it since I have the optics. Also insulation will be important.

Any ideas on the fixture? Something 24"X15"X4-5"?


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## malaybiswas

For housing the lights I am thinking of aluminium cases like DVD player or amplifier enclosures. But I am not able to locate any seller who sells them in cheap. Any pointers?


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## malaybiswas

How would these be for heatsink?

http://www.radioshack.com/product/index.jsp?productId=2102857


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## evilc66

Barely adequate, especially if you are only running at 350mA. When I talk heatsink, I mean HEATSINK. I have used these guys on a number of projects with great success. Sure they are overkill, but it will support whatever size array you could want. Using the heatsink as the base of the fixture, you could skin the outside with acrylic or wood. If you are going to run everything at ~350mA, you could run a heatsink of this size passively.

After looking at your layout pictures (which was difficult), I think you have used the wrong angle in your lens approximation. The Fraen lenses are 25 degrees total output, not 25 degrees half angle. It looks like you have a 50 degree cone in your plans.

It does seem like 15 LEDs might do it. 18 would get a slightly better overlap, but might not be needed. One reason I was saying to stay away from the 25 degree lenses is the very high PAR levels you will hit, even while only running at 350mA. A wider angle lens will lessen it and get you back to a level that is still sensible for a high light setup.

From what I have seen, there is a slightly better selection of wide angle lenses for Cree LEDs over Luxeon. Don't know if you are sold on Luxeon or not, but I know a good place to get Crees for a good price and optics too.


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## Gatekeeper

Rather then using a dimmer, is there a way to have this wired so you have independent strings of LED's? 

This way, for example purposes, your have a 10x4 setup. The outside 10's would be on their own tied circuit then the inside 10's.

You won't get the "ramping" of light that you are going for, but can certainly get a burst.


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## evilc66

Sure, but it means more drivers and more cost unfortunately.


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## malaybiswas

evilc66 said:


> Sure, but it means more drivers and more cost unfortunately.


Exactly...too many drivers, timers and wiring....don't want to go there. Dawn/dusk effect is nice to have but not necessary. If I can make a dimmer circuit well enough or else not.


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## malaybiswas

evilc66 said:


> Barely adequate, especially if you are only running at 350mA. When I talk heatsink, I mean HEATSINK. I have used these guys on a number of projects with great success. Sure they are overkill, but it will support whatever size array you could want. Using the heatsink as the base of the fixture, you could skin the outside with acrylic or wood. If you are going to run everything at ~350mA, you could run a heatsink of this size passively.
> 
> After looking at your layout pictures (which was difficult), I think you have used the wrong angle in your lens approximation. The Fraen lenses are 25 degrees total output, not 25 degrees half angle. It looks like you have a 50 degree cone in your plans.
> 
> It does seem like 15 LEDs might do it. 18 would get a slightly better overlap, but might not be needed. One reason I was saying to stay away from the 25 degree lenses is the very high PAR levels you will hit, even while only running at 350mA. A wider angle lens will lessen it and get you back to a level that is still sensible for a high light setup.
> 
> From what I have seen, there is a slightly better selection of wide angle lenses for Cree LEDs over Luxeon. Don't know if you are sold on Luxeon or not, but I know a good place to get Crees for a good price and optics too.


Ok. I was considering the radioshack ones cos they are light weight 

As far as the enclosure is concerned, I am planning all aluminium box that I am going to build off sheet aluminium (found what I need). Even for the base of the LED it will be a 22 gauge alu sheet so that will also provide some heat sinking. Let me think over those.

The pictures in my plan are 25 degree. All dimensions (radius of 22" high cone base are calculated off 12.5 (1/2 25) degree angle. But I will double check anyways.

Is there any formula to calculate PAR level at a certain distance based on bulb specs (lumen output, wavelenght, voltage, current etc.)? I have a formula but not sure if that is correct.

I am inclined towards luxeon just becos I managed to find out all the specs and accessories to plan. Did not manage to find enough about cree yet. But if you and send me some pointers I would certainly like to compare those before buying anything.


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## malaybiswas

I have no idea why the last 2 images keep hiding in the first post. All 3 images are from the same album in picasa. Anyways, just in case if it happens again, I am putting the links separately as well.

Sorry about that.


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## kid creole

malaybiswas said:


> I have no idea why the last 2 images keep hiding in the first post. All 3 images are from the same album in picasa. Anyways, just in case if it happens again, I am putting the links separately as well.
> 
> Sorry about that.


404 on the links. I had something like this happen. I think you have to click share and the image size before the link is a public one.


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## malaybiswas

kid creole said:


> 404 on the links. I had something like this happen. I think you have to click share and the image size before the link is a public one.


The album is public. In fact the first image is from the same album. God knows what's going on. Anyways, I will upload them here instead.


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## Green Leaf Aquariums

I just came across this post on apc... http://www.aquaticplantcentral.com/...rimental-tank-started-later-6.html#post451612

It looks like he has grasped the LED concept pretty good


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## malaybiswas

Orlando said:


> I just came across this post on apc... http://www.aquaticplantcentral.com/...rimental-tank-started-later-6.html#post451612
> 
> It looks like he has grasped the LED concept pretty good


Yeah, I have already seen this thread. Besides I found some more useful threads from nan-reef.com (and evil66 has some good insight there as well)

The latest link I found is this one. Have to analyze it and hopefully I would get an idea to calculate PUR & PAR


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## evilc66

I was probably the guy Corey mentioned hitting 600+ PAR. I had an array over an 8" cube tank with 64W of Luxeon Rebel LEDs. Way too powerful for that setup, but was an interesting experiment. I almost had a 24" Solaris I4 beat at all distances. I had better color though. 

There is no way to truely approximate PAR. PAR is derived from the spectral output of the lamp and can't be approximated by using lumens/lux. Two different bulbs can have the same color temperature rating, and have the same lumen output, but can have very different PAR output, based on the spectral output. Only good way to get PAR numbers is to measure it.

Pretty crazy spreadsheet that guy has though.

On the enclosure, if you are going to stick to just a 22awg aluminum sheet to mount the LEDs to, adding a few inexpensive heatsinks to the other side will provide a little added security. Running at 350mA, you might get away with it. I'm used to running at 700mA+ and the heat builds up quickly.


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## malaybiswas

evilc66 said:


> I was probably the guy Corey mentioned hitting 600+ PAR. I had an array over an 8" cube tank with 64W of Luxeon Rebel LEDs. Way too powerful for that setup, but was an interesting experiment. I almost had a 24" Solaris I4 beat at all distances. I had better color though.
> 
> There is no way to truely approximate PAR. PAR is derived from the spectral output of the lamp and can't be approximated by using lumens/lux. Two different bulbs can have the same color temperature rating, and have the same lumen output, but can have very different PAR output, based on the spectral output. Only good way to get PAR numbers is to measure it.
> 
> Pretty crazy spreadsheet that guy has though.
> 
> On the enclosure, if you are going to stick to just a 22awg aluminum sheet to mount the LEDs to, adding a few inexpensive heatsinks to the other side will provide a little added security. Running at 350mA, you might get away with it. I'm used to running at 700mA+ and the heat builds up quickly.


I don't want to approximate PAR or PUR. I would like to know the method to calculate it. I am pretty sure there is a formula (or a set of them probably) to calculate it based on light energy properties (wavelength, intensity etc.). Since PUR and PAR are both derived properties (dependent on wavelength at least) without specific mathematical calculation(s) there is no way a PAR meter electrical device can be made. 

I know that PAR is dependent on wavelength. However in plain english, PAR is the amount of photons emitted. Apart from the wavelength the light density in a given area should also govern how many photons are hitting the surface. I don't have the right amount of physics knowledge on light energy to establish the fact, but it just seems logical to me. Check out this link. I have not completed reading it, but it seems Irradience has some effect on PAR. 

Anyways, the previous link I sent is good study link, but here is the summary link of the same thread.

This may be a over kill for a normal planted tank enthusiast, but hey, there is information out there, so if you are interested...


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## malaybiswas

evilc66 said:


> On the enclosure, if you are going to stick to just a 22awg aluminum sheet to mount the LEDs to, adding a few inexpensive heatsinks to the other side will provide a little added security. Running at 350mA, you might get away with it. I'm used to running at 700mA+ and the heat builds up quickly.


Yes, I think I should be good with that. Heat dissipation depends on the "exposed" metal surface. This is one more link which gives a good approximation and calculation logic to decide on heatsink selection. I rely on it since I saw the same thumb rule in electrical engineering text book in my local library. 

Going by it, each of my LEDs forward voltage is 3.99 (max) and forward current 350mA. So total power of 15 LEDs = 15 * 0.35 * 3.99 = 21 watts max.

Total square inch of open metal surface required = 21 * 10 = 210 sq inch.

The mounting surface (alu sheet 22g) is 24" X 15" = 360 sq inch on the top surface (opposite to LED mounting surface). Assuming 50% of the LED mounting surface is exposed, that would be 180 sq inch. So I have 540 sq inch of metal surface. This is already more than enough for the LEDs I have. Any additional heatsink (however small) should work.

Don't get me wrong here, I checked out heatsinkusa.com. But my goal is to keep it simple, cheap and light weight. And its experimental, so I want to try out what scientific calculations suggest. If things don't work, I want to find out why it did not work out before going to next stage to fix it.

So right now, my plan for heatsink is 24" X 15" 22AWG aluminium sheet on which LEDs will be mounted. In the test run, if they still get hot and burn out, I will add heatsinks on the surface but not one big piece, but multiple smaller pieces starting from the center and spreading out towards the periphery. That way I can estimate what is the correct exposed surface required for this configuration (hopefully I will never need to go there ).


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## malaybiswas

My first step on making an alumimium enclosure. I got a real simple idea, which needs no complex tools (just tin snip, a block of rectangular wood, screwdriver, 22AWG aluminium sheets, plexiglass and some sheet metal screws)

I will post the design and progress of the model as I proceed with making it.


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## evilc66

Calculating the actual PAR of your setup will be very difficult unless you can find the weighted spectral output of the LEDs you want at the drive currents you want to run at. The datasheets don't do into that much detail and typically on list the relative spectral output for color comparison. I'm not sure where you will be able to get that information.

That spreadsheet is the closest thing to being able to calculate PAR, but without the SPD numbers it's no good.


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## malaybiswas

*Calculations!!!*

So I referenced a whole lot of information from different sites and got a whole bunch of mind boggling calculations.

Before I get into that, I decided on using white and warm white instead of white and blue as evilc66 suggested before. After reading many articles I agree that this combination would be better in terms of photometric and radiometric (is that a correct term??) light (or energy) output.

