So I got my LEDs all wired up and they worked great for about 10 minutes. Then the blue chain went out. I took the hood apart again and now the first 4 blue lights lit but the last three are off. Also while it is plugged in the 6'th of the series will start smoking. I lifted all but the last blue light off the heatsink thinking it might be shorting somewhere. Can anyone recommend what to check, voltages, continuity, anything of that sort to help diagnose this problem?

The tank looked great when it was on though!!

I'm by far the last to help troubleshoot this, other than to ask what you are driving them with---

Are you using a buckpuck? If so then I'm pretty sure you have too many LED's, they are supposed to run 6, not 7.

Na, it is the Meanwell from the group buy. I have one driver for the blues and one for the whites.

I am running meanwells on mine as well, one thing to check is the amperage they are driving. When I tested my eln-60-48Ds one was drinving 1.4a and one was 2.0a from the factory. You have to tune them down using the internal pot.

i emailed old mate at heatsinks usa, for a standard width 5.735" heatsink and just 6" long, on the site it was $12 for the actual heatsink, and he quoted me a total of $57, which would mean it costs $45 postage for a 6" square of alluminium.. does this sound about right, i think i would rather go to bunning and just get a few lengths of 3,, by20-30mm bar and glue 2-3 bars on top of eachother..

would 10mm X 20mm rectangle of alluminium (900mm long) be enough to passivly cool 6 xr-e's at 1 amp.. if not what about 700ma??


ALSO, i emailed ETG about royal blue led's and she said 6 bucks each as i expected, allthough i wasnt aware they have a $75 minimum order..just for future reference, im sure its been mentioned before but i havnt come across it.. also are they on stars or bare emitters??

xcracer, I think Russ must have misunderstood something. I just bought four odd shaped offcuts from him (four pcs, 2X12" each) and the shipping was normal $10 flat rate. Your piece should be the same shipping, maybe less if it would fit in a small flat rate box.

I don't know if you are outside the USA, but if so, that changes everything.

HAHA i am in australia.. but still the shipping is like 4 times the cost of the product, which is just a chunk of steal haha, i understand it is heavy, but would take up next to no space and isnt fragile... will have to find somewhere that ships to australia economy post prices , or an aussie seller, (which i cant find..)

from my previous post.. could i use a few bits of flat alluminium (say 25mm (1")x3mm (.11")) glued on top of eachother have enough volume to keep 6 LED's cool over say a 36" distance.. so roughly 6" between each led.. and possibly a fan if needed, or is it just too unreasonable..

Here's the thing. Any LED array will be capable of keeping high light inhabitants. Going to lower power LEDs to reduce the output, doesn't really save you much money. You can't really go with fewer LEDs, as you will hurt your coverage. So, you will be stuck with an expensive fixture regardless of whether you want to go with high or low light livestock.

Anyway, 24 LEDs will be fine, but I'd change the arrangement. Go with an 8x3 arrangement, with 2.5" spacing between LEDs and 3" spacing between rows. That will get you pretty even coverage along the tank, and more than enough light for what you are looking to keep.

How long did you have everything running before you started seeing "smoke"? It's possible that the "smoke" you saw was solder flux burning off from the LED heating up. Question is though, why is it getting that hot? Not having the LEDs bolted down didn't help.

From the looks of the pictures, your solder joints are pretty poor. You have a lot of exposed copper on the wires, and makes me wonder how good your solder joints really are. A cold solder joint can increase your contact resistance, and increase the chance of joint failure. Not saying that this is the cause of the failure, but it will create issues later.

Check continuity between the positive and negative pads of each LED, preferably removed from the circuit. You shouldn't see any continuity, but if you do, that could mean a solder or flux bridge creating a short under the LED itself.

Like it was mentioned before, check you current on the driver. It could be set too high. A simple adjustment to SVR2 (turn it all the way counter-clockwise) could be the trick, but maybe not for the LEDs that are no longer lit. To test them, get two AA batteries in series (to make 3v) and touch them across the pads on the LED to see if it lights.


