DIY LEDs - The write-up

[stugray]

Drake1,

"what is an appropriate value? i have never seen a pot used for a current limit. how could you measure amps to adjust it, wouldn't you need a device attacted to it drawing wattage to get the amprage output? or are you talking about voltage? please explain more"


The "Pot" in this case is a trim-pot inside the constant current driver.
It sets the "set-point" for the driver to control the current to.

With my LED setups, I use tyco quick-disconnect ballast plugs. You can find them at HD with the wirenuts.

When I first hook up a driver, I have a little "harness" made of these quick-disconnects that run the current through my DMM.
I turn DOWN the current pot, plug in the LEDs, then adjust UP to about 700mA ( 0.7A ).

Then I shut it off, remove my measuring tool & plug the plug back in & it works.

Stu

 

[kcress]

That's a nice technique Stu. Have to remember that. :thumbsup:

 

[Drake1]

ok that makes sense, thanks stugray. looks like i have a use for that wattmeter i use on my rc planes

 

[Neogenocide]

ok that makes sense, thanks stugray. looks like i have a use for that wattmeter i use on my rc planes

Hmmm....I never thought of that. It should give you voltage + amperage. I may have to give that a try. Good thing I used Deans connectors for a quick disconnect when I wired mine up. lol


Scott

 

[g8gxp]

Stu

can you post up a brief pic of how you do the internal pot adjustment with your homemade harness?

 

[JACOXVIII]

ok have read so much I'm a little lost
I have a 155 bow front most zoas /softies some lps
what is my option in leds to light the tank
i would like to do it in 3 section so i can build one at a time
i like the 20k look
right now i use 3 250 20k reeflux 2 spider 1 LB lumen brite

 

[WmTasker]

ok have read so much I'm a little lost
I have a 155 bow front most zoas /softies some lps
what is my option in leds to light the tank
i would like to do it in 3 section so i can build one at a time
i like the 20k look
right now i use 3 250 20k reeflux 2 spider 1 LB lumen brite

If you are just wanting to keep you current corals, you can go with about 2 watts per gallon. That would be 36 LEDs over each section. 18 white, 18 blue, 3 Meanwell drivers. This will give you a total of 324 watts or 2.1 watts/gallon for 108 LEDs total. If you want to keep SPS and some higher light required corals, I would go closer to 3 watts per gallon. This would be 48 LEDs above each section. 24 blue, 24 white, and 4 Meanwell drivers. This setup up will give you 432 watts or 2.8 watts/gallon forr 144 total LEDs.

An advantage to using the 48 LED layout is you can put dimmers on the drivers and turn them down to keep your current coral. If you ever decide to get sps or something else you can just turn the lights up with the dimmer.

Just my 2 cents.

 

[perikaruppan]

Hi,
can these High Power LED's be used instead of CREE? they seem very economical and when enquired they say that their power rating and output's are similar to that of CREE.

http://www.hyledchina.com/High-Power-LED/New-Structure-RGB.html

Since in India, we are unable to get the CREE/luxeon LED, thought of getting these, they are around 2-3$ a piece!

 

[Drake1]

If you are just wanting to keep you current corals, you can go with about 2 watts per gallon. That would be 36 LEDs over each section. 18 white, 18 blue, 3 Meanwell drivers. This will give you a total of 324 watts or 2.1 watts/gallon for 108 LEDs total. If you want to keep SPS and some higher light required corals, I would go closer to 3 watts per gallon. This would be 48 LEDs above each section. 24 blue, 24 white, and 4 Meanwell drivers. This setup up will give you 432 watts or 2.8 watts/gallon forr 144 total LEDs.

An advantage to using the 48 LED layout is you can put dimmers on the drivers and turn them down to keep your current coral. If you ever decide to get sps or something else you can just turn the lights up with the dimmer.

Just my 2 cents.

this seems like alot of lights for an lps tank i would say 80 leds with 60 degree lenses

 

[WmTasker]

Hi,
can these High Power LED's be used instead of CREE? they seem very economical and when enquired they say that their power rating and output's are similar to that of CREE.

http://www.hyledchina.com/High-Power-LED/New-Structure-RGB.html

Since in India, we are unable to get the CREE/luxeon LED, thought of getting these, they are around 2-3$ a piece!

Someone needs to figure out how to wire these 50 watt LEDs.

http://www.hyledchina.com/High-Power-LED/50W-High-Power-LED.html

 

[WmTasker]

this seems like alot of lights for an lps tank i would say 80 leds with 60 degree lenses

I haven't used lenses yet, but I've read that they cause to much light on corals at the top of the reef due to the way the optics focus the light.

