Fixed Lighting Heatsink for MC-E/P7/LuxV?

[Illum]

I received my MC-E'd KL4 from AaronM along with a couple generous gifts: LuxVs removed from presumably KL4s...including the LuxV from mine

The greatest challenge is to find a heatsink that can sustain it for 3-6 hour operations without putting blisters on my hands or smelting electronics mounted by double sided tape to it. So far what I've tried simply by clamping it down will get dangerously hot in a little over an hour.

I happened to have a spare xitanium 700ma so the power supply is set, location is determined, wiring is all stripped and ready to go.

I'm hoping someone where who have used quad-die LEDs in fixed lighting can advise on some suitable heatsinking methods,

TIA

 

[Ken_McE]

I'm hoping someone where who have used quad-die LEDs in fixed lighting can advise on some suitable heatsinking methods

Aluminum bar stock is popular. A piece of copper flashing should work too.

 

[jeffosborne]

Hi Illum! The LED itself can get hotter than we want to touch and still not be degraded. Isolation from that heat is needed, though. I have been experimenting with a heatsink setup for a desk lamp I am making, which has 3 neutral-white 100-lumen per watt Rebels. The lamp will have 3 levels, 800ma, 240ma, and 50ma, so I've been testing the lamp head at 800ma for heat, close enough to your quad-emitter spec. The top aluminum surface that the LEDs are glued to gets to about 190 degrees and stays there after 20 minutes or so. Too hot to touch, yes, but below the manufacturer's spec of 250 degrees. The little tower of two square heatsinks underneath are arctic-alumina'ed to each other. The smaller heatsink has a hole drilled and tapped for a 6-32 screw, and mounts inside a little Bakers and Chefs stainless steel condiment cup (Sam's Club, 10 for $4). The cup gets right warm, but never too hot to touch. I drilled some holes in the cup for ventilation. The two hex spacers mounted near to the LED's will hold a round lexan cover. I have not yet built the base/controller/battery. The heatsinks were cheap at Future Electronics. Cut the top side 1/8" aluminum piece myself. Photos below.
Cheers,
Jeff

 

[Illum]

Tj = 125C is by spec...but I prefer to keep things around Th = 120F, or about 50C at any given time. Aluminum bars is what I'm currently trying with...but I'm also contemplating the addition of some heatsink's with fins and a fan on top of it.

I ran a test on the LuxVs yesterday...at 700ma they were weaker than I had expected for work bench lighting without optics compared to 6 CREE XR-E NWs driven at 350ma

Given the way things look...they won't be performers but they'll do what they do best given the circumstances.

jeffosborne, :wow: neat lamp assembly:naughty:
good job hand soldering those rebels

 

[purduephotog]

Hi Illum! The LED itself can get hotter than we want to touch and still not be degraded. Isolation from that heat is needed, though. I have been experimenting with a heatsink setup for a desk lamp I am making, which has 3 neutral-white 100-lumen per watt Rebels. The lamp will have 3 levels, 800ma, 240ma, and 50ma, so I've been testing the lamp head at 800ma for heat, close enough to your quad-emitter spec. The top aluminum surface that the LEDs are glued to gets to about 190 degrees and stays there after 20 minutes or so. Too hot to touch, yes, but below the manufacturer's spec of 250 degrees. The little tower of two square heatsinks underneath are arctic-alumina'ed to each other. The smaller heatsink has a hole drilled and tapped for a 6-32 screw, and mounts inside a little Bakers and Chefs stainless steel condiment cup (Sam's Club, 10 for $4). The cup gets right warm, but never too hot to touch. I drilled some holes in the cup for ventilation. The two hex spacers mounted near to the LED's will hold a round lexan cover. I have not yet built the base/controller/battery. The heatsinks were cheap at Future Electronics. Cut the top side 1/8" aluminum piece myself. Photos below.
Cheers,
Jeff

Jeff-

Nice setup! Sounds like you've hit the thermal capacity of that little guy- I didn't realize those rebels would get THAT hot.

The only other thing to try is swapping out the plate with copper. Copper's higher capacity, while not raising the temperature as much, will soak more heat away from LEDs. However you're still going to have the passive heat issues.

May I suggest 'ducting' the air coming into the cup? As it stands from the design I see you will have air racing up the inside of the cup and out the ventilation holes- but at no point is it *forced* into the heat sink. With nearly a 120F deltaT you should be able to get quite a bit of forced air rising- but if the air can bypass the sink it'll only act as a stagnant air source.

Thus a little 'mating collar' that goes from the edge of the heat , about 30% up from the base, to the edge of the cup will force the air to rise through the heat sink material and then out the top of the holes. You don't want air to be forced back in and around the dam that you've effectively built, so placing the vent holes at the top or around the top of the cup is probably best.

I no longer have the modeling software to do this but you could always light a small stick of incense under the light as it's on and observe the smoke patterns- that'll tell you where you have stale air and where you'll eventually have dangerous heat buildup.

I did have one question- where did you get the sweet metal bendable arm- the only place I found was Moffatt and they want nearly 50$ for 1-offs.

Jason

 

[Illum]

from the looks of it it may have been from a flashlight.
Winchester rebranded a type of LED light with that style of neck


I have one...somewhere. A gift from Sigman and uses 4xLR44s

if your looking to build a light I'd advise to look into microphone goosenecks
say...
http://www.samedaymusic.com/product--MUP6576
or
http://www.interstatemusic.com/weba...10001&storeId=10051&langId=-1&productId=89218

 

[jeffosborne]

Yes, the small gooseneck was from a $2.99 LED flashlight with laser pointer, at the counter at Walmart. It is a bit lightweight for the application, but supports the head okay.

I have two 19" mic goosenecks mounted to 6" round wooden bases, and have used them for supporting my photography LED lights. The problem with them is that it is possible to bent them over so far that they want to tip over. I hope to use a 12" section of 3/8" dia. lamp pipe from the base up the the small gooseneck, for support. That way the gooseneck is not so big as to fall over. Perhaps a 6" mic gooseneck atop a 12" mic stand pipe would work.

Purduephotog, thanks for the insights. Porting as you describe may help my heatsink setup. Those two heatsinks are designed for passive cooling, and do have a lot of surface area, for their small size. And you are right about the copper, good idea. Hey, what were you going to do with the gooseneck you were looking for?

Salute!
Jeff

 

[purduephotog]

Yes, the small gooseneck was from a $2.99 LED flashlight with laser pointer, at the counter at Walmart. It is a bit lightweight for the application, but supports the head okay.

I have two 19" mic goosenecks mounted to 6" round wooden bases, and have used them for supporting my photography LED lights. The problem with them is that it is possible to bent them over so far that they want to tip over. I hope to use a 12" section of 3/8" dia. lamp pipe from the base up the the small gooseneck, for support. That way the gooseneck is not so big as to fall over. Perhaps a 6" mic gooseneck atop a 12" mic stand pipe would work.

Purduephotog, thanks for the insights. Porting as you describe may help my heatsink setup. Those two heatsinks are designed for passive cooling, and do have a lot of surface area, for their small size. And you are right about the copper, good idea. Hey, what were you going to do with the gooseneck you were looking for?

Salute!
Jeff

I was going to make the monster of all reading lamps with it A gooseneck with a 3 color RGB 3 watt LED. But I never got around to it... baby came