10 Gallon Iwagumi Re-Scape (Update: Led Fixture)

[cainechow]

Switching power supply? I am not wise in the ways of electronics :P. It is about half the size of my palm and while running it might be 25c to 30c. It has a metal casing but has no vents. Does that make it switching?

I am relying on the hollow aluminum extrusion to be my heatsink. The light side of the LEDs are pretty warm, maybe 45c or 50c, hot but not scorching. The extrusion side is just warm to the touch. One of the reasons I went with the XTEs is their higher efficiency and lower heat output so that I wouldn't have to go with a huge ugly heatsink.

Here is a picture of how I made the swivel. It is a 18" acrylic tube with flexible hose in the middle and ends that give it a snug friction fit that still swivels.

Everything seems to be growing just fine under these so far.

[AquaInspiration]

absolutely brilliant

[Iceturf]

I like the simplicity of your design. So far as switching power supply, I was curious because the seller didn't specify. Switching means that instead of using energy to 'force' the output to be within certain ranges, switching chops up the AC and puts it in the same direction, then smooths it out with other components. More efficient, costly but often smoother power.

Also, I'm going to check out your idea for the aluminum heatsinks - see how they measure up.

Edited May 7, 2013 by Iceturf

[cainechow]

I've actually bee trying to figure out a way run water through the extrusion so that the heat from the LEDs is heating tank water. Bit if one had to run a pump to do so, it would just be another point of failure. I wonder if there is some way to use convection current or something like that to move the water.

[cainechow]

Switching means that instead of using energy to 'force' the output to be within certain ranges, switching chops up the AC and puts it in the same direction, then smooths it out with other components. More efficient, costly but often smoother power.

With more reading it seems that this should be a switching power supply because it drops voltage all the way down to 12-20v from 90v up to over 220v?

[Iceturf]

I am curious, do you have a voltmeter to quickly test the output characteristics? I wonder how it knows how much potential difference to create, for ~9$ I'm a little suspicious. In terms of the power supply, the 'lesser' type uses a transformer to step down the voltage first before 'modifying' power characteristics. For this reason, it will weigh a disproportional amount to it's size. If I get around to designing my own, I think I'll throw in a few pieces before the LED's to help ensure smooth input. You could probably add them to your design easily enough.

Also, I did a brief preliminary estimation of the aluminum's characteristics and it would appear to be able to handle the LED's needs. I assumed that it was a 1/8" heatsink with two 1/8" fins. You would get better performance if you made it a "U" shape. I will have to look up some more definitive analysis techniques though because I just ran a very rough guess. I don't know if it can dissipate enough energy from the small footprint of the LED fast enough though. I remember reading a while back that these LED's can take some temperatures pretty high though, 80-150*C? I can't remember, I'll have to look at their speck sheet again.

If you had a way of determining the temperature at the surface of the LED that would tell us plainly the performance of your bar. Otherwise its just varying accuracy of guesswork. Good idea to use the "Arctic Alumina Ceramic Thermal Adhesive".

I know you didn't ask for anyone's opinion in terms of the heatsink and stuff - I really liked your design though so I want to see if its enough for myself :P .

[Iceturf]

I've actually bee trying to figure out a way run water through the extrusion so that the heat from the LEDs is heating tank water. Bit if one had to run a pump to do so, it would just be another point of failure. I wonder if there is some way to use convection current or something like that to move the water.

Do you think your custom filter intake would be enough to suck or push water through a pipe you could put in the aluminum bar? Putting water so close to the electronics makes me nervous but inside of the aluminum bar would give an extra layer of protection.

I like your swivel mount, I was thinking something similar but with rollers for a while for myself. The swivel is very KISS though.

[cainechow]

Anyone have one of those infrared temperature readers?

[Ron]

Anyone have one of those infrared temperature readers?

I have a couple from my reptile keeping days, what do you need to know?

[cainechow]

Anyone have one of those infrared temperature readers?

I have a couple from my reptile keeping days, what do you need to know?

I was hoping to get a temperature reading of the LED emitter to see how hot they are really running. Do the ones you have do spot measurement? Like the 99.00 gun shaped ones with the laser for aiming?

[cainechow]

I think I know how to do water cooling on this fixture... I have a recirc loop in my sump coming off the return pump. I just have to tap into that and run a line up to the light and setup some stainless hard line that runs through the extrusion. I'd need to use Arctic alumina again for heat transfer. That should keep the water loop contained and almost closed system as far as the electronics are concerned.

Now the hard part. Finding the appropriate stainless steel hard line without breaking the bank? Any suggestions?

[cainechow]

Turns out PM Hobby is my ticket.

Remember when it was PMS Hobby?

[New_from_Peru]

Hey,

I love the idea of heating the tank with the light fixture - but as summer is round the corner I am going for a cooling system first.

I see the cree's are working well and you mention all the plants are growing - great news!

As far as thermal cooling of the LEDs my understanding is the disappation of heat is increasing the MTBF (mean time between failure) numbers for the LEDs. Just like cooling a PC - the cooler it runs the longer it will last.

I love this light fixture and I worked on one for my Fluval Edge which is working great - got a tag along piece of HC in there now making progress.

PC components for cooling / heating type systems is cheap and you can get it from Memory Express Etc - if you could braze the steel hard pipe to the back side of the aluminium (correct spelling) you would get fantastic heat transfer from the light into your water. I don't think you would need a pump as natural convection would take care of the circulation, even think of a closed loop with a heat exchanger in the tank? Titanium or S Steel coil transfering the heat into a corner of the tank? Would be more visable but it's closed so less likely to go wrong - same idea as a liquid cooler for a PC CPU (Corsair H60- http://www.corsair.com/hydro-series-h60-cpu-cooler.html ) You have the hard pipe as the CPU block and some kind of heat exchanger in your tank / fliter instead of the radiator in the link.

Great job so far.

DP