Battery capacity test method and apparatus
First Claim
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1. A battery capacity tester for determining a remaining capacity of a battery electrically coupled to the battery capacity tester, said battery capacity tester comprising:
- a constant current sink, electrically coupled to the battery, constructed and arranged to draw at least a first and a second substantially constant current from the battery; and
a battery characterizer, operationally coupled to said constant current sink and the battery, constructed and arranged to determine a remaining capacity of the battery based on a predetermined relationship between battery impedance and capacity for the battery,wherein an instantaneous internal battery impedance is determined based on a battery voltage measured during each said draw of said first and second substantially constant currents.
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Abstract
A battery capacity tester method and apparatus are provided. The battery capacity tester determines the present internal battery impedance by measuring terminal voltages during successive applications of a known load, each load drawing a predetermined current from the battery. This calculated internal battery impedance is used to determine battery capacity based on a precharacterization of the battery that establishes a relationship between the internal battery impedance and the remaining battery capacity.
61 Citations
20 Claims
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1. A battery capacity tester for determining a remaining capacity of a battery electrically coupled to the battery capacity tester, said battery capacity tester comprising:
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a constant current sink, electrically coupled to the battery, constructed and arranged to draw at least a first and a second substantially constant current from the battery; and a battery characterizer, operationally coupled to said constant current sink and the battery, constructed and arranged to determine a remaining capacity of the battery based on a predetermined relationship between battery impedance and capacity for the battery, wherein an instantaneous internal battery impedance is determined based on a battery voltage measured during each said draw of said first and second substantially constant currents. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for determining a remaining battery capacity of a battery, comprising:
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(1) determining an internal battery impedance of the battery comprising (a) causing the battery to supply a first substantially constant current, (b) measuring a first terminal voltage of the battery during said step (1)(a), (c) causing the battery to supply substantially constant second current, (d) measuring a second terminal voltage of the battery during said step (1)(c), and (e) determining the internal battery impedance as a function of a ratio of the difference between said first and second voltages and said first and second currents; and (2) determining a remaining battery capacity using said determined internal battery impedance and a predetermined relationship between internal battery impedance and remaining battery capacity for the battery. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A defibrillator comprising:
a battery capacity tester for determining a remaining capacity of a battery installed in the defibrillator and electrically connected to said battery capacity tester, wherein said battery capacity tester comprises; a constant current sink, electrically coupled to the battery, constructed and arranged to draw a plurality of constant currents from the battery; and a battery characterizer electrically coupled to said constant current sink and the battery to determine a remaining capacity of the battery based on a predetermined relationship between battery impedance and battery capacity for the battery, wherein an internal battery impedance is determined based on a battery voltage measured during each said draw of said plurality of constant currents. - View Dependent Claims (17, 18, 19, 20)
Specification