Heat sinking necessary?

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**DONOTDELETE**

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I was about to put together an array of 19 white Nichia leds when I read the discussion on heat-sinking awhile back...and the project has been sitting ever since. I have had no cash to buy any copper sheeting, and am not sure how I would drill all those holes accurately anyway; I was just using perfboard. So the question is, if I just solder them up in the perfboard, will they overheat if I keep the current down to 20mA?
 

Chris M.

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will they overheat if I keep the current down to 20mA?

I wouldn`t have thought so. Keep within the manufacturer`s specifications and you should be fine. 25mA is a reasonable maximum.

Things start hotting up when you begin overdriving. That`s when the copper sheets and thermally conductive epoxy come in to play.

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I have successfully driven an array of 24 Nichias at 840 mA (35 mA per LED) with only minor heating.

That is pretty much the edge. Slightly more current, and they do the "thermal runaway".
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I'd say you'd be perfectly safe at 25 per, and almost guaranteed safe at 30.
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PeLu

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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Go, Go Gadget Flashlight:
I have successfully driven an array of 24 Nichias at 840 mA (35 mA per LED) with only minor heating.

I'd say you'd be perfectly safe at 25 p
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<HR></BLOCKQUOTE>

I know people who drove home completely drunken. Have they proven that it is safe?

OK, serious: If you are lucky and have only little tolerances in between your LEDs it MAY work.
Henry from HDSystems (ActionLight) thinks that 10 LEDs parallel at 15mA each is enough for an unregulated circuit. Somewhat conservative, but save.
And actually, what counts is the die temperature.
Try to get a good heatsink, it's not that difficult.
 
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