A battery pack (1) is connected to an external equipment (9) and to a power source circuit (10) designed to supply the power to the external equipment (9). The communication of the information is made between a micro-computer (11) in the battery pack (1) and the external equipment (9) via a terminal...http://www.google.com/patents/US5680027?utm_source=gb-gplus-sharePatent US5680027 - Battery pack including internal capacity monitor for monitoring groups of battery cells 
