Showing papers on "State of charge published in 1992"

Battery monitor and method for providing operating parameters

Abstract: A battery monitor which monitors the operating parameters of a battery to provide an indication of, for example, the absolute state of charge, the relative state of charge, and the capacity of the battery under battery discharge, rest, and recharge conditions. The battery monitor includes a current sensor for sensing battery current, a voltage sensor for sensing battery voltage, and a temperature sensor for sensing battery temperature. A processor approximates to a high level of accuracy the battery parameters utilizing an iterative process based upon predetermined relationships, employing empirically determined constants and parameters determined in the immediately proceeding iteration stored in memory. Output signals indicative of the determined parameters are provided and may be utilized for many different battery applications.

Battery state of charge monitor

Abstract: An apparatus and method for monitoring the state of charge of the battery having a shunt resistor connected in series with a battery and an integrating circuit connected across the terminals of the shunt resistor which includes a large capacitance element having the capability to store charge for long periods of time, so that the integration can be performed along the same curve even if power to the integrating circuit is interrupted during continuous or intermittent use. The apparatus and method are applicable to batteries for automotive vehicles. Temperature compensation schemes to adjust the state of charge monitoring circuit to correct for changes in battery performance characteristics with temperature are provided. A circuit for detecting the existence of a defective battery cell is provided. A system for monitoring charging and discharging of the battery over time and identifying various battery conditions and potential battery or battery charging system failures is provided.

Battery with Electrochemical Tester

Abstract: The present invention relates to an electrochemical cell and a related state of charge indicator comprising an electrochemically generated display. The state of charge indicator comprises two electrical contacts and an electrochemically generated display connected therebetween. The display comprises an electrochemical cell that may be permanently connected to a main cell in a parallel configuration via the contacts. The condition of the main cell may thus be continuously displayed on the indicator.

Method and apparatus for monitoring batttery capacity with charge control

Abstract: A battery detect circuit (32) is connected to the battery with the current input to the battery and extracted from the battery measured with a sense resistor (50) and then converted to charge and discharge pulses with a V/F converter (52) A microcontroller (64) is operable to increment a Nominal Available Charge (NAC) register (180) during a charge operation, and to increment a Discharge Count Register (DCR) (184) during a discharge operation The NAC register (180) indicates the available charge, which value is output to a display (34) The maximum value to which the NAC value can rise is limited by a value stored in the last measured discharge register (182) This value represents the value stored in the DCR (184) whenever the battery is discharged from an apparent full state to a fully discharged state This results in a qualified transfer to the LMD register (182) such that no knowledge of the actual battery charge is necessary The charge rate is varied as both a function of temperature, voltage and also of the state of charge A fast charge rate is initiated when the charge state is above a predetermined low voltage threshold and less than full When the charge state reaches a level within approximately 80% of full charge, the charge rate is reduced At full capacity, the charge rate is further reduced to a top off charge rate which continues for approximately two hours If the temperature falls below a predetermined low temperature threshold, the charge rate is again reduced to a safe, slow, effective rate Trickle charge is provided to replenish charge adaptively in accordance with a self-discharge counter The trickle charge operates to momentarily pulse the battery (10) at a predetermined charge rate

Battery thermal control system and method

Abstract: A battery thermal control system and method is provided which selectively heats or cools a storage battery in accordance with the battery temperature and state of charge. The thermal control system includes a battery housing having an internal airspace between the battery and the housing which extends between two openings in the battery housing, a reversible fan configured to generate an airstream along the airspace, a temperature sensor mounted to detect the temperature of the battery, and a control circuit for monitoring battery temperature and voltage and for controlling the operation of the fan. Battery state of charge is approximated by measuring battery voltage and monitored to prevent excessive battery discharge by the thermal control system. When the battery voltage exceeds a predetermined voltage and the battery temperature is outside of a predetermined range of suitable operating and storage temperatures, the thermal control system operates the fan to heat or cool the battery, as needed.

