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Old 02-07-2012, 01:53 PM
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Quote:
Originally Posted by DiverDude View Post
I dunno, that wire seems awfully thin for the kind of current that array is going to draw....

Where'd you get the Hakko 936 ? Those have been discontinued for a while now (I have 2 of 'em)
Ya, 28AWG is small stuff. I think it's still within the ampacity limits for the current he's running, but might be worthwhile upsizing that several iterations to pad the safety factor. Thinner wire also presents more resistance & therefore voltage drop. This could be a factor depending on how many are hooked up in series with that tiny wire. Look up ampacity & you'll find plenty of charts. Here's one example:

http://www.powerstream.com/Wire_Size.htm

According to the chart, max current for 28AWG in a chassis wiring application is 1.4 amps or 1400 milliamps. That stuff could be tricky to solder as well. A little too much heat & the insulation will shrink back a ways or even start cooking.
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Old 02-07-2012, 02:14 PM
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I will post few more pictures and info later on tonight as the array was finished yesterday.
The wire I am using is of no hassle and is of correct amperage resistant to what its used for and its a little tricky not to strip it whyle soldering.
Unfortunately I need to upgrade to a bigger heat sink as the U Chanel aluminum gets too hot if run the array at full blast witch what I intend to do.So I have to wait a couple days to receive a 1.8" X 36" heatsink from Martin.
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Old 02-07-2012, 02:43 PM
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I run that type of U channel no problem with 3w leds run 2" apart. They are barely warm to the touch, no fans. I mount them so the fins are facing up though I think that would make a difference. I also paint them with a high high flat black paint. My research indicated that a painted heat sink has better heat dissipating properties (emissivity).

I definitely would have went with a larger awg wire.....for the small cost it's a nice piece of mind.

Last edited by reefermadness; 02-07-2012 at 02:46 PM.
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Old 02-07-2012, 11:22 PM
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I think the reason for over heating my array is because I placed 22 LED running at 700ma in a U shaped aluminum of 34" length.witch gives me a gap of aprox 1.4" between each LED.
I just placed another U shaped aluminum on the back side (with heat transfer grease) and turn the array on so far 15 minutes passed and its running warm that maybe the answer as more surface area for heat dissipation
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