LED Arrangement on Heatsinks

[bu11itt]

I just wanted to run my LED placement for my DIY build by the group for review and comment.

I have a standard 75G that is currently cycling. In the future I am not sure what corals, clams, inverts, light requiring flora/fuana I want to keep, just want to build a fixture that could cover just about anything I can think of now (although being new to the hobby that list is pretty small). Below is a list of the equipment ordered for the build:

Equipment:
30: CREE XT-E Royal Blue
20: CREE XT-E Cool White
4: Meanwell ELN-60-48D drivers
2: MakersLED Heatsink kit – 18”

My original plan was to have 14 RB and 10 CW per fixture (48 total LED’s), but the 6 pack was cheaper for the RB so I got two extra LED’s to throw in the mix. I currently plan on running two drivers per heatsink; 1 with 15 RB’s and 1 with 10 CW’s. The drivers will be controlled via an Apex system.

Due to the size and type of canopy the lights will be about 4” from the water surface (no optics) and mounted over the back 2/3rds of the tank. I’m planning on angling the fixtures slightly forward to cover the front of the tank.

I have come up with two options of the same theme for light placement that can be seen below.

Options 1 is a set pattern across both fixtures:

http://i1271.photobucket.com/albums/jj622/bu11itt/Misc/38146E99-E07E-4B9B-BA1A-ED96745EB0A7-220-0000000D45C0CC6C.jpg

Option 2 is the same pattern on the first fixture and mirrored onto the second fixture:

http://i1271.photobucket.com/albums/jj622/bu11itt/Misc/5E514B50-509C-4E0C-893E-DC055A3DBBE0-220-0000000D4553AD53.jpg

Also, any others comments on the overall build would be appreciated. Thanks.

[mcgyvr]

now thats an@l :)
it won't matter which one.

[mcgyvr]

oh.. and 15 RB in series is too much for the driver. 9 to 13 max leds per string
Vf=3.4V max
15 x 3.4 = 51VDC.. the driver is 48V max.. not gonna work.

[Gorgok]

Technically the ELN-48 can get up to 52.8V with adjustment, but not sure if it would be worth it to do that instead of dropping 1 blue off the string.

[mcgyvr]

Technically the ELN-48 can get up to 52.8V with adjustment, but not sure if it would be worth it to do that instead of dropping 1 blue off the string.

MAX 12 LED's per string and don't mess with the voltage pot.. do it right.

[reefergeorge]

MAX 12 LED's per string and don't mess with the voltage pot.. do it right.



That is the sure thing number since the fv differs from led to led. The standard output is 48v and max of 60 watts.. I have 14 on all seven of mine and haven't had a problem for two years now.

[mcgyvr]

That is the sure thing number since the fv differs from led to led. The standard output is 48v and max of 60 watts.. I have 14 on all seven of mine and haven't had a problem for two years now.

yes many of us get lucky from time to time. 14 is really pushing it. Vf is different/changing with color/temps/life,etc...

Do It Right and enjoy it. :beer:

[bu11itt]

now thats an@l :)
it won't matter which one.

Ha! I won't deny my OCD tendencies. I spaced my moonlights exactly 8.125" apart (3 in the front and 2 in the back) and was bummed when I had to move the middle one because it was directly over my center brace.

Having mentioned my OCDness, I think I'll go with option 1 because even though I can make identical fixtures, on option 2 I'd have to mount one with the drivers facing forward.

oh.. and 15 RB in series is too much for the driver. 9 to 13 max leds per string
Vf=3.4V max
15 x 3.4 = 51VDC.. the driver is 48V max.. not gonna work.

I was planning on turning the max current down on the driver from 1.3A (to around 1A) even though the XT-E's are rated for 1.5A; mainly just to keep from running the driver at full capacity.

However, I am not opposed to taking the advice from the more experienced and dropping two blues from each string and wiring them up with the whites. That'll give me 13 (all RB) and 12 (10 CW & 2 RB) per driver respectively.