In addition to the AA-cell minimags with Luxeons, they also now offer
3 watt "bulbs" that will drop right into standard maglights that take
2,3 or 4 C or D cells. $18 at Wal-Mart. I bought a 2-cell version up today to check it out. Just the bulb, already had a 2 D-cell Maglight.
I'm impressed.
This one really does work at 3 watts and the regulation is excellent. At 2 volts (1 volt per cell, batteries 83% used up) the current drain was 1.7 amps -- 3.4 watts. At 3 volts (fresh batteries) the drain was
1 amp -- 3 watts. No noticable change in brightness between these two levels. Power draw may be higher at lower voltage because the elex are less efficient(a guess) while boosting the voltage more to continue delivering close to rated current and power to the Luxeon. It starts petering out below 2 volts, though it still produces very usable light at 1.8 volts (about 0.9 watts). So, there is plenty of warning when it's time to renew the batteries.
After dark, I stuck it in a 2-cell Maglight. This is easily a
100-yard flashlight. The spot is very crisp, white of course, and well defined. It is very visible on a house 100 yards away. When I swung the beam past my side neighbor's yard I saw two big green eyeballs shining -- a deer. I "shined" that deer from there all the way until it disappeared around the house behind me, which is a good
100 yards.
There are several other Luxeon "bulbs" available, e.g. TerraLux. This one seems to be as good as any, better than some, and lower in price than the other good ones.