Shipping won't be cheap. It's not the size thats the issue, but the weight. A heatsink that size might weigh about 2-3lbs. That won't be cheap for international shipping. the quoted price seems high though. You might want to ask what shipping method it was. I think over a certain weight he ships UPS, versus USPS.

If you can't find a good heatsink, a thicker bar of aluminum would work. Something in the 5-6mm range. Don't try glueing thinner pieces together. It doesn't create the same effect. A fan would probably be required.

I wasn't trying to go with lower power LEDs. I am going with the CREE leds that everyone else is using, I was just wondering if I should go with 24 leds or if I would be fine with a fewer amount of leds like say 18 or 12.

Also, I have a questions about the 8x3 arrangement... that would get me great coverage left to right but what about front to back? Also, i was planning on no optics so I dont know if that changes things.

Thanks for the help.

This will get you plenty of coverage. 3 rows works out pretty good for an 18" wide tank.

Like I said before, going with fewer LEDs will really hurt your overall coverage and color blending.

I gotcha... I miss understood you, I thought you originally ment going with cheaper, lower powered LEDs. 24 it is.

I need some help.
I have drilled and tapped the heatsink and mounted all my led stars.
But I can't seem to solder to the terminal pads on top of the stars.

I have some flux paste used with copper pipe, and thought about using a dab on top of the terminal, but wasn't sure that was such a good idea.

Any pointers from the pros?

I keep my tips tinned nicely if it helps.

Thanks,

d.

some more info would be good.. WHY cant you solder the wire to the stars??
what wattage is your soldering iron?? i think the minimum reccomended is 40w, because if it cant get hot enough fast enough then the heatsink will just drain the heat from the iron and then some.. i bought a CHEAP 40w and struggled to keep the heat still..

nd incase you didnt know you have to heat the "pads" on the star hot enough for the solder to stick otherwise it will just pop off..

Soldering link

I have to learn this as well I think this link shows how to tin the wire and gives an entirely irrelevant discussion toward the end.

Tinning the wire and the pad is important. Using good solder is too. A good 60/40 rosin core solder is a must. Don't try using the lead free, silver bearing, or low temp solders as they are garbage.

The guides online make it look pretty easy, and for wires it really is. Once you get to something that can pull a ton of heat away really quickly, it gets harder. The right equipment is important here. Higher wattage irons are important (this is not a measure of the tip temperature) so you can basically overpower the heatsinking effect. The quicker you can get the pad up to temp, the less chance of damaging the LED from excessive heat. Like it has been mentioned before, 40W should be the minimum you should be looking for. If you can afford more, go for it. I use an 80W temperature controlled Weller solder station, and even then it can be tough.

Do you have any endorsements for irons that might be even easier than yours? I think my timetable to get to soldering LEDs is about 6 weeks.

Well, my soldering station costs $350, so I don't know how much better you want to get

If you want a quality iron that will last and be very useful for a variety of things, including LED work, then try this. It's 40W, but adjustable and comes with a nice stand. It can usually be found for under $60.

This one is a little better as it's 50W and temperature controlled, but goes for about $85

thanks for the reply guys.

i have a 40 W Weller. I changed to a slightly larger tip and let the iron get really hot, tinning as it heated up, then put a dollop of solder on each pad i wanted to connect to.
Then put a pre-tinned wire end on the solder bead, heated the solder quickly and let the wire get sucked in. Sometimes I had to gently close the bead over the wire with my iron as I pulled it away.

Hopefully this might help other newbs, and I'm certain the experts around will correct if I'm wrong.
At each soldered pad, a tiny area around the pad looked a little discolored; I though maybe that was the rosin? Is it?

Thanks

d.

Lol, I found a dual-wattage Weller at our shop the other day, 140/100W. Looks like I'm good for that when it comes time.


Anyhow, a quick question on heatsinks. I have a 2" wide, 24" long heatsink I got as a piece of drop from heatsinkusa.com



How many LED's would this heatsink safely handle without worrying about fans?

Thanks!

Matt

Maybe 8-10 without needing a fan, but that's with the heatsink in open air. If it's in a hood, more like 6.

