DIY LEDs - The write-up

[NanoReefWanabe]

thanx guys i will just get 2 of the 24V wallwarts then and be done with it...i assume there is no difference having +2V or +6V over what i need...off to the lovely world of online purchasing i go...

 

[der_wille_zur_macht]

<a href=showthread.php?s=&postid=15170757#post15170757 target=_blank>Originally posted</a> by NanoReefWanabe
i assume there is no difference having +2V or +6V over what i need...

Only a few percent efficiency.

 

[james3370]

when ordering the wall warts from that ebay seller, be prepaired to wait....they come on a slow boat from hong kong.....think mine took about 1.5-2 weeks to get here

 

[der_wille_zur_macht]

More thoughts about drivers. Can someone justify why buck drivers are overwhelmingly more common?

I'm looking at application notes for some ICs that can be run in buck or boost topology (i.e. the On Semi NCP3065) and it looks like efficiency is a few percent higher in boost mode, plus there are actually fewer external components required (so it would be cheaper/easier to make.)

 

[dtech]

From what I gather it is that they are easier to wire up, they are readily available, they are reliable, and don't cost much for what you get. I just recieved mine (10 1000ma dimable pucks) a couple of days ago now I need about $200 more saved up and I can get the led's then start wiring it all up.

 

[NanoReefWanabe]

are you guys using any sort of liquid electrical tape or anything on the solder connections on the front of these stars to prevent corrosion since the surface of the LED is exposed to salty air?

or how are you preventing the salty air from being a problem...

 

[timmmysli]

<a href=showthread.php?s=&postid=15171425#post15171425 target=_blank>Originally posted</a> by james3370
when ordering the wall warts from that ebay seller, be prepaired to wait....they come on a slow boat from hong kong.....think mine took about 1.5-2 weeks to get here

I ordered my cree xre's from hong kong and had to wait nearly 1 month but I got them for $7.50AU each delivered so it was worth the wait

NanoReefWanabe,

I've used the liquid electrical tape, just make sure you shake the tube up before using it otherwise it runs. I've also used a thin plastic film to protect the leds.

 

[Iwishihadgills]

So im getting 100 leds from from china. I will have
50 white
25 blue
10 red
10green
and 5 yellow

these are all 3 watt and 750 mA /3W/25-30lm.

How would i go about powering these babies?

 

[timmmysli]

Have you already paid for them?

cree xr-e leds at 3.7watt output over 200lm.

 

[der_wille_zur_macht]

<a href=showthread.php?s=&postid=15173535#post15173535 target=_blank>Originally posted</a> by Iwishihadgills

these are all 3 watt and 750 mA /3W/25-30lm.

I'd be interested to see the spec for each color, since typically they are vastly different. Some of the highest-performance colored LEDs aren't putting out much more than what you are quoting, but high performance white LEDs should be like six or eight times the lumens.

How would i go about powering these babies?

The typical approach in this thread for large arrays is to split the LEDs into strings of 6, then wire them in series to buckpucks at the chosen current output (700mA, for instance.)

Then, determine the forward voltage of a string when powered at that current. Typically it's 3.4 - 3.7 v per LED, but you really need to look at the datasheets for the model and bin you're using. Let's assume 3.5v/LED. Each string will have 21v drop. You need to power the buckpuck with a DC supply that has at least 2v more than the string of LEDs. In this example, that means each buckpuck needs to see 23v. 24v supplies are easy to get, so it would make a good choice.

You can wire multiple buckpucks to the same power supply, in parallel, if you do not exceed the rated current capacity of the power supply. Let's assume you have 6A supplies. You can run 8 buckpucks off each supply.

So, to power your 100 LEDs, you need to break it into strings of six. That's 17 strings. If you are doing 8 pucks off each power supply, you need just over two power supplies. You could buy two of the 6A supplies and one smaller one (1A for instance.)

A more flexible approach would be to do strings by color, so you can dim and contol them independantly (get dimmable buckpucks if you want to do this.) Unfortunately, your counts of each color are not in nice round multiples of 6, so if you go this route, you'll either lose efficiency (you'll have several pucks running less than 6) or you'll have to mix colors. You could break it down as follows:

1 puck of: 5 yellows, 1 white
2 pucks of: 5 greens, 1 white
2 pucks of: 5 reds, 1 white
4 pucks of: 6 blues
7 pucks of: 6 whites
1 puck of: 3 whites, 1 blue

Or, less efficiency but more color control:

8 pucks of: 6 white
4 pucks of: 6 blue
2 pucks of: 5 green
2 pucks of: 5 red
1 puck of: 5 yellows
1 puck of: 2 blue, 1 white (or just leave these three as spare parts)

Then, if you want to be able to turn each color on and off individually, each color needs to be on it's own power supply, or you need to use relays to switch downstream of the supply.

