How does one heatsink a 5mm LED?
- Thread starter ken2400
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Marduke
Flashaholic
Lots of epoxy is usually the best you can manage.
Gunner12
Flashaholic
Pretty much, you don't.
If you really want to try, I guess you can sand the LED down until you can attach a good piece of metal to the die part of the contact.
If you really want to try, I guess you can sand the LED down until you can attach a good piece of metal to the die part of the contact.
Marduke
Flashaholic
All the epoxy dome LED's are not really well suited for high output which needs heatsinking. You gotta use a high power LED and properly heatsink it for long life.
enLIGHTenment
Enlightened
With great dificulty
TigerhawkT3
Flashlight Enthusiast
Actually, 5mm LEDs are often driven more than hard enough to need heatsinking. It's bright, impressive, and costs pennies per LED, but (since they're not designed for that, as this thread indicates) they'd get dim or even die pretty quickly, although you'd probably only notice any reduction in output when the warranty is already expired. 
I read around here once that maybe you could use really wide circuit board traces for the connection. Frankly, though, you'd be better off using multiple 5mms at reasonable currents (they're dirt cheap, after all), or, if you really need the single-point-source output, a power LED (Lux, Cree, etc.).
I read around here once that maybe you could use really wide circuit board traces for the connection. Frankly, though, you'd be better off using multiple 5mms at reasonable currents (they're dirt cheap, after all), or, if you really need the single-point-source output, a power LED (Lux, Cree, etc.).
Gunner12
Flashaholic
When it comes to heat, the 3mm and some 8mm and 10mm LEDs use the same size parts(minus the epoxy) so heatsinking would be the same. Depending on the task, a high power LED might be better.
So maybe the 3mm give off heat better since there is less epoxy between the die and the outside?
That is a good question. I have read that heat can kill the 5mm so I thought maybe a heatsink of some sort would help.
Looks like I will have to underdrive them and use a photo cell to cut the time down on them.
Thanks for the inputs so far.
Looks like I will have to underdrive them and use a photo cell to cut the time down on them.
Thanks for the inputs so far.
Jarl
Flashlight Enthusiast
dip the legs in liquid nitrogen??
Just making night lights.
rizky_p
Flashlight Enthusiast
why not using a cheap P4/P3 or Luxeon I/III clone($2@DX) and drive them very low, you dont need to heatsink the LED at low current.
enLIGHTenment
Enlightened
There is no need to cool small numbers of 5mm LEDs as long as you drive them within the manufacturer's specifications. If you were mounting a hundred+ 5mm LEDs in a very closely spaced array then it would be worth while to consider some kind of cooling, but there's no need to worry about it for a handful of LEDs.
LEDninja
Flashlight Enthusiast
All the 5mm night lights I and many other CPF members got have dimmed significantly in 6 months and useless in about a year.
I finally gave up and put ! watt LED bulbs in regular lamps. They are also available in warm white as well which is more soothing to the eyes. 2+ years and still going strong.
http://eliteled.com/products/lightbulbs/e26baselightbulb.html
jayflash
Flashlight Enthusiast
Might a glob of heatsink compound around the LED's base and leads transfer a worthwhile amount of heat to the PCB? Although PCBs aren't as conductive as metal it may be better than nothing.
