Re: Battery Vampires - Lights that you can feed your "dead" cells to, listing..
1xCR123A: Peak McKinley. In a recent informal runtime test, my McKinley 1 LED model was still going strong at 7 hrs. 45 min. on an RCR123A when I ended the test. Seemed to maintain fairly flat output as well. I imagine on 1 primary CR123A, its times would be impressive, but I'm too cheap to sacrifice a cell to find out.
Provides a decent amount of light on a well-spent primary. Beam, however, is much prettier on the 7 LED McKinley, mentioned below.
My 7 LED (old style) HP model is another runtime champ. In the same test, its RCR123A's protection circuit kicked in at 7 hrs. 45 min., and it maintained good regulation up to that point. Just tried a well-spent primary cell in it, and it put out a nice dim circle of light, similar to the Matterhorn on a spent alkie, referenced below.
1xAAA: Peak Matterhorn. On a semi-spent alkie, puts out a smooth even large spot, fairly dim and perfect for reading in bed. Mine is a 3 LED (old style) HP, so I'm sure a 1 LED model would be even better.
2xAA: Gerber Trio. Once described as a (CMG Infinity) "Ultra on steroids", this nicely built light puts out a very wide, even flood beam, with a bluish tint. It's decently bright for ~ 6 hrs. on 2 AA eneloops, then dims and maintains a very long tail. On well used alkies, it still puts out useable light, and I imagine for a very long time.