DIY 120g Led Lightning Project - some help needed.

VeL · 09/19/2011, 05:47 AM

Greetings.
First of all I want to say how great the forum is and how friendy the people here are. Reading the DIY Led threads made me taking the course of building my own led lightning, even though I am quite electronics dummy. Also I want to thank brassmonkyballs and nuclearheli who helped me a lot to decide what I need for this project. Anyhow, here is some information, prior to my questions:

The tank dimensions are - 130cm/60cm/60cm or around 50"/ 24" / 24".
I plan on growing all kind of corals so I decided to go with higher led count. So I ended up with this setup:

96x Total Cree LEDs & 2x 660nm Reds

1x HLG-185H-42B (4.4A)
36x Whites XP-G
4 Strings - 9 CW / 9x NW / 9x CW/ 9x NW
Running at 1100 mA (will be dimmed of course)

1x HLG-185H-42B (4.4A)
50x Royal Blues XP-E
5x Strings - 10x RB each string
Running at 880 mA (will be dimmed of course)

1x ELN-60-48D
Series - 10x Blue XP-E , 2x Red (660nm)
at 800 mA

In order to avoid spotlight and in order to get more coverage, and after I read about "FWHM - Full Width Half Maximum" I decided to go with 80 degree optics.

It may sound stupid but after ordering all the supplies, now I am unsure how to ...... place the leds. The point is to get good penetration, good coverage and to consider the FWHM (meaning that the optics focus at full power only to the first 50%, or 40 degrees in my case with 80 degree optics).
I know that the recommended spacing is like 2 inches between the leds. If I do the math though, in order to cover 50"x24" ill need 300 leds, which doesn't sound right.
So any help on that matter will be greatly appreciated. I need to decide how long & wide the fixture should be, how many leds per row and what spacing between them, and how high above the water level is the best in order to get good penetration and coverage with 80 degree optics. My appologies if this has already been explained somewhere but at least I could not find any information about it. Thanks in advance!

5pacey · 09/19/2011, 08:31 AM

Well... when you come up w/300 LEDs are you assuming that the fixture/heatsink will cover the top completely - IOW, will be 50"x24"? If that is so you should be able to significanly reduce that. For example, I built a fixture w/24 XRE's (CW/RB even split) over a BC29 tank. Rougly 18" deep and 18x20 footprint. The actual heatsing/fixture size was 6"x12". I too got the 80deg optics thinking I'll need them but in the end I ended up not using them beause the fixture was only 2-3" above water. Got great PAR, no spotlighting but I did get color separation.

Spacey

5pacey · 09/19/2011, 08:37 AM

Based on my experience, in your case you should be able to get away w/well under 100 LEDs. For example I am building a 90 now... standard american size is 48w x 18d x 24h... given a good fixture (good LED placement and colors) I can probably cover it w/24 LEDs for each 24" of the tank width, particularly w/lenses, and would most certainly be more than well covered w/36 LEDs for each 24" of tank width.

Your tank is rougly 2" wider and 6" deeper so roughly what would be a 120g in the US (48x24x24)... you can probably do 36-48 to be have power to spare. So 72 to 96 LEDs. I assume Cree XRE's or XP-e/XP-g's...

My $0.02,

Spacey

VeL · 09/19/2011, 02:10 PM

5pacey, thank you for your comment!
I however know what and how many leds I need and I already purchased them

The problem is that I am not sure how I should place them in order to get the best of them. I do not want to guess what will be a good placing, I need to *know* and why I am doing it in a certain way.
I was thinking to have 4 bars with 24 leds each bar, placed equally over the tank, however that means the led stars would be right next to each other and I am not sure if that will affect the coverage somehow. I see that many people make the led bars with at least 2" spacing between each led. Maybe I should make 5-6 bars instead with lower leds count on each one? So again it is for 50/24/24 tank, 94 leds, 80 degree optics.

VeL · 09/20/2011, 08:05 AM

Any suggestions will be greatly appreciated. I basically have everything ready, just need to decide how the leds should be arranged and I start soldering...

terahz · 09/20/2011, 08:55 PM

VeL, just make 4 8"x11" heatsinks with 24 (9 white and 15 blue) evenly spread leds each. That should give you a good coverage. When you build one you can move it up and down to find the best spot for it height wise and you're all set.

If you absolutely must know, you'll have to learn something like Solidworks and model everything to see how the lights will mix and what will cover... unnecessary IMHO.