At any rate, the specs you gave aren't complete (we need to know the forward voltage of each LED at the current you plan on using) but, in a rough sense, you're looking at 17 - 18 buckpucks, and 3 - 5 power supplies. The buckpucks are $15 - $20 (from ledsupply) depending on which model you pick, and power supplies should be $15/ea (from MPJA). So the cost to power your LEDs should be $300 - $400.

Then you need heat sinks. . . And some optics. . .

 

[der_wille_zur_macht]

Other than what has been posted or described in this thread, does anyone know of or have any design tools for working out the details of LED rigs?

I'm working on a spreadsheet to help answer questions like the the one I just attempted to answer (I have X, how can I use LEDs? or, How many LEDs do I need? or, How do I power these things?) and would love to see anything other people have or are using.

 

[CJerome21]

I am finished my builds but I just noticed another group buy is open on nano reef for CREE LEDs and lenses (80, 60, 40, 25, and 8 degree) I know some of you were looking for those.
Note I am not involved with the group buy nor do I know the organizer.

Lenses are also available direct from ETG Corp(Where the group buy is being done from I believe) there is never a discount on lenses, they are always $1 each. I am not sure what the minimum order is but most of you are building for big tanks so it should not be a problem. My order from them was 38 LEDs 12 lenses.

 

[shackscs]

Thanks to this great thread I have been able to fully rework and create new boards for my Solaris fixture.

I am having a problem with locating this connector:

Any one have an idea what it would be called or where I can get it from? It is a four wire connector that plugs into a four wire receiver.

Yes, I have tried to google search everything I could come up with but I can not locate it.

Thanks

 

[kcress]

There's always Digikey.

 

[shackscs]

Thanks...Chatting with them now.

 

[Iwishihadgills]

<a href=showthread.php?s=&postid=15173604#post15173604 target=_blank>Originally posted</a> by timmmysli
Have you already paid for them?

cree xr-e leds at 3.7watt output over 200lm.

No not yet but i can get 5 of these for $13 instead of like $8 for one.

What do you think about that? Are they gonna be good enough?

 

[Iwishihadgills]

At any rate, the specs you gave aren't complete (we need to know the forward voltage of each LED at the current you plan on using) but, in a rough sense, you're looking at 17 - 18 buckpucks, and 3 - 5 power supplies. The buckpucks are $15 - $20 (from ledsupply) depending on which model you pick, and power supplies should be $15/ea (from MPJA). So the cost to power your LEDs should be $300 - $400.

Then you need heat sinks. . . And some optics. . . [/B]

Um i might rethink this whole led idea lol Are they really worth it over metal halides? Cause right now they are seeming a lot more pricey.


Also is that enough to light up a 24" deep tank that i plan to grow sps under?

Thanks for your time

 

[der_wille_zur_macht]

Depends on what you mean by "worth it." The upfront cost is surely more than halides done on the cheap, but consider this - at their standard lifetime rating and being run 8 - 10 hours a day, LEDs will last 10 - 15 years. Over that 10 - 15 year period, you will have spent hundreds or thousands on replacing MH bulbs, plus hundreds or thousands more in electricity to power the MH vs. the LEDs, for roughly the same result in terms of light getting to your corals.

I'm sure others can chime in here, but if we took a standard example (say, a 4' 120g tank) and assumed a 10 year lifetime, I bet the difference in upfront cost between LED and MH would be offset within the first 3 or 4 years, and the lifetime cost to own MH would be close to double that of the LEDs.

 

[dtech]

Cost savings will be seen over a time period, as the led's won't need replaced for a long time(unless a failure), and the savings in your electric bill. There also is not the heat issue that halides push into your tank so a savings on chillers or extra fans and such. They will work over a 24 deep tank even deeper depths, but you will most likeky need to run optics on them. Also the led setups can be tuned to a greater level that halides can't.

 

[fernandokng]

What i love about these LEDs so far is the heat management. Growth is hard to measure as it is also dependent on flow, water quality, etc. So far, I can see my corals starting to color up, and I think again, it's the blue Crees

Every time I used to turn on my halides, my tank would go up 3-4 degrees. Now, they don't go up at all. I love it, and I won't have to buy a chiller.