I need an Electical Engineers help for LED's

[DeadlyFoez]

Ok, I'm planning on making 300 watts of leds in a few different arrays and also some dangling into the middle of my plant. I dont know electricity enough to know how to poer something like this or to even wire it and use transistors or resistors or whatever. But I need you help. Please tell me what I need to know to be able to do this or links as to where I able to find this info.

I planning on using 5w Blue and 3w Red LED's. I'd like to make maybe 5 arrays.

 

[2buds]

Tag, LEDS for growing, good luck.
Contact one of those ebay guys selling the leds, they should have all the answers or possibly some diagrams they can email to you.
Good luck

 

[Heady NUGs]

clicky

 

[DeadlyFoez]

Yeah, I know about that site, but I still aint no electrical engineer or someone who claims to know how to do this.

Plus, I'm also going to be using 2 different led's of different wattage. I have no clue as to wiring this thing up. I dont know what else I need other than the led's.

 

[JollyGreenGiant]

You're going to need to get some PCB's etched and it's going to be a lot more complicated than you think. Do you know how to solder? Digikey and google are going to be your friends...

 

[DeadlyFoez]

Hey, I'm not bad at soldering. I've never heard of digikey, but I'll google it

PCB's?? Are those circuit boards?

I'm not sure if I want an "array" of led's, but more of an expandable system that can spread out as the plant does to evenly cover the plant and also to dangle a few into the middle of the plant.

 

[DeadlyFoez]

These are the LED's I wanna use.

http://www.luxeonstar.com/item.php?id=1770&link_str=196::198&partno=LXHL-LD3C
http://www.luxeonstar.com/item.php?id=372&link_str=199::201&partno=LXHL-LR5C

I'm starting on this project hopefully in 2 weeks. Can someone put in their input. I really need help with this in a big way.

My plan is 600 watts total. 180 Red LED's and 12 Blue LED's. I figure to make then into 12 arrays. 10 of the arrays would be mounted on a panel and the other 2 array would by my dangling leds for hanging into the middle of the bush.

Please any one with information on my power requirements of what I would need to use for a power driver to handle these and any ideas on a design diagram would be appreciated. Thank you

 

[een]

I'm an electrical engineer and can do this for you, but science, and by now some people's experience, have shown that it doesn't work very well. However, if you still want to do it you can get a custom PCB made and delivered for under US$200 these days.

 

[DeadlyFoez]

I'm an electrical engineer and can do this for you, but science, and by now some people's experience, have shown that it doesn't work very well. However, if you still want to do it you can get a custom PCB made and delivered for under US$200 these days.

More info please.

I changed my mind on the royal blue LED's. Instead of the 5 watt version, I'll go with the 3 watt version. I will use 20 of these to give me my propper ratio.
http://www.luxeonstar.com/item.php?id=390&link_str=196::198&partno=LXHL-LR3C

I decided this because I figured it would make it easier for power requirements if I used the same wattage LED's altogether because the 5 watter riquires a higher voltage which would add a little more unneccessary complication when theres an easier way around.

If possible I would use a computer psu. But i pretty much need to know how to do it then I can wire it all up myself to my liking. The luxeon star LED's feature a board already attached so you can line them up and solder pretty much.

I want to be the ginuea pig for this experiment and see if I can further along peoples interest into it.

If you could really help me out and mentor how to wire it up and what resistors to use I would greatly appreciate it and maybe even send you some finished product for your effort. No one else has been able to step up for me to give me a hand and I've been looking for a bit.

One thing that I am also thinking about is that I should get some other LED's of different wave lengths, maybe 660 and some UV A and B, but just a handfull. I would have the UV LED's turn off when I open the door to my cabinet via a relay so I'm not affected by the rays.

Check out my cab going on.
http://www.icmag.com/ic/showthread.php?t=33660

 

[Chester]

You can also use the perforated "project" boards from Digikey.com, mouser.com, and possibly Newarkinone.com. These can set you up with a power bus and are pre-drilled for easy mounting of your components.

