Over at the CandlePower Forums mod discussions, the Seoul Semiconductors Z-Power LED P7 has been one of the most popular LEDs. The reason is simple: it puts out 700-900 lumens at 2800 ma. That’s very bright.

In the Home Made and Modified Lights section, jirik_cz modded his Ultrafire C2 flashlight with a SSC P7. For power, he used a Li-Ion 18650 3.7V battery directly driving the LED. It is a simple and elegant mod.
I happened to have a spare Ultrafire C2 flashlight waiting for a great idea like jirik_cz’s mod. I already had the P7 emitter (C bin) mounted on a heat sink base. An advantage of having the P7 emitter on a heat sink base is that the positive base of the bare emitter is isolated from ground.
I used a Dremel to enlarge the Ultrafire pill so the P7, on some heat sink compound, fit perfectly.
For the positive battery contact side of the pill, I stripped a 17mm diameter circuit board and soldered the LED leads to it. To accommodate the larger diameter LED, (the Ultrafire C2 uses a Cree XLamp® XR-E LED), I enlarged the hole in the reflector with a reamer.
Thanks to jirik_cz, now I have a 5″ (130mm) long flashlight that is a bright as my Roar of the Penguin.