DIY LED Hood: Prebuild Thoughts...

[GMGQ]

Hi All,

I'm just getting back into the hobby, and I know I have to change the bulbs in my setup (it's been over 2yrs!). I have 2x250W MH, and 2xT5 Actinics lighting my 70gal tank (48"L x 20"D x 18"H approx).

Rather than spend $200+ on new bulbs, I'm looking into this whole LED thing. When I first heard of LEDs a couple years ago, they were over $1000 for a setup, and werent that powerful. Now the story has totally changed. Plus with Milad's group buy setup, how can I NOT go this route?? I built my own stand, did all the plumbing, and wired up the power center by myself, so I'm pretty hands on. I'm pretty excited to jump right into this LED thing, it seems easy enough, but I know I better do my research first.

So having said that, I figure I'll ask some questions here and pick the brains of you awesome reefers! I've engrossed myself in researching this stuff for the past week, but I figure I'll ask some questions here, in case anyone else was wondering the same thing (no such thing as a dumb question, right?). Part of this is also me thinking out loud :P

LEDs:
- I want to maintain the 10K colour that I have now with my MH's. Milad told me that this is achieved with 1:1 of Cool Whites and Royal Blues. And with dimming, I can create the whole range of colour temps as well.
- Regarding the number of LEDs, I've been told that 48 is a good number to achieve something equivalent to 250-400W MH. Just looking at my crude piece of excel art, if I had a 36" heatsink, I could evenly fit 9 LEDs per each 6" section, and that would come to 54 LEDs. I like symmetry :P

Optics:
- So I guess these lenses help focus the LED beam down at 40-65 degrees, like a spotlight. Since the LEDs will be at least 10" or higher above the water, it's a no brainer that optics will be needed, yes? OK, then how to decide which angle to choose? I'm thinking either way, the LEDs will be placed only a few inches from each other, so would it really be necessary to get anything wider than 40*? There should be plenty of overlap anyways. If I go wider, I assume the coverage will be a bit wider, but the intensity will be lower? (i.e. not as many PARS reaching the bottom of the tank). But again, there will be lots of overlap. Maybe just have the last row of LEDs on the furthest Left and Right of the heatsink at 60*, and the rest of them at 40*?

http://lh5.ggpht.com/_1RcSbBe1YJ0/TTd-h7ACmfI/AAAAAAAAA0Q/PseB7xR5Vd8/Lens.jpg
(Yes I was bored at work).

Heatsink:
- Speaking of heatsinks, I'm tempted to go with one big 36" long one. They weight is about 18lbs. I'm not too concerned about the weight, I'll rig something to hang it from chains, and I dont intend to mount the drivers in this LED hood. I'm more concerned with even coverage of the 48" tank. I could go with 2-3 smaller heatsink chunks, and I'll probably never notice any gaps of coverage betwene the chunks. But it seems nicer to have one big heatsink...

Driver:
- I see most builds have 4 drivers to power 48 LEDs (12 LEDS per driver). But I saw other builds (i.e. Milad's) that use 2 larger drivers to control them all. Sure, why not? More hardware = more to wire up + more ways to screw up :P I dont intend on running the lights east to west to simulate the sun, so I dont really see a need to get a bunch of smaller drivers... Agreed?
- Regarding dimmability, I guess dimming is a good thing. I do want to be able to have a controller slowly raise the intensity during the day, then slowly reducing it at night, then I want to run the blue LEDs at a lower intensity for moonlights.

Controller:
- I'm a bit stumped here. As per above, I want to slowly raise the daylight intensity, slowly reduce it, then run the blues at a lower intensity in the evening (like actinics), then lower the blues even more at night for moonlight. What kind of controller will do this for me Automatically? I looked up the Neptune AquaController Apex System, but that sucker starts at $500! Is there a cheaper alternative that will automate the lighting intensity for me? I dont really need all the bells and whistles of the Apex system, I just want something to control the lights on a timer for me...