Charge balancing of batteries during charging

Abstract: A battery system comprises a plurality of sodium-sulfur storage cells connected in series to form a battery, with voltage measurement leads attached across each of the individual storage cells. A charge-limiting circuit controllably isolates an individual storage cell from a charging current applied across the battery when the measured voltage across that individual storage cell exceeds a preselected maximum storage cell voltage. Preferably, the charge-limiting circuit includes a bypass circuit connected through the voltage measurement leads and a circuit element that becomes conductive when the voltage across the individual storage cell exceeds the preselected maximum storage cell voltage. There are a plurality of charge-limiting circuits, one for each of the storage cells of the battery. In operation, a high charging current is imposed on the battery while measuring the voltage across each individual storage cell, until the voltage measured across at least one of the storage cells exceeds a preselected reduced-current voltage that is less than the preselected maximum storage cell voltage. The charging current is thereafter reduced to a low charging current while continuing to charge the battery. The low charging current is bypassed around each of the individual storage cells as that storage cell reaches the maximum voltage, until all of the storage cells reach the same state of charge.

Battery charge indicator

Abstract: A battery charge indicator is permanently incorporated into a battery to indicate the state of charge. In one embodiment, the indicator includes a compressible chamber which is filled with a viscous gel and which is exposed to the expandable cathode of the battery. As the battery discharges, the cathode expands thus causing the gel within the chamber to be extruded out through an outlet into a viewing channel in an overlying disk. The amount of gel flowing into the viewing channel is proportional to the amount of expansion of the cathode and, thus, indicates the amount of discharge and, conversely, the remaining life of the battery. In a second embodiment, a piston assembly is caused to move with a deformable end wall of the battery and indicia on the side wall of the piston assembly is viewed through a lens as a measure of the remaining amount of expect expansion of the cathode.

Battery charge monitor

Abstract: An arrangement for detecting the state of charge of a vehicle battery (B201) in an electrical system (Z201) of a vehicle comprises an array of diodes (BD201) arranged to detect the initial voltage drop across the load when energised by a switch (M201). Each diode in the array defines a predetermined forward voltage drop and the diodes are arranged to energise respective thyristors (S201 to S208) when they conduct. These thyristors energise respective LEDs (201 to 208) which form a bar graph display, whereby the greater the voltage drop across the load (Z201) the greater the number of diodes which conduct and the greater the number of LEDs which are illuminated. Accordingly the bar graph display indicates the state of charge of the battery.

Battery with integral condition tester

Abstract: The present invention relates to an electrochemical cell and an integrally related state of charge indicator. The state of charge indicator has two electrical contacts and a display means connected therebetween. A first contact is connected to a first cell terminal and a second contact is unconnected to either terminal. A switch means permits electrical connection of the second contact to the second terminal to visually indicate the condition of the battery by the display means.

Battery-driven hand tool e.g. electric screwdriver - has separate battery pack and state-of-charge indicator plugging into rear of tool housing, forming rechargeable unit

Abstract: The electric screwdriver (10) has a motor housing (12) with a pistol-type hand grip and finger-operated trigger At the rear is fastened a battery pack (36) with a meter (32) with LCD display to indicate the state of change The meter is a module interposed between housing and battery pack and is detachable, the connections being small lugs These lugs provide the electrical connection between battery pack and the motor The meter unit also has an LED to indicate power-on For recharging, the battery pack and meter unit are detached as a block and clipped into a battery charger ADVANTAGE - Provision of state-of-charge indicator allows optimum usage of battery pack and thus extends its life

Method for monitoring battery discharge by determining the second derivative of battery voltage over time

Abstract: The state of charge of a rechargeable battery (12), such as those made from lithium, nickel-cadmium or metal hydrides, can be accurately determined by monitoring the rate of change of battery voltage over time (dv/dt), which parameter has empirically been found to change dramatically as the battery reaches complete discharge.

