DIY LEDs - The write-up

[der_wille_zur_macht]

Excellent writeup again Fishman. Only thing I would change would be to add links to the LED results and reference thread and the Have you done a "different" LED build? thread. I'm hoping these two threads can take off as practical references to what people have done, in addition to the "theory" you outlined so well - combined, it should help people get ideas about what works/doesn't work and so on.

 

[TheFishMan65]

I will add them now and they will be in the next post. I would guess about page 220-225.

 

[DustinB]

Ok I'll drop the whole idea of using a PC power supply to run the led's. By the way, thank you FishMan, you're summaries make like so much easier!
I'm just confused on one thing. I would like to make my own drivers and from the reading it is not recommended to run multiple strings from one driver. But running multiple drivers from one power supply is ok. Right?

Do anyone know of a good website/book/video for electronics 101 or circuit boards 101? =P

I wouldn't necessarily drop the idea of using a PC power supply under certain conditions if the application allows. ie: using a custom driver at 24v. Especially if you have one laying around and want to save some money.

You can take the +12v and use the -12v as ground. This will give you a 24v regulated supply. Unless someone sees a problem with this?

Just be very careful modding the PSU. Some of the capacitors may still have a good enough charge to hurt or possibly even kill you.

 

[der_wille_zur_macht]

Most computer PSUs have a very small current limit on the -12v rail (i.e. if it's got 25A on +12v, it might only have half an amp on -12v).

The only time I can really see using a computer PSU would be if you have one laying around for free, and you're doing a smallish build and only want a few LEDs on each string anyways (i.e. a situation where 12v is preferable to 24v). Otherwise, the $15 for a common POTRANS 6.5A 24v supply, or maybe a few bucks less for a lower-current 24v wall wart, is going to put you in a better position functionally and isn't really going to break the bank.

 

[TheFishMan65]

I just noticed on the cutter site that XR series is not recommended for new designs. IMHO their site is hard to navigate (of course I don't use it often so it could be the operator) so I might have been in the wrong area. BUT has any one else heard anything about this?

 

[der_wille_zur_macht]

XR are very old in terms of HP LEDs. As far as I know Cree is shutting down production as they're getting really hard to find. I bet the XR-C and XR-E are not far behind (maybe within the next year) as they're getting old, too. Probably won't impact our hobby much as I'm not aware of anyone using XR LEDs.

 

[TheFishMan65]

Ok, I see the difference I meant XR-E, but I can't seem to find them in royal blue (or any color but green). So I did a search that only listed the XR series and my confusion. Anyone know how to find things on their site?

 

[onetrickpony]

der_wille_zur_macht

What do you think of these LEDs
http://www.satisled.com/Wholesale-3w-power-led_c19

 

[der_wille_zur_macht]

Luck. :lol:

Here's the main Cree page, where you can pick a model:

http://www.cutter.com.au/categories.php?cat=Cree+LEDS

The real frustrating part is once you're on the page for a model, you get all sorts of products mushed together - optics, bare LEDs, mounted LEDs, white LEDs, colored LEDs, and so on. Sometimes you have to dig through popup menus to actually "select" a certain product.

Adding to the confusion, Cutter doesn't stock many XR-E colors, they seem to prefer XP-E - which is fine for most people as they're pretty interchangeable. The

 

[der_wille_zur_macht]

der_wille_zur_macht

What do you think of these LEDs
http://www.satisled.com/Wholesale-3w-power-led_c19

Same as any other vaguely unknown china-special bargain HP LED. Will it light up a fish tank? Sure, definitely. Will it "perform" as well as the LEDs most commonly used? Depends on your definition of "perform" but generally the answer is a big huge "no."

If you don't care about efficiency, or just want to fool around with some cheap LEDs, by all means those are fine. If you're trying to eek every last drop of performance out of a rig that will be run longterm on a reef tank, you might want to look elsewhere.

 

[EdsterG]

I wouldn't necessarily drop the idea of using a PC power supply under certain conditions if the application allows. ie: using a custom driver at 24v. Especially if you have one laying around and want to save some money.

