Fenix P3D Q5, with extended body and 2x17500 cells?

Fenix P3D Q5, with extended 3x123 body and 2x17500 cells?

Basically, what kind of runtime can I expect and how many lumens?

Should be similar runtime as stock 2xCR123's. Brightness will remain the same.

Meaning about 2 hours on Turbo based on SilverFox's charts, as I read them.

RCR123A get about 1 hour on Turbo, or half of primaries, FWIW.

2 x 17500 usually gives the same runtime as 3 x CR123, meaning you most likely will get 3 hours of runtime on Turbo.

Yea, would be a fair bit longer than 2 CR123s.

I'd estimate at *least* 25% more runtime on 17500s compared with CR123s.

(output stays the same)

I am debating between:

Fenix P3D Q5 with extended body and 2x17500

vs.

Surefire 9P with Malkoff M60 module and a Leef body with 2x18650.

The latter is more expensive, probably a few more lumens. The runtime should be about the same. I sill be able to run only 18650 in that body, or else resort to the original 9P body to run 123s. Fenix should be more compact and can run either 123s or 17500s. Opinions?

It really depends on what you are going to use them for. I have both P3D with extended body and Malkoff on 2 x 17500 in a 9P and Malkoff on 2 x 18500 in a Leef body with 6P/9P bezel and Z58 clicky.
The P3D is more a general purpose light for me, it goes into my jacket pocket and is skinny, so I often EDC it, and I often use its tailstanding capabilities. Its light weight is also a plus.
The Malkoff setups are what I'm going to use if have to go search for something outdoors or take a trip in the dark woods, but they are too large for a general purpose light for me, and they also lack the multiple modes the P3D have (but not having multiple modes can also be an advantage sometimes).

Are you saying that with an extension, P3D becomes a 3x123 lite therefore able to take 2x17500? Given each 17500 cell is 1.5 times longer than the 123 cell, that works out just fine.
It should also have the OAL of L2D, which I've EDC for a while.

If so, that seems neat.

I realize a 2x18650 is a big lite, almost the size of 2D M*g, length-wise. But you should get good runtime.


Actually, let me ask you - if I standardized on the 17500 cell, I could also use it in the Surefire 9P, without an extension? That 2 of them would work just fine and not require double-clicking?

A CR123 is a 16340 size cell.

3 of them end to end works out to about 100mm.

So 2 17500s end to end, is also about 100mm.

An AA cell is 14500 size.

I'll let you connect the dots.

I use my P3D with PEU's tactical 3xCR123 body sold by 4Sevens. It is then the same length as a L2D.
My experience is that you always can exchange 2x17500 for 3xCR123, and they are also almost the same output voltage so no problem there either. The only obstacle is if the body is to tight to fit the cells. However, the 9P have room for them so it can be used right out of the box with 17500 cells.
Previously, double clicking was a big issue (when used with hotwires), but AW has upgraded his cells so it is not such a big issue anymore I think, maybe with the P91 module but not with the P90 module.

I am kind of leaning towards Surefire, especially because M60 module has better heat sinking? (P4 vs. Cree)