Come in and join me....

[jpndave]

A better alternative, albeit slightly harder to work with, is a circuit based on the ST Micro STCS1 driver. It's a buck driver that needs very few external parts. It's surface mount only though. I have built up a few of these drivers and they work great. Takes up to 40v @ 1.5A! The dimming control is a pwm input, which you can make from a 555 timer (look up "555 pwm"). You can tie all the inputs to the timer and dim using that. Very low current on that side of the circuit.

 

Is that this circuit?

http://www.instructables.com/id/1.5A-Const...-for-/?ALLSTEPS

 

I wanted to try that one out but decided the other was an easier way to start. Do you like the performance better? What is the advantage with that chip/circuit?

[jpndave]

OK, here are a few pics....

Not hooked up yet but sitting in place.

 

Refugium showing front and back, this attaches with velcro to the back wall:

 

BC8 light front and back (the solid portions are where the screws go through to mount it to the hood).

 

I should have them drilled and wired shortly. The LEDS are soldered and tested good.

[evilc66]

Wow! Thats a mighty meaty heatsink you are using for the fuge! That could be passively cooled.

 

Thats the circuit. They modified theirs to have an additional voltage output, but you can use the reference design from the datasheet to build a simple one. It is tricky to work with. I used some SOIC adapter pcbs to build mine up. It's super small and low profile. Runs a lot cooler. Nice thing about this also is that you can run at much higher voltages than most DIY drivers, and at much higher currents without it getting warm.

 

A little advice on the main heatsink. Polish it. Sand it down with 800 grit wet/dry and polish it so it's nice and shiny. The smoother surface will help promote better heat transfer.

[jpndave]

Wow! Thats a mighty meaty heatsink you are using for the fuge! That could be passively cooled.

 

Thats the circuit. They modified theirs to have an additional voltage output, but you can use the reference design from the datasheet to build a simple one. It is tricky to work with. I used some SOIC adapter pcbs to build mine up. It's super small and low profile. Runs a lot cooler. Nice thing about this also is that you can run at much higher voltages than most DIY drivers, and at much higher currents without it getting warm.

 

A little advice on the main heatsink. Polish it. Sand it down with 800 grit wet/dry and polish it so it's nice and shiny. The smoother surface will help promote better heat transfer.

What did you use for the board to make those up? I would like to try out that circuit. The surface mount doesn't scare me anymore. I just need to find a source for the boards that is reasonably priced. If there is enough interest here, maybe we could get together a small production run and a board company.

 

Thanks for the input on the heatsinks. I do plan on just using natural convection to cool it, no fan. It just worked out that size to fit the back of the tank best. It will make more sense when it is done.

 

As for the main array. I did plan on polishing thing up a bit after it is drilled. I also am going to use heat transfer tape under each LED chip.

[evilc66]

http://cgi.ebay.com/ME-PB-SM50-8-SMT-surfa...oQQcmdZViewItem

 

Thats the pcb I used. They work out fairly well.

 

Don't use thermal tape under the LEDs. Use a good quality thermal paste like Arctic Silver. Much lower thermal resistance. Reason being is that a thermal tape creates a physical gap between the two parts. The thermal paste is there to fill in the voids between the two mating surfaces. The surface to surface contact of the two parts is the primary path for heat. The paste just pushes out the air that would act as an insulator.

[jpndave]

Who makes High Power UV LEDs? I can't find anything in the Luxeon lineup and I could have sworn Cree has one but can't locate it.

[evilc66]

Cree does (or at least did), but it's hard to find. The ones I have been using are from Kai Domain. No brand name, but they have decent output.

[iMaGin3]

I have been lurking around these threads for the past week or so and admit I am a complete noob.

 

If anyone would be so kind as to provide a complete list of materials for me as well as quantity. Also I am not the greatest in the electrical field so a diagram of wiring would be awesome too! I am having a hard time understanding what is what and what everything is for. My dad is an electrician but I dont want him helping me, if anything he could check everything before I plug it in JIC .

 

I have a 5.5g AGA 16" tank.

 

The one thing that I have really decided on is the white cree xr-e q5 leds from DE but dont know how many. Thinking about just buying the blue Cree leds from DE also. The LEDs are probably gonna be the same as the ones npain316 is using. I think I may go with the buckpucks with pots(adjusts color/output?) from ledsupply, but dont know which one and how many. I have no idea where to get a decent sized heatsink for this tank. I know I sound annoying haha but these threads got me really interested. Any and all help is needed. Thanks!

[roxy25]

I have been lurking around these threads for the past week or so and admit I am a complete noob.

 

If anyone would be so kind as to provide a complete list of materials for me as well as quantity. Also I am not the greatest in the electrical field so a diagram of wiring would be awesome too! I am having a hard time understanding what is what and what everything is for. My dad is an electrician but I dont want him helping me, if anything he could check everything before I plug it in JIC .

 

I have a 5.5g AGA 16" tank.

 

The one thing that I have really decided on is the white cree xr-e q5 leds from DE but dont know how many. Thinking about just buying the blue Cree leds from DE also. The LEDs are probably gonna be the same as the ones npain316 is using. I think I may go with the buckpucks with pots(adjusts color/output?) from ledsupply, but dont know which one and how many. I have no idea where to get a decent sized heatsink for this tank. I know I sound annoying haha but these threads got me really interested. Any and all help is needed. Thanks!

 

+2 I been reading about DIY work on LED aquarium lighting I found this link

 

http://www.ashevillemarine.org/bb/viewtopi...1f63aabfd25f228

 

I have no idea what I am doing and that link has helped me understand the basic parts you would need.

I would like to know for a DIY noob what would be better LED cree or Luxeon ?

