A battery management system is provided for one or more batteries. The system includes a display unit, and a controller coupled to the display unit and programmed to determine when a healthcare delivery system is coupled to the one or more batteries, to control the display unit to display an initial number corresponding to a time remaining on battery (TROB) when the healthcare delivery system is coupled to the one or more batteries, to determine if the TROB is within a reserve range extending up to a reserve range maximum, the reserve range maximum being less than a maximum TROB, to change the TROB according to an operational state of the healthcare delivery system if the TROB is greater than the reserve range maximum, and to decrease the TROB without regard for the operational state of the healthcare delivery system if the TROB is less than the reserve range maximum.