EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: botcrusher on May 01, 2016, 05:39:40 pm
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I figured i can get away with a computer heatsink for one of these, but I'm less sure about oh, let's say four. While yes, i have quite possibly gone mad, halogen bulbs of comparable light output are nearly the same price. While the halogens only need a passive heatsink, they are prone to self destruct if fingerprints / the wrong dust particle gets on it at all.
Now, back to the chips, how should i go about cooling them. I figure that four computer heatsinks in close proximity might be pushing it, do i dare go for a waterblock style?
The aim is to keep it as cheap as possible. This is for an auditorium in a public high school. We scrounged together $1000 (CAD, f u exchange rates!) from a provincial drama festival, and want to make the most of it. (Most of this is going towards buying moving head fixtures.)
How should i go about this? I want these chips to last a very long time.
Slight complication, the fixture could be placed in a hot location.
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Do you have any thermal data on those 100W LEDs? That would help a lot.
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Think about the amount of power that a modern CPU is consuming and then converting to heat, it's a lot, which is why computers have those big heatsinks and fans. Modern LEDs are very efficient and a lot of the power consumed actually does get radiated as visible light so when you combine this with a CPU heatsink and a fan you should be OK.
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Old AMD heatsinks are rated for 100W, I've made a light some time ago and it still works very well -> https://www.circuitsathome.com/diy-2/high-power-led-grow-light-a-build-log (https://www.circuitsathome.com/diy-2/high-power-led-grow-light-a-build-log) . Understand that at RT the LED voltage drop will be quite a bit higher than specified - choose your power supply accordingly.
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If you are talking about typical theatrical light fixture locations, they are far enough away from the audience that small, quiet fans wold keep the LEDs cool enough to be safe. And thermal cutout switches are cheap enough that I would add one of those to each device to remove power in case of thermal runaway.
Are home-made electrical products allowed to be used in public places in your country? That is prohibited by law in many (most?) parts of the developed world.
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Modern LEDs are very efficient and a lot of the power consumed actually does get radiated as visible light
Uh... no.
Yes they're "very efficient" compared to the lousy <5% of an incandescent bulb, but they typically still aren't above 10-15% or so.
So a 100W LED will still dissipate 85-90W of heat. That's your typical mid to high end CPU's dissipation, so you'd really want a CPU cooler per LED especially in potentially hot environments.
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Some time ago, I was thinking about having an array of power LEDs and for cooling I was thinking about using those cheap-ish CPU waterblocks from ebay. When I'll have money I will order those and some big radiators and try this ;D