Building a 1 watt LED light

[screwdriver]

I got impatient so I moved her up to 4". There also seems to be some action going on underneath. I guess the bright white on the leaves is the reflection of IR. Looks pretty.

I checked the overall power on the light. It draws .45A which makes a 54 watt cob. It takes 11.2 watts to make the 42.8 watts that the LEDs use to make the pretty colors.

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[bombbudpuffa]

That thing is going to have tons of flowers!

 

[screwdriver]

That thing is going to have tons of flowers!

I hope they bloom under the light. Poor girl, she better hurry because I got other priorities.

Done testing with ambient conditions. This is a graph of how fast these things heat up. I put the light in its new home with duct work.

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[screwdriver]

Step 1: Decide to build a light.

Buy circuit board and ferric chloride, you can use finger nail polish or buy the rub on transfer lines. I used nail polish this time.
Hope you have drill and bits, maybe a dremel and a tap for the screws.
You can use 2" wide quarter inch thick piece of aluminum from the hardware store or online. This design uses the heatsink edge being flat and not milled like the 1 watt board.
You don't really need the circuit board, a piece of masonite would work also then just use wire to interconnect the LEDs. Just needs to be fairly thin eighth of less and stiff. The buck circuit, LDD1500L also comes as a wired in/out instead of the pinned package. The LEDs that I am using are the same as the 1 or 3 watt in size. I drilled half inch holes and mounting holes for the heatsink.

Paint circuit board
Each circuit board
Clean circuit board
Solder to new circuit board.

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[screwdriver]

How drill the holes in the right place?

I used a predrilled board for proper hole placement but you can also use a piece of paper with the component pushed thru. Take the paper, lay over circuit board and drill holes. Use a tiny drill bit but try not to break it.

For the heatsinks I drilled holes for a 6-32 tap.

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[screwdriver]

Here it is sort of put together, minus all the LEDs. Still waiting.
The golden stuff on the ends is Kapton tape. Its a high temp insulating tape.
There it is in the tube.

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[screwdriver]

The schematic. I think its correct.

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[bombbudpuffa]

Screwdriver can I use crees with the bridgelux as long as they're rated the same? I can't find the answer to this anywhere.

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[bombbudpuffa]

The crees themselves

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[bombbudpuffa]

Nevermind. Seems the seller had the listing wrong. The cree xb-d are rated for 350ma not 700ma. I have 350 and 700 drivers so I'll have to put them on separate drivers. Thanks anyway though.

 

[screwdriver]

Its always good when I don't do anything and you still get the answer.

The nice thing about LEDs is you can drive them with a wide range of current. The more current, the more heat and light. On some LEDs that would affect the luminous efficacy.

In the 5 watt light, I'll be using 1500mA instead of the rated 1100-1200mA for the reds. More light and if the heat is controlled the LED should survive. The blue and full LEDs will be driven at 750mA in the parallel/series center string. They are rated for 560-700mA. I'm also adding a little protection on those LEDs that I didn't include in the schematic.

 

[bombbudpuffa]

Are you using cheap Chinese components like me?

 

[screwdriver]

Are you using cheap Chinese components like me?

Sadly, yes but I refer to cree datasheets .

 

[screwdriver]

Nevermind. Seems the seller had the listing wrong. The cree xb-d are rated for 350ma not 700ma. I have 350 and 700 drivers so I'll have to put them on separate drivers. Thanks anyway though.

I think you can drive them at 700 for the 3 watts or about 3 watt output. Driving them at 350 will run cooler but at a lower light output.

 

[bombbudpuffa]

I'm going to see how hot they get on 350 first. I might just make a different light with the crees without any nm chips but K chips instead...out of curiosity.

 

[bombbudpuffa]

Sadly, yes but I refer to cree datasheets .

Hey those cree I bought from China are outdated but rated at 300lm per chip. That's 3x more bright than the cheap epistars. Sometimes you can get some good deals. My full spec stars were $3 for 10 and they're bridgelux.

 

[screwdriver]

I'm going to see how hot they get on 350 first.

Thats always a good idea.

Here are some pics from the datasheet. The first image shows if you increase the current you increase the luminosity but the important part is at the top, Tj=85c.

The second image shows what happens to the luminosity as the LED heats up. Thermal management is kind of important in keeping these things alive and putting out light.

The LEDs that I'm using don't have this type of spec in writing but all LEDs follow a similar path.

Has anybodys light overheated and took out multiple LEDs or even one LED?

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[bombbudpuffa]

I haven't had any led chips blow out and all I've used is the cheapos.

 

[bombbudpuffa]

Finally got my nuts and bolts. Have to even the chips out n solder it altogether.

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[screwdriver]

What are the colors in your pattern?