So some facts
1. Will use 7 white and 8 warm whites
2. Tank dimensions
20 gallon (22 gallon minus appro 2 gallon worth of substrate)
Substrate surface area approx 24" * 15" or 0.23 sq meter
Distance of LED from substrate surface approx 22" or 0.53 meter

Calculations
1. PAR-watt/sq meter.
Benchmark - 22 = low, 45 = medium, 75 = high and 135 = very high (found it one one site, cannot say if it's correct or not). Following the formula, I tried to calculate my setup of 15 LEDs. First thing required is PAR rating of bulbs. Did not find any authentic source, so I referred to several LED bulb products using Luxeon LEDs which had PAR ratings for the bulb. I divided the PAR rating by the number of LEDs used to approximate the PAR rating of each bulb.

Very approximate, but logically should be correct. PAR is amount of photons emitted by the bulb per unit time. If x number of bulbs emit y photons at at certain power (w), then the average number of photons emitted per LED is y/x (at the same wattage). Since these are Luxeon bulbs, the wattage is same as mine (1 watt or actually 1.2 watt max as per my calculations).

So what do I get. PAR ratings vary between 2-4 PAR-watt. I am assuming 2.67 for the LEDs I will use based on the proximity to the PAR rating calculations for bulbs manufactured with white LEDs

*All calculations are approximated*
a. Total PAR-watt for 15 LEDs = 15 * 2.67 = 40
b. Assuming 60% of the light reaches the substrates surface, PAR-wattage at substrate surface = 24 (why 60%, I refered to some documentation from a plant growth light manufacturer who suggest assuming 75% of the light reaching the target at similar distance. Since this is under water, I assumed 60% instead).
c. PAR-watt/sq meter = 24 / 0.23 = 104 (High light)

Note that, this assumes that there is no overlap which is not true. However with lenses, and the layout I planned, If I assume that a single LED lense directs 1 unit of light vertically down the axis and the intensity reduces radially on the bottom (e.g 0.9, 0.8 etc.), with the overlap, the cumulative effect of 2 or 3 lamps should always provide 1 unit of light at any point (or more if same point receives light from 3 lenses). E.g. one point on the substrate receives 1 unit from bulb 1 and 0 units from bulb 2 (this point is vertically below bulb 1). Move out a little (radially) and the next point should receive 0.9 units from bulb 1 and 0.1 units from bulb 2 (further from bulb2 and closer to bulb 1). Makes any sense???

2. Lumens/gallon
a. total lumen of 15 lights = 7 (white) * 45 + 8 (warm white) * 20 = 475 lumen
b. Lumen/gallon = 475/20 = 23.75 (High??)
c. If 30% is lost due to refraction etc that would be 16.625 lumens/gallon


3. Watts/gallon
a. Total wattage of 15 LEDs = 1.2 * 15 = 18
b. WPG = 18/22 = 0.82 WPG (high efficiency of LED = low WPG but high PAR??)

4. PGL (Plant Growth Lumen)-hr/gallon
Benchmark (again referenced but unsure about accuracy)
100 = low, 200 = med, 300 = high

a. Total lumen output of 15 LED = 475
Read some where that white light is approx 11% blue, 59% green and 30% red.

Approximated 
11% blue light @ 460nm = 0.11 * 475 = 52.25 lumen
59% green light @540nm = 280.25 lumen
30% red [email protected] = 142.5 lumen

b. Spectral output for plant (P) = 52.25*0.198 + 280.25*0.263 + 142.5*0.509 = 166.94

c. Spectral output for human (L) = 52.25*0.06 + 280.25*0.951 + 142.5*0.108 = 285.05

d. P/L = 166.94/285.05=0.59

e. PGL = 475 * 0.59 = 278

f. Running lights for 10 hrs a day for 20 gallons = (275 *10)/20 = 139 PGL-hr/gallon (medium low??)

If you are wondering where I got all these weird factors and formulae, refer here.

So as you can see I have beaten it to death and have not been able to reach any justifiable clue.

However anything more than 15 LEDs do seem to point towards wastage of the light energy (or may be not = algae).

So for now I will give myself a break from this and finalize with 15 LEDs as I planned. We'll see how it goes.

*evilc66*, I checked my layout plan with 45 degree lenses. Pratically I need only 2-3 LEDs to cover the ground surface and a lot of light wasted outside tank (or too many LEDs overlapped). So I will stick with the 25 degree lense for now.


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## malaybiswas

Ordered the luxeon LED and accessories today. projected to come in by March 12. So I have sufficient time to check on the dimmer circuit by then.

Meanwhile I finished the first of 2 fixtures. I will post the DIY process tomorrow.


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## Shoey

*Heatsinks*

EBay has several at $10 ~ 20.

I am going to use 3 ~ 12" over my 90 gal


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## malaybiswas

Shoey said:


> EBay has several at $10 ~ 20.
> 
> I am going to use 3 ~ 12" over my 90 gal


How many LEDs do you have?


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## Shoey

*LED fixtures*

Plan on using 3 banks of 10 each 3w CREEs, but.............

I will be using optics which are specific to my scape. For example in the foreground, more spot type (~45 deg) optics will be used to penetrate to the substrate, the background optics will be more flood type (~90 deg). I know this can create hot spots but I hope to balance flood and spot to eliminate this.

Worst case I will use 90 deg on all of them. The optice are cheap on EBAY


Al


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## malaybiswas

Shoey said:


> Plan on using 3 banks of 10 each 3w CREEs, but.............
> 
> I will be using optics which are specific to my scape. For example in the foreground, more spot type (~45 deg) optics will be used to penetrate to the substrate, the background optics will be more flood type (~90 deg). I know this can create hot spots but I hope to balance flood and spot to eliminate this.
> 
> Worst case I will use 90 deg on all of them. The optice are cheap on EBAY
> 
> 
> Al


Cool. I am not planning to use any heatsinks separately (unless they really get hot). My fixture is all aluminium and the LEDs will be setup on a aluminium sheet. Based on my calculations that should be enough and my enclosure is all perforated aluminium sheet so the heat should escape easily. So I will get heatsinks only if necessary.

I am getting 25 degree optics as well. I calculated the spacing of the lights with the optics to ensure that I am getting an even distribution of light on the substrate.


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## deleted_user_16

i thought u were gonna post pics? D:


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## malaybiswas

fishman9809 said:


> i thought u were gonna post pics? D:


I am. Just had to finish the first part of the project. But promise...within the next couple of hours


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## Shoey

*Heat is killer*

Watch your heat, it is a :icon_evil

You may want to start at a lower current check your temps and work your way up from there. If you see the the LED discolor (yellow) when turned off you most likly got too hot. Been there done that, but that is another story, bicycle light.

Al


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## malaybiswas

*LED Light fixture DIY...Part I...raw material*

I realized that I have got too many pictures for this, so I need to to breakup the posts instead of one gigantic one.

First, the raw material

1. Perforated aluminium sheet. Many reasons why I chose this....light weight, easy to cut and bend, almost no drilling required, will allow heat to dissipate out of the enclosure from all sides and will look cool (probably) 

The only downside is that when you bend it along perforations, they tend to break off, but there is a fix for that too.









A closer view









And the exact name under which it is sold in Lowes









2. Sheet aluminium (1/2" wide)...this will be used as reinforcements









3. Angle brackets. Also for reinforcement, hold on the bent sheets and maintain the 90 degree angles on the edges









4. nuts and bolts. 6-32 (1/2") works best. Also had a few 4-40 in my garage but probably they won't be required.









5. Aluminium angle bracket (48" long)









6. Plexiglass sheet (1/4" thick) cut into 24" X 15" piece









7. Flat aluminium sheet. 2 pieces (18" X 12") to be cut to proportions. They will be the base for the LEDs and the heatsink.


----------



## malaybiswas

*Tools*

1. Measuring ruler









2. my beloved portable work bench









3. tin snip









4. wood blocks, for bending aluminium sheet









5. hammer (also for bending sheet) and screw driver









6. clamps









7. marker









8. drill. I'll still need it to drill holes in the other aluminium pieces without holes


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## malaybiswas

*Plan*

The plan is simple. The perforated sheet will be cut as shown below. The overall dimension of the enclosure is 24" X 15" X 3" (1" depth reserved from the bottom for the optics. 1" from the bottom will be the aluminium plate with the LEDs. The 2" about it will house the adaptor and other circuits (if I make any)

.I kept the side wings to 2" depth so that the LED base plate can be slipped in or out of the enclosure from the sides without any disturbance. That's why I chose 2 - 12"X18" base plate sheets instead of one so that they can be slipped in from either side (the plates will be cut into 12" X 15" plates so that the combination provides a 24" X 15 " surface area).


----------



## malaybiswas

*Construction process*

1. Cut the enclosure aluminium sheet into 26 " (24 + 2 + 2) X 21" (15 + 3 + 3) proportion










Pretty easy to cut with the tin sip









2. Bent the edges using the wood blocks and hammer. Actually the plate is thin enough to be bent with hand. The hammer can be used at the end to sharpen the corners.









And this is how it looks.









3. Next I fixed all the edges with the angle brackets



























4. Cut the 1/2" wide aluminium sheet into 15" pieces (4 of them in total)









5. Two of the 4 pieces were fixed on the sides to provide rigidity to the wings









6. I cut the 48" L bracket into 2 24" strips...









...and fixed them at the 2 long bottom edges. 


















These will form the rails on which the plexiglass cover will be slipped in...









...like this









7. I fixed a series of L brackets at 1 " depth from the bottom along the 2 24" long wings. These will hold the base plate with the LEDs as shown below (actually the plate will be on the other side of the brackets so that they don't crash into the plexiglass sheet when the enclosure is hanged upside down










And this is approximately how it will look from the bottom









8. Finally the other 2 pieces for reinforcing the rear cover.










I did a minor weight check to make sure it will be able to hold on to the total weight of the stuff inside. Did pretty well given the thickness of the perforated sheet.

This is as much I can finish up for now. The rest of the construction will commence after I get the LEDs in hand. Finally I have to device the hanging mechanism as well.


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## evilc66

Starting to come together nicely.


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## malaybiswas

evilc66 said:


> Starting to come together nicely.


Thank you. My LEDs are projected to arrive on March 12th. Can't really do much before that, except

1. Build the second fixture
2. Learn, calculate and prototype the dawn/dusk dimmer circuit.


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## CL

um, awesome! It looks great!


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## Hilde

malaybiswas said:


> Forgot about the goal. Not sure if I understand the question totally.


All this work on lights, why?


malaybiswas said:


> I am not really sure what is a good measure for lights for plants.


I am confused too. For I see tanks with less than 2 wpg having great plant growth. I am beginning to wonder if the bulbs with red photons are more important to the plants than the wattage. Lumens seem more accurate mathematically. How do find the lumen's of the bulbs though?


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## malaybiswas

Hilde said:


> All this work on lights, why?


I always wanted LED fixture - great light, long life, low power consumption. ready made stuff are too expensive and diy is always interesting, so diy is my way to go.


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## malaybiswas

Finally after 1 month, my LEDs have been shipped. Hopefully I'll get them by next week. 

