# Heat management in 1W LEDs



## wandererrob (Aug 8, 2007)

Hi folks,

Have any of you played around with lighting your haunt using 1W LEDs? In my quest to find an adaptable, low voltage, low budget lighting solution I built a bunch of 1W LED spotlights last year and was quite happy with how they worked out. 

The LEDs came mounted on aluminum star boards and the setup I built packed the LED, LED driver and LED lens into a small, sealed PVC housing. 

My main concern there was heat buildup inside the housing as these LEDs do get rather hot as they run. Throughout testing of the design, they performed fine for hours on end. However, come Halloween, I had a few meltdown on me. They got dimmer and dimmer as the night went on and the post-mortem revealed that the few that failed (3 out of 18) had indeed fried themselves. The LED lens housing had melted as had the plastic bits of the LED itself. The diodes were brown. They cooked themselves but good.

So, the question is, how would you go about making a compact, weatherproof light using 1W LEDs that will suitably manage the heat they generate.


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## typoagain (Feb 27, 2012)

I guess that would depend on what LEDs you are using, budget per light, and what you are trying to accomplish. 
Do you want single colors (what color), did you want RGB, or just white?
Voltage?


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## Hippofeet (Nov 26, 2012)

I would run them at 6v if they are 12v. or at 9v.


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## heresjohnny (Feb 15, 2006)

I would start with a metal enclosure to dissipate heat, instead of pvc which would
act as an insulator and retain heat.


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## niblique71 (Dec 2, 2009)

I used Sched 40 pvc for my 3W LEDs and left the business end open to the air, only sealing the backside. The LED driver was safely tucked in the sealed section between the Test cap and the backing cap. I also used a small piece of hardwood to mount the Starboard onto, not to dissipate heat, but to insulate the heat from the plastic parts.

They do get exceptionally hot if enclosed.

Here'sJohnny is right that a metal container might help dissipate heat. Short of that, Leaving the actual LED exposed (No Protective lens) is the Only way I can see doing this without a meltdown.


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## wandererrob (Aug 8, 2007)

For the record, I'm using white LEDs (then coloring he light using gels for greatly flexibilty) and running the drivers off 12v power. I can run them at lower voltages (usefully down to 5v) but their brightness suffers a lot as you go below 12v.

Maybe I could find a happy medium at 9v.

As for budget. I have the materials already on hand for ~10 more. Current cost was about $4/light.


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## heresjohnny (Feb 15, 2006)

Have you verified that you are driving the LED within the rated current at 12 volts?


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## heresjohnny (Feb 15, 2006)

If LEDs are directional, you could also drill some ventilation holes at an angle.


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## wandererrob (Aug 8, 2007)

heresjohnny said:


> Have you verified that you are driving the LED within the rated current at 12 volts?


Yup, everything is within spec. I think they are simply falling victim to being in a sealed housing combined with being cheap, Chinese LEDs 

I've considered ventilating them, but then I'd lose the weatherproof-ness. Of course, if they burn themselves up weatherproofing is kind of a moot point.

I used the drivers for the sake of flexibility of power (they're rated for 12-24V). I could also run them straight off 3.3V (computer power supply), but all the driver does is step that voltage down to that anyway.


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## heresjohnny (Feb 15, 2006)

You could ventilated just the closed area that houses the LED, angling the holes down so rain would not enter. Seems like a couple holes on either side would allow air flow.


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## niblique71 (Dec 2, 2009)

I'm not 100% sure that the LED driver has only that one purpose. I'd love someone else to speak to that.

As far as weatherproofing. The Lens is sealed, it's on a heat sink, and it has to small wires going to the solder point. but that's it. I think it could stand up to a month of weather for 3-4 years with no problem as long as you keep the Driver in a back weatherproof section. I'll have to do a small presentation to show my design which ironically look VERY Similar to Hpropmans newest incarnation for a housing. It's servacable and handles the heat pretty well.

I get the "Color Jell" concept, But it seems that the heat issues are insurmountable in a sealed chamber that doesn't have a heat sink. I have also experienced the same issues with the newer generation of 10 MM High power LED.s I did a big experiment this past winter and have yet to post my results. But for now... the 3w and 5w "Star disc" LED's seem to have lower heat issues an purer/brighter light. Also the newer 5mm LED's are brighter, have NO heat issues an are substantially brighter than the ones I posted from asia engineer.


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## Zombie-F (Apr 12, 2004)

Does the driver just step the voltage down or does it step it down and set a pulse width and period?


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## wandererrob (Aug 8, 2007)

Zombie-F said:


> Does the driver just step the voltage down or does it step it down and set a pulse width and period?


I believe it just steps the input voltage down to 3.3-3.5V.


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