A bus line address changing apparatus for use in an electronic instrument including a plurality of battery unit attaching sections configured to accommodate a plurality of battery units respectively composed of at least one battery. A bus line receives a communication signal from at least one battery unit. A body side controller receives the communication signal from the at least one battery unit via the bus line. A bus line address storing device stores a plurality of bus addresses allocated for and corresponding to the plurality of battery unit attaching sections. In addition, a bus address selecting and setting device is provided to select and set one of bus addresses according to the battery unit attaching section when the battery unit is attached to the electronic instrument and electrically connected to the bus line.
An electrical power management system is provided for effectively managing available electrical power for recharging batteries used in a plurality of battery-powered computers. The electrical power management system is of particular value when current from the available power supply is limited relative to the total charging current required for the batteries. Charging currents can be sensed to better manage the recharging process. Charging data can be sensed and recorded to optimize battery charging for a plurality of battery-powered computers.
