Apparatus and method for indicating remaining battery life in a battery powered device
First Claim
1. In a battery powered system which includes a portable battery powered device and a battery connected to said device for supplying electrical power thereto, the combination therewith of an apparatus for predicting the remaining useful life of the battery during the normal use discharge cycle of the battery, said apparatus comprisingdata storage means for storing a predetermined value representing the total number of usable hours expected to be obtained from a fully charged battery during a normal use discharge cycle,means for counting the number of hours of actual use of the battery,means for comparing the number of hours of actual battery use with said stored predetermined value to determine the number of hours of usable battery life remaining,means for displaying the thus determined remaining usable battery life, andmeans operable in response to the occurrence of a full discharge cycle of the battery in normal use updating said data storage means to store therein as said predetermined value for the expected useful life of the battery in the next normal use discharge cycle, the value for the number of hours of use actually obtained from the battery in the current discharge cycle, so that subsequent predictions of the battery life will be based upon the immediate past history of actual battery life.
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Abstract
The remaining battery life of a battery powered device is predicted by monitoring the immediate past history of battery life and employing this immediate past history as a basis for subsequent predictions of the useful life of the battery. By this approach, the present invention is able to take into account the deterioration of battery life which occurs during the life-time of a rechargeable battery. The device includes a data storage means for storing a predetermined value representing the total number of usable hours to be expected to obtain from a fully charged battery during normal use, means for counting the number of hours of actual use of the battery, and means operable in response to the occurrence of a full discharge of the battery in normal use for updating the data storage means to store therein as the predetermined value for the expected useful life of the battery in the next cycle of normal use, the value for the number of hours of use actually obtained from the battery in the current cycle, so that subsequent predictions of the battery life will be based upon the immediate past history of actual battery life.
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Citations
7 Claims
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1. In a battery powered system which includes a portable battery powered device and a battery connected to said device for supplying electrical power thereto, the combination therewith of an apparatus for predicting the remaining useful life of the battery during the normal use discharge cycle of the battery, said apparatus comprising
data storage means for storing a predetermined value representing the total number of usable hours expected to be obtained from a fully charged battery during a normal use discharge cycle, means for counting the number of hours of actual use of the battery, means for comparing the number of hours of actual battery use with said stored predetermined value to determine the number of hours of usable battery life remaining, means for displaying the thus determined remaining usable battery life, and means operable in response to the occurrence of a full discharge cycle of the battery in normal use updating said data storage means to store therein as said predetermined value for the expected useful life of the battery in the next normal use discharge cycle, the value for the number of hours of use actually obtained from the battery in the current discharge cycle, so that subsequent predictions of the battery life will be based upon the immediate past history of actual battery life.
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5. In a battery powered system comprising a portable battery powered instrument, said instrument including microprocessor means for carrying out predetermined instrument functions, display means for displaying the results of the instrument functions, and a battery for supplying electrical power to the instrument, the combination therewith of an apparatus for predicting the remaining useful life of the battery during the discharge cycle of the battery, said apparatus residing in and operated by the same microprocessor means which is used for carrying out said instrument functions, and comprising
data storage means in said microprocessor means for storing a predetermined value representing the total number of usable hours expected to be obtained from a fully charged battery during a normal use discharge cycle. means for counting the number of hours of actual use of the battery, means in said microprocessor means for comparing the number of hours of actual battery use with said stored predetermined value to determine the number of hours of usable battery life remaining, and for displaying the thus determined remaining usable battery life on said instrument display means, means for monitoring the voltage of said battery during the discharge cycle and sensing when the battery voltage falls to a predetermined minimum usable voltage, and means operable in response to the ocurrence of a full discharge cycle of the battery in normal use for updating said data storage means to store therein as said predetermined value for the expected useful life of the battery in the next normal use discharge cycle, the value for the number of hours of use actually obtained from the battery in the current discharge cycle, so that subsequent predictions of battery life will be based upon the immediate past history of actual battery life.
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7. A method for predicting the remaining useful life of the battery employed in a battery powered device, comprising
storing a predetermined value representing the total number of usable hours expected to be obtained from a fully charged battery during a normal use discharge cycle, counting the number of hours of actual use during a discharge cycle of the battery, comparing the number of hours of actual battery use with said stored predetermined value to determine the number of hours of usable battery life remaining, displaying the thus determined remaining usable battery life, monitoring the battery voltage during the discharge cycle and sensing when the battery voltage falls to a predetermined minimum voltage which is indicative of a full discharge cycle of the battery, and in response to the occurrence of a full discharge cycle of the battery in normal use, updating said stored predetermined value for the expected useful life of the battery, with the value for the number of hours of use actually obtained from the battery in the current discharge cycle, so that subsequent predictions of battery life will be based upon the immediate past history of actual battery life.
Specification