Novatac XM-L mod question

maroast

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Apr 5, 2008
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Ok, I'm going to show my ignorance here. I have a Novatac 120T (P) that I'm planning on switching the P4 emitter out for a Cree XM-L U2. I've read other posts on candlepower and it seems as though this is a fairly strait forward mod that will work well.

Also, I'm planning on buying the HDS battery tube so that I can use an 18650 for better run times. My question is, can I use two CR123s or RCR123s with the XM-L emitter in this modified light for a real pocket rocket. I've read that the XM-L can handle 3amps…But in this setup will 2* 123 batteries burn up the emitter, driver, or explode the batteries? I don't know what the output of the stock driver is (I did search). Would my hand catch on fire as soon as I turned this light on ?!?! Any input from the master moders would be great. Thanks.
 
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think2x

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You CANNOT use 2xcr123's, you will kill the driver.

XM-L swap will easily get you in the 250 lumen range.
 

moderator007

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"I'm planning on switching the P4 emitter out for a Cree XM-L U2"

Should make a noticeable difference.

"My question is, can I use two CR123s or RCR123s with the XM-L emitter in this modified light for a real pocket rocket."

I would not try it unless someone else verifys it will work. The light appears to be made for a 4.2v input. So 8.4v may kill the driver. You could probably mod the light with a 8-amc7135 driver for 3amps from a single 18650.

"I don't know what the output of the stock driver is"

Take a tail cap measurement should get you close.

"Would my hand catch on fire as soon as I turned this light on ?!?! "

Maybe if you don't change the driver. The xml running at 3 amps will generate some heat not enough to burn you in the light but hot. The light is small so it will get hot while using it and the led may experience a color shift if allowed to get to hot. With small lights its better to cut back on the current a little or only use high for short burst.
 
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Pöbel

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it will be much more than 250 lumens. The Novatac driver goes beserk on emitters with low Vf. Runtimes will suffer heavily though!
 

maroast

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Wow. I just dropped in the XM-L U2 emitter....huge increase in lumens! Huge! I love this light again. I'm ordering the body extender so I can run an 18650.

I didn't even reflow the emitter onto the 8mm board I bought. I just cut the 16mm disc down to fit where the old P4 and green MCPCB use to be. Works great. Easy $6.50 mod.
 

think2x

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Wow. I just dropped in the XM-L U2 emitter....huge increase in lumens! Huge! I love this light again. I'm ordering the body extender so I can run an 18650.

I didn't even reflow the emitter onto the 8mm board I bought. I just cut the 16mm disc down to fit where the old P4 and green MCPCB use to be. Works great. Easy $6.50 mod.

P4 and Green board. Sounds like a late model 120T, just before they switched to the chinese lights. I modded a 120M that was that way. The older ones only had the 8mm hole that the P4 fit in and a pair of slots running to the driver output wires.
 

maroast

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Yeah, that's the one. I plan on doing a little Jerry-rigging. I've been toying with the idea of using a hacksaw blade to cut a small channel inside of the tube and epoxying in a conductive wire so it's more permanent. Well see thought, depends on how motivated I am.
 
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