DIY LED for Biocube 29...luminous flux question

[verkion]

Hey guys,
Back in the day they had the "watts per gallon" guidelines, but I suppose a better measure is the luminous flux per gallon (depth of tank notwithstanding). I'm thinking of building an LED solution for my Biocube 29 but was unsure how much "lighting" I would need.

Do you guys know how many lumens the stock 36W Coralife 10K lamp put out? Then I'd have at least a guideline for what I should be aiming for (or surpass).

Thanks!
verkion
P.S. Yes, its CO2 injected, EI dosed and will be "heavily planted"!

[verkion]

Incidentally, has anyone done a build with LED strips from Dealextreme? They have 16W 950 lumen 6000k-7000K, LED strips. I figure maybe 3-4 of these suckers should put out more than enough light for my freshwater biocube...

High-power 16W 950lm LED emitter strip 12-14V

Thanks!
verkion

[timbit1985]

curses, i missed these when I was building mine from DX. Phooey. You have to be careful about the light spectrum emitted by LED's, as sometimes they can be on the narrow side and they may not provide a sufficient range for plants.

[verkion]

I was looking at the spectral output of the XM-Ls as well and was thinking 3 or 4 of them being driven at 3A would be LOTS of light. Like 3000 lumens...just undecided about spectrum. The CRI on them aren't spectacular but was thinking 2 cool white and 2 neutral white should do the trick.

[teija]

This is a good idea...are you planning on using LED's and entirely replacing the CF bulbs? I am now thinking this would be a much more fun way of going than replacing my broken ballast - and possibly cheaper too..! Keep us updated on your progress!

[timbit1985]

I was looking at the spectral output of the XM-Ls as well and was thinking 3 or 4 of them being driven at 3A would be LOTS of light. Like 3000 lumens...just undecided about spectrum. The CRI on them aren't spectacular but was thinking 2 cool white and 2 neutral white should do the trick.

Those xm-l's are crazy bright, but do be careful with the heat output on them. Those suckers are not terribly efficient, so convert a lot of that energy to heat. You'll need to heat sink and maybe even force air over them. I have my LED's mounted directly on a large piece of scrap aluminium kicking around. I'm driving 8 of them at ~1amp. The heatsink (ii.e sheet aluminium gets slightly warm to the touch.

Don't put too much trust in those spec sheets listed on deal extreme, a number of times what they have shipped me was NOT what they quoted. DX is great for cheap prices, but sometimes you get a dud...and it takes them ages to fix it. If you do go the XM-L route, make sure you buy a couple extra, just in case. Also, do you know what you will be powering them with? You need a regulated power supply, most wal-warts will not output sufficient current to drive a bunch of those xm-l's. I drive my LED's with an old ATX computer power supply I had kicking around. The

[timbit1985]

Also, you might not need to drive those xm-l's at 3 amp. The amount of light energy output decreases as you increase the current, you'll get slightly less light at 2 amps, but the LED's will last way longer.

[verkion]

Ok...Reconsidered options. So now what I am thinking is a Rapid LED 5.9x9" Heatsink for $30. And, from DX:

4 x 20W 2000 Lumen LED Emitter Plate

4 x Plastic Smooth Reflector Don't really know if its really needed but...eh.

Either 2 x 1A 30W Constant Current LED Driver I can run 2x20W LED Emitters in series, slightly under-driven, (1A instead of the full 1.4A, so essentially 15W per LED instead of the full 20W)
OR
4 x 1.3A 20W Constant Current LED Driver

And, yes, I'm worried about the CRI quite a bit...I don't think they will have a great "spectral coverage." That said, I'm hoping the sheer intensity--somewhere in the 6000-8000 lumen range--should be enough to ensure even the weakest spectral wavelengths are at a high enough intensity.

What do you guys think? Overkill? Maybe I should go with 4x10W LED Emitters? Anyone know what a stock 36W Coralife 6700K bulb puts out in terms of Lumens?

Thanks!
verkion

P.S. In case any of you really like blinding your fish...100W 8000LM LED Emitter!!!

[verkion]

Ok, just pulled the trigger on a Nanocustoms Heatsink!!! I'm still deciding on which LEDs to use actually. Looking at the typical spectral output of cold white and warm white LEDs, I think it would be best to use a combination of both. Any suggestions from anyone?

BTW, the total cost of doing something like this is about $200 + time. This, I think, puts out FAR more light than most Cree XR-E or XP-G setups which tend to be the typical commercially used LEDs. To achieve this, you'd need to drive approximately 30 or so XR-E at 1A which is approximately 111W of power. Things look better with XP-Gs. Only need about 15-18 of the XP-G to get the same output if you drive them at 1.5A a piece resulting in about a total of 80W of power.

Then it comes down to cost. $5.40 / XP-G x 15 = $81. $5.30 / XR-E x 30 = $159. $18.48 / 20W Emitter Plate x 4 = $73.92. Add in the cost of the drivers $25 or so for 4x20W drivers and you are just about at $100.

8000 Lumens of light (minus the obligatory 10% over-rating) so...maybe 7000-7200 lumens. I'm guessing, since I haven't actually found HARD DATA, this is FAR, FAR, FAR more than the Coralife 2x36W 10K PC bulbs produce...and its directed downwards instead of in a 360 degree dispersion.

It'll take a couple weeks for the items to get here, but I'll post pics after!

Thanks!
verkion

P.S. I noticed that DX has a lot of Emitter plates being added for Saltwater tanks. 15K, 20K color temperatures etc.