Ok, those are my initial ramblings. Thanks in advance guys, I'm very excited! :D

Gary

[StirCrazy]

Hi All,


http://lh5.ggpht.com/_1RcSbBe1YJ0/TTd-h7ACmfI/AAAAAAAAA0Q/PseB7xR5Vd8/Lens.jpg
(Yes I was bored at work).


Gary

is your angle drawign repersentitive of the fixture being 10" above the tank? I would say if that is a 20" deep tank you are trying to figure out the angles with the fixture 3" above the tank.

Steve

[GMGQ]

StirCrazy:

No no, the height of the hood is not to scale. It's just to visualize the 40* vs 60* spread of the optics.

It's just MS-Excel, man! :P

[mseepman]

Well, it seems you've thought a lot about this already.

In regards to optics, just note that 40 degree optics really tend to spotlight the LED's so I would consider doing a bunch of 60's myself. If you go with fewer drivers..you need to do a little more detailed wiring to include fuses and resistors. When you do that, you will need to balance the strings, (move some LED's around) which is really tough if you use any method other than screwing the LED's to the heatsink. I tell you this because screwing them in means you need to tap the heatsinks (a bit of work).

As for controllers...I think the Apex lite can use their 1-10V add-on and it would be cheaper.

I'm a huge fan of LED and will be doing one of these myself with 180 LED's or so.

[GMGQ]

So instead of jumping into the big LED hood build, I figured I'd do a small scale project first.

I want to build a refugium LED light with 6 LEDs:

4 x Cree XP-G CW (3W, max drive = 1500mA, forward voltage = 3.0 @ 700mA)
2 x Cree XP-E RB (3W, max drive = 1000mA, forward voltage = 3.4 @ 700mA)

I plan on using a buck puck with a potentiometer. Will this one work?

http://www.ledsupply.com/03021-a-e-1000.php

If so, what power supply would I need for it to drive the 6 above LEDs? (24V, 1000mA as per the buck puck?).

And I assume I should wire them in series?

Thanks guys.

[mseepman]

Unless dimming these is of utmost importance to you (for a fuge I would think not) I would get either a meanwell LPC-35-700 or a LPC-60-1050 (if you want higer mA). This way you just wire it and go...if you need to add more LED's you can (up to 12). The buckpuck costs the same, but you still need to buy all the extras to make it run and it caps out at 6 LED's.
Just my humble opion though. Here's a link where you could get the Drivers. http://www.rapidled.com/servlet/the-Drivers/Categories

[GMGQ]

Well I want to dial back the voltage so that the LEDs arent running at 100%, plus this is a test project for me, so I want to see what varying voltages will do with the brightness/colour.

Also the buck puck is the size of a quarter, the meanwell is the size of a brick. I just figured I shove the buck puck into a little black project box from radio shack, and screw the pot into the lid.

What extras would I need with a buck puck? The one I linked to comes with the pot pre-wired, so I figure all I need is an AC power adapter?

LMK what you think thanks.


Unless dimming these is of utmost importance to you (for a fuge I would think not) I would get either a meanwell LPC-35-700 or a LPC-60-1050 (if you want higer mA). This way you just wire it and go...if you need to add more LED's you can (up to 12). The buckpuck costs the same, but you still need to buy all the extras to make it run and it caps out at 6 LED's.
Just my humble opion though. Here's a link where you could get the Drivers. http://www.rapidled.com/servlet/the-Drivers/Categories

[mseepman]

Fair enough... One thought would be that I'm not sure that LED's are the best Fuge light. They've been known to significantly cut down on algae in tanks as they don't put off as much light in the spectrums that many algae's like. Not sure that will help grow your macro-algae either.

