I am lucky that I get free 123s from work but I still love all my 18650s. AAAs are still hard to beat if you have got to pay for them.
AA. Honestly, if you stock enough of any cell you should be covered but in the event you would need to scavenge for batteries, AA would be easy to come by.
18650. The size to capacity ratio is the best available for anything I want to do. And with 18650 lights getting as small as they are ... Well, it's a no brainer for me. Pardon the pun, but the future looks bright.
I'm a AA fan too. When I first got into carrying a small flashlight everyday, I tried 123s but went to AAs since they are everywhere. The one exception, my Klarus Mi02 AAA keychain flashlight.
For me it is a toss up between the AA and AAA battery depending on the light... In an EDC light I am generally looking for something compact, easily carried and with enough output and runtime for general everyday tasks. So far AAA powered lights seem to fill this requirement best, with a decent balance between these factors that suits me well. For more specific use lights that I don't carry daily, I am happy trading off a little size for between runtime/output in a hand or head torch for situations like camping where function and practicality takes precedence over small size. For this AA batteries are ideal with some great options being available in AA or 2AA formats. The big thing that draws me to these options over the more advanced battery types is the fact that they are readily available - The knowledge that they are readily available in virtually any shop in the country means getting spares if needed is not an issue - if I am going to be away camping for two weeks it is trivial to get a supply of batteries to last me relatively cheaply, and beyond the world of lights these are also by far the most common lights for a wide array of other portable electronics, so are useful across many other items I may have.
18650's are my first choice because of the light weight and high performance. AA's are my second choice because they're common and bright enough for most tasks, not to mention you can substitute 14500's in some AA lights for more performance.
Exactly. I also believe that 18650 will probably make an emergence into more specialized consumer electronics in the near future. For exactly the reasons brought up in this thread.
