While today you have some great AA and AAA LED flashlights, CR123A powered torches offer the greater lumen output. The day will come when a single AA will put out 1000 lumens, but that same day you’ll be getting 2000 lumens from a single CR123A. As of today, the lithium flashlights operating on a single cell will double the brightness of their AA and AAA counterparts. This is why tactical flashlight manufacturers like Surefire use lithium batteries. CR123A batteries offer maximum brightness. They are also compact and have a nearly decade long “Best Before” date. I’m still going through some Surefires that are to expire in 2015, they are still going strong. If you have weapon mounted lights or optics, chances are they use CR123A batteries as well.
On the negative side of things, they are expensive and not as easy to find in smaller brick and mortar stores. This goes against the modern survival ethos of keeping things simple and using commonly available parts and spares when possible. I make my peace with this by keeping a 1xAAA LED flashlight in my keychain at all times.
So, which CR123A primary batteries should you stock up? While there are a few good cheap batteries you can buy in bulk, I’ll go along with Surefire´s recommendation and stick to Surefire, Duracell, Energizer and Panasonic batteries. These are all made in the same Panasonic factory in USA and are considered the best CR123A in the market. The guys over at candlepower forum did some detailed testing on different CR123A if you like to read more about it. http://www.candlepowerforums.com/vb/showthread.php?67078-123-Battery-Shoot-Out
Other than the labeling, these American made batteries are all pretty much the same, made by the same manufacturer to top standards.
Just look around and buy any of these in bulk.
According to the guys at candlepowerforum and several posts that Ive read, Tenergy seem to be some of the best perfoming “cheap” batteries, costing a dollar a pop when buying bulk. Check the link provided to see how these perform compared to Surefire, Duracell, etc.
Here’s the vid I made on this topic.