Looking to start an LED build and I am pricing out LEDs. I seem to remember someone giving a good reason not to buy the Cree XR-E Q5 from DealExtreme but can't seem to find the post. Can anyone see a downside for buying the following:

Cree XR-E Q5 WG - http://www.dealextreme.com/details.dx/sku.2394

Most people seem to be buying from ETG instead, is there a reason?

If I remember the DealExtreme ones are not as good of a star but if the price is good enough....
Also, They were not always the Q5 WGs there.

Thanks. I think you are right, I am pretty sure they weren't WGs.

As for the R2s, it looks they give you a 10% increase in lumen for about 20% more $. Any good reason to go for the R2s over the Q5s.

There is no good reason not to. Only thing I don't like about them is they have a bit of a green tint compared to Q5s.

I've got alot of reading to do on this thread - but one quick question that will gauge how much I want to read on this topic of L.E.D. lighting.

How do they compare in terms of heat ouput ( in terms of creating heat in a room ).

If T5 is on the cooler end - and Halogens are on the hot side in terms of Aquarium lighting - Where on this spectrum would a comparable the L.E.D. lighting system fall. Right now - I can't even consider a Halogen for an aquarium - b/c the room I'd be putting it - is already warm to begin with.

Thanks

Well, you get the intense light of the Halide/Halogen, but less heat than the T5. At least from what I can tell by my system and experience.

Sorry if I am too late to add my two pence worth, did you say you have your LEDs already mounted on heatsink? Well this would be your first problem when trying to solder while fasten on to your main heatsink, the heatsink would take a lots of heat away from your soldering point. My suggestion would be to unfasten your LEDs from the main heatsink and then solder them with good quality heat gun... good luck

So, I wanted to post the 2 layouts I came up with for my 48"L x 24"W x 18"T. I think I prefer the offset layout, but wouldn't mind some comments/critique/advice. The 2 rectangles around the LEDs are different size heatsinks. Thanks!

What are most people using for pot knobs? Is there a specific "size" I'm looking for for the buckpuck with wired in pot? I assume most people just pick them up from Radio Shack but just want to double check the size before I head out.

I think either one will work for you. The offset layout can minimize the spotlight effect in some instances, especially when tight optics are used.


Radioshack won't have knobs that small. All they have are 1/4" shaft ones. I can't remember if the pots are 1/8" or 5/32", but you will have to find them online.

Hi Evil,

Whilst trawling thru various suppliers in the UK I came accross a new part number not listed in the current Cree datasheet.

Part is a Cool white XRE - XREWHT-L1-0000-00E01, 5000k 114 lumens at 350mA, not available for purchase until early 2010 (I assume Q6, as Q4 is 100lumens & Q5 107lumens).

Any thoughts? Do we need any brighter than the Q5?

I have heard rumblings of an updated XR-E coming through. Most of the attention is on the XP-G right now. Sounds more like a neutral white R2 more than anything with the color temp at 5000K.

Do we need it? Not really, for two reasons. First, it's neutral white. A bit too yellow for most tastes, even with royal blues to back it up. Second, Q5 cool whites are plenty bright. There is nothing stopping you from going with brighter. It's just that for most applications, you would just have to turn them down further.

I pick up a pack of these http://www.radioshack.com/product/index.js...amp;tab=summary and a pack of the plug type as well. My question is, when you unscrew them, there a 2 posts, a short one in the center, and a longer one towards the outside. I'm assuming the smaller one is intended for the positive wire?

Center positive, outside ground.

Can 3 buckbucks be wired to 1 potmeter? and how?

You would think after reading through all the posts that I would know the answer to this... but I'm still trying to figure a few things out...

When discussing the CREE XR-E Q5 Cool White LEDs... we also talk about "Bin". I've seen "Q5" called the bin, but I've also seen "WG" used to describe the bin. So I'm totally confused. When I looked up the part number, I thought I had the right part: XREWHT-L1-0000-00D02, but then I seen someone else parts list, and they had XREWHT-L1-0000-C01. Could someone help clarify this for me? If I were to order a specific part number, do I have to specify bin as well?