I got a circuit for the dimming effect, but it is too complicated for me. As such no dimming right now....just the simple fixture for now.


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## Hoppy

I wish I had found this thread sooner. Great project, and very informative for me. My own "project" isn't going nearly as well, since I am limiting myself to a much lower total cost than you are. So, for now I am still in the learning mode. 

I hope you will be able to borrow, buy or steal a PAR meter to test this fixture when it is finished. One thing that is still very lacking is actual measurements of the light that a LED fixture produces.


----------



## malaybiswas

Hoppy said:


> I wish I had found this thread sooner. Great project, and very informative for me. My own "project" isn't going nearly as well, since I am limiting myself to a much lower total cost than you are. So, for now I am still in the learning mode.



Yeah, doing you background study will help you a lot in making the right choices to get the right setup without over spending. Since LED fixtures are not so widely available, they are expensive. Making your own would certainly bring down the cost but it might not necessarily cheap up front.

My total cost would probably run upto $500. But getting the comparable market product will probably mean $1500. On the other hand if I continue with my T5s and replace them every year it will cost me around $100 each year for my 4 T5s. That means $1000 in 10 years. That's the same lifespan my $500 budget LED fixtures will provide.



Hoppy said:


> I hope you will be able to borrow, buy or steal a PAR meter to test this fixture when it is finished. One thing that is still very lacking is actual measurements of the light that a LED fixture produces.


I don't know if I would get into PAR testing. I have seen enough theories on the web and I tried to compare them here and found them to contradict each other to some extent. As long as I cannot find a specific matehmatical derivation of PAR, I don't think I would just trust a PAR meter.


----------



## Hoppy

malaybiswas said:


> Yeah, doing you background study will help you a lot in making the right choices to get the right setup without over spending. Since LED fixtures are not so widely available, they are expensive. Making your own would certainly bring down the cost but it might not necessarily cheap up front.
> 
> My total cost would probably run upto $500. But getting the comparable market product will probably mean $1500. On the other hand if I continue with my T5s and replace them every year it will cost me around $100 each year for my 4 T5s. That means $1000 in 10 years. That's the same lifespan my $500 budget LED fixtures will provide.
> 
> 
> I don't know if I would get into PAR testing. I have seen enough theories on the web and I tried to compare them here and found them to contradict each other to some extent. As long as I cannot find a specific matehmatical derivation of PAR, I don't think I would just trust a PAR meter.


It isn't the absolute value of the PAR intensity that is important at this time, just numbers obtained with the same instruments that are being used to measure the PAR for other types of lighting. That gives us a correlation that is very lacking today. From my own testing I know that around 50 micromols is enough, with good CO2 to grow most plants, but slowly. What I lack is any good means of relating that to the output of any LED. But even one measurement, knowing the specific LED and geometry of the lighting would help a lot.


----------



## malaybiswas

I have read some articles that suggest PUR not PAR is more accurate. Besides, whatever an instrument can measure should have a mathematical support based on some basic factors like wavelength, intensity etc. But I could not find any so far. So I am not sure how much to trust on an instrument reading. It seems more practical to try and see different settings. Good thing with diy led is that as long as there is some range to play with the power available, I can easily change the configuration of the bulbs till I get some satisfactory settings. much more difficult with metal halide or t5s.


----------



## Hoppy

If we actually had a basis for saying the anubias need 23.5 micromols, crypts need 31.6 micromols, etc. then I would agree that using an inexpensive PAR meter wouldn't gain us much. But, that isn't the case at all. We are still just correlating readings to results at this point. But, your approach can result is a lot of benefits in the end, so I hope you can find the theoretical basis you need.


----------



## malaybiswas

Hoppy said:


> We are still just correlating readings to results at this point.


That can actually provide some usable data for average planted tank lovers who are inclined towards LED. If you can come up with some level of consistency (e.g. crypts need 30-35 micromols in an average established tank, and n # of 1watt white/blue/red LEDs provide that from 2' distance etc.) then that would really be useful.


----------



## Dalban

malaybiswas said:


> My total cost would probably run upto $500. But getting the comparable market product will probably mean $1500. On the other hand if I continue with my T5s and replace them every year it will cost me around $100 each year for my 4 T5s. That means $1000 in 10 years. That's the same lifespan my $500 budget LED fixtures will provide.


I'll ask you the same question I asked Hoppy: why assume that you'll change your bulbs every year? T5 bulb end of life lumen maintenance is reported to be better than 95% -- and their life is rated at 20,000 hours (and that assumes a typical on-off service cycle that is much more aggressive than the typical aquarium usage).

What about LEDs? Luxeons, for example, have a 100,000 hour rated life but are purported to dim "precipitously" at 60,000 hours. Phillips itself reports that light intensity of white Luxeons drop off to about 92% after only 6,000 hours (although under "stressed" operation).

I just don't understand the economic justification. The heat-direction justification, yes. Color tweaking justification (if you're running more than just white LEDs), yes. The excitement of blazing new paths in uncharted technological realms, yes. The economics? No.


----------



## malaybiswas

Dalban, I will share my points on your analysis but that is going to be a little descriptive so need some time.

Meanwhile this is a link I found which shows some real life visual comparison of LEDs. Remarkable in my opinion.
http://www.candlepowerforums.com/vb/showthread.php?t=223773&page=2


----------



## malaybiswas

Received my luxeon package today. Exciting!!! Unfortunately (or Fortunately...touch wood) my work pressure is pretty high, so I have to wait till next weekend to start assembling them

Full package









Xitanium drivers

















Lenses

























LEDs


----------



## CL

wow, awesome goodies! I'm looking forward to the final product!


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## malaybiswas

Couldn't keep my hands off these, so finished a few things today

Attached the drivers on the roof of the fixture and connected the power cables to them. Each fixture will have 2 drivers, 1 1050mA driver for 15 white LEDs, and 1 350mA driver for 2 blue LEDs (nightlight).










Next marked the positions of the LEDs on the aluminium panel and attached the LEDs with silicone (yes it works). The silicone will need at least 24 hrs to set properly but it has 6 more days anyways.


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## Dalban

Nice crate of goods! It also looks like you ordered all of this from one place. Please let us know where you ordered from.


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## malaybiswas

Dalban said:


> Nice crate of goods! It also looks like you ordered all of this from one place. Please let us know where you ordered from.


Thank you. They are from luxeonstar.com. Compared them with ebay. When buying in bulk it comes cheaper than ebay.


----------



## redman88

http://www.luxeonstar.com/everled-tr-48in-fluorescent-replacement-led-tube-br-white-p-385.php


i wonder if anyone wants to try one of these


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## malaybiswas

redman88 said:


> http://www.luxeonstar.com/everled-tr-48in-fluorescent-replacement-led-tube-br-white-p-385.php
> 
> 
> i wonder if anyone wants to try one of these



I had considered those but did not work out for me because of
- higher watt rating (my job is done with 36w for 2 tanks)
- 48" long (i need 24" long coverage area)
- much higher lumen rating than what I need. Also it is linear so I am not sure how evenly the light will spread across the width of the tank.

But it has all the goodies like fully dimmable, no hassle of wiring etc. It can be a good consideration for longer and bigger tanks.


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## monkeyruler90

wow, thats gonna look awesome.


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## giga

> Next marked the positions of the LEDs on the aluminium panel and attached the LEDs with silicone (yes it works). The silicone will need at least 24 hrs to set properly but it has 6 more days anyways.


If I understand that this sentence right-you did a big no no. High power LED's need to be either attached by arctic silver or dill holes in the heatsink where the groves in the Star pcb is or your gonna burn the LEDS out very quick! Your thermal conversion is going to be really really bad


----------



## malaybiswas

Dalban said:


> I'll ask you the same question I asked Hoppy: why assume that you'll change your bulbs every year? T5 bulb end of life lumen maintenance is reported to be better than 95% -- and their life is rated at 20,000 hours (and that assumes a typical on-off service cycle that is much more aggressive than the typical aquarium usage).
> 
> What about LEDs? Luxeons, for example, have a 100,000 hour rated life but are purported to dim "precipitously" at 60,000 hours. Phillips itself reports that light intensity of white Luxeons drop off to about 92% after only 6,000 hours (although under "stressed" operation).
> 
> I just don't understand the economic justification. The heat-direction justification, yes. Color tweaking justification (if you're running more than just white LEDs), yes. The excitement of blazing new paths in uncharted technological realms, yes. The economics? No.


Took a while but I did not forget 

I like the last couple of sentences you said. That's actually true. Theoritically there is savings but it varies on different factors. I'll try to justify it for my personal calculations for what I need to consume for the 2 tanks I have

1. Light replacement - Luxeon LEDs are rated for 100,000 hrs but are expected to remain at 95% light output till 50,000 hrs. That is of course if they are not stressed (not enough heat sinking, prolonged blinking etc.). Non of those apply to me so I assume it to be 50K hrs = 10 years @ 10 hrs a day. T5s although rated at 20K hrs, supposedly retain 90% or higher of the light intensity upto 40% of the rated life or approximately 8000 hrs = little over 2 years @ 10 hrs a day. That would mean that I buy T5s not maybe after every 8-9 months but still 5 times in a span of 10 years. 

My setup has 4 T5s which can cost about $60 @ $15 a piece. In 10 year, 5 replacements mean $300.

2. Initial setup - T5 fixtures can cost anything between $60 - $250 or more. I take an average of $150 for a quality product (have not seen too many good reviews on the cheaper models). That is $300 for 2 fixtures for my setup. A commercial grade LED panel can cost from $250 - $500 or more. So that is not a cheap option at all, but with DIY I could make both under $500. Still no savings there. On top of it since I already have T5 fixtures that I paid for, the entire $500 DIY cost is an overhead

Running total $300 - $500 = ($200) over 10 years = NOT JUSTIFIED economically

3. Electricity - My electricity consumption always runs above baseline and here it is 13-25 cents/kwh for above baseline consumption (based on range). Since this is a hobby of mine, I would consider the cost of electricity as the last bit I consume in my house @ 25 cents/kwh.

My T5 setup consumes 4 X 65w X 10 hrs = 2600wh or 2.6 kwh or power a day. That is 9490 kwh in 10 years = approximately $2370

I replace them with 60 1w LEDs or 60w. That saves me 200w = 2kwh/day = 7300 kwh in 10 years = approximately $1800

Running total = $1800 + ($200) = $1600 savings in 10 years. Seems justified in the long run....THEORITICALLY

If we think practically would I be running this setup exactly the same way for 10 years. I don't know. It's like buying a honda or toyota in 1990 and driving it till 2000. Does a darn good job even then but with newer cooler cars on the line up who would drive a 5-10 yr old car unless they cannot really afford to buy a newer model.

So at this point yes, it is the blazing new technology I guess that drives me (and others) to try it out, but the cost analysis is just to console ourselves on the extra expenditure (and explain my wife ).


