Running 1 Seoul or Cree with Fatman ?

dom · May 13, 2007

Hi Guys
I have a Fatman i would like to run with 1 LED and using AW's R123 ,3.2V batteries. They come off the charger at around 3.37V
Would there be enough drop in the voltage thru the Fatman and wires not to fry the LED ?
I notice Fred has some VOI Seouls with Vf 3.25 -3.5V but i already have some of his VOH Seouls with Vf 3.0 - 3.25 -which i would prefer to use if possible.
I have some of Bernhards groupbuy Q2 Crees as well -but i don't know the Vf of those.

Any help appreciated :grin2:

Cheers
Dom

cmacclel · May 13, 2007

The voltage in must be less that the LED forward voltage. I don't think you can run 1 LED with a single R123 you may be able to run 1 LED with a 3v Primary.

Mac

glockboy · May 13, 2007

dom said:
AW's R123 ,3.2V batteries. They come off the charger at around 3.37V

My AW's R123 come off the charger at 4.20v.
If yours come off the charger at around 3.37V, you can DD the Cree.

dom · May 14, 2007

Thanks Fellas
I was thinking if the fatman runs at 90% efficiency -will that drop the voltage enough to use a pot,or do you need more headroom.

Glockboy - can the emitter take a little more voltage without blowing up?

Cheers
Dom

glockboy · May 14, 2007

On my Crees, I direct drive it at 1800 mah with a very good heat sink.
http://candlepowerforums.com/vb/showthread.php?t=158356

Running 1 Seoul or Cree with Fatman ?

dom

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cmacclel

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glockboy

Flashlight Enthusiast

dom

Enlightened

glockboy

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