Method and circuit for determining battery capacity
First Claim
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1. A method of determining the capacity of a battery comprising the steps of:
- imposing an increasing charge on a battery during a plurality of charge intervals and a plurality of discharge intervals interspersed with the charge intervals by applying a charge current to the battery during each charge interval;
applying a load to the battery during each discharge interval until the battery voltage decreases to a selected level;
removing the load in response to the attainment of the selected level to end the discharge interval; and
sensing the duration of each discharge interval as an indication of the capacity of the battery.
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Abstract
The capacity of a battery is determined while charging the battery by measuring the time it takes the battery voltage to decrease to a selected voltage level during discharging intervals interspersed between charging intervals. The state-of-charge is also determined by measuring the voltage level during a discharge interval while monitoring the duration of the charge cycle. Additionally, faulty cells of the battery are detected by measuring the voltage of the individual cells at the end of a discharging interval during the charging of the battery.
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Citations
11 Claims
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1. A method of determining the capacity of a battery comprising the steps of:
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imposing an increasing charge on a battery during a plurality of charge intervals and a plurality of discharge intervals interspersed with the charge intervals by applying a charge current to the battery during each charge interval; applying a load to the battery during each discharge interval until the battery voltage decreases to a selected level; removing the load in response to the attainment of the selected level to end the discharge interval; and sensing the duration of each discharge interval as an indication of the capacity of the battery. - View Dependent Claims (2, 3, 4)
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5. A method of determining the capacity of a battery comprising the steps of:
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imposing an increasing charge on a battery during a plurality of charge intervals and a plurality of discharge intervals interspersed with the charge intervals by applying a charge current to the battery during each charge interval; applying a load to the battery during each discharge interval until the battery voltage decreases to a selected level; removing the load in response to the attainment of the selected level to end the discharge interval; and measuring the cell trough voltage at the end of the battery discharge interval of each individual cell in succession. - View Dependent Claims (6)
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7. A method of determining the capacity of a battery comprising the steps of:
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imposing an increasing charge on a battery during a plurality of charge intervals and a plurality of discharge intervals interspersed with the charge intervals by applying a charge current to the battery during each charge interval; applying a load to the battery during each discharge interval until the battery voltage decreases to a selected level; removing the load in response to the attainment of the selected level to end the discharge interval; applying a shunt in the path of the battery discharge current; developing a signal in response to the voltage across the shunt during each discharge interval with the signal having a duration determined by the duration of the discharge interval; and applying the signal to a bar chart display. - View Dependent Claims (8)
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9. A battery charger analyzer comprising:
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a charge current source; means for applying a selected amplitude of charge current from the source to a battery for a selected interval of time; means for discharging the battery at the end of each charge current interval; means for sensing the battery terminal voltage during discharge; means responsive to the sensing means for terminating each discharge interval upon the battery terminal voltage decreasing to a selected level; means for sensing the duration of each discharge interval; and means for displaying this duration as a measure of the charge capacity of the battery. - View Dependent Claims (10, 11)
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Specification