1/2 AA size batteries may be rare, but they are commonly found in many unseen applications, such as memory (CMOS) backup, real-time clocks, utility meters, wireless alarms and security contacts, emergency beacons and small industrial and professional grade electronic devices. What is the best type of chemistry for these applications? Lithium Thionyl Chloride batteries also known as lithium primary batteries. With an average shelf life of 10 years, 1/2 AA size batteries offer the optimal solution for long term battery use. Find your battery from our selection of Saft, Tadiran and Xeno batteries below, or call us for assistance.