----------



## malaybiswas

Finished the basic setup and wiring over the last 2 days










Closeup on one LED. I used GE 100% silicone II to fix the LED to the board. Found the technique in instructables.com and it can actually do the job since it can withstand upto 400 degrees.









Tried to take a snap of the drivers inside the fixture









Moment of truth









Nightlights









Not too bright huh!...wait for the next post


----------



## malaybiswas

I had debated on using lenses with 1 watt LEDs or using 3 watt LEDs without lense. Based on the calculations (earlier in the post), 1watt with lenses seemed to be ok to do the job and the combination is cheaper than 3watt LEDs and also consumes less power. So that's the way I decided to go. And I am pretty happy with the results.

Single LEDs without lenses
Warm white









White









Blue










Same LEDs with lenses (from same distance)
Warm white









White









Blue









and the whole panel from top









Ilumination on the ceiling (4-5 feet away)










Some more pics


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## malaybiswas

The sad thing is that I cannot try this baby yet. I have to make a second piece since I have 2 tanks and the T5 fixture I use is 48" covering both tanks.

So this will go for stress test tomorrow (24" continuously lit, will check heat on aluminium surface every 6 hrs)

LEDs for second fixture on the way. Till then I'll get the fixture ready.

Comments, suggestions welcome.


----------



## malaybiswas

giga said:


> If I understand that this sentence right-you did a big no no. High power LED's need to be either attached by arctic silver or dill holes in the heatsink where the groves in the Star pcb is or your gonna burn the LEDS out very quick! Your thermal conversion is going to be really really bad


The method I used has been tested many times and can be found in instructables.com.

- I used GE 100% Silicone II which can withstand 400 degrees and conducts heat efficiently without melting
- I am using 1watt LEDs so the energy dissipated is practically 1/3 of 3watt LEDs most people use. The heat dissipation is dependent on the surface area of the conductor. The 2 surfaces of the aluminium base has more than enough surface area required for the number of LEDs I am using.

Here is the link I referred. http://www.instructables.com/id/E2GE6QLQGSEWIFNW98/

And the link for heatsink selection http://www.instructables.com/id/EMUDU41I6BEWIFNW4W/

Tomorrow is stress test day to find out whether the configuration matches the specs and expectations or not.


----------



## giga

Just to let you know I warned you. If you keep them attached via silicone after long use your going to burn them up.


----------



## giga

malaybiswas said:


> The 2 surfaces of the aluminium base has more than enough surface area required for the number of LEDs I am using.



But the heat won't be transferred to the heat sink because the thermal conversion between the heat sink and star is bad.


----------



## malaybiswas

giga said:


> Just to let you know I warned you. If you keep them attached via silicone after long use your going to burn them up.


When you say "long use" what do you mean...long regular duration or long overall usage?


----------



## giga

I mean both because after say 8 hours perday it will start to wear on them and as time goes on they will loss thier brightness and might totally fail alltogether


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## CL

it looks awesome, but the leds will get hot, the aluminum won't get nearly as hot


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## giga

*This statement defies Classical Heat Transfer Theory... There MUST be a medium for effective heat transfer from the aluminum CREE star to the heatsink. This is a fundamental 'law' when designing any system that requires heat transfer from one surface to a heatsink. The air gap created from asperity/porosity between the surfaces will dramatically decline heat transfer. Aluminum is one of the best 'conductors' (copper is another but heavy and $$$) and can run circles around convective heat transfer. With a thermal gap you are relying on convection and therefore are shooting yourself in the foot w/o some transfer medium. I personally prefer thermal epoxies over grease.


not my words but better explains it 
*


----------



## deleted_user_16

uhhh thermal compound please? you use thermal compound for the heat and screw them down to hold them in place.


----------



## malaybiswas

Okay. While I was following the conversation from clawtkins and giga (thank you both), I wanted to do me beta testing before joining back.

I don't know why we are considering silicone as a bad heat conductor. Using traditional thermal epoxy and screw mechanism provides conductive medium and adhesion respectively. Silicone provides both. Air pockets can cause bad conduction and that's why the silicone has to be applied properly but the same problem is with any thermal epoxy as well if not applied properly.

GE Silicone II compounds are known for good heat conduction and can handle upto 400 degrees of temperature so I don't see why it cannot do the job.

Anyways, if you guys are disagreeing, it is to my best interest to understand the concerns you are raising because I will be the one to loose if anything.

So I did a mini test today for 7 hours. I placed a small wood block besides the bulbs and placed a spare scarp of aluminium on it as close to the bulb as possible. The wood was to make sure no heat passes from the heatsink to this piece. So the heat this piece is getting is purely convective.
Next placed 2 temperature probes, one on the scrap aluminium and another on the heat sink. Switched on the lights and kept them on for 7 hours straight. And the readings are

Temp on Scrap Temp on heatsink
Start 45 47
After 2 hrs 71 126
After 4 hrs 78 142
After 6 hrs 77 141
After 7 hrs 78 141

I don't see how the heatsink can get so hot with pure convective heat when I have absolutely no physical barrier for the air to not pass. 

So I am not exactly sure that the silicone is a bad heat conductor or generates more air pockets. My question right now is if the temperature of 140+ degrees directly relates to the max heat being generated by the bulbs. As long as this temperature reflects the max heat generated, it should be ok. If not, there is problem. More math time.


----------



## kev82

I agree with the silicone concerns, especially since you are basically just sitting the stars on a blob of silicone. Silicone itself isn't the worst conductor (altho I'm not sure about aquarium silicone, which has additives), but the layer of silicone you're using is probably much thicker than optimal. If you would have pressed the star down with screws while the silicone was still wet there would be the least possible amount of gap between them and thermal conductivity alot better.

Metal to metal is always the best conductor, thermal paste is just used to fill the inevitable tiny gaps that will occur due to microscratches and such.


This is based on my experience with 3W LEDs. You may get away with this with your 1W LEDs, but I think your LED lifetime might be seriously degraded.



P.S.
Do you have a laser temperature meter to measure the temperature of the LED itself? About 70°C is the absolute max temperature they can handle before starting to wear really quick. If they're running at say, 50°C or hotter, you probably need to rethink your attaching strategies. If not, I may just have to retract my words and stand corrected


----------



## Hoppy

Since the LED, even attached to its "star" has very little mass, it has to reach an equilibrium temperature very quickly after it is powered up. Attach it in any way to a big piece of aluminum and it will still reach an equilibrium temperature quickly, but not as quickly, and at a lower temperature. Running the LED for hours looking for the maximum temperature doesn't make any sense. If it took 5 minutes to reach an equilibrium I would be very surprised, and would wonder how that could possibly be.

I see two issues in how the LED is attached to the heat sink. One is the desire to be able to replace one LED with another, which precludes attaching it with any type of adhesive. The other, and most important, is gaining good heat transfer to the heat sink. The first would cause me not to use the silicone method, but I haven't seen any data to say that silicone wouldn't provide adequate heat transfer to the heat sink. Is that data available?

Here is one bit of very non-scientific evidence against silicone: when you caulk with a silicone material you get the stuff on your fingers, especially because you use a wet finger to smooth it. But, you can barely feel it on your finger, and tend to spread it all over because you don't realize you have a blob on a finger. That is one bit of evidence for poor heat conductivity. You sense wetting of a finger by the substance conducting heat from your finger, so you feel it as a coolness. Irrelevant? Probably.


----------



## malaybiswas

Hoppy said:


> Since the LED, even attached to its "star" has very little mass, it has to reach an equilibrium temperature very quickly after it is powered up. Attach it in any way to a big piece of aluminum and it will still reach an equilibrium temperature quickly, but not as quickly, and at a lower temperature. Running the LED for hours looking for the maximum temperature doesn't make any sense. If it took 5 minutes to reach an equilibrium I would be very surprised, and would wonder how that could possibly be.


The only reason I tested it for a long duration is to monitor any temperature variation. Yes the temperature rises quickly at the beginning. But I had no data suggesting how fast it can reach equilibrium so I wanted to run it for a long duration to see what kind of fluctuations I notice over time to get an idea of the equilibrium temperature.



Hoppy said:


> I see two issues in how the LED is attached to the heat sink. One is the desire to be able to replace one LED with another, which precludes attaching it with any type of adhesive.


Based on my practical experience this is not an issue. I had initially attached them incorrectly and had to reattach them. Even after 36 hours I could easily scrape off the LEDs from the panel pretty easily without any force. Just like peeling of a new credit card from the paper to which it comes attached. And then peeling of the dried glue from behind the card.



Hoppy said:


> The other, and most important, is gaining good heat transfer to the heat sink. The first would cause me not to use the silicone method, but I haven't seen any data to say that silicone wouldn't provide adequate heat transfer to the heat sink. Is that data available?
> 
> Here is one bit of very non-scientific evidence against silicone: when you caulk with a silicone material you get the stuff on your fingers, especially because you use a wet finger to smooth it. But, you can barely feel it on your finger, and tend to spread it all over because you don't realize you have a blob on a finger. That is one bit of evidence for poor heat conductivity. You sense wetting of a finger by the substance conducting heat from your finger, so you feel it as a coolness. Irrelevant? Probably.


I think the confusion is arising off the general GE silicone adhesive/sealants we see in HD/lowes for window, doors and bathrooms. This is not the same product. Check this technical spec sheet and you will know why. http://www.reinhardoil.dk/PDB/G641.pdf


----------



## malaybiswas

kev82 said:


> I agree with the silicone concerns, especially since you are basically just sitting the stars on a blob of silicone. Silicone itself isn't the worst conductor (altho I'm not sure about aquarium silicone, which has additives), but the layer of silicone you're using is probably much thicker than optimal. If you would have pressed the star down with screws while the silicone was still wet there would be the least possible amount of gap between them and thermal conductivity alot better.
> 
> Metal to metal is always the best conductor, thermal paste is just used to fill the inevitable tiny gaps that will occur due to microscratches and such.
> 
> 
> This is based on my experience with 3W LEDs. You may get away with this with your 1W LEDs, but I think your LED lifetime might be seriously degraded.
> 
> 
> 
> P.S.
> Do you have a laser temperature meter to measure the temperature of the LED itself? About 70°C is the absolute max temperature they can handle before starting to wear really quick. If they're running at say, 50°C or hotter, you probably need to rethink your attaching strategies. If not, I may just have to retract my words and stand corrected


This makes sense. Agree that the space between the LED base and the heatsink should be minimized and the conductive material should only be enough to fill up tiny pockets and scratches. I took time pressed and held each LED is place for a while, till all the silicone spread out as evenly as possible. But then again it is manual so there is always chance of error.

I don't have laser/infrared temperature meters but I am going to get one from Fry's today to check.

I am not ready yet to remove all of LEDs to reattach them differently but just to make a good comparison, I will remove 4 of them and attach them to a separate piece of aluminum using screw and thermally conductive gel and see how the 2 configurations compare in terms of heat conduction.

