LED build

[thedoogan]

So I've decided to jump into a DIY LED light setup for my 5.5G. I am going to be keeping softies and LPS. Here is what I am planning on doing:

3XCree xr-e 6XBlue cree The blues will be wired separately and powered by 1000mA buckpuck the whites will be powered by another 1000mA buckpuck and both buckpucks will be powered by This laptop adaptor. I want to be able to dimm both the white and blue separately to control color temp. The LEDs will be mounted on a PC procesor heatsink and cooled by a pc fan.

What do you guys think?

[coolwaters]

now we wait....

[Splumph]

Ive actually made a unit using 5 of those white (on a different mount), and 5 blues, and it looks good over my 7g minibow. I am planning on adding some UV, maybe 2 more whites, and a red for night viewing. I will post a build thread once I get my tank set up, and put the finishing touches to the light.

[thedoogan]

Ive actually made a unit using 5 of those white (on a different mount), and 5 blues, and it looks good over my 7g minibow. I am planning on adding some UV, maybe 2 more whites, and a red for night viewing. I will post a build thread once I get my tank set up, and put the finishing touches to the light.

 

5 cree xr-e? and you are getting 2 more...its not bright enough with those???. What are you using to power them?

[Splumph]

Theyre bright enough, like I said, thinking of getting more whites I kept it simple and used these. They were free for me, since they came out of a defective light fixture, mine are the 24v version. I plan to upgrade to the buckpuck/power supply route eventually, but for now, they work

[evilc66]

You don't want to run those blues at any more than 700mA. They are not rated for 1A and will get very hot. Plus the gain in output will not be that great over 700mA.

 

Going with an additional one or two whites might not be a bad idea either. With having all the LEDs central in the tank, you will need more output to make the ends of the tank brighter. Normally I recommend spreading the LEDs out over majority of the length of the tank to get more even lighting.

[thedoogan]

I found this site, It seems helpfull.

 

LED Drivers Reference Guide Selector

[evilc66]

Nice if you are going to build your own driver. For simplicities sake, the Buckpucks are the best value for a standalone dimmable driver.

[thedoogan]

Yah going with buckpucks for sure. Check these out, You could mount the LED's directly to the fan if your in a tight space.

 

http://www.dealextreme.com/details.dx/sku.15346

http://www.dealextreme.com/details.dx/sku.13988

http://www.dealextreme.com/details.dx/sku.8944

[Splumph]

Those snowflake ones look nice...I still like the solid extruded aluminum heatsinks. Lots of mass to them in case the fan fails. You could prbably get a heatsink extruded that would completely cover your tank, then youd just have to put it on legs

 

I just noticed those crees you want are backordered..the ones I used are these Same LED with a slightly cooler color, but different mount. I did find the stars easier to solder though, so it may be worth the wait.

[coolwaters]

Yah going with buckpucks for sure. Check these out, You could mount the LED's directly to the fan if your in a tight space.

 

http://www.dealextreme.com/details.dx/sku.15346

http://www.dealextreme.com/details.dx/sku.13988

http://www.dealextreme.com/details.dx/sku.8944

 

dont get any of thoses. i got one before hoping to run some LEDs with it.

turns out the fan does nothing. its too close to the aluminum so it creates too much turbulence and does not cool down the heatsink.

 

to yourself a favor and spend a few bucks on a aluminum CPU heatsink

[thedoogan]

Those snowflake ones look nice...I still like the solid extruded aluminum heatsinks. Lots of mass to them in case the fan fails. You could prbably get a heatsink extruded that would completely cover your tank, then youd just have to put it on legs

 

I just noticed those crees you want are backordered..the ones I used are these Same LED with a slightly cooler color, but different mount. I did find the stars easier to solder though, so it may be worth the wait.

 

 

To bad I saw that now, I already placed the order under my invoice it did say under back order but now it just says pending, but the product page still says back ordered

[evilc66]

Call and cancel. It's barely enough for one LED nevermind a full array.

[thedoogan]

Call and cancel. It's barely enough for one LED nevermind a full array.

 

what do you mean "barely enough for one LED nevemind a full array"?

[evilc66]

The heatsink is very small. It would be able to keep a single LED, maybe two cool enough, but the sound from the fan would be pretty awful. You will need a much better (bigger) heatsink if you want a good sized array.

 

After re-reading your post, I saw that you were refering to the LEDs, not the fan. Sorry.

[thedoogan]

Does it matter if a heatsink is fabricated by welding the fins (1" high) on? will that conduct enough heat?

[evilc66]

I wouldn't do that. Get a cast/forged/extruded/skived heatsink. They are not hard to find and are pretty cheap. Check out http://www.heatsinkusa.com for some larger aluminum heasinks that I have used in the past with great success. They may be overkill, but at least if the fan fails, you won't cook your LEDs.

[coolwaters]

I wouldn't do that. Get a cast/forged/extruded/skived heatsink. They are not hard to find and are pretty cheap. Check out http://www.heatsinkusa.com for some larger aluminum heasinks that I have used in the past with great success. They may be overkill, but at least if the fan fails, you won't cook your LEDs.