No extras on the BP, I just like simple and drivers are simple. :)

[Lampshade]

I"ve been doing a lot of research on this aswell, i've seen a few nice tanks with 40 degree optics, some even with 20. They tend to be layed out in a cookie sheet way, staggerings each line of LED's. I think it's more dependant on your density of LED's and the height mounted oabove the tank. 10" above the tank is pertty common, If you are going more than 2.5" centers on the LED's i would suggest 60 degree, if less than 2.5" then 40 should be fine IMO. Check out as many pics as you can to see what you're getting into.



and if you are using XP-E's a 1:1 ratio will be a 14K balance, if you use XP-G white's you can get away with less whites, forget the combo for 14K though. The blue's don't help growth much, basically for our viewing and popping coral color (The datasheet for cree shows this with the light off the whites, it's very close to the PAR we're looking for)

As for heatsinks, there's lots of choices, but generally people WAY over build heatsinks. Cree's give off a lot of heat, no doubt, but you can calculate the heat gain vs loss pretty easy to see what you actually need.(i posted links on some other recent DIY thread)

Drivers have lots of choices, meanwell's are popular as with the buckpucks. More drivers gives you more "zones" for dimming/control. 1 driver dims all the lights together.

As for cheap controllers. Depends on how fancy you want to get... but look at arduino boards. There's LOTS and i mean LOTS of LED builds using these. Uses C programming, but i've found many chucks of code online that people have posted that got their LED's working and controlable. Arduino's start at $20 for something that will control 2 drivers with PWM outputs and $35 for something that'll do 6(Arduino Mega). If you get into it the arduino can do pretty much everything, i'm building a tank controller based off one right now.

[GMGQ]

Hmm, well this is mainly for my chaeto down there :P Right now I'm using 2 CF bulbs, and they're growing like weeds. I just wanted to reduce the wiring/lighting clutter.

It's a small weekend project, so I'll try it out and see how it goes.

I still need to figure out the AC power requirements though...




Fair enough... One thought would be that I'm not sure that LED's are the best Fuge light. They've been known to significantly cut down on algae in tanks as they don't put off as much light in the spectrums that many algae's like. Not sure that will help grow your macro-algae either.

No extras on the BP, I just like simple and drivers are simple. :)

[Lampshade]

I think the cheato should do fine, the cree white's are a 6500 - 10K bulb, that's what i use on mine and they grow great. I think the reason people have problems is the intensity of the light, most algee gets nuked in VERY bright lights, and LED's have the same intensity(lumens) per watt as some of the best MH bulb available. Just keep them up a bit and don't use optics and they'll do fine.

[GMGQ]

Thanks. Plus I'll tweak the intensity with the pot.

Now do you know how I would calculate the AC power requirements?



I think the cheato should do fine, the cree white's are a 6500 - 10K bulb, that's what i use on mine and they grow great. I think the reason people have problems is the intensity of the light, most algee gets nuked in VERY bright lights, and LED's have the same intensity(lumens) per watt as some of the best MH bulb available. Just keep them up a bit and don't use optics and they'll do fine.

[StirCrazy]

As for heatsinks, there's lots of choices, but generally people WAY over build heatsinks. Cree's give off a lot of heat, no doubt, but you can calculate the heat gain vs loss pretty easy to see what you actually need.(i posted links on some other recent DIY thread).

I don't see a problem with this at all, I would rather have an overbuilt heat sink anyday than one that is a perfect match. so many people try to skimp on some things for a matter of 20 bucks, this isn't one area that should be done IMHO. for example.. if you fan dies on a exact sized heat sink and you don't know about it then you run the risk of burnning out several LEDs, if you have a over sized heat sink it reduces the chance of losing LEDs as you are not as dependent on the fan.



As for cheap controllers. Depends on how fancy you want to get... but look at arduino boards. There's LOTS and i mean LOTS of LED builds using these. Uses C programming, but i've found many chucks of code online that people have posted that got their LED's working and controlable. Arduino's start at $20 for something that will control 2 drivers with PWM outputs and $35 for something that'll do 6(Arduino Mega). If you get into it the arduino can do pretty much everything, i'm building a tank controller based off one right now.

on this topic, have you seen any dimming programs for Arduino using a varable voltage output instead of PWMs?