As to the LEDs themselves. You need to limit the current flow through them and that usually requires a resistor between the positive voltage and the LED (actually doesn't matter which side the resistor is on) Then LEDs are also polarity sensitive devices and must be wired correctly (one lead is usually longer than the other). The size of the resistor depends on the voltage you intend to use (size=ohms, and computer PSU output is typically 3.3V, 5V, and 12V and will require an enable jumper to turn-on an ATX power supply)

A computer power supply may do the job, however you need to assess whether it will operate properly if you are only using the 5V output for instance... Some PSUs will not operate without some 12V load...

What you want to try isn't hard, just complicated. I'm not convinced that the light spectrum is there yet but an experiment can't hurt.... And the cooler operation is tempting...

Best of luck there.

 

[DeadlyFoez]

Awesome info.

What else would you recommend as a power source?

I think I'm getting the picture of how to run this. I just need to know what resistors I would need.

I'm also wanting to add nobs to be able to dim the arrays and also change the frequency or blink rate. Like if I could control it from 5hz to if possible 20khz. I figure you can since it's dc current. Am I correct?

But I understand frequecny would be a little tougher. but if I want to dim...correct me if I'm wrong...I could just setup my array with a resistor on each of the series and then just use a resistance nob on the main positive lead to be able to dim it some.

Thank you for your input. I greatly appreciate it.

 

[een]

That's $1500 of LEDs?!

Those LEDs are designed to be mounted on a big piece of aluminium, so as Chester said no PCB is needed except maybe to hold the resistors.

On 12V rail of a PC power supply, you would use:

45 strings of 4 red LEDs with a 0.13 ohm 1/2W resistor.
6 strings of 3 blue LEDs with a 0.3 ohm 1/2W resistor, and one string of 2 blue LEDs with a 4.2 ohm, 5W resistor.

Loss in resistors would be 20W.

Running these LEDs on 5V rail would be very inefficient and a PITA, so lets assume you use only the 12V rail... The current needed is 76.3A @ 12V. You can probably get that from a a single supply these days, otherwise you can use 2 in parallel I think.

 

[DeadlyFoez]

Yeah. Those are the links just to the specs to the LED's. I got a site that will sell them cheaper. I did my math and it would be about $850. But for the time being I think I'm going to do just 400 watts first and if it goes smoothly then I'll continue on. But it would be nice to have just one power supply. Do have any links to something that would handle these leds? I figure about 51 watts of leds per array.

The best thing about a computer psu is that there are already plenty of molex connections that I would be a ble to just plug in an array pretty easily.

Here a link I came across which sheds a bit more of light onto the efficiency of HIDs and why leds can totally blow them out the water if used propperly.http://www.ledtronics.com/ds/plantled/Commercial-Growing-Analysis-Recommend-s.pdf

 

[DeadlyFoez]

According to this article, 124 watts of leds whould be equal with the usable light output to a 1000 watt hps. If that is really the case then even 200 watts of leds would be more than enough for my cabinet. Hell, I only got a 400 watt hps in there now and my last plant grew freaking huge. But I still want the possibility of 600 watts for extreme growth and dense buds.

 

[een]

I'm not going to enter the HID vs LEDs debate lol but I can help you with calculations for power etc.

This beast can almost do it, 75A:
http://www.newegg.com/Product/Product.asp?Item=N82E16817194008
Or 2 of these:
http://www.newegg.com/Product/Product.asp?Item=N82E16817203004
Or 4 of these at $25 each:
http://www.newegg.com/Product/Product.asp?Item=N82E16817165004

The hardest bit would be building the LED panels, unless you can find someone else who has done it you are in unchartered territory.

