I've been using a FourSevens MIni MK II flashlight that uses a CR123a battery. Turns out that I am getting a few days at most use out of them before the battery needs to be recharged or changed. Days when I'm not working, it no big deal. Days when I am working, it seems like I am always running the battery out. I need some recommendations on carry containers for 1 or 2 batteries. It needs to be pocket carry. What is everyone using?