Can UF 504b be run on 2 X CR123?

Quick question. Answer is probably buried around here somewhere, but I'm unable to find it through search. I have one of the DD $14 UF 504b "Specials" black version 3 mode XM-L. Even if you can just tell me "yes" or "no" it'll be a big help. Or...

If anyone is willing to expand on the answer, I (and I'm sure others) would be grateful.

E.g: What governs a flashlight's battery options? The drop-in? Or the driver? Both? Are these two components independant of each other?

I know I've seen other sellers list 504b's as "1 pc 18650 or 2 X pcs CR123", though I can't recall where, and I wouldn't necessarily trust this. This one apparently takes 2 X 16340's:

Is this something to do with single mode? Or because it's R2 instead of XM-L (or XP-G, MCE etc) Or are there just different (quality?) 504b's?

Do not use 2 x CR123 since the voltage range is described to be only up to 4,2V. That´s the maximum from one 18650 or 16340.

Driver is the part, that defines what battery configurations can be used.

edit: in DX it states "2 x 16340" but in below it says

Voltage Input:

2.7~4.2, 4.2V max

So I´m not so sure before seeing the driver itself.

Thanks Cheap Thrills. So you mean that voltage input (battery configurations) depend on the driver and not the drop-in? So I couldn't just "drop in" a higher voltage drop-in, I'd also need to change the driver?

The driver is part of the dropin, so if you swap the dropin to a high voltage one it will work. If you have some soldering skills you can swap the driver in your current dropin to a higher voltage one also.

Ah! So a drop-in = ready made assembly of emitter, reflector, big spring and driver (did I miss anything?) And although the drop-in will be labelled by voltage and modes, e.g. like this one:, it's actually only the driver part of the whole drop-in module that controls the modes and voltage input? So changing the driver on my 504b drop-in would also change the modes, output, memory etc?

Also worth to mention that the wording UF 504B does only say what kind of host is used and absolutely nothing about driver, led emitter or short - drop-in. Fortunately you were toughtfull enough to post a link so we knew what to reply. :) The double CR123A will probably ratlle alot and almost surely burn the driver whic is a low quality one. I replaced all of those the same day upon recieving them.


Got it! Thanks guys I constantly refer to Flashlight Wiki but so often it's easier to understand this stuff when the question has been phrased in one's own words. So I could use this drop-in: and use 2 X CR123s because it's up to 6V. But if I wanted to use an extension tube for 3 X 18650 (not that I would, but just pretend) this one covers all bases, <18V:

So now I need to learn about drivers and soldering..

You got it! :wink: And that’s the beauty of drop-ins.

If I use 2 x CR123A in any of my P60 hosts I just wrap them cells in electrical tape to prevent rattling. Even with 18650s in my L2 and L2P, i have a piece of copy paper inside the tube because the cells will rattle ever so slightly if you tap the light. I don't like to hear anything at all when I hit the light against my hand.

I do that with 18650's too. :) German grade precision milling in China at budget price? Dream on!

The 504b uses a standard p60 drop-in. Why mess around with soldering and buying drivers when you can just order a dropin that will work with both 18650 and 2xcr123? You can find them on ebay, on manafont, and at, and if you go that route, then you have a spare if you need it.

Yeah, but just imagine German engineered high output flashlights. That would be awesome..

@ trooplewis: Of course, and that's what I will do, at least to start with. But I like to understand anything I'm interested in, and there's no better way than getting to grips hand-on. And I'd get to understand what the rest of you swap posts about..

Also, TBH, I've been unpleasantly surprised at the price of drop-ins. At an average of maybe about $12 for a multi-mode (Manafont) they're nearly as dear as the 504b complete. Might almost as well buy a Solarforce to start with..