Rechargeable batteries are very popular within consumer electronics. If one uses a cell phone or portable electric tool, she/he understands the need to have a reliable product and the need to remember to use the recharging systems that follow a cycle of charge/discharge. Rechargeable batteries are being called "green" energy sources. They are a growing industry and use the advancing technologies of chemical materials and complex control (charge and discharge) circuit designs that lead to announcements of newer products daily. This article reviews the types of rechargeable batteries that are available, including their composition and charging and discharging capabilities. (Contains 5 figures and 1 table.)