XP-G mini-mag?
- Thread starter ^Gurthang
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old4570
Flashlight Enthusiast
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 .
^Gurthang
Flashlight Enthusiast
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.
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.
Justin Case
Flashlight Enthusiast
- Joined
- Mar 19, 2008
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- 3,797
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.
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.
zelda
Enlightened
my minimag heatsinks:
http://www.candlepowerforums.com/vb/showthread.php?t=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
http://www.candlepowerforums.com/vb/showthread.php?t=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
greenLED
Flashaholic
Incidentally, I have a few of those heatsinks made by Zelda... EXCELLENT!!my minimag heatsinks:
http://www.candlepowerforums.com/vb/showthread.php?t=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
If you use 2 unprotected cells with a stepdown converter, its unsafe due low- discharge.
zelda