With regards to Optics, I went to ledsupplys website, and found the CREE XR-E optics, but I did not see anything to indicate they had various degrees of optics (i.e., 40, 60, 80, etc.). So I'm wondering if I was looking at the wrong parts. I was potentially getting 80 degree optics.

I'm just trying to get a solid parts list together so when I get ready to place my order, there's no confusion.

Thanks for your continued help and advice!

You're right. There are two bins. A lumen/brightness bin (the Q5, etc...), and the tint bin (WG etc...). Most of the time, you don't get to chose the tint bin, unless you order from Cutter. Most of the stores that stock cool white LEDs stock the WG bin as they are the most common tint. Works well for us too at 6300K. Nice and bright and a good warm tone once you couple them with royal blue LEDs.

LED Supply doesn't stock all the angles available from Cree. You can get them from other sources though, including Cutter, ETG, and Nanotuners.

Quick question for anyone--

I know the Royal blues are 450nm (in the XRE's at least, I assume all Royals are 450).


Are there any lower wavelength spectrums available that can be wired in series with the Cree XRE's driven by a buckpuck or meanwell? Something that might be in the 420nm wavelength, like our beloved "03 Actinic"?

I realize they may put out less PAR but if they make color pop, so much the better!

There isn't much between that and UV. The lowest high power LED I have found bottoms out at a peak wavelength of 440nm. You can find some UV LEDs that go up to about 410nm. The royal blue LED produces a very wide range of fluorescence though.

Cool, I have seen the pics you posted about the Sunpod actinics, and they look cool. I was hoping to get the violet color as well.


If only KZ would make a "Fiji Purple" LED and UVL would make a "Super Actinic" LED, I'd be some-kinda happy.

Wouldn't that just be the best. "Designer LEDs from UVL, KZ, ATI, and Geissmann."

Hmm.

How about this critter. Puts out between 415 and 445. And if I read this right, this is an 8 watt LED? (oh btw it's $120 USD according to their price sheet )
http://www.roithner-laser.com/All_Datashee...ED430-66-60.pdf

Main page below. To find the LED in the pdf above, just "edit:find: 430" should put you right on it.
http://www.roithner-laser.com/LED_HP_multi_chip.html

Got it. So it sounds like we don't concern ourselves much with the tint bin? Or do most people still try to ensure they are getting WG?

Don't really want to hijack too much, but as I don't have too much electrical experience but am interested in an LED option for my bc14 I thought I'd ask Evil... I just saw the new (?) Nanocustoms 3.6 LED retro kit on their website and wondered about it. Worth the price? Quality? LED quality? Etc...?

Once again, sorry about the hijack...

Super low output. It's only 14mW @ 240mA. A Cree royal blue is 375mW @ 350mA. Ridiculous pricetag too. Just wait till you start looking at short wavelength UV LEDs. That's a truely rediculous pricetag.


It's still nice to know that you are getting what you want. Most vendors do state it pretty clearly.


It's all dependant on what you want to get out of the kit. You can't get the adjustablility with the kit like you would for a DIY setup. It's down to the patent laws involved around LED lighting that it can't be offered with dimmable drivers. It is a quality peice of kit, and will save you a lot of time and effort.

A little tip about the HeatsinkUSA heatsinks...
If you've ordered one you know they are not exactly the best looking. You can get a brushed metal look by taking a scotch brite pad and using the green side and just scrubbing it in one direction. It will get a nice look.

Just finished and setup my build today.. love it! I'll take pictures and add it to the comprehensive list later

Evil, I stopped using NR and RC about 2-3 years ago. I've reluctantly come back to seek info on current trends. Im not a fan of thread hijacking, but Im going to commit that sin right now by telling you im very impressed. You are a helpful individual who backs up his statements with actual info. You respond to members with uncanny timing and good, sound advice. This hobby is lucky to have you bring your experience to the table. Im back, and things look bright for NR. Sorry this post is off topic, i was blown away.

not to worry Tank. a lot of us are and it is always good to see that people do appreciate the help of others and stop to thank them. i too was in the same situation as you and just wish i could could help as much but everything counts