Is my build ok? LED is really really hot! HELP!!!!

castrojc

New member
This is the LED that I bought: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110948748333

I just bought a big enough heat sink that the led would fit on. I used rubber bands to hold the heat sink and led together which is quickly looking like a bad idea. Used thermal grease as well. I touched the heat sink and had to quickly let it go. Is the heatsink way too small? It is only one led so I didn't think I would need a big one, although it is 10W. And I used a 3-10W waterproof driver. Did I do something wrong? Please help!

Is this a fire hazard??

This is the driver I bought: http://www.ebay.com/itm/290750531079?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

This is the heatsink: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170909387068

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I always get heatsinks capable of handling greater wattage than the one I have and use PC case fans on top of that to play it safe.
 
After looking at the links that heat sink is for a one watt led, you have a 10 watt. I don't think a pc fan is enough. Maybe liquid cooling for a CPU chip.
 
Same place you got the LED should have power supply for a fan. You still would need a bigger heatsink IMO.
 
I didn't realize the heat sink was rated for only 1W until putting the links up. I ordered one rated for 10W. But my question is, will this solve the issue? And what should I do in the mean time? Just turn it off? Any advice on hooking up a pc fan?
 
You need to correctly mount that LED using screws and heat sink thermal paste.

And use a bigger heat sink.
 
I just noticed that the driver is hot to the touch as well, I can hold it tight for around 10 seconds before it feels uncomfortable hot. Is that normal? Is that driver I am using ok?
 
Tc on the driver is the max temp the case is allowed to get. 60C is really hot to touch... You could try to measure it, but i doubt its running hotter than that, since even cheap china stuff has derating things built in to prevent fires.
 
You could get away with a fanless heatsink, try a local computer shop for a used Intel OEM heatsink, like one with a dead fan (which should just clip on). I run an LED at 10w with just a CPU heatsink and no fan, it runs about 50C or so but has much worse design for fanless operation than the intel ones do.

If you keep running that LED with that tiny heatsink (and not properly attached at that) you will find that it will have a severely reduced life and it will quickly burn the phosphors and chips (matter of hours if the temp is very high).
 
This is some awsome DIY! Please submit this to the ghetto rig thread, you'll win accolades. I had a good chuckle... this is a troll right?

In case I misunderstood and you're serious and you really want some suggestions for what to do to fix this I'll weigh in. First, as the other posters before mentioned you need toaffix the heatsink with either thermal adhesive, screws or clamps. Mounting pressure really helps with heat transfer.

That heatsink looks like a motherboard chipset HS. These are usually adequate for 10-20 watts without a fan if the chip is able to handle 70C and the case has some airflow. I think you should at the very least add a small fan to that HS convection isn't going to cut it.

An important change (for your personal safety) would be to insulate the exposed wire with some shrink wrap. You also shouldnt suspend the light from the electrical conductors, it's just a bad idea. Creative bending of a wire coat-hanger would go a long way to solving the suspension issue as well as scoring you ghetto points and free cooling if it wraps around the HS : D
 
That heatsink more than likely has a thermal resistance of 21 deg C/W... so 10W would be a temp rise of 210 deg C... which is why it runs WAY too hot..
Plain and simple is NOT suitable for 10W dissipation.
 
thanks guys, I ordered the new heat sink.... and as far as the rubber bands, that was me not being patient and looking for a quick fix. It has since been fixed, just gotta wait for the new heatsink to come in. I am wondering if I am going to need a fan though, any suggestions? and how would I set that up?
 
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