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View Full Version : Review my LED Build? Please?


MechEng99
09/20/2013, 03:35 PM
Hi all,

First up is the obligatory disclaimer that I have cross-posted this to make sure I'm not missing anything. I'd really appreciate any thoughts/concerns you have. It's my first build, so I want to make sure it's done right. Thanks in advance!!

Tank: 150g tall (48" long by 24" wide by 31" tall)
Inhabitants: Mostly SPS, some LPS
Previous lighting: 2x400W MH + 2x54W T-5
Controller: Neptune Apex

LEDs:

Total LED Max Wattage: 312W, dimmable

Cree XM-L2 Neutral White (5000K)
Cree XT-E Royal Blue (455nm)
Exotic Deep Red (660nm)
Exotic Turquoise (495nm)
Exotic Cool Blue (475nm)
Exotic Hyper Violet (430nm)

Layout:

http://i258.photobucket.com/albums/hh254/Reef-d_Up/Aquarium/DIY/Lighting4x12_v2_zps25590477.jpg

LEDs & Forward Voltages:

http://i258.photobucket.com/albums/hh254/Reef-d_Up/Aquarium/DIY/Supplies1_zps4cb4321f.jpg

Drivers:

http://i258.photobucket.com/albums/hh254/Reef-d_Up/Aquarium/DIY/Supplies2_zps1bd0ed7e.jpg

Misc. Supplies:

http://i258.photobucket.com/albums/hh254/Reef-d_Up/Aquarium/DIY/Supplies3_zps75ea610e.jpg

I guess my last two big remaining questions are regarding driver/light combos.

The Cree XM-L2 operates at 3000mA, so the forward voltage is 3.3V. I assume I can run the XM-L2's on the Mean Well ELN-60-48 at 1300mA, with no problems, right?

Any recommendations on the Cree XT-E scenario above? The max voltage I'd have is 108.8V, but two Mean Well ELN-60-48 will only run 105.6V. I'd hate to run a third driver for that small of a difference.

Thanks in advance!

Aqualund
09/20/2013, 05:23 PM
I would suggest the meanwell LDD drivers. With these, you would just get the drivers and then run them off a common power supply like one from steve's leds. They cost much less money, and they dim to zero.

http://www.kutop.com/meanwell-ldd-h-dc-dc-constant-current-step-down-led-driver.html?___store=default

Also, I think chlorophyll A is absorbed at 417nm? Maybe you want to get 410-420 UV's as well? Otherwise everything else is on the right path.

On a side note, I've installed and used over 500 of the chinese leds from fedy led and they work great for the price...if your trying to save money, its a good option...and the lens mounts for that style of led are much easier to manage and less messy. The lenses just slide on with no glue. IMHO the lens scheme for cree leds is a pita and woefully lacking in design.

You will also find that the apex programming for lighting leaves much to be desired. The choppiness in the ramping of power is pretty much unbearable for the amount of money spent on the unit. For less than the amount of money you spend on the vdm module, you can buy the components to have more channels and smoother control with a touch screen interface by using Jarduino (do a search for it).

If you dont do that, you can at least still make your own apex cables with rj5 connector and ethernet cable.

You don't want to use solid wire for the leds as it can break and you wont know where since its enclosed. also, you will need about 200ft total.

Oh and are you planning to do parallel or series?

you can do parallel for the xte situation by using resistors and transistors if you're feeling adventurous. plenty of thread written on this subject.

http://www.reefcentral.com/forums/showthread.php?p=21858074#post21858074

MechEng99
09/20/2013, 07:12 PM
Thanks for the feedback!

I'll look into the LDD drivers...wasn't familiar with those.

You're right, Chl A does absorb a bit lower. I was trying to hit the 428nm absorption area, but I'll see if I can squeeze in some 405nm's as well.

I've heard decent things about various brands, including the Chinese ones...but I'm not trying to save money on this build as anything will still be cheaper than my current setup. My first priority is for high performance for coral, next is to look nice (don't want the typical DIY-look), and lastly is control.

My neighbor is running his LEDs on PWM, but I can't bring myself to go away from the Apex quite yet. Don't ask for logic on that one. I was honestly planning to build my own cables, but I threw them into the spreadsheet just in case I started running short on time.

Hmm...use stranded wire instead of solid? That sounds like an utter pain to solder (I'm a newbie to soldering). I was going to use the solid between LEDs and the stranded for everything else. I'll research that one some more then. Thanks for the tip on wire length!! I had no idea how much to order.

I was planning to do series for the majority of the build, but I was looking into parallel for the RB XT-E like you suggested. Thanks for the link.

Thanks again!!

asid61
09/20/2013, 07:35 PM
Chl A peaks a 428nm.

Soldering stranded wire is not much different from soldering solid. I started with stranded and to me it felt easier to heat up.

Running the XM-L2 at 1300ma is a good idea. Above 1500ma the efficiency goes way down.

Run a third driver for the XTE. It won't kill you to spend another $20 to save a driver and $40. :)

You might also want to add some amber Rebel ES leds. Apparently they are good for color. You could also replace the Crees with Luxeon Ms, which are more efficient.

Aqualund
09/20/2013, 08:55 PM
ah yeah thats right, absolute max at 428 and secondary max at like 415 or whatever, thnx for getting me right :)

But yeah stranded man. I mean yeah solid will work, but with the number of bends and finagling and what not, I have had better luck with stranded :)

asid61
09/20/2013, 09:30 PM
Oh, I also forgot to mention. You might want to change your layout on the heatsink to be more compact. You gain nothing by putting space in between the led stars.
As long as you have fans, cooling won't be a problem.

tdb320reef
09/20/2013, 09:40 PM
+1 LDD On PCB and terminals. Small form factor, clean install,PWM support and cost effective.

MechEng99
09/21/2013, 07:16 AM
Thanks for the suggestions! Keep them coming!!

You might also want to add some amber Rebel ES leds. Apparently they are good for color. You could also replace the Crees with Luxeon Ms, which are more efficient.

I was just reviewing the pigment & fluorescent absorption spectra, and I'm not seeing much that matches up to the Rebel ES output (585-597nm). Any idea why the amber is beneficial? I think Chl c has a small absorption peak at 584nm...but I think I'm hitting the majority of the absorption peak at 448nm. Thoughts?

Oh, I also forgot to mention. You might want to change your layout on the heatsink to be more compact. You gain nothing by putting space in between the led stars.
As long as you have fans, cooling won't be a problem.

I read somewhere that spacing should be about 1.5" for 60* optics (planning to run about 12" off the surface). I researched the thermal resistance of various heat sinks, and if I ran the LEDs at 100% (which I won't), then the MakersLED heat sink with that sort of spacing (without a fan) had a safety factor of 1.28 (which isn't much of a safety factor.) Obviously, a fan will improve that safety factor. I wanted to make sure that if I had a fan failure later that I wouldn't threaten the health of the LED system until I could get a replacement. The SF of other heat sinks with my design running at 100% (without a fan) was only around 0.55...not acceptable in my opinion.

What distance do you recommend? I was thinking 1.5" would also be fairly easy for wiring.

+1 LDD On PCB and terminals. Small form factor, clean install,PWM support and cost effective.

Arrrgggghhhh...I really wanted to have everything controllable through the Apex. I'm still considering this, but it's hard. :headwally:

asid61
09/21/2013, 12:01 PM
Steve's Leds sells a 10v analog to 5v PWM converter. It's a bit pricey, but worth it IMO.