Device for detecting residual capacity of a battery both in load and no load conditions
First Claim
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1. A device for detecting residual capacity of a battery, comprising:
- a pair of battery connection terminals connected to a battery which has a discharge characteristic such that an open-circuit voltage thereof without an external load being connected or a closed circuit voltage with the external load connected becomes lower as its discharge becomes deeper;
comparator means for comparing the open-circuit or closed-circuit voltage of said battery with a plurality of detection voltages set to predetermined voltage values nd for providing an indication of a charge state of said battery; and
means for compensating for a difference between said open-circuit voltage and said closed-circuit voltage so that said comparator means can compare either the closed-circuit or open-circuit voltages with said plurality of detection voltages such that the indication of battery charge state is substantially unaffected by whether or not the load is connected to the battery.
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Abstract
A device for detecting and displaying residual capacity of a battery comprises a comparator comparing detection voltages set to predetermined values and open circuit voltage. The device further contains circuitry to compensate the difference of the open circuit voltage and the closed circuit voltage of the battery. Thus the device can detect the residual capacity of the battery under conditions both with and without the external load.
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Citations
7 Claims
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1. A device for detecting residual capacity of a battery, comprising:
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a pair of battery connection terminals connected to a battery which has a discharge characteristic such that an open-circuit voltage thereof without an external load being connected or a closed circuit voltage with the external load connected becomes lower as its discharge becomes deeper; comparator means for comparing the open-circuit or closed-circuit voltage of said battery with a plurality of detection voltages set to predetermined voltage values nd for providing an indication of a charge state of said battery; and means for compensating for a difference between said open-circuit voltage and said closed-circuit voltage so that said comparator means can compare either the closed-circuit or open-circuit voltages with said plurality of detection voltages such that the indication of battery charge state is substantially unaffected by whether or not the load is connected to the battery. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification