DIY LED Hood: Prebuild Thoughts...

GMGQ · #1 01-19-2011, 11:04 PM

Hi All,

I'm just getting back into the hobby, and I know I have to change the bulbs in my setup (it's been over 2yrs!). I have 2x250W MH, and 2xT5 Actinics lighting my 70gal tank (48"L x 20"D x 18"H approx).

Rather than spend $200+ on new bulbs, I'm looking into this whole LED thing. When I first heard of LEDs a couple years ago, they were over $1000 for a setup, and werent that powerful. Now the story has totally changed. Plus with Milad's group buy setup, how can I NOT go this route?? I built my own stand, did all the plumbing, and wired up the power center by myself, so I'm pretty hands on. I'm pretty excited to jump right into this LED thing, it seems easy enough, but I know I better do my research first.

So having said that, I figure I'll ask some questions here and pick the brains of you awesome reefers! I've engrossed myself in researching this stuff for the past week, but I figure I'll ask some questions here, in case anyone else was wondering the same thing (no such thing as a dumb question, right?). Part of this is also me thinking out loud :P

LEDs:
- I want to maintain the 10K colour that I have now with my MH's. Milad told me that this is achieved with 1:1 of Cool Whites and Royal Blues. And with dimming, I can create the whole range of colour temps as well.
- Regarding the number of LEDs, I've been told that 48 is a good number to achieve something equivalent to 250-400W MH. Just looking at my crude piece of excel art, if I had a 36" heatsink, I could evenly fit 9 LEDs per each 6" section, and that would come to 54 LEDs. I like symmetry :P

Optics:
- So I guess these lenses help focus the LED beam down at 40-65 degrees, like a spotlight. Since the LEDs will be at least 10" or higher above the water, it's a no brainer that optics will be needed, yes? OK, then how to decide which angle to choose? I'm thinking either way, the LEDs will be placed only a few inches from each other, so would it really be necessary to get anything wider than 40*? There should be plenty of overlap anyways. If I go wider, I assume the coverage will be a bit wider, but the intensity will be lower? (i.e. not as many PARS reaching the bottom of the tank). But again, there will be lots of overlap. Maybe just have the last row of LEDs on the furthest Left and Right of the heatsink at 60*, and the rest of them at 40*?

(Yes I was bored at work).

Heatsink:
- Speaking of heatsinks, I'm tempted to go with one big 36" long one. They weight is about 18lbs. I'm not too concerned about the weight, I'll rig something to hang it from chains, and I dont intend to mount the drivers in this LED hood. I'm more concerned with even coverage of the 48" tank. I could go with 2-3 smaller heatsink chunks, and I'll probably never notice any gaps of coverage betwene the chunks. But it seems nicer to have one big heatsink...

Driver:
- I see most builds have 4 drivers to power 48 LEDs (12 LEDS per driver). But I saw other builds (i.e. Milad's) that use 2 larger drivers to control them all. Sure, why not? More hardware = more to wire up + more ways to screw up :P I dont intend on running the lights east to west to simulate the sun, so I dont really see a need to get a bunch of smaller drivers... Agreed?
- Regarding dimmability, I guess dimming is a good thing. I do want to be able to have a controller slowly raise the intensity during the day, then slowly reducing it at night, then I want to run the blue LEDs at a lower intensity for moonlights.

Controller:
- I'm a bit stumped here. As per above, I want to slowly raise the daylight intensity, slowly reduce it, then run the blues at a lower intensity in the evening (like actinics), then lower the blues even more at night for moonlight. What kind of controller will do this for me Automatically? I looked up the Neptune AquaController Apex System, but that sucker starts at $500! Is there a cheaper alternative that will automate the lighting intensity for me? I dont really need all the bells and whistles of the Apex system, I just want something to control the lights on a timer for me...

Ok, those are my initial ramblings. Thanks in advance guys, I'm very excited!

Gary

StirCrazy · #2 01-19-2011, 11:31 PM

Quote:

Originally Posted by GMGQ

Hi All,

(Yes I was bored at work).

Gary

is your angle drawign repersentitive of the fixture being 10" above the tank? I would say if that is a 20" deep tank you are trying to figure out the angles with the fixture 3" above the tank.

Steve

GMGQ · #3 01-19-2011, 11:33 PM

StirCrazy:

No no, the height of the hood is not to scale. It's just to visualize the 40* vs 60* spread of the optics.

It's just MS-Excel, man! :P

mseepman · #4 01-19-2011, 11:36 PM

Well, it seems you've thought a lot about this already.

In regards to optics, just note that 40 degree optics really tend to spotlight the LED's so I would consider doing a bunch of 60's myself. If you go with fewer drivers..you need to do a little more detailed wiring to include fuses and resistors. When you do that, you will need to balance the strings, (move some LED's around) which is really tough if you use any method other than screwing the LED's to the heatsink. I tell you this because screwing them in means you need to tap the heatsinks (a bit of work).

As for controllers...I think the Apex lite can use their 1-10V add-on and it would be cheaper.

