1W SE in cheap torch

georges80

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Well, finally got some copper heatsink slugs from a friend (with access to a machine shop). Here's some pics of my mod to a cheap Target torch.
torchopen.jpg


Next pic shows the SE epoxied (thermal stuff) to the copper slug. The circuit board is my own current regulator driver PCB. It's a step down converter with current regulations. Works down to about 4V and then goes out of current regulation. The torch runs on 4AA NiMH batteries.

modtorch.jpg


Next pic shows the installed SE in the torch head

head.jpg


This pic has the SE beam on the left and a Star/O on the right.

comparo1.jpg


cheers,
george.
 

georges80

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Thanks - it's my own converter. The inductor is a Coilcraft unit. I designed the board primarily for 12V operation, but is capable of running from quite a voltage range.

http://www.geocities.com/george_tlc/led.html for more details. At the end of that page is a bit of writeup to go with the above pics.

cheers,
george.
 

James S

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I have that exact same flashlight sitting right in front of me on a shelf waiting for an SE mod of some kind. For a $4 light it has a very nice reflector and I wanted to preserve that.

So now perhaps I'll get busy on it... Course, I'll have to buy a metal lathe first to make the heat sink. Or find some other way to handle that
wink.gif


So is the driver board you're using the same one you're selling for use in the car lights?

Thanks!
 

georges80

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James, yes I'm using the same drive board. It runs down to 4V (with a 3.19 Vf SE) before going out of current regulation - then the is just gets dimmer. Perfect match for 4 NiMH AAs.

Yeah, that cheapy torch has a pretty good reflector for the money. It is actually metal - so the copper slug I have dissipates heat via direct contact. Since it's my stock driver board it runs the SE at 350mA - still VERY bright. Picked up a Sears Craftsman version of the same torch this morning ($8 - with a red/yellow/green status led for battery life). It has a textured reflector - softer beam and I'll have to get some new copper slugs made that are a bit 'shorter'. The focus sweet spot requires the SE to be further back towards the battery end of the reflector.

Just ordered a minilathe about a week or so ago - so I can do my own little projects. But I'll probably get my friend to make me a few more copper heat slugs - his work as CNC machines so once set up that just fall off the line...

cheers,
george.
 

James S

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Please do post if you get some more of the heat sinks made, I'll be watching to see!

I've done work with wood lathes, but know nothing about metal ones. I'm curious as to the make and model of what you've ordered. I'm still in the research and learn about it phase of my own metal working hobby
wink.gif


Thanks
 

georges80

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James, I'll be asking (nicely) for my friend to make some more up - I've had some local interest in modifying a few more lights for their use. BUT, which slug you need really depends on whether you have the textured reflector (ala Sears Craftsman version) or the smooth reflector (ala cheap Target brand). The SE needs to sit lower for the Sears to get a good spot, otherwise it's more of a flood - which could also be good if that's what you want.
I ordered a Harbor Freight $330 wonder - 7"x10" minilathe. Checked on the web and there's a bunch of minilathe nerds that are very happy with it - lots of setup hints & tuning hints. They're nearly as nerdy as the flashlight nerds
grin.gif


cheers,
george.
 

LightBright

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georges80, where is the heat from the Luxeon going to go after a few minutes of operation as the temperature in the copper slug continues to rise? It seems like the flashlight insides will melt down after a while, there's no heat path to the outside that I can see.
 

Rothrandir

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that is a very nice mod! is the beam white? i noticed on my se mod, the beam was ...white..., the most perfect white you could imagine.

please let us know how you like the lathe and where you purchased it...i need one.

my requirements for one are
-knurling
-threading
-able to make reflectors

grin.gif
 

georges80

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Lightbright: The reflector is metal (plastic coating on the rear. I found this out when I did a star/o mod - I thought I could just cut the plastic - dremel found metal real quick ;-( But, great for the SE mod. The copper slug contacts the metal of the reflector - so the heat will dissipate through the reflector - which is quite large on this cheapy torch. I'm not overdriving the Luxeon - it's getting only 350mA.

Rothrandir: Yes VERY white - painfully bright - I can project light from my front door to across the street on the neigbhour's garage door - and they have a street light in front of their house. Very impressive for such a simple mod & cheap torch. I'm about to finish up a similar mod but with a Sears/Craftsman version of the same torch that has a textured reflector.

The lathe is a 7"x10" minilathe, US$330 from Harbor Freight. So far I like it and the web reviews show it to be good value for money. Check out http://www.mini-lathe.com/ as a good start. Mine at least was RED in colour.

cheers,
george.
 

Vikas Sontakke

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Would you be willing to sell those copper heatsink slugs? I presume those are "exactly" right sized as a replacement for standard PR bulb i.e. the focal point of the Luxeon SE matches with the PR bulb filament lenght.

And can you tell me where you bought the Luxeon SE? I would love to convert my Radio Shack 3C into a Luxeon based flashlight and this looks like the most straight forward way.
 

georges80

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Originally posted by Vikas Sontakke:
Would you be willing to sell those copper heatsink slugs? I presume those are "exactly" right sized as a replacement for standard PR bulb i.e. the focal point of the Luxeon SE matches with the PR bulb filament lenght.

And can you tell me where you bought the Luxeon SE? I would love to convert my Radio Shack 3C into a Luxeon based flashlight and this looks like the most straight forward way.
<font size="2" face="Verdana, Arial">Yes they are sized to drop into a standard bulb receptacle. The focal point does vary someone - depends on the torch - some are built for a tight beam, some for flood. So I can't guarantee the quality of the beam. From the pictures you probably cant see that there are two holes drilled axially through the slug through which the two wires for the LED run. They come up just next to the contacts of the emitter. The picture of the just the slug didn't have the holes drilled yet.

I bought the SE's from Future Electronics. Actually they started life out as Stars - I just bent the aluminium (after desoldering the contacts) and removed the emitters.

I have to make some more up but would be willing to sell them if there's interest. Hit me offline at [email protected].

cheers,
george.
 
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