Modding C & D cell lights with CR123, anyone do it?

Has anyone here modded a C or D cell light to run on CR123's? I suppose some of you have do this with AA's.

Basically, I'm just wondering what this does for run times. I'm assuming C & D has a LOT more juice than a CR123, just less voltage.

What can be done to multiply voltage to a steady level short of using more batteries?

people on CPF have been doing it for years.

Most people stuffing CR123's in there aren't too interested in runtimes.

I've been reading here for awhile and it seems to me that the key to hotwire performance is voltage. Whereas common mags run 3V or 4.5V, with CR123's you can easily pump that up to 9v or 12v. I have a 2C mag with 3 CR123's in it and a Radio Shack KPR112 bulb. It is much brighter than a standard mag, but if I remember correctly the runtime will only be 30 to 45 minutes. I don't use my lights for long periods of time so that doesn't concern me.

Yeah, the two common builds are 3x123 cells with a KPR112 or KPR113 bulb or 4x123 cells on the KPR118 bulb. Runtime isn't great and bulb life isn't great. I usually sputter the reflector for a smoother beam and larger hotspot at the cost of a slight loss in throw.

Some folks also like the 6 cell Xenon bulb on the 3x123 cells and I think this throws a bit better than the KPR112 with 3 cells.

Unless you're just dying to have an overdriven bulb in too large of a host, the Streamlight TL-3 is an outstanding value in a 3 cell light.