Steve

[Lampshade]

on this topic, have you seen any dimming programs for Arduino using a varable voltage output instead of PWMs?
Arduino's can't output a variable voltage, but you can buy filters that will change PWM outputs to a 0-5v or 0-10V. check out:http://www.nano-reef.com/forums/index.php?showtopic=230743 - different values work for different pulse widths, there's online calculators to see what you need.

As for heatsinks you are right, overbuilt is no problem at all with me either. I'm not going to go buy 60" of 10" pure aluminum heat sink with 1.5": fins now though, after calculating it a bare piece of aluminum with a fan on it would work "in theory". I'm going to probably run aluminum channel, and also I'm going to have an arduino running my LED's, so for $2.50 i can get a thermometer on the heatsink to shutoff for overheating, i'll proably put 4-5 of them on just to be sure.

[Lampshade]

Now do you know how I would calculate the AC power requirements?

Your AC should be pretty much Watts in = Watts out/efficiency

Drivers vary efficiency depending on how well they're used(they like to be run near max all the time). usually >70% though. so 48LED's, driven at 3v per LED, at 750mA(3/4 load) would be about 86.4W at 80%, so 0.72A at 120V. Not bad at all...

[GMGQ]

How did you calculate that?

And what is that in terms of a power supply's AC_out and Amps? So in your example, would this one suffice?
http://ledsupply.com/04004-p96.php




Your AC should be pretty much Watts in = Watts out/efficiency

Drivers vary efficiency depending on how well they're used(they like to be run near max all the time). usually >70% though. so 48LED's, driven at 3v per LED, at 750mA(3/4 load) would be about 86.4W at 80%, so 0.72A at 120V. Not bad at all...

[Lampshade]

Watts is just P = EI, or watts = voltage * current

[GMGQ]

For guys that have DIY LED setups, do you just run the royal blue array at the lowest voltage for moonlights? Or would that be overkill (i.e. if you had say 24/48 in blue LEDs)?

Or did you install a separate set of blues for moonlights? And if so, how many do you run? My tank is 48" wide, will 5-6 LEDs evenly spaced be sufficient?

[GMGQ]

Just an update on my mini LED build. I'm going down to point roberts on saturday to pick up a bunch of stuff that I ordered:

- Weller 40W Soldering Station (figure it's time to upgrade from my old 25W Radio Shack soldering iron)
- 7"x6" heatsink from HeatsinkUSA.com
- Meanwell LPC-35-700W driver from RapidLED.com

And I already have the LEDs from Milad (4 x XP-E CW, 4 x XP-G RB).

I'm going to pick up some Artic Silver Thermal Adhesive from NCIX (I get a discount there), and I should have enough misc electrical supplies in my toolbox. Oh I want to get some ballast quick disconnects from Home Depot.

I should also pick up a sheet of Acrylic from IP&P to make a splash guard.

[TheMikey]

I can't find the thread, but when I was considering doing a DIY, I came across a thread on RC about LED optics.

The poster looked at the PAR range between 40, 60, and 80 degree (I think) optics and found that the 60 degree optics were the most efficient and gave the best PAR.

I'll dig around a bit longer and see if I can find it...

[TheMikey]

Alright, I lied. But at least I found what I was looking for!

Looks like 70 degree optics make the most of your LEDs:


Source (http://www.reefledlights.com/how-to-diy-led/optics-evaluation/)

However, reading through this again, they didn't test the 40 degree. My assumption is that this source is trying to show you how to get the most par using the least LEDs. Take it with a grain of salt, I'm no expert :)

[Bryan]

Here is an interesting read on optics in a tank

http://www.nano-reef.com/forums/index.php?showtopic=261525

[claymax]

what would be optimal for a diy fluval edge, in regards to optics, as the canopy forces them to be kept very close to the surface.

[Bryan]

With the Edge you don't want to use optics as the opening is so small, you want the light to scatter as much as it can When I get a chance I will upload a couple pics of the DIY LED lighting for my edge.

