Building a 1 watt LED light

[screwdriver]

Looking at this information. The three strings of red, circuits 1,3,5 each have a different voltage drop across the LEDs, 21.5, 21.48 and 21.68. That's the differences in the manufacturing some have an easier time doing what they are supposed to do. Each string still has the 350mA flowing thru it. The blues and pinks have the 350 flowing and those voltage drops are slightly different also.

I was going to measure the drops across each LED for the fun of it but the lights were so bright, I couldn't really see, on my attempt anyway I may have touched something I shouldn't have and the string went out. oops moment.

One advantage to using the LDD350L, it does have circuit protection from overload. It shuts down the output until the problem is removed. So instead of that rush of current, because of the short, taking out the LEDs it just shuts off.

If LED opens, Turns off that string, doesn't affect any other LED in that string (other than turning off) or in other strings on light.

If LED shorts, Not much, LED goes out, current not affected in that string therefore the remaining LEDs operate normally. LDD350L compensates and the output voltage is lowered while maintaining the 350mA output also.

View attachment cob.png

 

[bombbudpuffa]

This is basically what I'm shooting for. LEDsupply didn't send enough nuts or bolts to screw them all in place. Was going to contact them but it would be quicker to just run out and buy more.

Crees still haven't arrived and I'm impatient. If I want to I can switch out chips later.

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[screwdriver]

Is the back side of the stars blank?
Do you use thermal compound ?

 

[bombbudpuffa]

Yes they are blank and yes I do use thermal compound.

 

[screwdriver]

Update on the cob.
I have been checking the temperature of the heatsinks, mainly the heatsink with the 6 LEDs. The sinks with 5 red LEDs temps are 110 degrees F and the 6 LED sink runs about 120f. Those temps are without an exhaust fan on. I think its running cool enough without a fan but it will eventually put into the cabinet with a fan.


So, thinking this might be for flowering. 4 to 5 5watt LEDs per heatsink with eight heatsinks. This one will need to be in a cooltube. I got to do it again but I think the crosssectional open area is more than the area between the tube and the bulb socket of the HPS. There's enough spacing on the sink for the LEDs, can expand if I need but probably not needed.

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[Kraven]

Been following along and i'm really impressed. Looks like your well on your way to a working prototype. Thats where the tweaking really begins, good luck and green mojo.

 

[screwdriver]

Been following along and i'm really impressed. Looks like your well on your way to a working prototype. Thats where the tweaking really begins, good luck and green mojo.

Thanks.

This is my test subject I commandeered from work. Our secretary didn’t realize it needed water. She’s more into shoes than plants. I eventually found it in my rubber tree planter on its death bed for a second time. The first time it went without water it lost all the pretty flowers. She thought it would suck water from it when I watered the rubber tree. So I carried it out on a gurney.

I transplanted and watered. She quickly formed a support group in a sunny window. She looked much better just getting a little water on a regular basis. Nothing extra special just a little love. It was about two weeks of that.

I put her under my light at 18/6 and about 16 inches away. Soon after, it just looks happier. Don’t know if it is just because she looks prettier under the light. The stems feel stiffer, the biggest improvement is the feel of the leaf. Before, with the winter light and water, the leaves felt dry and stiff like they would crack if I flexed them too far. Now, with 18/6 super LED, the leaves feel more pliable and velvety. Very happy with the results so far.

Moved her closer to the light, she’s about 11 inches away now.

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[bombbudpuffa]

Great work screwdriver! Do you think you'll have to add any exhaust to keep it cool...the components.

 

[screwdriver]

Great work screwdriver! Do you think you'll have to add any exhaust to keep it cool...the components.

Thanks.


So far, everything is running at or below 120F. That’s about 50c. Which is well below any ratings in the specs. I believe the interface between the LED and heatsink are cool enough. The best I can check is with an IR thermometer. I can’t find any area that is over 120F no matter where I point on either side of the board. I also get fairly close to narrow the reading area. The other component temperatures are about the same, also within their operating range. So far so good. This testing is in a “large volume” room and there is a small fan kind of pointing towards the hole moving a little air but definitely not like an exhaust fan. In a small cabinet there would be a need to remove that amount of heat with an exhaust fan.

 

[bombbudpuffa]

That's really awesome. No way mine will just passively cool. I'm going to have to add a fan to my heatsink.

 

[Budlight]

Just out of curiosity what is your guises thoughts on those 50 W LED chips that come with the built-in driver

 

[screwdriver]

Just out of curiosity what is your guises thoughts on those 50 W LED chips that come with the built-in driver

I'm no expert. With that type, all the ground work is done for you. Don't have to worry about the spectrum, heat, lens, power. Nothing wrong with letting others do the work for you.

A slight advantage to the 1, 3, 5 watt LEDs are they have a built in lens.

 

[screwdriver]

She's still looking good. Leaves feel thicker. Moved to 7" from light,(not the tall stem)

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[bombbudpuffa]

Looks like the color is blending very well. I'm so anxious to get mine together and running...just keep hitting road blocks. Now I have to wait for more nuts and bolts because I couldn't find them locally.

 

[screwdriver]

I lost my confidence in the ir thermometer. I put a thermocouple in two of the heatsinks, one on the center 5 red LED and the other on the 6 LED heatsink. The full spectrum LED really heat up fast and the hottest, the blue ones don't put out much heat and the red ones fall in the middle.
The latest picture, the heatsinks heat up within the first hour.

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[bombbudpuffa]

I lost my confidence in the ir thermometer. I put a thermocouple in two of the heatsinks, one on the center 5 red LED and the other on the 6 LED heatsink. The full spectrum LED really heat up fast and the hottest, the blue ones don't put out much heat and the red ones fall in the middle.
The latest picture, the heatsinks heat up within the first hour.

Good info. I hope it's the same with the 3w diodes since my light is heavily blue. How's the begonia doing?

 

[screwdriver]

Good info. I hope it's the same with the 3w diodes since my light is heavily blue. How's the begonia doing?

Awesome. She looks so much happier. Moving her up couple inches later on. Waiting to see any damage from the light. Even when she was 16 inches away I saw improvement under the light.

 

[screwdriver]

Moved her up a bit. Most of her is at 5.5 in. Still don't see any damage to the tall one. Temps are running the same. Seems to be stable.

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[screwdriver]

Here's the next project. This design will be much simpler. Will be used in flower. I'll be using the meanwell LDD1500L this time. It will deliver the constant current for the 27 5 watt LEDs for a grand total of 135 watts. Similar to the 1 watt design but anybody should be able to do this if they have patience to tap 6-32 screws. I'm still thinking about the power but I think I'll be using what I got for now, 12vdc constant voltage power supply.
I'm also using a parallel circuit for the blue and the full spectrum LEDs and a little overdriving of the red LEDs.

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[bombbudpuffa]

That one is going to be really nice!