Building a 1 watt LED light

At one time I wanted to be able to turn off some strings but changed my mind. Now, I just want to run them all the time and no dimming feature either. Your example would work, for 3w, but there are different ones that work for 1w. I got to make a circuit board for my light.

Heres the latest pics.
Timer module installed.
Buck board and power supply mounted.
Power cord connected.
One end mounted with blower sleeve.

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screwdriver said:

At one time I wanted to be able to turn off some strings but changed my mind. Now, I just want to run them all the time and no dimming feature either. Your example would work, for 3w, but there are different ones that work for 1w. I got to make a circuit board for my light.

Heres the latest pics.
Timer module installed.
Buck board and power supply mounted.
Power cord connected.
One end mounted with blower sleeve.

Click to expand...

No dude those will actually run 1 and 3w chips.

Nearly ready to test.

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Now that looks awesome! Can I see the other side of the board if at all possible?

Here's the configuration I believe I'm going with. Now a few things could change but this is basically what I'll have. Sorry for the crappy drawing. The chips will be spaced a lil better on the actual light.

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Heres a pic thru the hole. I just milled some quarter inch aluminum so the quarter inch squares would stick thru the board. The back side of the circuit board also had copper on it but most came off. The copper on the back side doesn't electrically connect to anything.

On a side note:: Wear some sunglasses while working on light. Went to bed last night but could still see the lights with my eyes closed.

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bombbudpuffa said:

Here's the configuration I believe I'm going with. Now a few things could change but this is basically what I'll have. Sorry for the crappy drawing. The chips will be spaced a lil better on the actual light.

Click to expand...

Do you solder all the wires onto the stars then place into slot or place the stars then solder?

screwdriver said:

Do you solder all the wires onto the stars then place into slot or place the stars then solder?

Click to expand...

I'm going to put them in place then solder.

Testing 1, 2, 3, Testing

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Nice!!

Looking good buddy :48:

Thanks peoples.

Parallel circuit.

Yes, you can run your LEDs in parallel. I will you use the above image (post#59) of the driver and some 1 watt LEDs. The specs I read are: 30 - 70 vdc @ 680 mA. The LEDs forward current will be 350 mA. With the constant current output of the driver I can run two strings of the LEDs in parallel. There will be 340 mA running through both strings. Since the voltage is from 30 to 70 volts and in this case, the voltage drop on each LED will be 3.2 volts. I can have from 10 to 21 LEDs in each string. BUT....


The 3.2 volts is an estimate at a given current. Each strings total voltage drop difference allows more or less current to flow in that string. Instead of 340 mA in each string, you could have 360 mA on one string and 320mA in the other. This would simply cause one string to be brighter than the other. Depending on the differences of individual LEDs, you may or may not be able to see the difference. There may also be enough of a difference to significantly impact the light. As in the forward voltage drops of the LEDs on one string are in the upper range ,3.4, and the other string they are at the lower end 3.2. That would be .2v per each of the LEDs for a total of 4v. My guess is you may see smoke from one side conducting harder than the other.

So what if an LED fails?

In the second drawing the LED fails by opening. The rest of the LEDs in that string just go out with no damage. But the 680mA of constant current has to go somewhere. Which, with only one other path, the full current of the driver goes through the other string. That much current through the LEDs most likely will damage the whole string until one goes out in that string.

What if it shorts out instead?

Anybody?

Bueller.
Bueller.

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Can you solder a resistor of some sort on each led?

bombbudpuffa said:

Can you solder a resistor of some sort on each led?

Click to expand...

There are two answers to that question, yes and no. The yes side says with a few extra components and more complexity it can be done (not to each LED). The no side says, use that LED driver in post #59 to power LEDs that can handle that current level output. The image actually shows 12-20 @3w

Barring any failure it still can be used just with two strings of parallel 1 watt LEDs between 10 and 21 per string. You may have to compensate during the build by measuring the voltage drops on each string and each LED so the two strings match but that brings up other negative factors we'll discuss infused into later posts.

This is the schematic of my light. The lighter red LEDs are 620-625nm, darker reds are 660nm, blues are 440-450nm and the pinks are the full spectrum 380-840nm. The light pattern shown is the same on the light. The other spec on the LEDs that I measured was the lens angle. While it may not be exact, the majority of the light spread measured from within an inch of the LED are: for blue the lens angle was 90 degrees and 120 degrees for the rest. I could have choosen a more narrow len angle and then I would just need a little more distance from plant. Since my head room is limited I was aiming for the wide angle.
Why the different wavelengths and how to choose?
I guessed, whatever looked pretty in my head. Don't look at the light after you build it.
Here's some thinking stuff.
This could have been made in a completly different way and be even better but this is more of my path. At one point I wanted to control different strings and maintained the ability to add that in the future if and when somebody claims that a light schedule of 5 minutes of blue on then 2 minutes of red on while blue is off for 3 minutes. Then when red goes out for 8 minutes the blue blinks at a rate of no more than 39.99 hertz. Opps, sorry I got cynical up in your as. I'll continue.
How big did I need to go? I don't know couldn't really make heads or tails of the needs or wants. So I looked around at what I had. Some things in my design are because I have it versus using the more appropriate item. I wanted to use a 12 volt 15 amp power supply but got discourged when I couldn't find the other pieces of the puzzle quick enough and the thing is HUGE (say it right). I settled for a 24vdc 60watt power supply (constant voltage). Plug the input to my 120VAC outlet, the other side will go to the circuit board. Whatever the amount of LEDs I used I wanted to keep the total output power of the light box to be around 50watts. The 60 watts of my power supply fit that bill.
Then I moved on to how many LEDs I could power with the power supply I choose. Using intelligent guessing and Ohm Law Break

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Pictures

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Glad I don't have to do all that work. Mine is basically plug and play besides soldering the chips together. The hardest thing about mine is deciding on the colors.

You're light looks like it should produce. Can't wait to see it growing.

screwdriver said:

Pictures

Click to expand...

Yea....that's really good looking. Anxious to see how they perform.

bombbudpuffa said:

Glad I don't have to do all that work. Mine is basically plug and play besides soldering the chips together. The hardest thing about mine is deciding on the colors.

You're light looks like it should produce. Can't wait to see it growing.

Click to expand...

I agree.