XP-G mini-mag?

While doing a bit of research I noticed that the Cree XP-G emitter has a Vf of between 3.0 to 3.5. Has anyone tried an XP-G DD in a mini-M@G?

I missed my opportunity recently as SB is back ordered for XPGs on stars..... just curious if this simple mod has worked.

^Gurthang said:

While doing a bit of research I noticed that the Cree XP-G emitter has a Vf of between 3.0 to 3.5. Has anyone tried an XP-G DD in a mini-M@G?

I missed my opportunity recently as SB is back ordered for XPGs on stars..... just curious if this simple mod has worked.

Click to expand...

I got a XP-E Q5 , in my LED mini mag [ 2xAA ] ..
No reason you could not go with a XP-G R5 ,

For incan mods , should also work , 3v Direct drive , should work .

My own incan 2xAA has a XR-E Q5 , and is a little dim with 2xAA compared to a single 14500 @ 700mA DD + Dummy cell .

Need some more Mini Mags , but XP-G R5 DD should be a simple mod and should give decent returns .

4570,

Thanks. I did find the "show us your Mini-M@G mods" thread after I posted this.... my main reason for asking was to find out if anyone else had tried a low Vf XP-G in direct drive w/ 2 X AA.

Of course now that the NiZn rechargeables are available it sort of makes the emitter Vf binning a moot point. Guess its time to order a couple of XP-Gs on small stars.

Like old4570, I have built a DD XR-E Q5 Mini Mag.

2xAA NiMH probably won't work well with even a low Vf XP-G. I've typically measured about 3.2V at ~1A drive current. But you aren't going to get 1.6V per cell with NiMHs. Let's say that you get 1.4V per cell under load, which is probably about the best case. At a Vf of 2.8V, the XP-G datasheet suggests a drive current of about 150mA. For that drive current, the relative luminous flux is about 40%. If you have an XP-G R5, that gives about 55 emitter lumens. After the usual approx 1/3 optical losses, you are left with about 40 OTF lumens. Not that great, but better than stock. However, this low ~150mA drive level is probably a good thing if you don't have a good heat sink for the LED.

2xAA NiZn probably will work well. This discharge curve shows that the NiZn cells should be able to hold 1.6V each, or 3.2V total. That is a good match for the XP-G.

If you do drive the XP-G at 1A drive, however, you better heat sink it. This copper Mini Mag heat sink works well.

my minimag heatsinks:
https://www.candlepowerforums.com/threads/126086
It's much easier, if you can make this heatsink in copper, instead of aluminium. (no groundig problem, just solder the driver to heatsink.)

the protected trustfire 14500 "900mAh " give you around 660mAh at 0.7A discharge rate, but they are maybe too long to fit 2 cells in a 2AA host.
If you use 2 unprotected cells with a stepdown converter, its unsafe due low- discharge.

zelda

zelda said:

my minimag heatsinks:
https://www.candlepowerforums.com/threads/126086
It's much easier, if you can make this heatsink in copper, instead of aluminium. (no groundig problem, just solder the driver to heatsink.)

the protected trustfire 14500 "900mAh " give you around 660mAh at 0.7A discharge rate, but they are maybe too long to fit 2 cells in a 2AA host.
If you use 2 unprotected cells with a stepdown converter, its unsafe due low- discharge.

zelda

Click to expand...

Incidentally, I have a few of those heatsinks made by Zelda... EXCELLENT!!