3W CNC123 LDO R123 mod

andrewwynn

Flashlight Enthusiast
Joined
Apr 28, 2004
Messages
3,763
Location
Racine, WI USA
that's a lotta abbreviations.

Well.. 'modding fun' is over, i got 'one last sneaky one in' before the heads arrived for the nano today.

here is the webpage

(dunnow what happened at first with that url)

and a preview image:
Image-8F94F4BB677C11D9.jpg-thumb_202_269.jpg


you maybe notice a bit of a difference in this 'sandwich'.. looks a bit like a UFO.. anyhow because i didn't want to pot the driver.. i made the anode board large so it holds the kroll pring pressure. of course.. this means the ground path is on the top of the anode board.

I set the power level to exactly 3W.. came out to about 830mA.. and the driver worked very well. The only change to the driver from the nano was putting a second sense resistor parallel.

oooowhiee did the inside get toasty during a full-run.. 195F max temp of IR themo scan of the emitter/heatsink. the outside felt warm, but measured surprisingly hotter than it seemed. 120F

check out the pics and see how clean it came out.

OH.. for all those with a CNC123.. or just about any light that opens in the middle and has a clickie tail.. the reason i didn't want to pot it.. 'not done yet'.. I deigned a full variable dimmer that works in conjunction with my driver and is a 'drop in' for the CNC123. I will be working with others to bring it to market asap.

I will have the prototype running within a week or so.. when i can take a break from nano construction.
 

andrewwynn

Flashlight Enthusiast
Joined
Apr 28, 2004
Messages
3,763
Location
Racine, WI USA
I've since made some VIP-driver based pills for the same light. click here for pics.

Image-4AD88F078BDE11D9.jpg-thumb_269_202.jpg

here is a sample image.

Some key ingredients.. i put in a potentiometer vs a resistor to set the current, but measure the resistance and set the current level with the formula provided by taskled.

the VIP driver is much bigger diameter than the .55 of the hole meant to fit a standard pill.. but also much smaller than the .75" hole inside the cnc123.. so i wrapped some 22ga wire i have around it.. soldering it solid into a ring.. i size it so it's extremely tight and it's pressed on.

There is no place for ground to touch on the VIP so i solder a wire from the ground to this ring.. and two more wires up from the ring over the top of the PCB... look in the pictures.

I find no reason or need to pot the driver in epoxy.. i put some foam in between the driver board and emitter disc (heat sink) to push the emitter disc solid into the body (not for electrical but heat conduction)

I put some arctic alumina on the heat sink for good conduction.. you can get away with the cheap-o silicone heat grease from RS.

Keep the wires really close to the emitter there is not a lot of space through the hole.. i actually drill the holes after the emitter is glued to the heatsink right between the emitter lead that is cut off and the 'stubby' emitter lead.

I used a solid silver disc i cut myself for this driver, and copper for others.. it's really hard to cut but i use a 'plug cutter' and a lot of oil and it makes a perfect disc.. it's really easy to use the same plug cutter to cut out of double-copper PCB..

the only complication i had was that the VIP board intruded into the battery space so makes the spring very tight.. i put an o-ring between the body and head which takes up some of that space and makes a water-tight seal at that junction to boot.

questions... email me: [email protected]

-awr
 
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