 

 

if i could redo my whole LED array i would have gotten those heatsinks. the CPU heatsinks are good but the surface area isnt big enough. run a 120mm PC fan over it at low speeds and your good to go for the thermal part. (120mm are very common and cheap now also u get high air flow with low noise at low speeds)

[thedoogan]

if i could redo my whole LED array i would have gotten those heatsinks. the CPU heatsinks are good but the surface area isnt big enough. run a 120mm PC fan over it at low speeds and your good to go for the thermal part. (120mm are very common and cheap now also u get high air flow with low noise at low speeds)

 

Those heat sinks will come to around 60$ shipped for me...This heatsink that I can have made (welded fins) would be free. The base would be 13X6" at 3/8 inch thick with 1" fins. If the welds do not conduct that much heat onto the fins, will the large surface of the bottom 13X6 plate with the "limited" fins+ 1 or 2 120mm fans still cool the LEDs enough?

 

Dealextremes ongoing backorder of the crees has me wanting to cancel and go with cutters leds...if i could only find another good power source to power both buckpucks + arrays.

[Reeferton]

Welded fins? Do you mean solder or actual arc-weld? We're talking about aluminum right?

I don't think you could weld aluminum thin enough to be a good heat sink without burning holes through it, unless your a master aluminum welder.

You can't solder aluminum. Even if you could, the solder would corrode easily because to make solder, you take the "base" metal and add "crap" metals to lower the melting point.

If this is steel, then it will not conduct heat half as well as aluminum (literally).

 

EDIT: You can get the crees from ledsupply.com

[thedoogan]

Welded fins? Do you mean solder or actual arc-weld? We're talking about aluminum right?

I don't think you could weld aluminum thin enough to be a good heat sink without burning holes through it, unless your a master aluminum welder.

You can't solder aluminum. Even if you could, the solder would corrode easily because to make solder, you take the "base" metal and add "crap" metals to lower the melting point.

If this is steel, then it will not conduct heat half as well as aluminum (literally).

 

EDIT: You can get the crees from ledsupply.com

 

Im not sure...the guy making it works at an aluminum/metal fabrication place...he says he can do it...

ledsupply does have some power sources..perhaps I will cancel dealextreme...does anyone know if they refund EMS shipping ? .So will THIS power supply power both buckpucks+arrays (1 array=5white 2nd array=6blue) ...Im a beginner at this so... the LEDs run at 3.3Vf each, so one buckpuck ( require 2 extra V's ) + leds needs 18.5V and the other buckpuck+LEDs need 21.8V...If both buckpucks are powered by that one power supply with they both recieve 24V or will it be divided?

 

 

Oh, and ledsupply's cree is "CREEXRE-W100, White Cree Q4 XR-E Star " is the w100 Q4 much different than deal extremes Q5?

[Reeferton]

Well there ya go, the guy works at a fab shop then your good to go. (Its all about having the right tools.)

 

As for the difference I have no idea, you could always ask them.

[evilc66]

If you could machine a heatsink as opposed to weld one, it would be far better. If you are stuck welding one, TIG will be far better than MIG, and use as thick of a base as is practical. The extra mass will help pull the heat away, while the fins try as hard as they can to reject it.

 

The 24v power supply will just make it. The Cree LEDs run at a slightly higher Vf than most, and at 700mA (for the blues) you could see Vf's as high as 3.6V. That could put you at 21.6V which is just under the limit of the Buckpuck working correctly.

 

The difference on the Q5 vs. the Q4 is output. The Q4 is about 25lm less than the Q5. On a small tank, it won't make that great of a difference. ~180lm each is still a lot of light.

[thedoogan]

If you could machine a heatsink as opposed to weld one, it would be far better. If you are stuck welding one, TIG will be far better than MIG, and use as thick of a base as is practical. The extra mass will help pull the heat away, while the fins try as hard as they can to reject it.

 

The 24v power supply will just make it. The Cree LEDs run at a slightly higher Vf than most, and at 700mA (for the blues) you could see Vf's as high as 3.6V. That could put you at 21.6V which is just under the limit of the Buckpuck working correctly.

 

The difference on the Q5 vs. the Q4 is output. The Q4 is about 25lm less than the Q5. On a small tank, it won't make that great of a difference. ~180lm each is still a lot of light.

 

 

Ok, thanks for all the info. .so the 1 24v powersupply going into both buckpucks, the 24v will NOT be divided? but im guessing the 2.2amps will be divided ? is that how it works.

 

That could put you at 21.6V which is just under the limit of the Buckpuck working correctly.

You mean what each buckpuck is capable of dishing out? It says they can put out 32VDC max.

[evilc66]

Ok, thanks for all the info. .so the 1 24v powersupply going into both buckpucks, the 24v will NOT be devided? but im guessing the 2.2amps will be diveded ? is that how it works.

 

Right. When you connect in parallel, the current is divided. When you connect in series, the voltage is divided.

 

 

You mean what each buckpuck is capable of dishing out? It says they can put out 32VDC max.

 

It's a little misleading. The max input voltage is 32v. The Buckpuck requires 2v above the total vf to work properly, so you have only a max of 30v out.

 

The basic rule of thumb will be, the output available for LEDs will be 2v less than the input voltage. If your total vf starts to step into that 2v operating range for the Buckpuck, it may not work properly.