Max spread between LEDs on DIY fixture?

[ChadO]

Greetings,

I am working through the best layout for my LED light fixture that I am building. I have a drilled and tapped 6x20" fixture that has four rows of nine to hold a total of 36 LEDs. My kit is for 24 LEDs, and that doesn't span evenly across the pre-drilled heat sink. However, I have laid the LEDs out, and if I add some additional tap sites in a few places, I can utilize the sink quite well and come up with an even spacing. However, the spacing that balances so nicely puts the LED spread right at 3" between them.

The details:
- 24 LEDs in 4 rows, 6 LEDs per row spread across a 20" heat sink
- Heat sinks to be hung in a canopy that will put them about 6" above the water
- The LEDs will have 80 degree lenses attached to them

Does this spacing sound like it is too far apart and will incur some spot lighting?

Thanks,

ChadO

 

[trido]

It very well could depending on how you mix your whites and blues together.
I just built my 60 light 24" heatsink with 60 degree optics at 12" above the water and I notice a tiny bit of spotlighting under the whites. Believe it or not. Adding two greens (no optics) to my fixture the other day helped alot with the overall blending of my whites and blues. I was surprised.

Almost forgot; my LEDS are spread apart 2" one way and 1 3/4" the other way

 

[ChadO]

Wow, 60 lights across 24" heatsink, that is some intensity! Mine will only be 48 LEDs across two 20" heatsinks. This is what was recommended by RapidLED for my 75g. I have a mix of Royal Blue XT-E, Blue, Cool White and Neutral White. In a short while, they will have additional colors for the solderless kits that I am using, and since I am screwing mine to heat sink, I may just unscrew and swap a few out like you did to get that nice range of color spectrum.

So, another update. Looking it over some more, I realized that I could pretty easily make the layout matrix into a 3 row, 8 column, and it would be less extra drilling than what I had before. It also puts the LEDs on a 2 1/4" square (i.e. 2 1/4" horizontal and vertical from each other). With the 80 degree lenses, I think this will be the best layout option I can get without adding more LEDs.