Smart battery with maintenance and testing functions, communications and display

A smart battery that self-monitors and maintains information about itself that includes its state of charge, its need for maintenance, and for conditions that indicate that it has reached the end of its useful life and should be discarded. The information maintained by the battery is then either displayed on an on-board display or is communicated to another device on a communication bus. The state of charge quantifies the smart battery's ability to reliably deliver charge to a host device and is dynamically adjusted over the lifetime of the smart battery. The state of charge may not exceed a full charge capacity value maintained by the smart battery and initially set to an estimated value. This full charge capacity value is dynamically adjusted throughout the life of the smart battery using information accumulated and maintained by the smart battery that indicates the smart battery's actual performance during use and by using messages received from a battery maintenance and testing system. The smart battery also accumulates and maintains information that indicates that the smart battery requires maintenance. A battery maintenance and testing system can read this need for maintenance from the smart battery and take the steps necessary to automatically maintain the smart battery. Conditions that indicate that the battery is defective or has exceeded its useful life are also maintained by the smart battery and communicated through the on-board display or to another devices over a communication bus. The battery is specially configured for easy assembly.