Showing papers on "State of charge published in 1980"

Monitoring apparatus and method for battery power supply

Abstract: A monitoring apparatus and method are disclosed for monitoring and/or indicating energy that a battery power source has then remaining and/or can deliver for utilization purposes as, for example, to an electric vehicle. A battery mathematical model forms the basis for monitoring with a capacity prediction determined from measurement of the discharge current rate and stored battery parameters. The predicted capacity is used to provide a state-of-charge indication. Self-calibration over the life of the battery power supply is enacted through use of a feedback voltage based upon the difference between predicted and measured voltages to correct the battery mathematical model. Through use of a microprocessor with central information storage of temperature, current and voltage, system behavior is monitored, and system flexibility is enhanced.

Battery state of charge evaluator system

Abstract: A microprocessor based electric vehicle traction battery monitoring system evaluates the state of charge, interfaces with a traction motor control system, and controls recharging. The state of charge is evaluated during the first part of discharge by integrating the current after compensating it for rate of discharge and during the last part of discharge by dividing the battery into sub-packs and evaluating the state of charge from the lowest sub-pack voltage compensated for polarization voltage. The charge storage capacity is also calculated from the lowest sub-pack voltage. The maximum traction motor current is progressively limited during the last part of discharge. During charging, the charge withdrawn is replaced while progressively reducing the charging current and the battery is then charged at a constant current until the rate of rise of the lowest sub-pack voltage falls below a fixed level.

System for measuring state of charge of storage battery

Abstract: A system for measuring the state of charge of a storage battery is disclosed which corrects charging and discharge electrical quantities of the battery in view of temperature and charging efficiency of the battery, and the like to precisely measure the state of charge thereof by digital-operation. There is also disclosed a system correcting, by digital-operation, the variation in capacity of the battery due to the variation in life of the battery and/or the self-discharge thereof as well, to thereby measure the state of charge with higher precision.

Microprocessor-based state of charge gauge for secondary batteries

Abstract: A state of charge gauge for measuring the state of charge of secondary batteries, such as the type employed in electric vehicles, includes a microprocessor which, when supplied with data varying in accordance with battery discharge current and battery terminal voltage, determines battery resistance. Having determined battery resistance which is a dynamically varying parameter dependent on battery temperature and age, the microprocessor computes the total battery charge capacity. Comparison of the quantity of battery charge already depleted with the previously computed total battery charge capacity yields an accurate indication of remaining battery charge.

Electrical energy storage system

Abstract: An electric storage battery and a method for monitoring the operation of the battery and automatically replenishing chemicals employed to operate the battery and provide its electrical energy output. In one form, a computer or microprocessor receives, processes and automatically analyzes signals received from a plurality of sensors which sense the battery condition and operation. The microprocessor generates control signals for controlling the flow of chemicals to and from the battery operating chamber or chambers. As a result, the battery is kept in a predetermined state of charge or operating condition.

Charge/float motor vehicle electrical system

Abstract: A motor vehicle electrical system having a charge mode of operation wherein the motor vehicle battery receives charging current at a temperature compensated voltage from an engine-driven generator, and a float mode operation wherein the battery charging current is reduced to a low value, sufficient only to prevent self-discharge of the battery. The charge and float modes of operation are alternately engaged as a function of the battery state of charge. During the charge mode of operation, a sufficiently high state of charge is detected as a function of the magnitude of the charging current, and during the float mode of operation, a depleted state of charge is detected as a function of the battery voltage. A timer provides a periodic return to the charge mode of operation to sample the battery state of charge.

State of charge battery monitor

Abstract: There is disclosed a monitor for monitoring the state of charge of a battery having an internal charge transfer medium. A monitor includes detecting means arranged to be disposed beneath the surface of the charge transfer medium and arranged for sensing the specific gravity of a fluid medium, enclosure means for enclosing the detecting means, and a fluid medium within the enclosure means. The fluid medium exhibits specific gravities related to the degree of electric charge therein and the enclosure means is formed at least partly from a non-permeable electric charge transmissible material to enable the fluid medium to assume the electric charge of the charge transfer medium while substantially separating the fluid medium therefrom. The monitor further includes indicating means responsive to the detecting means for indicating the specific gravity of the fluid medium and thus the state of charge of the battery.