P.S.
I am not disagreeing with you all just to make my case. But I have done my background work by studying different application techniques on the web and then by literally visiting 10s of local eletrical and lighting shops around and visually checking all kind of LED products I could get my hands to (high and low power). I was also lucky to find a shop that make and sell plant growth lights using cree leds. And I did not find a single commercial product that uses screw type fasteners. All the products I have seen so far use thermal epoxies and some use a combination of regular epoxies for structural adhesion and thermal epoxies for heat conduction. And they are warranted anywhere between 5-10 years based on the type of LED used.

I am probably not doing a professional job at home, but I still want to try out the techniques and materials these guys use to build commercial products.


----------



## kid creole

Hoppy said:


> Since the LED, even attached to its "star" has very little mass, it has to reach an equilibrium temperature very quickly after it is powered up. Attach it in any way to a big piece of aluminum and it will still reach an equilibrium temperature quickly, but not as quickly, and at a lower temperature. Running the LED for hours looking for the maximum temperature doesn't make any sense. If it took 5 minutes to reach an equilibrium I would be very surprised, and would wonder how that could possibly be.
> 
> I see two issues in how the LED is attached to the heat sink. One is the desire to be able to replace one LED with another, which precludes attaching it with any type of adhesive. The other, and most important, is gaining good heat transfer to the heat sink. The first would cause me not to use the silicone method, but I haven't seen any data to say that silicone wouldn't provide adequate heat transfer to the heat sink. Is that data available?
> 
> Here is one bit of very non-scientific evidence against silicone: when you caulk with a silicone material you get the stuff on your fingers, especially because you use a wet finger to smooth it. But, you can barely feel it on your finger, and tend to spread it all over because you don't realize you have a blob on a finger. That is one bit of evidence for poor heat conductivity. You sense wetting of a finger by the substance conducting heat from your finger, so you feel it as a coolness. Irrelevant? Probably.


The cool "wet" sensation, like when you put your hand into a solvent is a measurement of the evaporation, not conduction.


----------



## malaybiswas

kid creole said:


> The cool "wet" sensation, like when you put your hand into a solvent is a measurement of the evaporation, not conduction.


Did not think about it but that's actually true. Your body temperature is same as the environment and when it looses some heat it feels cool. That does not mean that the solvent is not conducting surrounding heat to the fingers.


----------



## lovingHDTV

To help everyone out a little with thermal conductivity comparisons. Most values gotten from WIKI

G641 Thermal Silicon 0.7 W/mK (from the specs)

Air 0.025
Thermal grease 0.7-3
Thermal epoxy 1-7
Aluminum 200
Silver 429

So it looks like it is pretty comparable to what you would expect for "low"quality thermal grease. Obviously the silver passed thermal greases are better, but this does not look too bad.

dave

Wiki Page:
http://en.wikipedia.org/wiki/Thermal_conductivity#List_of_thermal_conductivity_values


----------



## Hoppy

Most of us have a body temperature higher than normal room temperature - in the 90's F versus in the 60-70's F, so conduction of body heat is a part of the "feel" of gooey substances, and evaporation is a bigger part.

Malay, the data sheet you linked to is for a metal oxide filled silicone material, made specifically for good heat transfer properties, but you referred to what you used as GE Silicone II, which is not a filled material. So, that doesn't say what you used, if it is Silicone II, is equally good. But, given how thin the layer of adhesive is, big changes in conductivity might not make a big difference in LED temperature. The rate of heat transfer is proportional to the area of contact and inversely proportional to the thickness of the film. I'm still not convinced that you have committed a mortal "no-no". Your 4 LED test will be very convincing evidence.

You did convince me that mounting them as you did doesn't make it a problem to replace them if you wish to do so. I think I would lean to using that technique rather than risking a screwdriver slipping and ruining one trying to attach it with screws.


----------



## malaybiswas

Hoppy said:


> Most of us have a body temperature higher than normal room temperature - in the 90's F versus in the 60-70's F, so conduction of body heat is a part of the "feel" of gooey substances, and evaporation is a bigger part.
> 
> Malay, the data sheet you linked to is for a metal oxide filled silicone material, made specifically for good heat transfer properties, but you referred to what you used as GE Silicone II, which is not a filled material. So, that doesn't say what you used, if it is Silicone II, is equally good. But, given how thin the layer of adhesive is, big changes in conductivity might not make a big difference in LED temperature. The rate of heat transfer is proportional to the area of contact and inversely proportional to the thickness of the film. I'm still not convinced that you have committed a mortal "no-no". Your 4 LED test will be very convincing evidence.
> 
> You did convince me that mounting them as you did doesn't make it a problem to replace them if you wish to do so. I think I would lean to using that technique rather than risking a screwdriver slipping and ruining one trying to attach it with screws.



Finally some encouraging words  thank you Hoppy.

I referred to as GE silicone II because GE silicone II comes in different configurations like sealant, general purpose glue etc. The basic adhesive components are same, and the additional constituents determine the other properties of the product (e.g. window and door silicone has insulator components).

The G-641 component is blended in a specific range of the silicone II which has different label on them to highlight it and also specifies the conductive and heat resistant properties of the product.


----------



## Hoppy

At the moment I am thinking of using 24 LEDs on a fixture, and I have been very nervous about trying to attach that many parts without damaging one, so the idea of attaching them with an adhesive is very attractive to me. Be sure to let us know how the 4 LED test comes out. Where did you find the G-641 silicone?


----------



## redman88

why not use thermal past on the back of the star and just hold the it down with a bead of silicon around the edge of the star? i would be less worried about a slip of the screw driver braking the star, and more about over tightening the screw and braking it.


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## Hoppy

A #4-40 screw in aluminum will strip the threads if you breathe too hard while tightening, and long before you would damage anything else - I think.


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## malaybiswas

Hoppy said:


> At the moment I am thinking of using 24 LEDs on a fixture, and I have been very nervous about trying to attach that many parts without damaging one, so the idea of attaching them with an adhesive is very attractive to me. Be sure to let us know how the 4 LED test comes out. Where did you find the G-641 silicone?


I got mine at ace hardware but it should be available at any hardware stores. 

P.S.
Not sure if you checked this link. This is where I got the idea of silicone for the first time. Nice DIY guide http://www.instructables.com/id/RGB-Color-Controllable-High-Power-LED-Room-%2b-Spot-/


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## malaybiswas

redman88 said:


> why not use thermal past on the back of the star and just hold the it down with a bead of silicon around the edge of the star? i would be less worried about a slip of the screw driver braking the star, and more about over tightening the screw and braking it.


This is also a good idea. I have fixed my lenses with silicone along the perimeter. Both the led star and lenses are extremely light so they should hold on fine.


----------



## giga

> GE Silicone II compounds are known for good heat conduction and can handle upto 400 degrees of temperature so I don't see why it cannot do the job.


The point of a heat sink is to remove heat from the intended object(LED) and with silicone your insulating it more or less then getting the (IR)heat away from the LED. Your best bet would be to drill holes and just bolt them down with a little drop of thermal grease. OR just use artic silver epoxy. You can use what you want but this is the RECOMMENDED way of doing it. It's a simple fix then having to replace pricey LED's

those being 1w you may or may not have a problem but I wouldn't take that chance with $$ involved

either way I would like to see the results of the plant growth, health etc...


----------



## malaybiswas

Hoppy said:


> At the moment I am thinking of using 24 LEDs on a fixture, and I have been very nervous about trying to attach that many parts without damaging one, so the idea of attaching them with an adhesive is very attractive to me. Be sure to let us know how the 4 LED test comes out. Where did you find the G-641 silicone?


I got one of these infra-red thermometers from frys. 

http://shop1.frys.com/product/5725672;jsessionid=zerS0S36H0HetbOMHbM93Q**.node1?site=sr:SEARCH:MAIN_RSLT_PG

I did the 4 led test with thermal epoxy (used arctic silver from frys again http://shop1.frys.com/product/3252731?site=sr:SEARCH:MAIN_RSLT_PG). 

No big surprises on the results. On both combinations the junction average temperature was about 140-142 F (<63 C) and the heat sink surface temperature was about 15-20 F less. I tested both over a span of 10 hours.
I can't say if it is for 1 or 3 watt leds but I did not see more residual heat in one vs the other.

That said, I am not quite happy with the warm whites. The tank looks a bit dull with it. I am feeling lazy to upload the pictures right now. Maybe later in the day or tomorrow I'ill upload old and new shots of the tank for comparison. I'll update my pending order with luxeonstar for the next batch of LEDs to all cool whites and also add some more the replace the existing warm whites. They can find other use in the house.

Second thing I want to improve is the fixture. Although it is just 3" high, it feels rather bulky on the tank. I have an idea to replace a few parts of make it ultra thin and slick.

I'll try that for my second fixture. If it works out well, I'll refactor the first one and post the pictures.


----------



## Hoppy

Those are interesting temperature results. As I understand the data sheets for the LEDs, 60C is not a problem for a junction temperature, giving less than 10% loss in light output. I am surprised that the silicone and thermal paste gave the same results, but only because intuitively I would expect any form of plastic, filled or not, to insulate more than a paste made to be conductive. Clearly the GE material is well designed for this purpose.

Again, from the data sheets, the manufacturers are very adamant about using screws to hold the LED hard against the heat sink. My guess is that for absolutely the highest output from the LED that is preferable. 

I'm going to check my local salvage metals store to see if I can get aluminum 2" or 3" channel a lot cheaper than a heat sink extrusion. It looks to me like if each row of LEDs is on a channel, it has more than adequate heat sink capacity. And, construction becomes a lot easier, plus I can put gaps between adjacent channels, giving better convective cooling of the heat sinks. Doing this gets my cost for what I want to make down into more friendly territory too.


----------



## malaybiswas

Hoppy said:


> Those are interesting temperature results. As I understand the data sheets for the LEDs, 60C is not a problem for a junction temperature, giving less than 10% loss in light output. I am surprised that the silicone and thermal paste gave the same results, but only because intuitively I would expect any form of plastic, filled or not, to insulate more than a paste made to be conductive. Clearly the GE material is well designed for this purpose.


There can be couple of reasons for that. The LED wattage can be 1 factor. Besides, I was checking the chemical compositions of thermal grease and pastes. There is some amount of adhesive components in those too that is non conductive. The third one possibly is the thickness of the paste applied and the uniformity. If the thickness is more I think a thermal paste might show better result than a silicone based product. Last but not the least, my fixture is pretty open. It is not boxed where the heat has more obstructions to escape. That might be helping a bit as well.



Hoppy said:


> Again, from the data sheets, the manufacturers are very adamant about using screws to hold the LED hard against the heat sink. My guess is that for absolutely the highest output from the LED that is preferable.


 Guess that is true.



