DIY LEDs - The write-up

[F35-Joint Strike Fighter]

This is not going to turn out well.. :hmm4:

any suggestions why?

 

[der_wille_zur_macht]

It's fixed-voltage and autoranging current output.

That's essentially the OPPOSITE of what you want. If you connect an LED across the output of that PS, it's going to feed it 5v, suck a ton of current, and pop. LEDs are like shorts, from the perspective of a power supply - they just suck everything you give them until they self-destruct. You need something in the circuit (a driver, resistor, etc.) to limit current.

 

[der_wille_zur_macht]

Speaking of the light angle issue and yes a little of topic (is there a better forum). I always wondered if current lighting was some what wrong anyway. Current lighting tends to flood the tank. In real life the sun rises in the east and slowly rises. So one side of the coral would get light, but at what point does it become useful. When it first rises I imagine the light is going through so much water that very little is useful to the coral. Then it sets with everything in reverse. So how much light does the north and south side get. So I pose the question might we get more realistic growth with LEDs directing the light straight down?

Or is all this wrong since the light is bounced of stuff in the water.

I guess it depends on how picky you really are. Corals in conventional tanks can grow pretty close to natural growth forms. I think an important note is that there really isn't a single fixed growth form for any species of coral in the wild, much less an easily-describable range of growth forms for many species. So it's hard to know what the standard for comparison is.

I definitely hear you though, and that's another reason why I'm interested in angling some of the lights on my tank. Even if it's not "better" for the corals, it'll look cool to me, and in my book, that counts for something.

 

[stugray]

DWZM,

"To add a thought to the above, I'm waiting for people to start making more use of angled LEDs to control "waste" outside the tank boundaries"

That's another advantage of my LED tubes with the Al channel.
I will be able to angle the front ones towards the back ;-)

I could even put them all on a motor & tilt them through the day.....

Stu

 

[der_wille_zur_macht]

I could even put them all on a motor & tilt them through the day.....

Stu

Stop stealing my ideas! :lol:

I was pretty committed to motorizing the strips of LEDs to change the angle of light through the day, but now I'm considering fixing different strips at different angles.

I'm trying to design a system that'll be reliable for a 10 year lifespan and I have a feeling that motorizing things in that manner would throw that out the door.

 

[HeneryH]

CDIweb.com just quoted me 2-3 weeks for the ELN-60-24-D and 6-7 weeks for the ELN-60-48-D both at $26.71 (10-15 qt pricing). Auth cc on order but billed on ship.

Julie (julie.williammee at cdiweb dot com) has been great to work with so feel free to mention to her that this is part of the Reef Central hobby group.

I'm really not sure which way I want to go here. I'm leaning towards the 24V Matrix (yes, I hated that term orignially but originally failed to notice the bus-bar wiring between strings).

My -24-D units shipped so that makes a ship time of 8 days.

 

[dnahas]

First off, thanks to all for your help if I can ever return the favor please don't hesitate to ask. Like adding a wiki to the reefcentral site/servers -hint, hint

I have wrapped up putting my "fixture" together and I am about to start the electrical side of things. I wanted to confirm a few more things before I start.

Wiring in series is, by a vast margin, the most common practice, but I think the "best" practice would depend on your personal criteria and the exact components you had to work with.

I am using 4 x eln-60-48d with 12 LED's per meanwell, and my personal criteria would be to do it right the first time.

I don't want to junk up the thread with my pics and I cant get the attachments to work correctly so here's the URL's

http://www.reefcentral.com/forums/picture.php?albumid=1621&pictureid=11463

http://www.reefcentral.com/forums/picture.php?albumid=1621&pictureid=11464

The PIC's show resistors but I "think" they should not be used if I have the meanwells.

 

[der_wille_zur_macht]

No resistors. And from the looks of your diagram you're putting all the LEDs in parallel - you want them in series. i.e. connect the + from the driver to the + pad on the first LED, then one wire goes from the - of that LED to the + of the next LED, then another wire from the - of that LED to the + of the next, and so on. The final LED's - pad gets connected to the driver's - wire.

 

[The Grim Reefer]

Tripped over this for heat sinks

http://www.surplussales.com/Heatsinks/HeatSink1.html

 

[stugray]

"Tripped over this for heat sinks"

Some of those look nice.

The only bummer is the "various holes" means we might have a minfield of holes to work around.

I love the look of the " Heavy Duty Heatsink Chassis" - 5-7/8" x 8-1/4"

That's just about perfect size for our needs as individual pendants.

Stu

 

[The Grim Reefer]

Some of those cases look cool too.

That place has all kinds of priceless treasures. Kind of a high tech Sanford and Son. I would have tried them out but already ordered aluminum channel, couldn't find any I liked locally.

