Method for determining state of charge of lead-acid batteries of various specific gravities
First Claim
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1. An apparatus for determining a state of charge (SOG) of a lead-acid battery comprising:
- a power supply;
a control module comprising an analog-to-digital converter, a digital-to-analog converter, and an electronics control system, wherein the control module controls the power supply to apply a current to a battery;
a control relay electrically connected to the power supply;
a sensor that detects at least one of a battery voltage response to a current ramp and an open circuit voltage at a rested state, the sensor electrically connected to the control relay; and
a processor, wherein the processor determines the specific gravity of the lead-acid battery by comparing the maximum battery voltage detected in the battery voltage response divided by a number of cells of the battery, to an SGLim, where the SGLim is an upper limit of the maximum measured battery voltage for a low specific gravity battery divided by the number of cells of the low specific gravity battery.
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Abstract
In accordance with various embodiments, there is a method for determining the state of charge of a battery. Various embodiments include the steps of determining the specific gravity of the battery and measuring an open circuit voltage of the battery at rest. The open circuit voltage at rest can be used to determine the battery state of charge from a correlation function dependent on the battery specific gravity.
16 Citations
13 Claims
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1. An apparatus for determining a state of charge (SOG) of a lead-acid battery comprising:
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a power supply; a control module comprising an analog-to-digital converter, a digital-to-analog converter, and an electronics control system, wherein the control module controls the power supply to apply a current to a battery; a control relay electrically connected to the power supply; a sensor that detects at least one of a battery voltage response to a current ramp and an open circuit voltage at a rested state, the sensor electrically connected to the control relay; and a processor, wherein the processor determines the specific gravity of the lead-acid battery by comparing the maximum battery voltage detected in the battery voltage response divided by a number of cells of the battery, to an SGLim, where the SGLim is an upper limit of the maximum measured battery voltage for a low specific gravity battery divided by the number of cells of the low specific gravity battery. - View Dependent Claims (2, 4, 5)
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3. An apparatus for determining a state of charge (SOG) of a lead-acid battery comprising:
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a power supply; a control module comprising an analog-to-digital converter, a digital-to-analog converter, and an electronics control system, wherein the control module controls the power supply to apply a current to a battery; a control relay electrically connected to the power supply; a sensor that detects at least one of a battery voltage response to a current ramp and an open circuit voltage at a rested state, the sensor electrically connected to the control relay; and a processor configured to determine a specific gravity of the battery based on a maximum battery voltage detected in the battery voltage response and configured to determine the SOC of the lead-acid battery based on the rested state open circuit voltage and the specific gravity of the lead-acid battery, wherein the current ramp comprises; a linearly increasing current to a predetermined limit; and a linearly decreasing current after reaching the predetermined limit. - View Dependent Claims (12, 13)
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6. A computer readable medium for determining a state of charge of a battery, the computer readable medium comprising:
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program code for applying a current to a battery at a rested state; program code for measuring an open circuit voltage in response to the current; program code for determining the state of charge from the open circuit voltage and a correlation function, wherein the correlation function depends on the specific gravity of the lead-acid battery; program code for applying a current ramp to the battery; program code for measuring a battery voltage response; program code for detecting as points; program code for calculating a maximum voltage battery cell of the battery; and program code for comparing a maximum battery voltage detected in the battery voltage response divided by the number of cells of the battery, to an SGLim, where the SGLim is an upper limit of a maximum measured battery voltage of a low specific gravity battery divided by the number of cells of the low specific gravity battery. - View Dependent Claims (7, 8, 9, 10, 11)
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Specification