Hoppy said:


> I'm going to check my local salvage metals store to see if I can get aluminum 2" or 3" channel a lot cheaper than a heat sink extrusion. It looks to me like if each row of LEDs is on a channel, it has more than adequate heat sink capacity. And, construction becomes a lot easier, plus I can put gaps between adjacent channels, giving better convective cooling of the heat sinks. Doing this gets my cost for what I want to make down into more friendly territory too.


You can also check at HD/Lowes (i prefer user friendly well organized aisles to local hardware stores  but that's just me) as well. In the plumbing sections, they have aluminium channels that I am planning to use in my new fixture design. About $6-8 for 4' length so it takes 2-3 pieces for me (< $20) and then cut it to size with a hacksaw.


----------



## malaybiswas

giga said:


> The point of a heat sink is to remove heat from the intended object(LED) and with silicone your insulating it more or less then getting the (IR)heat away from the LED. Your best bet would be to drill holes and just bolt them down with a little drop of thermal grease. OR just use artic silver epoxy. You can use what you want but this is the RECOMMENDED way of doing it. It's a simple fix then having to replace pricey LED's
> 
> those being 1w you may or may not have a problem but I wouldn't take that chance with $$ involved
> 
> either way I would like to see the results of the plant growth, health etc...


This time I will take your advice giga...at least partially . I confirmed replacement order for my LEDs. This time I am getting 2w LEDs for one tank and 1watt (cool whites replacing existing warm whites) for the other. 2watt for the tank that has more surface cover plants. For the 2w LEDs, I will use arctic silver epoxy. For the 1watt silicone (641) as before.

I still don't want to screw each LED. I sent this question to Luxeon. Let's see what they have to say.


----------



## giga

Well hurry up and get this over your tank so I can build some Highpower LED spotlights:thumbsup:


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## kev82

malaybiswas said:


> This time I will take your advice giga...at least partially . I confirmed replacement order for my LEDs. This time I am getting 2w LEDs for one tank and 1watt (cool whites replacing existing warm whites) for the other. 2watt for the tank that has more surface cover plants. For the 2w LEDs, I will use arctic silver epoxy. For the 1watt silicone (641) as before.
> 
> I still don't want to screw each LED. I sent this question to Luxeon. Let's see what they have to say.


I'm not sure why you guys think screws are so bad.. I just screwed 10 3w LEDs to a heatsink without incident (20 screws:icon_eek::icon_roll). Using thermal epoxy seems a bit silly to me because if one led malfunctions it's stuck there forever.. Why not just screws and normal thermal grease? Using aquarium silicone seems even sillier to me.

Why oh why not just go with manufacturer recommendation and use screws and thermal paste? They have done the research so you don't have to, so why risk your expensive-ish LEDs?


----------



## kid creole

kev82 said:


> I'm not sure why you guys think screws are so bad.. I just screwed 10 3w LEDs to a heatsink without incident (20 screws:icon_eek::icon_roll). Using thermal epoxy seems a bit silly to me because if one led malfunctions it's stuck there forever.. Why not just screws and normal thermal grease? Using aquarium silicone seems even sillier to me.
> 
> Why oh why not just go with manufacturer recommendation and use screws and thermal paste? They have done the research so you don't have to, so why risk your expensive-ish LEDs?


Where I work we screw M4 screws into Aluminum all day long without problem.


----------



## Dalban

Thanks for the response, even if belated  Here's my belated response to yours.



malaybiswas said:


> 1. Light replacement - Luxeon LEDs are rated for 100,000 hrs but are expected to remain at 95% light output till 50,000 hrs.


Luxeon's are rated for *70% (not 95%)* LM at 50k hours.



malaybiswas said:


> T5s although rated at 20K hrs, supposedly retain 90% or higher of the light intensity upto 40% of the rated life or approximately 8000 hrs = little over 2 years @ 10 hrs a day.


Small correction: 95% (not 90%) according to every published source I can find. It is unclear, but presumably the efficiency of the lamp doesn't deteriorate precipitously after 40% of life. 



malaybiswas said:


> My T5 setup consumes 4 X 65w ...
> I replace them with 60 1w LEDs or 60w.


So, you're going to replace 260 watts of fluorescent lighting with 60 watts of LED lighting. How do you expect to have the same lighting output? Even if lumens aren't equal to PAR, they're still a good relative intensity indicator. 

Luxeon K2s are rated at 60lm/watt: @ 60 watts = 3,600 lm
Typical T5HO fixtures are rated at 90lm/watt: @ 260 watts = 23,000 lm

Is there something I'm missing that will enable you (and others who are trying) to somehow squeeze 100% (or even 50%) more lumens out of each watt? Presumably Phillips is already doing everything it can to up its efficiency numbers.

Finally, is there reason to believe your T5 grow-lights are going to be a lot worse at producing PAR compared to your generic-daylight-white LEDs? Seems more likely the opposite. At least if you were using only blue and red LEDs you could claim that you were gaining efficiencies by not wasting electricity making green light.


----------



## Hoppy

I'm not going to argue that, at this time, LEDs are vastly superior to T5 lights. I'm not even sure they are equivalent. One thing they are is fun!

LEDs produce all of their light in a cone extending in one direction, while T5 and other fluorescent bulbs, produce light in all directions around the bulb, along most of the length of the bulb. So, it is easier to utilize all of the light from an LED than from a T5 bulb. Whether that makes up for the lower lumen output per watt I don't know yet. We will know before long though.


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## malaybiswas

Got reply from Luxeonstar on my question. Does not prove anything but here are the facts for record



> *Question:*
> I recently purchased some 1w Luxeon Star white LEDs for my aquarium. I
> got some ideas about using GE Silicone II to fix LEDs to the heatsink
> rather than the recommended thermal grease + #4 screw method. This is
> the site where I got the silicone idea from
> http://www.instructables.com/id/RGB-Color-Controllable-High-Power-LED-Room-+-Spot-/.
> 
> My question. Between the options of using silicone, thermal epoxy
> (e.g. arctic silver) and #4 screws, what might be some of the impacts
> on the light intensity, longivity etc? Are there any comparative data?
> 
> I am not a big fan of screwing each LED to the heatsink. I would like
> to try the silicone or epoxy way unless they can cause considerable
> degradation in performance.
> 
> Need your advice to make a well informed decision.





> *Answer:*
> I am not aware of any comparative analysis for different mounting systems. I do know that other customers have used all of these methods of mounting, and we have not had any reports of problems.
> 
> The biggest impact on light intensity and longevity is letting the LED get too hot. So as long as the method you use keeps the temperature of the LED below its rated operating maximum level, you should have not problems.
> 
> Whatever method you use, you can also supplement it by adding exhaust fans. This can provide additional cooling if the LEDs are in an enclosed area.
> Cheers!


I will take the exhaust fan idea and install a couple of 60mm case fans on my new fixture.

Unlike my last shipment, this one is arriving early. Expecting to get it this weekend so hopefully I will have my new fixture on display over this weekend.


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## Hoppy

My impression is that a lot of flying blind is being done with LEDs! Of course the cooler they can be kept the longer they will last, so one could argue that a copper heat sink, with a liquid freon cooling system would be the way to go. (I won't argue that, though.) I suspect that good cooling air flow is at least as important as anything else in keeping them cool enough. So, I plan to use fans for mine - but those things start to cost real money when you restrict yourself to quiet ones.


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## redman88

hoppy if you are using "C" channel metal find a fan the will fit the end that way you can direct the flow of air


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## Hoppy

redman88 said:


> hoppy if you are using "C" channel metal find a fan the will fit the end that way you can direct the flow of air


Yes, ideally one could fit a fan to blow along the length of either a finned cooler or a channel extrusion, but air doesn't follow along a surface like that without objections. It will take the path of least resistance, which could well be to go around the "heat sink" and down towards the tank. Notice that the "heat sinks", that are fan cooled in computers, have the fan blowing directly at the finned back of the "heat sink". This whole subject is a lot like trying to design an airplane without knowing how an airfoil works.


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## lovingHDTV

put a chiller on your aquarium like the reefers do then go water cooled. You'd get major cool points


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## malaybiswas

Hoppy said:


> Yes, ideally one could fit a fan to blow along the length of either a finned cooler or a channel extrusion, but air doesn't follow along a surface like that without objections. It will take the path of least resistance, which could well be to go around the "heat sink" and down towards the tank. Notice that the "heat sinks", that are fan cooled in computers, have the fan blowing directly at the finned back of the "heat sink". This whole subject is a lot like trying to design an airplane without knowing how an airfoil works.


You are worrying too much  If it is drawing out air off an enclosed area , then there will be very little air movement anyways, so the fans will pretty much force the air in a particular direction.

I have my heat sink exposed completely to allow the heat to rise away from it. The fans will help remove the hot air from within the fixture which is more enclosed.


----------



## Hoppy

Yes, I am worrying the subject.....and enjoying every minute of it! 

You can cool by natural convection, which it seems you are, with the fans just exhausting the heat from the closed compartment. Or, you can use forced convection, with the fans blowing against the "heat sink", hopefully gaining a higher heat transfer coefficient, as I hope to do. Without any test data I have no idea how the two methods compare for effectiveness - still flying blind. (And, still enjoying every minute of it!)


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## redman88

most computer heat sinks have the fan on top pulling the air up through the Fins. if you mount the "c" against the top of the hood to turn it into a box you can place the fan in the center you can pull air up and through from the ends. then exuast it up through a few holes in the hood.








and if you place the ends against the ends of the hood you can pull air through from outside the hood


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## malaybiswas

redman88 said:


> most computer heat sinks have the fan on top pulling the air up through the Fins. if you mount the "c" against the top of the hood to turn it into a box you can place the fan in the center you can pull air up and through from the ends. then exuast it up through a few holes in the hood.
> View attachment 12886
> 
> 
> and if you place the ends against the ends of the hood you can pull air through from outside the hood


this may be applicable for hoppy since is using an existing fixture as the base. My fixture is pendant style and the heatsink is not the traditional fin type. It is flat top and the top of the heatsink is exposed so no worries about "air cooling" it. My fans will be built into the heatsink and remove the hot air from the area between the heatsink and the acrylic cover of the fixture


----------



## malaybiswas

Some pics of the old fixture

Vegas?
















In front of my existing setup with T5s









Comparison
1. Tank with T5 about 20" above substrate









2. Tank with LEDs 18" above substrate. Not bad but looks dull with the warm whites


----------



## malaybiswas

I could not accomplish as much as I wished to do this week due to a sudden peak in work pressure. But anyways, wanted to share a sneak preview of the new fixture.

First, the old fixture...bulky









The new one....sleek









The bottom...the LED positions marked. Added C channels on 2 side to slide an acrylic cover.









From the top. The casing in the center will hold the power supplies. The chains on the 2 side for hanging them from the light bar. I got 12 feet of the chain from walmart. can cutting them to 3' lengths. The height can be adjusted by changing the links that are attached to the hooks on the end.









fans installed on 2 ends

















Attached the extension cords in the power supply section. One for daylight and one for night light.