I'm a huge fan of LED and will be doing one of these myself with 180 LED's or so.

GMGQ · #5 01-26-2011, 08:27 PM

So instead of jumping into the big LED hood build, I figured I'd do a small scale project first.

I want to build a refugium LED light with 6 LEDs:

4 x Cree XP-G CW (3W, max drive = 1500mA, forward voltage = 3.0 @ 700mA)
2 x Cree XP-E RB (3W, max drive = 1000mA, forward voltage = 3.4 @ 700mA)

I plan on using a buck puck with a potentiometer. Will this one work?

http://www.ledsupply.com/03021-a-e-1000.php

If so, what power supply would I need for it to drive the 6 above LEDs? (24V, 1000mA as per the buck puck?).

And I assume I should wire them in series?

Thanks guys.

mseepman · #6 01-26-2011, 08:49 PM

Unless dimming these is of utmost importance to you (for a fuge I would think not) I would get either a meanwell LPC-35-700 or a LPC-60-1050 (if you want higer mA). This way you just wire it and go...if you need to add more LED's you can (up to 12). The buckpuck costs the same, but you still need to buy all the extras to make it run and it caps out at 6 LED's.
Just my humble opion though. Here's a link where you could get the Drivers. http://www.rapidled.com/servlet/the-Drivers/Categories

GMGQ · #7 01-26-2011, 08:54 PM

Well I want to dial back the voltage so that the LEDs arent running at 100%, plus this is a test project for me, so I want to see what varying voltages will do with the brightness/colour.

Also the buck puck is the size of a quarter, the meanwell is the size of a brick. I just figured I shove the buck puck into a little black project box from radio shack, and screw the pot into the lid.

What extras would I need with a buck puck? The one I linked to comes with the pot pre-wired, so I figure all I need is an AC power adapter?

LMK what you think thanks.

Quote:

Originally Posted by mseepman

Unless dimming these is of utmost importance to you (for a fuge I would think not) I would get either a meanwell LPC-35-700 or a LPC-60-1050 (if you want higer mA). This way you just wire it and go...if you need to add more LED's you can (up to 12). The buckpuck costs the same, but you still need to buy all the extras to make it run and it caps out at 6 LED's.
Just my humble opion though. Here's a link where you could get the Drivers. http://www.rapidled.com/servlet/the-Drivers/Categories

mseepman · #8 01-26-2011, 08:58 PM

Fair enough... One thought would be that I'm not sure that LED's are the best Fuge light. They've been known to significantly cut down on algae in tanks as they don't put off as much light in the spectrums that many algae's like. Not sure that will help grow your macro-algae either.

No extras on the BP, I just like simple and drivers are simple.

Lampshade · #9 01-26-2011, 09:38 PM

I"ve been doing a lot of research on this aswell, i've seen a few nice tanks with 40 degree optics, some even with 20. They tend to be layed out in a cookie sheet way, staggerings each line of LED's. I think it's more dependant on your density of LED's and the height mounted oabove the tank. 10" above the tank is pertty common, If you are going more than 2.5" centers on the LED's i would suggest 60 degree, if less than 2.5" then 40 should be fine IMO. Check out as many pics as you can to see what you're getting into.

and if you are using XP-E's a 1:1 ratio will be a 14K balance, if you use XP-G white's you can get away with less whites, forget the combo for 14K though. The blue's don't help growth much, basically for our viewing and popping coral color (The datasheet for cree shows this with the light off the whites, it's very close to the PAR we're looking for)

As for heatsinks, there's lots of choices, but generally people WAY over build heatsinks. Cree's give off a lot of heat, no doubt, but you can calculate the heat gain vs loss pretty easy to see what you actually need.(i posted links on some other recent DIY thread)

Drivers have lots of choices, meanwell's are popular as with the buckpucks. More drivers gives you more "zones" for dimming/control. 1 driver dims all the lights together.

As for cheap controllers. Depends on how fancy you want to get... but look at arduino boards. There's LOTS and i mean LOTS of LED builds using these. Uses C programming, but i've found many chucks of code online that people have posted that got their LED's working and controlable. Arduino's start at $20 for something that will control 2 drivers with PWM outputs and $35 for something that'll do 6(Arduino Mega). If you get into it the arduino can do pretty much everything, i'm building a tank controller based off one right now.

GMGQ · #10 01-26-2011, 09:44 PM

Hmm, well this is mainly for my chaeto down there :P Right now I'm using 2 CF bulbs, and they're growing like weeds. I just wanted to reduce the wiring/lighting clutter.

It's a small weekend project, so I'll try it out and see how it goes.

I still need to figure out the AC power requirements though...

Quote:

Originally Posted by mseepman

Fair enough... One thought would be that I'm not sure that LED's are the best Fuge light. They've been known to significantly cut down on algae in tanks as they don't put off as much light in the spectrums that many algae's like. Not sure that will help grow your macro-algae either.

No extras on the BP, I just like simple and drivers are simple.