[claymax]

k cool!

[oupulino]

It is interesting read .What is best height to hang if you using 70 deg optic for DIY fixture

[GMGQ]

Here's a good link:

http://www.ledgroupbuy.com/pages/Choosing-the-right-optic.html

But it also depends on how deep your tank is. The higher you go, the wider the spread, but the less penetration you'll get at the bottom of your tank.

But with a wider optic like 70*, you can afford to go lower, as the spread is already wider. Just think of a flashlight. Take one and hold it vertically, pointing down, and see how the spread is.

Realistically, I would hang the fixture as low as possible, while still giving you enough clearance to reach your arm into the tank to do daily maintenance.

It is interesting read .What is best height to hang if you using 70 deg optic for DIY fixture

[oupulino]

That link is very good,thanks.

[GMGQ]

The LEDs game last friday, so I spent the evening gluing them onto the fixture and wiring everything up!

DIY Aluminum Fixture:
http://reefblog604.files.wordpress.com/2011/05/20110523-022325.jpg?w=530
I used 2 of the left piece side by side for the main body, and I interlocked and riveted in all 4 sides with the right piece.

Top View:
http://reefblog604.files.wordpress.com/2011/05/20110523-014300.jpg?w=530

Bottom View:
http://reefblog604.files.wordpress.com/2011/05/20110523-014336.jpg?w=530

Side View:
http://reefblog604.files.wordpress.com/2011/05/20110523-014405.jpg?w=530

LEDs:
http://reefblog604.files.wordpress.com/2011/05/20110523-011446.jpg?w=530
http://reefblog604.files.wordpress.com/2011/05/20110523-011528.jpg?w=530
I was going to install a piece of plastic on the bottom as a splash guard, but I havent gotten around to getting the plastic. But now I'm wondering if it's even necessary. I'll probably hold out.

Grommets for running wires through:
http://reefblog604.files.wordpress.com/2011/05/20110523-011733.jpg?w=530

Wired up (48" strip of blue LEDs as Moonlights wrapped around fixture):
http://reefblog604.files.wordpress.com/2011/05/20110523-011747.jpg?w=530
http://reefblog604.files.wordpress.com/2011/05/20110523-011759.jpg?w=530

Temp electrical station :P
http://reefblog604.files.wordpress.com/2011/05/20110523-011805.jpg?w=530

Top view with fans (80mm Aluminum fans with blue LEDs, fitting):
http://reefblog604.files.wordpress.com/2011/05/20110523-011848.jpg?w=530

Front View:
http://reefblog604.files.wordpress.com/2011/05/20110523-011843.jpg?w=530

Fixture runs COOL TO THE TOUCH on full load. Blues at 800mA, Cool Whites at somewhere over 1000mA. One of my goals was to demystify the belief that you need those honking 20lbs+ Amplifier style heatsinks. Pretty cool that ALL the parts of the fixture are aluminum, from the body to the rivets, and even the 2 fans and the screws are Aluminum. I'm very happy with this LIGHT WEIGHT fixture.

I had made the 8LED Fixture, and now this. It's been really good practice. This second one took me no time at all. It's all about the planning. However, I did not anticipate building this 28LED fixture, so the big fixture for my display tank has been pushed back to next year. I just got a new order of bulbs, so they should hold me over until the next LED build (I'm thinking around 60 LEDs next year).

[Milad]

Nice job!! that looks fantastic. People never believe me when I tell them they can use U-Channel for their heatsink.

Keep an eye on the frags at the top of the tank,t hey might bleach with all the new light.

[GMGQ]

Thanks for getting the LEDs out to me man!

Yeah, just look at CPU heatsinks these days, they now have LOTS fins are literally 'paper thin.' It's all about surface area, and dissipating the heat energy from the surfaces, so that the material can continue to "sink heat" away from the LEDs.