That's all for now


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## giga

Now we need to see the growth of the plants


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## malaybiswas

giga said:


> Now we need to see the growth of the plants


way to go. This is just the fixture. no LEDs, no wiring yet


----------



## giga

malaybiswas said:


> way to go. This is just the fixture. no LEDs, no wiring yet



Well get to work! Chop chop


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## malaybiswas

My LEDs did not get delivered on time. New expected delivery date is 4/10


----------



## malaybiswas

Finished up as much as I could without the LEDs.

The wiring behind on the power supply unit
2 1750mA xitanium drivers for the 2w daylight (amber)
1 700ma xitanium driver for 1w dawn/dusk light (green). I will use some of the warm whites for dawn/dusk
1 350mA xitanium driver for the blue moonlight (blue)









Fixed the blue moonlight LEDs


----------



## malaybiswas

After much await, I received the final set of LEDs (2w Luxeon rebel stars), but they goofed up and sent me one less than ordered. That has to be fixed, but I had enough in hand to finish up the project.

with 6 tiny solder pads, they were truely "rebels" for soldering. Anyways after 6 grueling hours I managed to finish the soldering on both panels.


















Too many LEDs? Actually I made 6 groups

- 24 2watt white LEDs that will form the main daylight
- With the old 1watt luxeon stars, I just added them as dawn/dusk lights for the time being till I device a dawn/dusk simulator. I put resistors in series to reduce current by 50% to give a dim look. They will run on a separate timer.
- 2 1w blue moonlights per panel


----------



## malaybiswas

Today was the inauguration of the new light panels. The first attempt loosened one of the solder points, so I had to redo it again. Finally



















They are too bright!!


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## deleted_user_16

looks like too many LED's you will probably need very high co2 and ferts to keep up with that lighting. im only going to use 6 3w cree xr-e's on my 30c (7g)


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## malaybiswas

Oh! forgot to post the last picture of how the fixture looks from front on the light bars.










The wiring is a bit messy right now that needs to be tidied up. The 2 steel wires on the light bars were for hanging the old T5 fixture. I'll keep them for a couple of weeks just in case if these have any problems and I have to resort back to the T5 till I fix the problem.

Edit: The thing I am happy about the new model (heatsink open to air and 2 cooling fans) is that it is maintaining much lower temperature. The center is ranging about 105-110F and corners about 75F. That is after 10 hours of continuous running. Much better than the temperatures that ran on my last fixture (about 140F after 6 hours)


----------



## malaybiswas

fishman9809 said:


> looks like too many LED's you will probably need very high co2 and ferts to keep up with that lighting. im only going to use 6 3w cree xr-e's on my 30c (7g)


Actually the reflection from the aluminum panel makes it look too bright. Count wise although there are many, at daytime only 24 will provide light to each tank (22 gallons). Each LED is 2watt so about 48watts. Per your configuration it is actually low (6, 3w = 18w for 7g = 54w for 21g). Besides my tank is 18" deep and the light panel is about 8" above the tank surface (about 23" above substrate level).

From the intensity I am getting (I will post pictures shortly), depending upon your lumen rating for the crees and how high you plan to mount them, you might need less than 6 for 7 gallons.


----------



## malaybiswas

Now some tank pictures.

Dawn/Dusk (This was taken at dusk, after the day pictures below. Meanwhile, during the day I changed the water so there is difference in water level)









Day


















Night


----------



## malaybiswas

And today's final post. This is just to track plant growth under the new lights

4/12/2009 - Day1
Pruned and replanted some of the Limnophila Aromaticas on the right side, to see how they grow (including additional time required for root development) compared to the established plants









Nothing changed in this tank. Just check how the plants maintain the growth and color


----------



## Hoppy

That looks great, but it seems like a lot of light. Can you borrow a PAR meter and measure the intensity at the substrate level and how uniform it is across the whole substrate?

Starting over again, from scratch, how much would it cost you to make one of those lights?


----------



## kev82

Looking pretty good. Will be interesting to see growth shots in a week or two.


----------



## malaybiswas

Hoppy said:


> That looks great, but it seems like a lot of light. Can you borrow a PAR meter and measure the intensity at the substrate level and how uniform it is across the whole substrate?
> 
> Starting over again, from scratch, how much would it cost you to make one of those lights?


I have been looking for a PAR meter but did not find any in this area so far. If you happen to know/find out anybody in the bay area who has one and is will to lend it for a couple of days please let me know. But that is definitely on my next to-do list. Just need to find the equipment.


----------



## malaybiswas

Hoppy said:


> Starting over again, from scratch, how much would it cost you to make one of those lights?


I have some parts (optics) that I did not use eventually. Also the 1 watt LEDs are not the necessary components for the fixture. Leaving those and the tools aside, the cost of components is around $305+tax per fixture. That is about $50 over my original budget.

Not cheap for a hobby but compared to this Galileo product (that was my original inspiration) costing $700+ for a 21 LED unit, much cost effective to do at home.

However the expensive portion (outside the LEDs) was the xitanium drivers that eat up almost half of the cost. If you are using combination of salvaged power supplies and buckpacks (or home made drivers like the one you are making), then the cost can be reduced a lot.

The only reason I went for the xitanium drivers is to utilize their lightweight and compact size and ability to hookup directly to AC source. Since I planned to mount my entire power supply on top of the fixture, I wanted less clutter, less wires, and less weight.


----------



## malaybiswas

kev82 said:


> Looking pretty good. Will be interesting to see growth shots in a week or two.


Yep. That's the whole point (other than operating expense, look and feel etc.). I'll try to be as diligent as possible to post weekly or bi weekly updates over the next 4-6 weeks at least to monitor the progress of plants (and algae as well if that shows up). Hopefully it will be a good learning experience for me and others.


----------



## Temuchin

I find it interesting that every one has taken a different choice to deliver power to their fixture.

You are driving 120V AC. Kev82 is driving 24 V DC to a boostpuck. Hoppy is planning on driving something like 60 V DC to a resistivly limited circuit. I'm driving 12 and 5 V DC to boost pucks. All of these are valid ways to drive power. It just depends on what you want your light to look like, where you want the cords to lie, and how much you want to spend.


----------



## Hoppy

Temuchin said:


> I find it interesting that every one has taken a different choice to deliver power to their fixture.
> 
> You are driving 120V AC. Kev82 is driving 24 V DC to a boostpuck. Hoppy is planning on driving something like 60 V DC to a resistivly limited circuit. I'm driving 12 and 5 V DC to boost pucks. All of these are valid ways to drive power. It just depends on what you want your light to look like, where you want the cords to lie, and how much you want to spend.


You are right, that this is possibly the most significant difference in how we approached the problem. In my case cost was by far the most important factor. I did drop the resistor current limiter, and I'm shifting to an electronic, but cheap current limiter. When I found that I would have to spend almost as much for constant current drivers as for LEDs I stopped the whole process until I found acceptable alternatives.

Another difference is our approach to heat sinks.


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## Hoppy

malaybiswas said:


> I have been looking for a PAR meter but did not find any in this area so far. If you happen to know/find out anybody in the bay area who has one and is will to lend it for a couple of days please let me know. But that is definitely on my next to-do list. Just need to find the equipment.


Try a PM to Tom Barr to see if you could borrow his PAR meter. He has been extremely generous in helping people that way. And, you don't live so far from him that he couldn't mount a posse to reclaim it if you were to run to Mexico with it:hihi:


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## malaybiswas

Hoppy said:


> You are right, that this is possibly the most significant difference in how we approached the problem. In my case cost was by far the most important factor. I did drop the resistor current limiter, and I'm shifting to an electronic, but cheap current limiter. When I found that I would have to spend almost as much for constant current drivers as for LEDs I stopped the whole process until I found acceptable alternatives.
> 
> Another difference is our approach to heat sinks.


Yes, heat sinking is another aspect that has some wide variations. Today is my second day and I just measured the temperature at the junctions and different areas on my heat sink after 4 hours of running from the morning. Still stable at aroun 105-110F. 

I am pretty confident on this one and the model you have deviced and still like it over the standard heavy heatsinks. Seems a little overkill and a whole lot of added weight to the fixture.


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## malaybiswas

Hoppy said:


> Try a PM to Tom Barr to see if you could borrow his PAR meter. He has been extremely generous in helping people that way. And, you don't live so far from him that he couldn't mount a posse to reclaim it if you were to run to Mexico with it:hihi:


Cool, I'll give it a shot. If I run away, he can take my fixtures


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## malaybiswas

Bummer this morning. One of the hookup wires came loose of the solder pad of one of the rebel LEDs disconnecting that node. I had to resolder it. However I had problem soldering the rebels right from the beginning and not so confident on the solders as much as I am with the regular star solder pads.

Any quick tips/experience with soldering the tiny rebel solder pads?


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## malaybiswas

I decided to rescape one of the tanks. Partly because I was bored with the old scape and partly because I wanted to see the growth of the plants ground up under LED.

This is how it turned out and the new baseline to track upon. More pictures here.


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## malaybiswas

First week of new scape under LED.

1. Trimmed the cabombas since they almost touched the top level.
2. Glosso just started to spread out runners. some melted
3. One PITA LED solder kept coming out. Re-soldered it twice this week and has been holding on fine enough for the last 3 days now. fingers crossed.


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## Crystalview

Any up-dates?


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## malaybiswas

Yes, there have been but I did not post them here since I already maintain a separate thread for it. Please check http://www.plantedtank.net/forums/tank-journals-photo-album/79927-22-gallon-ada-style-tank-new.html

In short all plants are thriving.


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## malaybiswas

After 7 months of running the previous fixture, I decided to redesign it. The main reasons for redesigning it were
1. The fixture area covered the entire surface area of the tank. This hampered flexibility to reach the far corners of the tank without hitting or touching the fixture when it is 5-6 inches above the tank.
2. Since the light was evenly spread over the tank, the stem plants were growing in every direction instead of one.

So I decided to make on which occupies a smaller surface area that can be centered over the tank. That would allow me more space around it to reach the corners of the tank. At the same time all the stem plants will grow forward and towards the center of the tank.

Since I have less surface area, I had to go for a proper heatsink from heatsinkusa.com to have the required heat sinking surface area. I selected 11" medium heatsink.









For the fixture body, I got these wall sconces from Lowes. http://www.lowes.com/lowes/lkn?action=productDetail&productId=139688-1390-G3336-TWH-I&lpage=none

This is how to looked from below. 









And after cutting off the base plate 









I choose CREE 370lm White LEDs @350mA. Each fixture will have 10 LEDs. One 1050mA luxeon driver will run 3 parallel strings. Another 700mA will run 2 parallel strings. Each string will have 2 LEDs since each LED is a cluster of 4 in series that draws a total of 12V.









