System for indicating a low battery condition
First Claim
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1. A method for detecting a low charge state of a battery connected to a load for supplying power thereto, the method comprising:
- measuring a change in the operating voltage of said battery occurring responsive to a change in the power consumption of said load;
measuring a change in the current through said load occurring responsive to said change in load power consumption;
computing a ratio of said battery voltage change to said load current change;
comparing said ratio to a preselected threshold value; and
issuing a user warning signal indicating a low battery when said ratio exceeds said preselected threshold value.
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Abstract
A system for accurately predicting impending battery failure in battery powered electronic and electrical devices. The system continually monitors changes in battery voltage responsive to load changes and calculates a ratio of the change in voltage to the change in load. When the ratio exceeds a certain threshold value, indicating that the impedance of the battery has risen to near its final value, a user warning indication is generated.
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Citations
18 Claims
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1. A method for detecting a low charge state of a battery connected to a load for supplying power thereto, the method comprising:
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measuring a change in the operating voltage of said battery occurring responsive to a change in the power consumption of said load; measuring a change in the current through said load occurring responsive to said change in load power consumption; computing a ratio of said battery voltage change to said load current change; comparing said ratio to a preselected threshold value; and issuing a user warning signal indicating a low battery when said ratio exceeds said preselected threshold value. - View Dependent Claims (2, 3, 4, 5)
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6. A method for detecting a low charge state of a first battery connected to a load for supplying power to the load, the method comprising:
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measuring a change in the operating voltage of said first battery occurring responsive to a change in the power consumption of said load; measuring a change in the current through said load occurring responsive to said change in load power consumption; computing a ratio of said first battery voltage change to said load current change; comparing said ratio to a preselected threshold value; issuing a user warning signal indicating a low battery when said ratio exceeds said threshold value; and disconnecting said first battery from said load and connecting a second battery thereto when said ratio exceeds said preselected threshold value. - View Dependent Claims (7, 8)
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9. Apparatus for detecting a low charge state of a battery supplying operating power to a load, the apparatus comprising:
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a device connected to said battery for measuring the operating voltage of said battery; a device means connected to said load for measuring the current through said load; a voltage difference monitor connected to said voltage measuring device for monitoring a change in the battery voltage of said battery occurring responsive to a change in the power consumption of said load; a current difference monitor connected to said current measuring device for monitoring a change in the load current occurring responsive to said change in load power consumption; and a control circuit connected to said voltage and current difference monitors for computing a ratio of said operating voltage change to said load current change and for issuing a control signal when said ratio exceeds a preselected threshold value. - View Dependent Claims (10, 11, 12, 13, 14)
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15. Apparatus for electrically disconnecting a first battery from a load and electrically connecting a second battery thereto upon detecting a low charge state of said first battery, the apparatus comprising:
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a device connected to said battery for measuring the operating voltage of said battery; a device means connected to said load for measuring the current through said load; a voltage difference monitor connected to said voltage measurement device for monitoring a change in the operating voltage of said battery occurring responsive to a change in the power consumption of said load; a current difference monitor connected to said current measurement device for monitoring a change in the current through said load occurring responsive to said change in said load power consumption; a control circuit connected to said voltage and current difference monitors for computing a ratio of said operating voltage change to said load current change and issuing a control signal when said ratio exceeds a preselected threshold value; and a switch circuit connected to said control circuit for electrically disconnecting said first battery from said load and electrically connecting said second battery to said load responsive to said control signal. - View Dependent Claims (16, 17, 18)
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Specification