6g nano - LED lighting

[kev82]

Thought I'd document the start of 6g acrylic tank. Dimensions of the tank are 20x40x30cm. (8x16x12 inches)

It's lit by 10x 3w cree cool white LEDs from dealextreme.com. LED drivers are 1000mA dimmable buckpucks from luxeon. Then there's a 24v power supply to power the whole thing.

Other gadgets in the tank include a small internal filter, heater cables and red sea co2 kit, hooked up to a ~5lb co2 tank.

I live in Iceland, where ADA products are not readily available so for soil I have ocean nutrition "giovanni's starter", with tetra complete substrate on top of the starter. Everything is then topped up with small (2-3mm) gravel.

Rocks are just some river rocks from a river about an hour drive from Reykjavík.

Tank will be filled up and wrapping removed when I have added more plants, hopefully this weekend

Pics!


Soil.


Pearls on the HC already.. They must like the LEDs


LEDs + heatsink:




Comments are welcomed. I am very much a beginner aquatic gardener so I imagine not many of you will like my feeble attempt at an aquascape.

Any questions on the LEDs and/or heatsink construction also welcome.

Edit:
Realised this may not be the correct forum. I posted it here mainly for people wondering about LEDs and are interested in making themselves their own set.

[Wasserpest]

Nice, thank you for sharing. LEDs are sexay.

How hot do the LEDs get? Is there a need for the big ol' fan, or would the heatsink distribute the heat sufficiently?

[Hoppy]

Originally Posted by Wasserpest

Nice, thank you for sharing. LEDs are sexay.

How hot do the LEDs get? Is there a need for the big ol' fan, or would the heatsink distribute the heat sufficiently?

Aluminum will store very little heat, because of its low density and relatively low specific heat. It has a good thermal conductivity, though, so that makes it good for a heat exchanger, which is what our "heat sinks" really are. The fan helps move the heat from the aluminum to the air by forced convection. If we were to coat our "heatsinks" with a good, but very thin black paint, they would also radiate more heat away, and work even better.

[kev82]

More pics..




Maybe this thread should be moved to the nano forum or something?

[Craigthor]

Looks good. Any pics of the build? I've got an ADA Mini M that I would love to switch over to LED lighting.

So tempted to get another Mini Solar so I can disassemble it and turn it over to LEDs.

Craig

[Hoppy]

It looks like you are getting very good, uniform light with the LEDs. Do you have access to a PAR meter? If there is an aquatic plant club there, they might have one you could borrow. One thing still lacking with LED lighting is good data about how much light people get with various configurations of LEDs. That makes it hard to design an effective light for a given size tank.

[kev82]

Craigthor:
I don't have any detailed build pics, but this is quite simple actually. I used a 6mm thick aluminum plate for the heatsink, and attached 2 L brackets onto it with screws and thermal paste. I intend to add a couple more L brackets for better passive cooling, but as long as the fan is running this design is keeping the LEDs quite cool.

Then I just drilled holes to attach the LEDs (no tapping!), with artcic silver thermal paste between the heatsink and LEDs for optimal heat transfer. Then it's just a matter of connecting the LEDs in series (2x 5 LED series), and connecting the terminals to the buckpucks.

Buckpucks I bought from ledsupply.com for $15 each.
LEDs from dealextreme.com

I'm using a 3A 24v power supply I already had, and the fan I got from a local electronics store.

Total cost is $150-200, but keep in mind I live in Iceland so I had to pay import duties and all sort of extra cost which americans don't have to.

Hoppy:
I am really happy about the light coverage. I am not using any optics on the LEDs, so it's spread out pretty much all over the place. I do get a shimmer effect as the water ripples, which I like very much

I have no idea about PAR readings, and there's no aquatic plants club in Iceland so no help there. The plants have been in the tank for about 40hrs now, and ca. 3 hours ago I added co2 to the tank and the HC is already starting to pearl. Judging by that I'd assume the light is sufficient, but I'm not planted tank expert so I could be wrong.

[Craigthor]

kev82 What made you choose the 3W over the 1W? I've though about a similar pattern but using 14 1W CREEs. 3 Banks 5, 4, 5 without optics.

How many buck pucks are your running, 2?

Sorry about all the questions but I'm in thought land on setting one up.

Craig

[kev82]

Because 3w are much more powerful and can penetrate water much more effectively. You'd also need fewer LEDs, which means less wiring and soldering and a neater solution. I'm not sure the 1w crees would be powerful enough, except for a shallow tank. I don't have any hard data on that, just something I've read on a few forums, f.e. nano-reef.com.

I have personally tried 0.5w LEDs and they were nowhere close to powerful enough.

I'm running 2 buckpucks.

[kev82]

HC seems to like LEDs...



Also this plant, whose name I do not know.. There's been a steady stream of bubbles coming from it all day.

[Hoppy]

You obviously do have enough light, since you have pearling of the HC. My question about PAR is to get more data to help us design lighting for other tank sizes, which is a real bear!

You didn't tap the holes, that are used to secure the LEDs. Did you use a tiny bolt and nut to hold them? I enlarged your pic as much as I could and still couldn't see just how they are held on. I think nuts and bolts may be the way I go on my light. Much easier to drill holes and not have to tap them. And, that is as secure a mounting method as I have heard of.

[kev82]

I just used 3.5x16mm stainless wood screws. Drilled 3mm holes for them and carefully screwed them in, sometimes backing out half a turn so I wouldn't break the screws. It's a tight fit, but the screws handle it nicely. Bolts and nuts work too, but are a little more work, and more expensive.

On this pic you can see the ends of the screws pointing out above the LEDs. I used a dremel to remove those so I wouldn't hurt myself handling the heatsink.


Another pic..


I can take more detailed pics for you if you need..

[Hoppy]

Thank you! Now I see how you did it. I think I will use screws and nuts on mine. I would just be far too angry if I were to break off one of the screws while tightening it. It is a little more expensive, but very little. The use of screws with heads made for countersinking is a good idea too, since that means you don't need insulating washers under the heads.

[Craigthor]

Great Idea.

Did you use the prewided Buckpucks? Also I wonder how hte buckpuck that comes with the Potentiometer would be fun to play with.

Craig

[kev82]

I just made a buck with a pot myself. I have a decent collection of electronic components and just threw a 10k ohm potentiometer on the bucks. I'm running the LEDs at full blast tho.

I am also going to play around with atmega168 microcontrollers I have, to simulate a sunrise/sundown effect when turning on the lights. Probably going to add a safety circuit in there while I'm at it, turn the lights off if the temperature of the heatsink gets too high. So many possibilities with these things


Using nuts and bolts is definitely not a bad idea and the cost is so small that it doesn't really matter. I just used screws because I had them in my toolbox, they're quick to use and cheap