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LED lights?

PearlJamFan

PearlJamFan

Member
Screw it, I am going to place the order as is:
2,000 of the 660nm
1,000 of the 635nm
500 of the Blue 464
Some 400nm UV and sprinkle a couple of Green in there, I know I know!

I do have a generic iron, I will use that.
 
LED_experiments

LED_experiments

Member
i'll advice you via msn when you get the material (as i promised). i'll get that 400 back soon, so i can take a picture of back side of it or make a few pictures during the upgrading process.
there was a nice thread at OG, with pictures and all, how to wire leds into an array. but it is no big deal.
@packn2puff: try and report :pointlaug
 
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packn2puff

packn2puff

IC Official Assistant to the Insistent
Veteran
LED's usually use two lead identifiers..if it has a flat notch at the base of the plastic that is the cathode(negative)..or if one lead is shorter than the other that is also the cathode..generally the cathode is soldered directly to your negative source(call it ground)...the anode is usually soldered to a current limiting resistor..the value of that resistor depends on the voltage source...
to figure it out say a 12V source 20mA diode...(2V drop for diode, a constant for calculating, found 1.6V to be more real world)..
12V-2V=10V {this is source after diode drop}.. {this is what's left across the resistor}10V / 20mA {the series circuit current} = 500ohm..
Chose a resistor standard size next higher, say a 560 ohm..
Some diodes already have a resistor soldered on as part of the package..(package says 12V LED's)...
Sorry didn't build an array..but thinking about it you can use say a 120AC source directly with bigger resistor say 6k or so..but then the LED's flicker 60 times a second..
A good DC source Full-Wave power supply has capacitors to smooth out the ripple..no flicker..
Don't know if this helps any..just info :wave:
 
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PearlJamFan

PearlJamFan

Member
I found out that I have to pay cash! Damn it, I hate that. I can Western Union but it will add some $$, or I can DHL it to him.

What do you think?

Where did you get your breadboard or whatever it was you used to make the arrays?
 
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Tokin White Guy

Tokin White Guy

Member
wow i cant believe this thread is still active and that ppl are actually doin this. let us know how it goes and dont forget to celebrate the holiday :bongsmi: haha, yeah like anyone here would forget that....a friend of mine didnt know why 4-20 was a holiday....its my goal to get her high via brownies before we graduate :D :sasmokin:
 
LED_experiments

LED_experiments

Member
i tryed AC power supply, but the connections between the leds became abnormally hot, so i dropped that idea of powering them with AC and stayed with 12V DC.
if you have 12V DC PS (power supply), don't use resistors on each led. this is how you loose your efficiency. for example, if you have 100 leds, you have to use 100 resistors, which use much, much more power than those leds does. some of people that made led arrays used resistors for each string. for example 4reds+1blue (4×2V+1×3V=11V), so they had to lower the voltage just for 1V at 20mA. this is more efficient, resistors use less power than first option. i made my 400 led array of 8 boards, 50leds/board (10 strings of 5 leds) and use resistors only between the board and the power supply.
when you calculate what resistor to use, the first calculation is just "what should be" value. you have to use ampermeter to see what you really need. i made my lamp like this:
first of all i made all 8 arrays. when i calculated how many watts (approximately) they will use, i got the number arround 20W. i took a 20W halogen lamp (12V) and connected it to PS to see how does the voltage drop. i also checked the current and all (used 2 multimeters). when i got those data i had info for further calculations. the voltage dropped for arround 0.5V so i had 11,5V if loaded with 20W. i calculated that arrays run at 11V, so i had to lower the voltage for 1.5V. i had 10 strings on each board, so the current should be 10×20mA=0.2A. U=R×I > R=U/I = 1.5V/0,2A=7.5ohm. i connected a multimeter(MM) between board and resistors (board, MM, resistor, PS) so that i could see what current do i get with that resistor. if the current is too high, use more ohms, if it is too low, use less ohms. when you get to the number you need, use those resistors, that gave you that result. at the end connect all of board together, the MM between PS and resistors (boards, resistors, MM, PS) and the number should be the whole current (in my case 8×0.2A=1.6A).and don't be fool and believe the specifications that you get with leds. when i read those data, the max values were much higher, the peak values also, at the end i came to the conclusion, that i need 10.51V instead of 11Vtyp or 12.3Vmax to power them with the right, 20mA current.
 
