Battery backup remaining time arrangement

Abstract

For reducing the current consumption from a battery in order to lengthen a battery remaining time when an interruption in a mains supply voltage occurs and battery backup operation follows, a controller initiates shutdown operation of selected devices.—Some of the selected devices experience a shutdown delay of, for example, 1-4 minutes, referred to as a transitional shutdown delay interval, from a time immediately following the interruption to a time when shutdown is fully completed. During the transitional shutdown delay interval, battery remaining time is calculated by using a value that is indicative of anticipatory current consumption, instead of by using the actural real time current measurements. Thus, fluctuation of the current consumption, during the transitional shutdown delay interval, will have no effect on a signal containing the battery remaining time, during the transitional shutdown delay interval. Because the calculated battery remaining time is unaffected by the transient loading, during the transitional shutdown delay interval, any “race” condition and its potentially harmful effects will be, advantageously, prevented.

Dependencies are inferred from the claim text.