The frags have been accustomed to LED lights, as I had my original 8LED fixture on this tank. Lots of browned out frags have started to colour up under that light, so that test run is what inspired me to do the 28LED fixture. Now I can spread out the frags along the whole length of the tank.


Nice job!! that looks fantastic. People never believe me when I tell them they can use U-Channel for their heatsink.

Keep an eye on the frags at the top of the tank,t hey might bleach with all the new light.

[StirCrazy]

. One of my goals was to demystify the belief that you need those honking 20lbs+ Amplifier style heatsinks.



I don't anyone has ever said you need a big finned heatsink, what I believe has been said is that yes with fans you can get away with smaller and cheeper forms of heat sinks, even 1.25x1.25 al tube.

what has been said though and provin is that if you have a fan failure and are not home to catch it or didn't build over temp protection into your design then that cheeper lighter heat sink puts your whole system at much more risk than a higher watt/in2 heat sink would.

got any pics of it with everything on full?

Steve

[GMGQ]

Well there's no manual of what you should or should not do. I'm just saying from what I've seen in the forums, people who jump into a DIY LED project will typically go with what everyone else has been doing, and go with the big heavy heatsinks, as that is the "norm." Even the online stores that specialize in DIY LED parts are providing these heatsinks, as that is what the market has been demanding.

Even with a massive heatsink, I dont think you can escape overheating issues. I think of heatsinks like batteries/capacitors. Once you fill it up with heat energy, it will be full, and it will not be capable of drawing any more heat from the LEDs. The LEDs are not going to stop generating heat, so the heat has to go somewhere. Therefore I think you still need fans no matter what heatsink you use.

The beauty about a smaller heatsink with more surface area is that it is easier to dissipate the heat, rather than trying to cool down a thick piece of metal. I dunno, that makes sense to me.

Again I refer to CPU heatsinks. They have passive heatsinks like this now:
http://www.hiwtc.com/photo/products/6/00/65/6508.jpg
http://www.sundialmicro.com/images/products/items/s3kpguts04gp_main.jpg

Oh, and no, no pics of everything on full. It's insanely bright, and the camera just sees one big glare. The blues get totally washed out by the white, so I just turned it down to where I wanted, set it and forget it.


I don't anyone has ever said you need a big finned heatsink, what I believe has been said is that yes with fans you can get away with smaller and cheeper forms of heat sinks, even 1.25x1.25 al tube.

what has been said though and provin is that if you have a fan failure and are not home to catch it or didn't build over temp protection into your design then that cheeper lighter heat sink puts your whole system at much more risk than a higher watt/in2 heat sink would.

got any pics of it with everything on full?

Steve

[Milad]

I don't anyone has ever said you need a big finned heatsink, what I believe has been said is that yes with fans you can get away with smaller and cheeper forms of heat sinks, even 1.25x1.25 al tube.

what has been said though and provin is that if you have a fan failure and are not home to catch it or didn't build over temp protection into your design then that cheeper lighter heat sink puts your whole system at much more risk than a higher watt/in2 heat sink would.

got any pics of it with everything on full?

Steve

uh? Do you read all my posts or something, that you can say that for sure? Ive gotten flamed on other boards for saying you dont need the oversized heatsinks, you can use aluminium u-channel. I stopped saying it and started selling the oversized aluminium heatsinks but still tell people they can use the u-channel.

[claymax]

do you like the 1:1 rb/cw ratio?

[StirCrazy]

Even with a massive heatsink, I dont think you can escape overheating issues. I think of heatsinks like batteries/capacitors. Once you fill it up with heat energy, it will be full, and it will not be capable of drawing any more heat from the LEDs.

see and hence the problem, people don't know how heatsinks work or how they are rated.

here is a quick and dirty explanation.

heat sinks are rated by there ability to disapate heat and it is measured in watts/square inch. so when you build a set up you are putting a heat source (the LED) in direct contact to the heat sink. by doing this tyou are relying on the ability of the heat sink to release that heat to the air.