 

[DeadlyFoez]

Now wouldn't I be able to utilize that 650w one and use the 5v connection too. I know that it wouldn't be effecient, but it would be better than $350 on that 1000w one. I know that the power supply only puts out what is being used so I wouldn't be using the full rated amount.

But like I had said that I could use some other supplemental leds for other wave lengths, like uv and closer to 670nm. I think if I did a fair mix of all those plus the luxeon stars then I'd get closer for making chloryphyl a + b.

So if using those would I be able to use them on the 5v leads? then I think I'd have a better chance.

Now please tell me, how do you figure out what resistor to use. If I know this then I'll have a better chance to also be able to help myself. I'm sure its just math and I'm very good with it.

Thank you.

 

[een]

http://white-leds.co.uk/led-wiring-guide.htm explains it
(The Vf for your red is 2.95V and the Vf for your blue is 3.9V. They talk about running them at 0.02A but you would run your red leds at 1.54A and your blue at 1A.)

To run a red LED off 5V needs a 1.33 ohm 5W resistor and loses 3.16W to heat
To run a blue LED off 5V needs a 1.1 ohm 2W resistor and loses 1.1W to heat

http://www.theledlight.com/ledcircuits.html

 

[DeadlyFoez]

Blue Luxeon III are about 20% efficient (converting input energy to light), and red Luxeon III are between 25-30%). This let you more than 2watts as heat to dissipate per led. This heat must be dissipated by convection. PCB dont have enough cooling capabilities to deal with it (search in Phillips Lumileds, manufacturer of Luxeons, for Luxeon thermal management).

You must try to mantain die's temperature below 60ºC, in order to obtain a decent duration and a good perfomance (at 60ºC die temp, red output is 70% of nominal at 25ºC). You can glue the leds with electrical isolated thermal paste to a aluminium/copper (aluminium is easier to find and cheaper, but less effective) sheet of enough dimension (minimun 9 sq inches per watt).

Peace

PS: i dont know if you have buyed the leds yet, but in Future Electronics, the official Luxeon distributor, you can buy it at half price than in the link you posted, always you be in USA/Canada.

Yeah, thats where I was wanting to purchase them from. But they're online ordering is a little screwed up right now and I just haven't had the ambition to deal with someone on the phone yet. I'll make my wife do it soon

See, with the luxeon stars, they already have a piece of aluminum on the backside to help with thermal dissipation. After joing all the stars together I'd use a little artic silver thermal paste with some small copper heatsinks that I already got kickin around.

As for PCB boards, I'm only gonna be using them for other supplemental leds that I'd be running off of the 5v of a psu. I still have a lot of more research to do as far as what would be my best options for ratios of wavelengths.

I'd only run the luxeon stars off of the 12v. And i could use the wires that are ment for video cards and sli. That would all go together perfect.

Thank you for all the links. I got a lot of reading to do. I'ma try to figure it out mostly for myself but I'm going to need some help here and there. It would still be easier to pay someone to do it for me. I dont have much free time to try to figure this out, but we'll see.

I also downloaded CADSoft Eagle. I'm going to try to learn that also so I can design my own pcb board once I got this all figured out so it wont be so thrown together. I may even have the stuff shipped out and have it all machine soldered.

I bet I'll be an electrical engineer by the time I'm done.

Does anyone know any good electrical engineer forums out there?

Thanx a whole lot guys. I'll take all the help I can get.

 

[DeadlyFoez]

Knna, I've been reading what you've been posting on cannabis.com. You really know your stuff so far.

I'm reading about ur whole escrow situation with that chinease company. Did it work out for you? Did you build something yet?

Now tell me, what are the wavelengths that you are aiming for? What have you found to be ur LED's of choice?

Where as you've done lots of research already, I'm hoping you can just pass of to me what you already know.

 

[Verite]

I'm not going to enter the HID vs LEDs debate lol but I can help you with calculations for power etc...

When a LED can throw useful light a distance of four feet maybe then they'll be able to compete with a hid.