 

[perikaruppan]

can i use these LEDs from china with Meanwell/Buckpack 700ma Drivers? i have a 5X2.25X2(height) tank... as per the general norms (since i am interested in an SPS/LPS high to medium requirement) and the tank being 1620Sqinches and taking about 12 square inches per LED, i require 135 LEDS (132 to get 11 meanwell drivers) ... is this correct? or can i reduce the LEDs?

since i am looking at a color temperature of about 14k, would 1/3W and 2/3Blue do the job?

all these with the current Chinese LED's.

 

[kcress]

can i use these LEDs from china with Meanwell/Buckpack 700ma Drivers? i have a 5X2.25X2(height) tank... as per the general norms (since i am interested in an SPS/LPS high to medium requirement) and the tank being 1620Sqinches and taking about 12 square inches per LED, i require 135 LEDS (132 to get 11 meanwell drivers) ... is this correct? or can i reduce the LEDs?

since i am looking at a color temperature of about 14k, would 1/3W and 2/3Blue do the job?

all these with the current Chinese LED's.

I'm not seeing any that are white...

 

[widmer]

I wonder why the red LEDs I see all are around 620 nm rather than the 660 which is optimal for terrestrial plant growth...

 

[perikaruppan]

the whites are here
http://www.hyledchina.com/High-Power-LED/LED-with-PCB.html

Peri

 

[der_wille_zur_macht]

I haven't used lenses yet, but I've read that they cause to much light on corals at the top of the reef due to the way the optics focus the light.

Check out the build I linked to (in the regular old Reef forum) a page or two ago - I forget the username, but someone did some PAR tests with and without optics. The differences (especially up close) are pretty shocking. IMHO optics shouldn't be played with casually. It can make more difference than switching from 350mA to 700mA drive current at some distances.

I wonder why the red LEDs I see all are around 620 nm rather than the 660 which is optimal for terrestrial plant growth...

Probably a matter of they make a color that's possible to make with the materials available, rather than being able to make the exact color they want. If that makes sense. . .

 

[widmer]

I just made a similar comment in the LED thread going over at reef discussion, thought I would put it here too...

I just got in some Cree LEDs and 6-degree optics from LEDSupply and I was playing around with them last night. I found that it casts a nice 12-inch diameter circle at 6 feet distance with a little but not too much spill/artifacts.

I'm finally putting the idea to work that you may find like 40 pages back in this thread, about simply mounting a fixture on the ceiling and beaming the light down into the tank with the right optics for a serious clutter-free rimless experience. So hopefully I'll have it up and running in the next couple weeks here and I'll keep you guys posted with the results.

 

[L98-Z]

I just made a similar comment in the LED thread going over at reef discussion, thought I would put it here too...

I just got in some Cree LEDs and 6-degree optics from LEDSupply and I was playing around with them last night. I found that it casts a nice 12-inch diameter circle at 6 feet distance with a little but not too much spill/artifacts.

I'm finally putting the idea to work that you may find like 40 pages back in this thread, about simply mounting a fixture on the ceiling and beaming the light down into the tank with the right optics for a serious clutter-free rimless experience. So hopefully I'll have it up and running in the next couple weeks here and I'll keep you guys posted with the results.

I wonder how much light is lost over that 6 foot of distance though. Does sound interesting.

 

[widmer]

I wonder how much light is lost over that 6 foot of distance though. Does sound interesting.

If there were no optics then certainly the huge majority of the light would be spilling out into the room. However, we can take advantage of the fact that LEDs are a point-source light, and use a lens to concentrate virtually all of the light produced into a beam however narrow we like.

I'm willing to conjecture that bringing them up high off of the aquarium and projecting a tight beam will actually increase the total light going into the tank, based on the fact that less of it will be coming in at a wide angle that causes much of it to reflect off of the water.

All that is left then is particulate matter in the air that might be blocking light. However, I'm also willing to conjecture that this is extremely negligible in six feet of air...

Hopefully I'll have a working model in the next couple of weeks...

 

[L98-Z]

If there were no optics then certainly the huge majority of the light would be spilling out into the room. However, we can take advantage of the fact that LEDs are a point-source light, and use a lens to concentrate virtually all of the light produced into a beam however narrow we like.

I'm willing to conjecture that bringing them up high off of the aquarium and projecting a tight beam will actually increase the total light going into the tank, based on the fact that less of it will be coming in at a wide angle that causes much of it to reflect off of the water.

All that is left then is particulate matter in the air that might be blocking light. However, I'm also willing to conjecture that this is extremely negligible in six feet of air...

Hopefully I'll have a working model in the next couple of weeks...

I'd still expect the 6' of air to have more than an extremely negligible effect, but I'm certainly interested in seeing this. I realize optics are obviously going to concentrate it, and you could even use 40 degrees, but you're also pulling the light source further from the desired destination.

I look forward to seeing your results.