in theory a heat sink that is rated higher than 3watts/square inch will not need any fans using 3 watt LEDs but that is under ideal conditions. humidity ambiant temp ect, all affect the rate at which a heat sink will disapate heat.

part of the rating is ambiant temp, humidity and temp differential between the heat sink and ambiant air. generaly you will see a heat sink rating at watt/square inch with the max efficiency at a 10 degree diff or some number like that. which means that to get the full watt/sq in the heat sink has to warm up to about 10 degrees above ambiant, so that is another thing to concider, as if you have a hood temp of 90 degrees the die temp will run about 100 degrees so lowering the ambiant temp will lower the die temp.

so to increase your ability to keep your LED die temp cooler you can do a few things, the easiest is to build a fan set up to force air across the heat sink surface increasing the amount of heat in can disapate.

another way is to use a hollow heat sink which you can run liquid through to adsorbe the heat. theroeticly you could run sump water though it and keep your heat sink at 80 degrees, but this could add to the heat in your tank so you may or may not get away with this unless you use a chiller or another radiator to disapate the heat somewhere else.

you could also run air through a hollow heat sink, this is what "steve's LEDs" does with his 1.25" square tube LED heatsinks.

but with out some sort of safety shutdown I would be hesident with this style as if the fan fails the LEDs have a very good chance of overheating.

the third main way is to increase the size of the heat sink to a higher watt/square inch rating. if you increase this enough you may not need fans as they heat sink will be capable of a higher rate of heat disapation than the LEDs can put in to it.

now us being over cautious we tend to do both, high rate heat sinks and fans. for instance I am using a high rate heat sink with fans and a way to monitor the temp of the heat sink, I am setting it up with a small quiet fan just to ensure a slight air flow over the fins to prevent any stagnent areas which could cause local hot spots, the second fan will kick on with a higher flow if the temp gets over a set point, and at another set temp 1/2 the lights will shut down and if temp still goes up the rest of the lights will shut down.

this seams like a lot of over kill and yes it is, but my intent is to run the LEDs at full current and keep them subcooled and prevent any premature LED faliures. could I do it with a cheep chunk of alumium flat bar.. hell ya, it would need a lot more fan cooling hence more power usage, more noise, ect but ya would be a little lighter and little cheeper.

I personaly don't care what people use to make there setups. could use tinfoil for all I care :mrgreen:, but what I do care about is when people critisize others for what they see as overkill because they don't understand how something works. So my hope is that this clears up some of the theory of how a heat sink works and maybe helps people to understand why some people chose to go a little over kill.

there is also they other factor.. finned aluminum can just look cool also :mrgreen:

Steve

[StirCrazy]

uh? Do you read all my posts or something, that you can say that for sure? Ive gotten flamed on other boards for saying you dont need the oversized heatsinks, you can use aluminium u-channel. I stopped saying it and started selling the oversized aluminium heatsinks but still tell people they can use the u-channel.

I agree with you. you can use a flat bar al if you want, just got to keep it cool.

Steve

[lastlight]

Does the thermal tape work as well as the silver paste?

The people that have been mounting with screws...is there paste used in these applications?

[GMGQ]

Thermal Tape is different from Silver Paste though.

Thermal tape is basically double sided tape, used to attach the LEDs to the heatsink, so that you can remove them later if you need to.

Silver paste is a thermal paste used between the LED and Heatsink to fill in the gaps between the 2 surfaces for optimal heat transfer. Yes, you should use some sort of thermal paste under the LED when using screws to mount them.


Does the thermal tape work as well as the silver paste?

The people that have been mounting with screws...is there paste used in these applications?

[GMGQ]

I like the colour i've adjusted them to now. It's kind of hard to say it's 1:1, as the whites can handle more voltage than the blues. Right now my blues are at about 800mA and the whites are around 1000-1100mA.

This fixture is on my frag tank, so I set it for a bit more white than blue, for better growth.


do you like the 1:1 rb/cw ratio?

[Milad]

thermal tape is so much easier to work with than grease