Another resistor question....

Sometimes I fell like a goofy posting these questions that for you may have obvious questions here. But, as a new "flashlightguy" (hehe), I have a lot of questions without answers:

What is the better resistance to put a 3w emitter on that flashlights:

maglite 3D, maglite 4D, maglite 5D, maglite 6D.

/ubbthreads/images/graemlins/crazy.gif Thanks. /ubbthreads/images/graemlins/whoopin.gif

Please read:

...you may have obvious questions here....

as

...you may have obvious answers here...

With what batteries? I would direct drive (no resistor) the 3D on NiMH and probably on alkaline. I'm not quite ready, but I intend to test a 3D (with 3Ds, also 4Cs) on alkaline & Nimh batteries before I decide what resistor to use. I have a .47 and a 1 ohm so I can test .47, 1, & 1.47ohms.

Note that the actual lights and 3w luxeons have enough variation and other variables that simply calculating a value is not good enough to suit me. It isn't going to bother me if the light operates the luxeon above the 1 amp level provided it isn't much over (maybe 1.2 amps?) and isn't over for a long period of time.

I wouldn't use a 5D or 6D with a 3w. You might do a search on this forum to see what others have used although very few people have used resistors. Resistors waste a lot of battery power especially when the voltage is way high like a 5D or 6D would be.

-RussH

I will always use alkalines.
My main doubt relies on the fact that D cells and C cells have different current levels. In a 3C, I will use a 0.56 ohm, in a 3D, I am not sure, because the higher current over c cells.

I don't think the voltage drop is going to be bad with 1 amp in either C or D alkalines. So your .56 ohm might work just as well with either, although maybe a little higher current flow with the Ds. For most alkaline applications, I size things for an average 1.35v. Then they work fine with NiMH as well. The period of time that the voltage is above 1.35v doesn't significantly affect the life of most items like electronics or motors. Flashlight bulbs are already sized for 1.2v per cell, normally
I have a friend who wants to use alkalines in a 3C, with a Lux3, so I'm looking real hard at about .5 ohms. The electronic shops in my small town don't have much of a selection in small, 2 or 5 watt resistors. So I may use some of this nichrome wire I have laying around for a custom value. But if it draws 1.1 amp or less with fresh batteries DD, I won't bother with the resistor. I'm mainly planning on a resistor with my 4C arrangement in a 3D mag, so I can use it either way.