DIY 150 Watt 18"X18" 48 diode grow panel

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Chockfullonuts

Active Member
I recently decided to switch the lighting in my grow box from cfl to LED. My box inside dimensions are 23"x23"x45". I like to do things for myself, so I figured that this would be a snap. NOT! LED array design is rather involved and quite technical. At least it seems that way to me. I'm in over my head, breathing thru a reed and the tide is coming in. Thought that maybe someone on here has built their own fixture and possibly could redirect my efforts.

I have already constructed the frame/heatsink (18"x18") out of aluminum channel, angle and bar stock. Have purchased red and blue leds and constant current drivers. My plan is for 4 strings of 12 leds in series then attach to power in parallel. I put together one string of lights, hooked up a driver and nothing happened. I checked continuity and polarity, it is correct. Tested all leds in string with a cobbled together double AA battery testing power supply...all lights work.

My guess is that the drivers and diodes are mismatched. I have no power supply, just have LED drivers.

If anyone is interested in giving me any input on this project, I will post specifications of products that I am using.

Since this is my first venture into this arena, I am using cheap Ebay diodes and drivers. After I get the kinks ironed out and my light is up and worling, I will consider higher dollar components.

Thanks in advance. Keep on toking!!

Chockfullonuts
 
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Chockfullonuts

Active Member
guod said:
need more info for a helping hand...
Click to expand...
Thank you for the reply, Here are the specifications of my leds and drivers.

No Name 30 watt constant current driver (5 Each)

Input: AC 85-265 V 50/60 Hz
AC 0.3 A
Output: DC 15-36V
DC .9 A (900 mA)
30 Watt

Led 20 mm star Bright Red 660 nm 3 watt high power (50 each)

Luminous flux 60-80 LM
Forward Voltage 2.0-2.5V
Forward current 800 mA
Color temp Red 660 nm
view degree 120 degrees

Led 20 mm star Royal Blue 450-455 nm 3 watt high power (10 each)

3 Watt
Wavelength 450nm-455nm
DC forward voltage (vf) DC 3.4V-3.8V
DC forward current (If) 700mA
Viewing angle 120 degrees
Luminous intensity (lv) 70-80LM
 
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Chockfullonuts

Active Member
I have 49 spots. I was thinking 4 strings of 12, or 3 strings of 12 and 1 string of 13. I was considering using all 10 blues.
Should I mix the red and blues on each string or have an all blue string? From my research I know that I don'tneed too many
blues. Is there an accepted red/blue ratio
 
guod

guod

Well-Known Member
the red blue ratio starts with 1blue on 4red and ends with 1blue on 8reds
a string of 12 leds
3red::1blue::4red::1blue::3red


driver:
Output: DC 15-36V
DC .9 A (900 mA) a bit high for 3W leds

red
Forward current 800 mA
Forward Voltage 2.0-2.5V

blue
DC forward current (If) 700mA
DC forward voltage (vf) DC 3.4V-3.8V

the current from the driver is just a bit high for this cheap leds.
with that we will see that the Forward Voltage goes up to 2.5V for the red and 3.8V for the blue.

voltage for one string is
10x2.5V + 2x3.8V --> 32.6V this will work as it is lower than the Output of the driver. max. 36V

btw. always connect the driver to the ledstring first, then power it up.
 
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Chockfullonuts

Active Member
guod said:
the red blue ratio starts with 1blue on 4red and ends with 1blue on 8reds
a string of 12 leds
3red::1blue::4red::1blue::3red


driver:
Output: DC 15-36V
DC .9 A (900 mA) a bit high for 3W leds

red
Forward current 800 mA
Forward Voltage 2.0-2.5V

blue
DC forward current (If) 700mA
DC forward voltage (vf) DC 3.4V-3.8V

the current from the driver is just a bit high for this cheap leds.
with that we will see that the Forward Voltage goes up to 2.5V for the red and 3.8V for the blue.

voltage for one string is
10x2.5V + 2x3.8V --> 32.6V this will work as it is lower than the Output of the driver. max. 36V

btw. always connect the driver to the ledstring first, then power it up.
Click to expand...
 
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Chockfullonuts

Active Member
Thanks. If you were to change something, would it be lights or drivers.
Although not perfect, you seem to think that this should work.
If they should, why do you think I could not get it to light up?
 
guod

guod

Well-Known Member
thinking that this is a driver problem. to check that, the first step i would do; kickin out two reds from the string, That will lowering the stringvoltage and maybe the driver now can handle it.
also try some of the other drivers. some work, some not.

a simple drivercheck without a multimeter:
connect two 12V halogenbulbs(>10W) in series to the driver.
no light, faulty driver ( ;) if the bulbs are good)

a pic of your build(leds and wires), as close as possible can help also.
 
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Chockfullonuts

Active Member
guod said:
thinking that this is a driver problem. to check that, the first step i would do; kickin out two reds from the string, That will lowering the stringvoltage and maybe the driver now can handle it.
also try some of the other drivers. some work, some not.

a simple drivercheck without a multimeter:
connect two 12V halogenbulbs(>10W) in series to the driver.
no light, faulty driver ( ;) if the bulbs are good)

a pic of your build(leds and wires), as close as possible can help also.
Click to expand...
 
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Chockfullonuts

Active Member
Just had some company arrive to spend the night. I will take some pics tomorrow. Just before my company got here, I inserted the blue leds into my series in the order that you suggested. Hooked up the driver...still nothing. I have tried two of my drivers. I will try another one tomorrow. I have checked my soldering for grounding to the star backer plate.. Did not find anything. One other thing. I tried to light up just one led with the driver. All it would do was flash, would not stay on steady .It would not tlight up two leds. I really appreciate the time that you are taking with this.
 
guod

guod

Well-Known Member
All it would do was flash, would not stay on steady
that´s OK
voltage is too low for the driver, we need 15V. one led needs only 2.5 or 3.8V
7 reds/ 5 blues will be the lowest count here. seems also that the driver works.

maybe polarity problem?... maybe!
pol.jpg
 
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Chockfullonuts

Active Member
Don't think so. I have gone down the string checking each led for function. They all worked and I never had to flip my tester to make one come on.
 
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Chockfullonuts

Active Member
Chronikool said:
Throw up some pix yo'sive.....we will see whatz up... :)
Click to expand...
II am going to try to post some pics of each individual led in the string that I am working with. It seems that the image posting method has changed since the last time that I posted here (year and a half). I'm sure that I will figure it out.

Here is where I'm at. Using 20 gauge solid bell wire. I know that stranded is recommended. I will use stranded for final build.
Stars with amber contacts are blue LEDs. I just checked all LEDs in this string for function by contacting" +" of one to" +" of the next led in string with my 3V test device. They all lit up in turn. I assume that since they all worked when I hooked up batteries that I don't have any grounding to aluminum star backer plate.

I haven't got image posting figured out yet...but I will get it.
 
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