Mod vs. New... Interesting ideas

Well, I'm thinking that if I do well this semester in school I'll reward myself with a nefty new light. After I get my firebird on the road again (crown vic got totalled).

Anyways, my two thought are either go with a certain fenix light; suffice it to say its a 2xAA rebel model, or mod my current Ultrafire XRE P4 1xAA.

Now, naturally modding the UF cree would be cheaper, and more fun. But I'm not sure about it, so I guess I'll ask you guys for some input. I'm considering throwing in a Q5 (http://www.dealextreme.com/details.dx/sku.2394) and using this driver (http://www.dealextreme.com/details.dx/sku.4735).

According to once reviewer, the stats are:
Vin Iin Vout Iout
1.00 0.40 2.92 0.12
1.20 0.72 3.03 0.20
1.40 1.03 3.07 0.27
1.57 1.14 3.07 0.32
2.50 1.22 3.18 0.59
3.00 0.95 3.10 0.65
3.50 0.82 3.37 0.68
3.98 0.89 3.27 0.93
4.28 0.95 3.51 0.97

Which would me I could run any type of AA I wanted, and it would still be brighter with better runtime than the current P4 setup. Even with fresh 2300mAh NiMH cells, I should still get over 2hrs runtime, probably a lot more as current consumption drops with voltage, right?

Other than the obvious reputation Fenix has, would there be any real benifit to going with a $50-$70 fenix over converting this <$15 light for under $20?

Besides more modes, a warranty, and possibly better build quality, there is no need to upgrade to Fenix.

The DX lights should be fine for everyday use and if you pot the driver, the light would be able to take a lot more abuse. So I'd say go with the mod (and you also get two more drivers if you plan on using the P4 LED from your Ultrafire in another light).

Actually, I'm not sure whether those drivers would be alright for the P4 since they have the higher Vf required by the Q5's. By 'pot' do you mean thermal epoxy it to the star? Wouldn't it already be affixed in such manner?

I've used both that sku 1892 as well as the MTE 5 mode 1aa rebel for many hours on my bike without issue, so they must be fairly robust.

By pot, I mean putting epoxy over the board so no components can pop off due to a bad solder joint(or break, remind me not to throw my already abused light onto concrete). Just make sure the board can still fit the pill.

If it is a good driver, then it should be fine with a higher Vf, you would just get less current.

Yeah, I suppose that makes sense, but wouldn't that possibly create a heat issue?

If the driver has a contact soldered to the pill, I don't suppose so since that would also conduct heat, though not much. On 2 AA batteries, the driver should be fine since it is about 80% efficient, no so with 1 AA battery.

If you are worried about heat, this driver is pretty efficient when set at a lower drive currents(disabling the modes).

Interesting developement... It seems the 2106F board I was going to install with the Q5 came installed in the light OEM...with the XRE P4 emitter.

Is this even possible? Ifits putting out around 3.x volts for the Q5, wouldn't it fry the P4? I'm confused now!

Nope, I was wrong; very wrong. They are both spec'd at 3.7V to the emitter. Sweet. This means I'll have an extra Cree P4 after the conversion, and a few extra boards.... Sounds like I need to find a 2AA host!