2.5g Pico Tank LED lighting!

[mrg02d]

I think I better understand what he was describing by parallel. He is going to run series strings off the same power supply. That should be fine, 100% if I do understand him clearly. Thats totally different than running individual LEDs in parallel to OTHER LEDs.

I believe I am almost ready to order. I will get my heatsinks from ebay, as heatsinkusa.com wants to charge me some sorta $5.00 fee for cutting, which turns a $15.00 heatsink into $20.00. Thats BS in my opinion! Especially for a normally stocked item/size!

Aluminum bar stock and acrylic will hold it all together.

On a side note, I am planning the scale up for my 20g. Measures 24in long, 13in wide and about 16in tall. Any idea how many LEDs id need for that? I was thinking about 18. That would be three rows of 6. Two dimmable drivers, one for each color for full color mixing. Id want to keep my SPS and clams in it under LED lighting... I may also use a microcontroller for running the whole thing. Might as well, as thats whats left for me to do before I get my electrical engineering degree! (microcontrollers, not reef tank, ahah)

Matt

 

[Kristall-99]

My turn to hijack.

Im looking at doing led's for a 10gal ill be switching out and using it for a smaller "frag" tank for in the bedroom. Im looking at running about 15led's (if this sounds like to little lmk as i havnt had much experience with the CREE XRE Led's Could I run ~9white and 6 blues running 2 this meanwell both on dimmable controllers. Is their anything else im missing? Can I run a regular power plug cord to power the unit to regulate the voltage for my series? Should I add more Led's?

Any Input to keep the costs down yet still have the same function?

Thanks Kristall

 

[Jimbo7]

For a 10g, 15 LEDs is going to be more then enough. Probably even way too much. 10 is going to be enough, possibly less. Are you looking looking to upgrade tanks soon?

 

[Kristall-99]

well i got the 55gal tank downstairs with a 250mh bulb for everything else. just wanted to look into a smaller tank for my personal room that didnt give off as much heat and less volume. Should I just get 6white 4 blue and run the different colors on different meanwells with the dimmer?

 

[Jimbo7]

I would go equal of both and have dimming drivers on both. You are pretty limited when you set in the 6 and 4 like that with the W/B contrast.

 

[Kristall-99]

So just go 5w 5b or 6w 6b depending on how im going to go about the space and just dim them down to the corals liking. Would I need that big of a meanwell to supply 6 leds? would i just use a regular power cord into the meanwell?

 

[Jimbo7]

Its easier to run them in series of 6, the voltage drops off almost completely, which means less heat coming back to your drivers. I don't know much about the meanwells, but if you are driving more then one set of lights, its cheaper to buy one power supply (mpja.com) and two separate drivers (ledsupply.com)

 

[Kristall-99]

Would It be possible to run them off a Laptop Power supply? I have one off a dead Laptop thats output is 19v at 4.74a. Assuming im using 3.3v led's id only beable to run 5 leds off the psu correct? ill look more into the power supply and drivers. How big of a Psu do you think id need to run 12 Led's?

 

[krap101]

If you have 1 string, you'd need a ~40V power supply (it needs to be able to supply at least 800ma. Two strings of 6, you'd need a 20V power supply that can give 1.6A. I was planning to use a laptop power supply, but I want to avoid that extra heat at the end (extra voltage, in your case ~2.5v) I'm still not sure about the switching power supply, but I talked to someone about a year ago that said that's how you avoid needing resistors at the end of the string.

 

[Jimbo7]

That power supply would work fine for driving all 10. As long as you do them in 2 series of 5.

A 24v power supply would be enough to run 12. You need ~4v per LED in series. all you would need is 24v and 1.5a to run several strands of 6.

 

[Kristall-99]

well it looks like it would just be easier to go the psu/driver way instead of getting 2 meanwells. So il lbe getting 6 white and 6 blue. one set on a 3023-D-E-1000mA Wired BuckPuck. Powerd by Power.

 

[mrg02d]

Good news, nanotuners responded that the 30-27D meanwell will indeed work with 5-6 CREE XR-E Leds. The guy that responded uses it himself with 5-6 CREE leds, so it will work well...

I guess I will go ahead and place an order. Too bad their heatsinks are quite pricey. It would be nice to save on shipping.

Now I must find a heatsink that will work. Doesnt need to be that beefy, just large enough to hold these leds and easy enough to drill some holes for the standoffs (acrylic splash guard).

Any ideas other than heatsinkusa.com?

Matt

 

[Kristall-99]

Does it need to look pretty? if not. Piece of metal to cover your area. and use thermal adhesive and put screw to the block. It works well..Some people have used it in heatsinks for their smaller controllers on their motherboards.

 

[mrg02d]

Does it need to look pretty? if not. Piece of metal to cover your area. and use thermal adhesive and put screw to the block. It works well..Some people have used it in heatsinks for their smaller controllers on their motherboards.

This is what I was wondering as well...I may not really need active cooling to keep the LEDs happy. A heatsink with fins (pricey) may not be required for 5 LEDs. Even at full power, the heatsink would be dissipating 15W minus whatever power is converted into light.

If they do need some active cooling, I might just bite the bullet and get two of these:
Nanotuners.com

Would wind up paying that much with shipping anyways...If I did this method, I would want to use 6 LEDs and have the LEDs arranged so that there would be a front row and back row. Whites in the front and blues in the back. So, two rows of three all in series. Sound okay?
BBB
www
Two inch spacing...

Im guessing with a tank this small, just about anything will work due to the large divergeance of the LEDs...

Matt

 

[Jimbo7]

It will probably be alright, you will probably be able to tell the difference from the sides or at an angle, but straight on it should look nice. How much is shipping from heatsinkUSA that ordering from nanotuners makes it worth it?

 

[mrg02d]

It will probably be alright, you will probably be able to tell the difference from the sides or at an angle, but straight on it should look nice. How much is shipping from heatsinkUSA that ordering from nanotuners makes it worth it?

HeatsinkUSA wants like $7.50 plus another $5.00 cut fee. That cut fee is idiotic. So its going to be $27.00 for a 4.3in by 8in piece of aluminum.


Its like McDonalds charging you to put the food in the bag. Its their product and I cannot go to their place and cut it. Sheesh! Their product is an 8in long by 4in wide aluminum heatsink. I dont understand why I have to pay $5.00 for them to go whack and cut it off their extrusion.

Matt

 

[mrg02d]

If it is going to look a bit odd, then thats a deal breaker for me. I am a stickler for things like that. Especially when spending $100+ on something, so I may figure out something else...Im sure I can find something on ebay that will suit my needs.

Matt

 

[Jimbo7]

I could be wrong, but it seems like you would be able to tell.

 

[mrg02d]

I could be wrong, but it seems like you would be able to tell.

Hmmm...Maybe I ought to get some paper, pencil, and my calculator to work out how the light should be cast. You said these LEDs have a divergeance angle of about 100deg, right? Using some Trig, I ought to be able to figure out how the light will be cast from each LED...

Matt

 

[Jimbo7]

http://ledsupply.com/docs/cree-xre.pdf

There is some more technical data there, The whites are typically 90 and the blues 100. Post up your diagram if you make one, it would be a good learning visual.

EDIT: Don't forget to take into account the refraction when it enters the water and how high off the water they will be. Thats going to be the hard part