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PearlJamFan

PearlJamFan

Member
If an LED says
"Continius Forward Current 30mA, Peak Fordward current 120mA"

Does this mean you can Juice them up to 40-60mA without it hurting the LED too much?
 
F

firstavailable

Member
it means what it says. You should not run them continously over 30mA, but if you get short spikes of 120mA, is no big deal.

That being said, there is something called "overdriving". That is when you run more current through an LED than it is rated for. You get more light, but the LED will die sooner. How soon all depends on how good the LED is, and there are no guarantees once you go oveer the rated 30mA. It could live for a long time, it could burn up right away. It's all a crap shoot.
 
LED_experiments

LED_experiments

Member
you have 3 info about the current (at least mine have)
first, the lowest number is normall condition. (in my case 20mA) - symbol I with index f
second, bit higher is called MAX Continuous Forward Current (in my case 50mA for reds, 30mA for blues) - symbol I with index f (signed in the MAX Rating data).
third, the highest number is 'Peak forward current (pulse duration)' (in my case 200mA for reds, 100mA for blues, both 10 micro secunds) - symbol I with index fm (also signed in Max Ratings data)
and if you power them with higher current, they die sooner (as firstavailable said).
 
PearlJamFan

PearlJamFan

Member
Here is some more info on the LEDs.

Prices:
1,000 of KTL053AxI-T, 632nm, 7800mcd, 120 degree angle, $38.33/K
2,000 of KTL051AxI-U, 660nm, 5800mcd, 25 degree angle, $35.38/K x 2 $70.76
500 of KTL050BUCI, 464nm, 4000mcd, 30 degree, $116.54 for 500
Shipping by EMS, $30.00
Total $255.63

Info:
KTL053AxI-T, 632nm, 7800mcd, 120 degree angle, http://www.kouhi.com/pdf/114KTL053.pdf
KTL051AxI-U, 660nm, 5800mcd, 25 degree angle, http://www.kouhi.com/pdf/114KTL053.pdf
KTL050BUCI, 464nm, 4000mcd, 30 degree, attached PDF
 
Æ

ÆROSPACE

New member
I just wanted to say how great it is that this is catching on.

PJF: Way to go. Did you order your parts yet? Were you able to find any UVB LEDs? Have you figured your total cost?

I'm can't wait to get started building mine. I have to wait for extra cash though.

Best to you all.


ÆROSPACE:joint:ut
 
packn2puff

packn2puff

IC Official Assistant to the Insistent
Veteran
PearlJamFan said:
Here is a nice tool I found to help build an array.

http://led.linear1.org/led.wiz
Click to expand...

That seems the best way, eat up the voltage by stacking the diodes..the resistor only has to control what voltage is left across it lowering the power rating needed for the diode..that's a good tool.. :yes:
 
G

Guest

nichia are the cadillac of leds. what kind of price are they quoting ?

One thing being overlooked is the FACT that typically 80%+ of the output of HPS and MH
lights are wasted in wrong spectrums. Add to that the huge heat factor waste and its truly amazing that anything grows under them but as we know.. they do !!

Current lights use the shotgun or grenade method to get 'enough' light to the plants.
LED's allow a designer to focus on ONLY the plant needed spectrums. No, leds are not yet to a point they are effective at a 24"+++ distance but leds can be set to within an inch of plants... flooding the photo receptors with EXACTLY what they want without all the negatives of HPS/MH type lights.

Most of the existing led lights out there are trying to replicate existing lights and there is their fault. You dont drive a 3 sec 1/4 mile car the same way ya drive an SUV.

Using leds to grow with simply requires thinking outside the box.... hr
 
G

Guest

thank-you for the LED mag subscribe link. i have a set of LED grow lights and am determined to get good bud with them exclusively. i just added my 4th red unit that should get the intensity up there, good. the mag will be good, too.
 
PearlJamFan

PearlJamFan

Member
Do you have any pics of your array?
How many LED's did you use for the current setup?

I am curious as to what it looks like. I know I have a lot of work ahead of me, solder wise and stuff. But I can't wait to have mine finished.
 
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