These are for hanging the fixture. I can adjust the height of the fixture by upto 4 inches by adjusting the screws.









For the end caps of the fixture I got some custom made plexiglass covers with cutouts for the plug point and the fan.


















Wall plug and cpu fan that will fit in the end covers









With the power line I got plugs so that I can hook the power line in the wall plug point in the end cover as well as the main power source


















For the plexiglass end covers to fit on the fixture, I got some flexible PVC lines, that I will glue to the end covers using plastic adhesive


















That's pretty much the raw material. I am also using a couple of blue LEDs as night lights. The blue LEDs and the fan will run on one line. So the blue LEDs will be on even during day hours. The will remain off between 10 pm and 6 am to optimize on electricity usage.

Since this post if getting too long, I'll post the construction in a separate post.


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## malaybiswas

*Construction*

1. Setup hanging mechanism. drilled a couple of holes on the top of the sconce and screwed them in



























2. Test run on attacing the wall plug and fan to the end covers


















3. Attached the PVC liner to the end covers 









4. Fixed the power adaptors inside the fixture. I have measured that there will be space between them and the heatsink. I cut a rough rectangular piece of aluminium sheet, drilled holes and screwed the adaptors and then screwed the plate to the fixture using the same screw that holds the hanging kit


















5. A whole bunch on end terminals for the wiring. All screwed to the fixture. The reason I used the terminals is so that removing the heatsink or the end covers will be easier.










6. Wiring between the power adaptors and the end terminals









7. Wiring from the plug and fan to the end terminals. Additional wires from the wire terminals will run to the LEDs on the heatsink.









8. LEDs fixed on the heatsink using arctic silver and adhesive









9. After all the wiring and soldering is complete, a test run is due before I place the heatsink in the fixture. First try and perfect! Never expected it but was happy anyways 









A closeup









And they ARE bright









10. After a successful test run, I fixed the heatsink to the fixture using 6-32 screws and put the end covers on. There will be a transparent plexiglass cover at the bottom, resting between the extenstions from the end cover









And installed









Tank under final setup









All this was as of last weekend. I waited for a week to see how it does. I was expecting the fixture to become quite hot, but it has been steadily under 72F for a week, so it all looks good so far. The daylight runs 11 hours a day and I do see the stems coverging towards the center.

The layout of the tank has been heavily changed too since the picture was taken, so I'll post a few new pictures within the next couple of days.

Thank you fort viewing.


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## Hoppy

Wow! That is a very nicely engineered fixture. A couple of things I would have tried to do differently, but still it looks very professionally designed. Do you notice any "spotlighting" effect from those powerful LEDs? As I recall people warned against using them for that reason.

I haven''t looked at LED prices for several months now, are the prices down much?


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## malaybiswas

Thank you Hoppy. There is no spotlighting effect that I have noticed. Infact clustering them centrally over a small surface area gives a overall spotlighting effect to the center of the tank just like metal halides.

Besides the shimmering effect is better to my liking. I'll post some pictures with the new layout. The light effect is better captured in the new pictures.

As far as prices are concerned, I did not notice any big difference higher or lower. How's your riparium coming along?


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## Green Leaf Aquariums

Very nicely done. I envy your extreme DIY skill..


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## malaybiswas

Thanks Orlando, but I don't think I am that skillful . I just have some ideas in my mind and roam around to find stuff that can work together.

Hopefully, I will be able to do a dawn-dusk with digital timer circuit that I can plug-in (someday). Only then would I give myself a pat on the back


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## Gatekeeper

Not to degrade from an excellent DIY fixture. Quite impressive and clean work, but whats the deal with this? 



> 2. Test run on attacing the wall plug and fan to the end covers


All the fancy stuff you did and the cover overlaps the rounded edge of the fixture housing? Did you grind that down or something to clean it up? Perhaps make a custom cover out of plexi instead??


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## malaybiswas

I did not want to hardwire the power cords to the fixture. I have whole bunch of wiring running behind the 2 tanks and for cleaning and maintenance, removing the fixtures was too much of an issue with a pair of 6 feet power cords to untangle. This time I decided to keep the plug points attached to the fixture so that I can simply unplug the cords and remove the fixture when needed.

Yes, I could do a custom plexiglass cover. Infact in nano-reef.com I saw a thread for a very beautiful custom plexiglass fixture. However, it used a flat alu heatsink instead of a regular heatsink. That would mean more surface area that I was trying to cut down. At the same time I did not want to experiment trying a smaller version with a regular heatsink to find out that it is unable to hold the weight. The wall scone has a metal backbone, so it is sturdier and looks nice too.

The rounded end covers were custom cut at tap plastics. I do not have gadgets at home to do those kind of cuts . I just glued the pieces with plastic cement.


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## Hoppy

malaybiswas said:


> Thank you Hoppy. There is no spotlighting effect that I have noticed. Infact clustering them centrally over a small surface area gives a overall spotlighting effect to the center of the tank just like metal halides.
> 
> Besides the shimmering effect is better to my liking. I'll post some pictures with the new layout. The light effect is better captured in the new pictures.
> 
> As far as prices are concerned, I did not notice any big difference higher or lower. How's your riparium coming along?


The riparium is being assembled, slowly, but surely, and my LED fixture will work perfectly with it (I think). I hadn't noticed that this fixture is much smaller than the tank, so yes, it will be a lot like a MH unit. My riparium is 6 inches longer than my old tank, so my LED fixture is about 10 inches shorter than the tank length, but the light intensity, by eye, looks pretty uniform over the substrate. I always wondered just how important it is to make a LED fixture be close to the size of the top of the tank - apparently not very important.

I keep wondering what LEDs at what prices will be available in another year!


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## Hoppy

duplicate


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## malaybiswas

I feel the concept of LED fixtures being the same size as tank surface evolved from the reef aquarium community where light source uniformly distributed over the tank produces better shimmering effect overall. Coupled with it was the fact that most fixtures were built in the hood so keeping the heatsink area same as the hood area was easier to assemble.

But yes, I know for sure right now, that it is not necessary. With my new fixture running for over a week now, my newly planted hairgrass are thriving and expanding even on the corners of the tank just as good as the taller and centrally located plants are. So the intensity and PAR they are receiving are definitely sufficient it seems.

I have been watching your riparium thread. Someday I'll have to setup one myself but for now I need to make a good looking nature scape first. Trying since the beginning of this year and not yet as happy as I would like to be 

EDIT: Living in bay area where most people seem overly fascinated to embrace the newest technologies at the earliest, I have not seen LEDs being embraced as fast (although BART is converting their trains to LED lighting for saving on power). So I don't feel prices will come down much in near future.


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## speedie408

malay,

Just wanted to give you a 'pat on the back' because that's a pretty awesome fixture you created there. Maybe one of these days I can come check out your setups  when we have plants to swap or whatever the case.


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## malaybiswas

Thanks speedie. Sure lets plan and do come over. This is actually a good time since I finished redoing my layout and things are blooming back to life.


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## malaybiswas

This picture captures the focused metal halide type effect best among the pictures I took. The edges are darker on the top than the center.


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## evilc66

Nicely done. I was quite surprised you went with the MC-Es, but they seem to be working out pretty well. Any chance of some clearer shots of the fixture itself installed over the tank?


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## malaybiswas

Thanks evilc66. I kind of gambled initially with MC-E to meet my objectives of a smaller surface area. On paper the dimensions of the heatsink and the power consumption requirements of the MC-E compared to the drivers I had worked out well, so I gave it a shot.

I was not sure about how the light distribution would work, but it is pretty even.

I'll upload a few shots of the fixture over the tank.


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## evilc66

I'd say it was a worthwhile gamble. The shots of the tank looks good.


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## malaybiswas

Here you go evil. Not too good shots but gives you the idea










From front









From the side









Birdseye view









Complete setup. Pardon the blurry picture and the uv filter (had some ick issue recently)


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## R33 GTR

That light is awesome how much did it cost you to build something like that because i want one for my 90-P but i am looking for it to grow hc and not having to pay the electricity bill my self with t5ho because in Puerto Rico the electricity cost is high


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## mysticalnet

Nice DIY project!! Awesome light! I suggestion, is there a way to put the wires behind the panel instead of in front?


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## malaybiswas

R33 GTR said:


> That light is awesome how much did it cost you to build something like that because i want one for my 90-P but i am looking for it to grow hc and not having to pay the electricity bill my self with t5ho because in Puerto Rico the electricity cost is high


At the time I made it it cost me around $300 per piece (without considering cost of tools used) with the bulk of the cost going towards the LEDs.


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## malaybiswas

mysticalnet said:


> Nice DIY project!! Awesome light! I suggestion, is there a way to put the wires behind the panel instead of in front?


Thank you. Yes, I can tie them along the pipes and run them behind. However all the pictures here are non-existent right now. These pictures were from my home in California. I recently relocated to Chicago area for my job and do not have any of the tanks running yet. Infact I am living in a temp accommodation, waiting to move in to my new home end of this month before I can restart my tanks again.


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## Hoppy

What new projects are you going to try as you restart your tanks in their new home?


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## malaybiswas

Hoppy said:


> What new projects are you going to try as you restart your tanks in their new home?


I don't plan to start any new project right away. I first need to setup the tanks and see how they work in the new environment. 

For future, I might play around with the filtration and plumbing to reuse/recycle water across the tanks. And a reef tank might be on the horizon :bounce:


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## malaybiswas

Hoppy said:


> What new projects are you going to try as you restart your tanks in their new home?


Decided Solar power will be my next venture. I want to add a 80+g tank but the power consumption will be higher than I want it to be (mortgage killing me), so some of the instruments can use solar power if I can work out something. Math time!


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## Hoppy

This would be a great time to cut a hole in the roof, install one of the "solatube" type skylights, and light the tank with the sun! I have always wanted to try that.


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## malaybiswas

I just saw that yesterday and it is exciting, but for me that is rather difficult to do. I am keeping all my tanks down stairs, which means I have to run the tubes thru my second floor bedrooms :drool:

On top of it my job might require me to move again in future so I do not want to make custom installations yet that might cause issues with selling my home if need be.

I have a pretty big backyard and deck that is not so heavily used. That got me started thinking, how about a solar plant here?


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## Hilde

So what was the final cost of the project? The light is unbelievable bright. Are you dosing Co2?


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## malaybiswas

Around $350/piece. Yes they are super bright and I use pressurized co2. These will soon move over my 100G (WIP) though.


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## Dave-H

Hoppy said:


> This would be a great time to cut a hole in the roof, install one of the "solatube" type skylights, and light the tank with the sun! I have always wanted to try that.


That is an awesome idea.


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## Hoppy

Dave-H said:


> That is an awesome idea.


Several months ago there was a thread here by someone in Mexico who was doing just that, very successfully, as I recall.


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## malaybiswas

Yeah. From what it saw from Hoppy's earlier post it is an amazing build.

Sent from my DROIDX using Tapatalk


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