 

I have a 8 gallon Jalli cube and I plan to gut the fixture out to replace them with LED.

I would also like a list but I am not sure how many LED to put in the fixture here is a link to the aquarium i have.

 

http://www.customaquatic.com/estore/contro...=AQ-JLFT-402630

[evilc66]

Cree and Luxeon are like Ford and Chevy. Not much difference, but it will come down to availability and cost. Crees tend to be a little cheaper and are easier to find.

 

For an 8g tank like that, you could use 12-14 LEDs in a 50/50 mix of white and blue.

[roxy25]

Cree and Luxeon are like Ford and Chevy. Not much difference, but it will come down to availability and cost. Crees tend to be a little cheaper and are easier to find.

 

For an 8g tank like that, you could use 12-14 LEDs in a 50/50 mix of white and blue.

 

Thanks for the reply , I have another question, I saw in this thread that the solaris has green LED I was thinking about adding 2 maybe to get a similar color what do you think ?

 

I will be reading pages at a time

[evilc66]

I don't see any point in green LEDs. They are not useful for photosynthesis, and using only two in a 25 LED array makes little to no difference in color. I would rather invest in more blue or white LEDs to increase my output. I have been using UV LEDs recently to see if they help with sps health, and they seem to be doing ok.

[roxy25]

I don't see any point in green LEDs. They are not useful for photosynthesis, and using only two in a 25 LED array makes little to no difference in color. I would rather invest in more blue or white LEDs to increase my output. I have been using UV LEDs recently to see if they help with sps health, and they seem to be doing ok.

 

Thanks for the info !

[evilc66]

As always, you're welcome

[cyberwollf]

I know that the max pulse current in LEDs is higher. Has anyone ran these at high switching rate with 50% duty cycle? should output more and not appear to flicker. Shorten life? If i remeber the datasheet right, cree's were 1.5A+ i think. thoughts?

[evilc66]

Can be done, but it's not for your average DIYer. It would need a controller to be able to set the duty cycle. I haven't seen a standalone driver do that yet. But when you think about it, what advantage would that get? For percieved brightness it would work, but for photosynthesis would it make a difference? I mean, you are getting more light, but only for 50% of the time. Would that equate into a benefit over running slightly less current, but with a 100% duty cycle?

 

I might try that out with my controller for giggles.

[cyberwollf]

like you said, its brighter only half the time. that would be interesting to test. For human eyes it would appear brighter and continuous,but i wonder what a PAR meter would say for 20khz 50% duty cycle. If you look at it simply from power output it doesn't add up. just a thought

[mabviper]

This is exactly what the buckpuck does. It runs a high frequency signal altering it's duty cycle from 0-100% to adjust the current from 0 to max rating. A buckpuck is just a dc-dc buck converter. They're more efficient than linear regulators because they use switching techniques.

[adinsxq]

E, in case you're wondering what the inside of an AI looks like, here's a photo:

 

For the record (and warranty reasons!), I am not saying this unit is mine. I just happen to have a photo of one that's been exploded so I thought I'd share.

 

[Omen]

I just happen to have a photo of one that's been exploded....

 

LOL....

[evilc66]

E, in case you're wondering what the inside of an AI looks like, here's a photo:

 

For the record (and warranty reasons!), I am not saying this unit is mine. I just happen to have a photo of one that's been exploded so I thought I'd share.

 

 

Thanks. I will enjoy looking at that when I get home. Work blocks most photo hosting sites.

[ccjung]

I mean, you are getting more light, but only for 50% of the time. Would that equate into a benefit over running slightly less current, but with a 100% duty cycle?

 

I agree. PWM gets the job done and works well with mechanical systems like fans, since they have inertia keeping the fan spinning despite fact that the power is being switched on and off rapidly.

 

I know asiansignals has some PWM based driver/controllers, but im not sure if PWM is used to drive the LEDs or control the buck/boost.

 

I would assume that the most benefit would be to keep a 100% duty cycle, as opposed to more power for less cycle time. Photosynthetically, I think the xoo will take a photon any way it can get it.

 

When we test our LEDs here at the shop for thermal/lumen maintenance, we often hit them hard > 1.5A and keep them cool. When you pop a PAR meter under there, you usually see diminishing returns as you push the limits of the LED. Whats REALLY fun is when you slam the things so hard that they shift blue. I've thought of this application in the REEF, since it seems much more like our kind of light, but I wouldnt recommend it for the life of the LED.

[evilc66]

Right. What most people don't see is that a 50% increase in current doesn't equate to a 50% increase in light output. The difference in light output as current changes is also different from one brand to another.

[ma_sha1]

Whats REALLY fun is when you slam the things so hard that they shift blue. I've thought of this application in the REEF, since it seems much more like our kind of light, but I wouldnt recommend it for the life of the LED.

 

This is so true. I've seen a link somewhere with a spectrum plot on driving LED to the limit,

with time, it shifted from 6500K to 9000K & the curve looks it's still going up in Kelvin.

 

I have been over driving a 3x3W cree flashlight head, it's rated Max 9V with an IC circuit board built in,

(I am guessing it's 700mA @ 9V). I tried 12V, almost cooked it, two of the led burned out & lost most of it's light after a few days.

 

I thought I had killed it, I reduced it to 11V, to my surprise, the leds recoverred after a month or so

& it's a lot brighter than when it was run at max recommended 9v & much whiter in color.

 

I have been running at 11v over 6 month, the color now look much whiter than my 10K MH bulb.

Don't know how long it's going to last, but I think it'll still out last my MH.

The good thing is that it keeps getting whiter where my MH gets yellower after 6 mth.

 

If anyone is curious, this is the 3x3W Cree that I've been over driving to 11v.

http://dealextreme.com/details.dx/sku.9358