Nice heatsink for Anglehead mods!

just an fyi: i have been making some anglehead/luxeon/micropuck mods, and intend to make a few more for family and friends.

the biggest hurdle was in creating a heatsink. it sucks trying to modify aluminum with a minimum of tools, so i have been searching for a stock heatsink that would drop in with minimal mods.

i just found one: from radio shack, part # 276-1363
Anodized aluminum heat sink for TO-220 packages.

it is square, but drops in nicely, avoiding the flat section and positive contact, as well as missing the negative contact at the side. it meets resistance right at a good "focal point" where the optics will not hit the lens, yet it is not too far back into the head.
i slide the heatsink in with the "fingers" pointing outward.

i had concerns about the heatsink being inadequate, but combined with the lux3 thick heatsink and moderate current, it should be fine.

my mod involves soldering the micropuck leads to the contacts in the anglehead.
then i take a star, use arctic adhesive to glue it to a heatsink. then i solder the micropuck leads to the star, and push the heatsink into the body, and use JB weld to hold it into place.

i custom make optic holders for fraen optics by using pvc pipe--it is very easy to cut and file to proper shape.

everything is carefully JB welded together. the idea is to have it as tough as possible.
my prototype has been thrown on a bare concrete floor 5 times in a row--and was only scratched.

for such an easy and relatively inexpensive mod, the results are incredible.

Bob<--really need to learn to take some pics.

Does the finned heatsink really do much good inside the head? There are two types of heatsink; the first provides a larger mass to absorb the heat and conduct it away from the source, hopefully to be radiated away. The second provides much smaller mass with a much larger surface area so that it can transfer the heat to the surrounding air. The second type typically has fins or vanes to increase surface area. The second type typically has little mass.

If the second type is enclosed in a small place, they very quickly heat the surrounding air and become in-effective. This can lead to a premature failure of your light.

I really expect to see active cooling used on at least one light in the future /ubbthreads/images/graemlins/smile.gif

Daniel

my previous heatsinks were simply thick sheet aluminum cut and filed to fit the ID of the ight.

i just today measured the heat right next to the die after 15 mins constant on, and it never went over 100F. i used a temp probe from my multimeter, so im not sure if it is accurate.

the head gets a little warm externally, and when i touch the heatsink with my finger, it is pretty warm, but not what i would call hot. it is NOTHING like a madmax, TL-2 LED or one of my 4.5v direct drive mods.

it seems to be working, but yes, i prefer to be safe...so i am still looking for the best method of sinking that heat away.

Bob

Did you have the light assembled during the 15 minute run? Convection will move a lot of heat if the heat sink + LED is just sitting on the bench.

It sounds like yours may be just fine.

Sears is selling a neat little infrared thermometer (about $50) that can take the temp just by pointing it at the light. It's instantaneous and also has a 'max' reading so you can sweep it back and forth.

Daniel

Micropuck only drives at 350mA, so he's probably way in the clear.

i left it running with the head assembled, then opened it to take the temp measuremant.

hmmm. i have a spare cheapie lens. maybe i will bore a tiny hole in it and snake my temp probe through. then i can measure the temp without opening the light.

thanks for the info!

Bob