Just do it and start posting photos already

09/19/2011, 05:47 AM	#1
VeL Registered Member Join Date: Jul 2011 Location: Europe Posts: 72	DIY 120g Led Lightning Project - some help needed. Greetings. First of all I want to say how great the forum is and how friendy the people here are. Reading the DIY Led threads made me taking the course of building my own led lightning, even though I am quite electronics dummy. Also I want to thank brassmonkyballs and nuclearheli who helped me a lot to decide what I need for this project. Anyhow, here is some information, prior to my questions: The tank dimensions are - 130cm/60cm/60cm or around 50"/ 24" / 24". I plan on growing all kind of corals so I decided to go with higher led count. So I ended up with this setup: 96x Total Cree LEDs & 2x 660nm Reds 1x HLG-185H-42B (4.4A) 36x Whites XP-G 4 Strings - 9 CW / 9x NW / 9x CW/ 9x NW Running at 1100 mA (will be dimmed of course) 1x HLG-185H-42B (4.4A) 50x Royal Blues XP-E 5x Strings - 10x RB each string Running at 880 mA (will be dimmed of course) 1x ELN-60-48D Series - 10x Blue XP-E , 2x Red (660nm) at 800 mA In order to avoid spotlight and in order to get more coverage, and after I read about "FWHM - Full Width Half Maximum" I decided to go with 80 degree optics. It may sound stupid but after ordering all the supplies, now I am unsure how to ...... place the leds. The point is to get good penetration, good coverage and to consider the FWHM (meaning that the optics focus at full power only to the first 50%, or 40 degrees in my case with 80 degree optics). I know that the recommended spacing is like 2 inches between the leds. If I do the math though, in order to cover 50"x24" ill need 300 leds, which doesn't sound right. So any help on that matter will be greatly appreciated. I need to decide how long & wide the fixture should be, how many leds per row and what spacing between them, and how high above the water level is the best in order to get good penetration and coverage with 80 degree optics. My appologies if this has already been explained somewhere but at least I could not find any information about it. Thanks in advance!

09/20/2011, 08:55 PM	#6
terahz 1x10^12 Hz Join Date: Oct 2009 Location: Stamford, CT Posts: 1,185	VeL, just make 4 8"x11" heatsinks with 24 (9 white and 15 blue) evenly spread leds each. That should give you a good coverage. When you build one you can move it up and down to find the best spot for it height wise and you're all set. If you absolutely must know, you'll have to learn something like Solidworks and model everything to see how the lights will mix and what will cover... unnecessary IMHO. Just do it and start posting photos already __________________ Аз съм българче! Current Tank Info: DIY 40 Breeder with LEDs

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09/19/2011, 08:31 AM	#2
5pacey Registered Member Join Date: Sep 2010 Location: D.C. Metro Posts: 334	Well... when you come up w/300 LEDs are you assuming that the fixture/heatsink will cover the top completely - IOW, will be 50"x24"? If that is so you should be able to significanly reduce that. For example, I built a fixture w/24 XRE's (CW/RB even split) over a BC29 tank. Rougly 18" deep and 18x20 footprint. The actual heatsing/fixture size was 6"x12". I too got the 80deg optics thinking I'll need them but in the end I ended up not using them beause the fixture was only 2-3" above water. Got great PAR, no spotlighting but I did get color separation. Spacey

09/19/2011, 08:37 AM	#3
5pacey Registered Member Join Date: Sep 2010 Location: D.C. Metro Posts: 334	Based on my experience, in your case you should be able to get away w/well under 100 LEDs. For example I am building a 90 now... standard american size is 48w x 18d x 24h... given a good fixture (good LED placement and colors) I can probably cover it w/24 LEDs for each 24" of the tank width, particularly w/lenses, and would most certainly be more than well covered w/36 LEDs for each 24" of tank width. Your tank is rougly 2" wider and 6" deeper so roughly what would be a 120g in the US (48x24x24)... you can probably do 36-48 to be have power to spare. So 72 to 96 LEDs. I assume Cree XRE's or XP-e/XP-g's... My $0.02, Spacey

09/19/2011, 02:10 PM	#4
VeL Registered Member Join Date: Jul 2011 Location: Europe Posts: 72	5pacey, thank you for your comment! I however know what and how many leds I need and I already purchased them The problem is that I am not sure how I should place them in order to get the best of them. I do not want to guess what will be a good placing, I need to know and why I am doing it in a certain way. I was thinking to have 4 bars with 24 leds each bar, placed equally over the tank, however that means the led stars would be right next to each other and I am not sure if that will affect the coverage somehow. I see that many people make the led bars with at least 2" spacing between each led. Maybe I should make 5-6 bars instead with lower leds count on each one? So again it is for 50/24/24 tank, 94 leds, 80 degree optics.

09/20/2011, 08:05 AM	#5
VeL Registered Member Join Date: Jul 2011 Location: Europe Posts: 72	Any suggestions will be greatly appreciated. I basically have everything ready, just need to decide how the leds should be arranged and I start soldering...