 

[der_wille_zur_macht]

Grim, you got me thinking on "surplus" heatsinks. A few minutes of googling yields some interesting potentials:

http://www.alltronics.com/cgi-bin/item/22Z014S/25/28-mm-sq-x-12-mm-Heatsink-Pkg-of-10

39 cents each! Use one per LED. It mentions "adhesive backed" though, and I don't think I'd trust a random adhesive on a surplus heatsink.

Some of the "medium" heatsinks from the place you posted could work for a small number of LEDs each, too.

This place has a TON of weird shapes:

http://www.alliedelec.com/fans-motors-thermal-management/heatsinks/?gclid=CPOnwMu9tKACFSFy5QodmRXCTw

 

[der_wille_zur_macht]

While we're on subject, this is the heatsink I used for several of my small builds:

http://www.mpja.com/prodinfo.asp?number=17045+HK

I put two 3-up Endor Stars and two XR-E on it, so 8 LEDs total.

It would be interesting to go back through all the builds that have been posted and determine typical costs per LED for the heatsink material people have used. I've always estimated $1/LED but clearly there's a pretty wide variation.

 

[The Grim Reefer]

Grim, you got me thinking on "surplus" heatsinks. A few minutes of googling yields some interesting potentials:

http://www.alltronics.com/cgi-bin/item/22Z014S/25/28-mm-sq-x-12-mm-Heatsink-Pkg-of-10

39 cents each! Use one per LED. It mentions "adhesive backed" though, and I don't think I'd trust a random adhesive on a surplus heatsink.

Some of the "medium" heatsinks from the place you posted could work for a small number of LEDs each, too.

This place has a TON of weird shapes:

http://www.alliedelec.com/fans-motors-thermal-management/heatsinks/?gclid=CPOnwMu9tKACFSFy5QodmRXCTw

Ya know. I just ordered a bunch of 2" channel. might be worth the effort to space something like that along the channel, gotta think on that one.

 

[ReefEnabler]

Stop stealing my ideas! :lol:

I was pretty committed to motorizing the strips of LEDs to change the angle of light through the day, but now I'm considering fixing different strips at different angles.

I'm trying to design a system that'll be reliable for a 10 year lifespan and I have a feeling that motorizing things in that manner would throw that out the door.

Thats acually my plan one day when i build a house around a giant reef. Several led fixtures mounted way above the tank and several feet away horizontally, each fixture capable of intense par. Then it woulc crossfade betwwen them.

Only problem is my houseguests might get blinded if they look u
into the lights. Would need a long stoplight style guard.


Btw if you go back and see my pics, i am already angling the strips towards tje back of the tank since the leds are over a front brace. Easy to angle them with a screw on each end.

 

[ReefEnabler]

Thats acually my plan one day when i build a house around a giant reef. Several led fixtures mounted way above the tank and several feet away horizontally, each fixture capable of intense par. Then it woulc crossfade betwwen them. Yes it might cost an assload which is why its half pipedream but not out of possibility.


Only problem is my houseguests might get blinded if they look
into the lights. Would need a long stoplight style guard.


Btw if you go back and see my pics, i am already angling the strips towards tje back of the tank since the leds are over a front brace. Easy to angle them with a screw on each end.

 

[dpieroni]

uv leds

uv leds

sorry for changing the subject but anyone can tell to where to find uv leds to add in a led system and how much? I have two panels of 24 leds 3w cree in my 80 gallon system.
thanks
diego

 

[daytriper]

I was wondering if you had a power supply 3.3 volts at 16 amps how would you regulate it and would it work?

 

[akindbro4u]

While we're on subject, this is the heatsink I used for several of my small builds:

http://www.mpja.com/prodinfo.asp?number=17045+HK

I put two 3-up Endor Stars and two XR-E on it, so 8 LEDs total.

It would be interesting to go back through all the builds that have been posted and determine typical costs per LED for the heatsink material people have used. I've always estimated $1/LED but clearly there's a pretty wide variation.

I'm at about $2 per LED using the heatsinkusa heatsink, but I went way overkilll just in case I decided to go crazy adding more LEDs later. Also I didn't want to actively cool the fixture. So you would have to take that into consideration with cost per LED with heatsink prices. Just my 1.5 cents

 

[der_wille_zur_macht]

I was wondering if you had a power supply 3.3 volts at 16 amps how would you regulate it and would it work?

That supply would be nearly useless. 3.3v isn't high enough to correctly drive many of the LEDs we're using, and you'd have to run them in parallel, which means either a very big overhead for current regulation (individual resistors/drivers per LED) or a very risky current regulation (one driver running them parallel).

You could use it with a switching regulator in a boost topology but you'd be waaaaaay out of the efficiency range for any chip I'm familiar with.