Cree drop-in using two C or D cells?

Is it possible to use one of the popular cree drop-ins to mod a two "C" or "D" cell flashlights? This would be 3 volts unless someone comes out with some 1.7 volt lithum primarys like the AA and AAA cells. What would be the extimated output for some of these? I'm sure the regulation circuit in the drop-in would be a factor to concider. I don't want to use multiple AA or AAA cells, only what the flashlight was designed to use.

Any suggestions?

I haven't tried it, but I'd imagine if you used, say, the Terralux 3-6 cell dropin with on 2 cells, the result would either be nothing or would be VERY dim.

They are supposed to have a 2 cell dropin coming out in about 50 or 60 days. Or you could try your hand at modding one of the existing 2 cell-compatable dropins with a Cree or SSC LEDs or possibly even use the Terralux bi-pin module intended for a Minimag, in the 2 cell PR adapter which would then fit in the PR base of the 2C or 2D Mag. I haven't read of anyone trying this yet, but it 'should' work.

In playing around with a couple of Cree stars from DX, I was surprised to discover that they'll produce a usable amount of light when direct-driven by just two fresh 1.5 volt alkaline cells. Granted, they're not NEARLY as bright as when driven at their rated current, but still bright enough to make them entirely usable as replacements for incandescent PR2 bulbs.

The spec sheet for the Seoul Semiconductor version shows even lower foward voltage characteristics, which implies that it might make an even better candidate for direct drive from two cells - However, I haven't confirmed that with any tests. The package shape would probably also lend itself better to being mounted and focused in a standard "bayonet" bulb base than the Cree version, too.

You could use a TerraLUX TLE-5EX with a BA-2 bulb adaptor if it's a PR base you're trying to fit; basically what cratz2 mentions above.

If you have a 2C cell flashlight, get the TerraLux 6EX Cree drop-in and run it with a couple of AW's 18500 3.7v protected cells ($10 each plus $15 for the charger). Best guess is 3-4 hours runtime. I'm just waiting for the post office to cough up cells and charger.

If you have a 2D flashlight you can probably fit in a couple of 18650s if you don't mind modifying the tailcap spring -- same voltage but more runtime.

EDIT -- hold on, just remembered that the 6EX is kinda Maglight-specific. It won't drop in to just any 2 cell flashlight.

bridgman said:

If you have a 2C cell flashlight, get the TerraLux 6EX Cree drop-in and run it with a couple of AW's 18500 3.7v protected cells ($10 each plus $15 for the charger). Best guess is 3-4 hours runtime. I'm just waiting for the post office to cough up cells and charger.

If you have a 2D flashlight you can probably fit in a couple of 18650s if you don't mind modifying the tailcap spring -- same voltage but more runtime.

EDIT -- hold on, just remembered that the 6EX is kinda Maglight-specific. It won't drop in to just any 2 cell flashlight.

Click to expand...

And actually, one can fit two 18650 cells into a 2C maglite by removing the spring entirely and removing the anodize from inside the tailcap and using either 1 or 2 neodymium magnets or using aluminum foil to fill the very small gap. I have 2 LED 2C Mags that run thus.

2 AW li-ion "C" cells fit in a 2D flashlight if it has a reasonably long spring.
They'll fit in a 2C Mag with an extender or a MagClickie.
Twice the capacity of 18500s, and half again what 18650s offer.