You can take the +12v and use the -12v as ground. This will give you a 24v regulated supply. Unless someone sees a problem with this?

Just be very careful modding the PSU. Some of the capacitors may still have a good enough charge to hurt or possibly even kill you.

That was a good idea, but DWZM is right. I checked, and most (if not all) PC PSU's have no more than 1A on the -12v line.

 

[DustinB]

Yeah, I never thought to check about the -12v. Maybe that's why they put that little "+" in there when they mention the +12v rating. That POTRANS supply is looking pretty good. $16 anywhere you go. Anyone noticed any caps or regulators failing early in them?

 

[czinn]

This is a question out of curiosity why does every one mainly use the royal blue leds that hits Photosynthetically Usable Radiation (PUR) wavelength of 450-465nm when coral pull form 400 to 550nm. The Cree XR-E blue hit 465-485nm and the Cree XR-E green hit 520-535. If I remember right Mh’s hit 450 to 530. So is there a reason why only a small band is targeted by the led fixtures and by the diy builds.

 

[widmer]

Excellent write-up Fishman, and good idea to put it on p200 which is easy to remember to direct people toward. Oh, and I'm honored to be included as a link

 

[TheFishMan65]

czinn, I don't believe there is particular reason some people are trying other color. The first one looked good and most have copied it. If you go two far away from the deep blue you loose some of the actinic glow is the only reason I can point to.

widmer - I think you have been there from day one

 

[der_wille_zur_macht]

This is a question out of curiosity why does every one mainly use the royal blue leds that hits Photosynthetically Usable Radiation (PUR) wavelength of 450-465nm when coral pull form 400 to 550nm. The Cree XR-E blue hit 465-485nm and the Cree XR-E green hit 520-535. If I remember right Mh's hit 450 to 530. So is there a reason why only a small band is targeted by the led fixtures and by the diy builds.

Partially what looks good, and partially tradition. Using royal blues along with whites mimics the common reefkeeping practice of blending actinic fluorescents with full spectrum MH lamps.

It's important to not get too wrapped up in the color numbers unless you're dead sure of your goals. For instance, just because PUR covers a certain range of wavelengths doesn't mean it's required or even desirable to have equal intensity across that whole range. Much of this is driven by hobbyists' personal preferences, which are often driven as much by visual appearance as by a desire for optimal growth. Since neither of those goals are things we can reliably define in simple terms, for all tanks/corals/environments, there's always going to be some variability in what different people think is optimal. But IMHO it's at least as important to base your choices on what's known to work and your own personal impressions vs. trying to use some formula or series of numbers to tell you which LEDs to use.

 

[skippyreef]

Sammy could you describes your build in detail such as LED type, LED ratio, LED spacing, LED group Spacing, optics, tank dimension ,etc)?

Is the color White/blue merge or you have a checkboard effect?

I also want to know if you can see good grow on your SPS?

Thanks!

What arethe deminsions of your heat sinks and is your 125 72*18??? I am taking down a 270 and going to a 60*24*20 125 rimless and like your lay out a lot. So I am asking for some pointers.

Mike

 

[thewire]

I got some at cost, and some pretty close to cost due to a group buy. Can't tell you who I bought them from because I received a massive discount due to the amount I ordered, a blotched group buy, and a military discount.

Hook a brother up....mind sell some to me No question ask

 

[SquidHC]

If I got the kits from RapidLED, the 48 bulb ones, how many of those would I need to light a 48x30x24? Also, since I can cut wire myself, and don't need the optics (I think), would it be cheaper to just buy all the pieces seperate? Also is this a dimmable deal?

 

[TheFishMan65]

You would probably want 1.5-2 sets. IIRC they use the LPC not the ELN so they are not dimmable. I expect the pieces (not kit) would be cheaper, but of course more hastle. Contact Anna at ETG and see what prices are running. In July RB XR-E where $5 for 10 plus.