Apparatus for and a method of balancing the state of charge of sub-units of a battery

Abstract: Apparatus for balancing the state of charge of a plurality of serially connected sub-units (1) of a battery comprises state of charge monitoring means operative to monitor the state of charge reached by each sub-unit (1). Discharging means (R) operate in response to the state of charge monitoring means to discharge sub-unit which store more charge than another sub-unit. The discharge is performed for a period of time in order to reduce the inequality in the state of charge between said sub-units (1). The state of charge monitoring means preferably includes a processor which monitors the voltage (V0, V2, V3... Vn) across the sub-units and applies control signals to terminals (T1, T2...Tn) in order to control the balancing discharge of the sub-units (1).

Research and development of model-based battery state of charge indicator

Abstract: A novel approach to developing a battery state of charge indicator for an electric vehicle is discussed. An approach to determining the state of charge by combing the available data of discharge characteristics of a lead-acid battery with an identification technique based on the battery mathematical model is presented. The basis for the approach is to introduce a nonlinear battery mathematical model, and to estimate the battery state of charge by least squares estimation. This approach was realized by a digital signal processor and its validity was confirmed by simulation tests using data measured during urban driving and road tests. >

Charging batteries rapidly and frequently, e.g. for electric vehicle - ascertaining battery charge, internal resistance and gas formation voltage in test cycle before charging from external current source

Abstract: Charging batteries involves using an external current source which is controlled to apply a defined charge voltage to the battery. The battery's state of charge, internal resistance and output voltage are determined before charging begins in a test cycle (31) involving increasing a test current whilst the voltage is continuously monitored. A gas formation voltage (29) derived from the voltage curve inversion point (20) is stored and the test current reduced, pref. to null. The voltage is then monitored for a defined period. A controlling charge current is then applied to achieve the gas formation voltage or lower. The test cycle is repeated at defined intervals during subsequent charging. ADVANTAGE - Rapid, frequent charging with long operating life achieved.

A method and an apparatus for charging a rechargeable battery

Abstract: A rechargeable battery is charged by connecting the terminals of the battery to an electrical power source. In order to avoid overcharging and undue temperature increase in the battery cell, the course of a least one charging parameter, such as the increase rate of the voltage, is surveyed during at least part of the process of charging the battery. This charging parameter surveyed is compared with a number of reference parameter courses representing idealistic or desireable processes of charging the battery for different starting states of charge of the battery. Such comparisons may for example be made by means of a microprocessor, which may also select the reference course with a starting state of charge similar to the actual starting state of charge of the battery. Thereafter the process of charging the battery may be controlled so as to approximate the course of said charging parameter to the selected reference course. The charging voltage may be limited to a maximum value (Vmax). When such value has been reached the charging process may be terminated after a certain predetermined time period being one of the reference values.

Indication method for state of battery charge in stored motor vehicles - is based on encoded flashes of radio theft-warning LED driven by comparator of battery voltage with full-charge and partial-charge thresholds

Abstract: A conventional radio receiver (R) is augmented with a control unit (S) and a processor (A) utilising existing hardware with function modifying software to compare continuously the battery voltage (UBatt) with two threshold values stored in memory. The higher threshold (1) is appropriate for a fully charged battery, and the lower threshold (2) for one retaining sufficient charge. According to the result of the comparison a pulse train with high, medium or low duty ratio is produced for distinctive flashing of the theft-warning diode (LD). USE/ADVANTAGE - In vehicles held at distribution depots or showrooms, an automatic and continuous indication of the state of charge is given without recourse to additional instruments or tools.Integrates method into conventional code-radio anti-theft warning diode.

Battery charge state indicator

Abstract: Proposed is a circuit designed to indicate the state of charge of a rechargeable battery, the state of charge of the battery being determined by integration of the current flowing in the load circuit. Various correction factors are applied to allow, for instance, for turn-on current surge, temperature, offset and self-discharge effects, thus giving a reproducibly accurate state-of-charge determination. A battery of this kind is particularly suitable for use as a power pack for electrically powered tools. Appropriately designed terminals make it possible to employ a universal battery charger and to use different types of battery for different electric tools.

A battery charge indicator apparatus and the method of operation thereof

Abstract: A battery charge indicator is disclosed which is permanently incorporated into a battery to indicate the state of charge. The indicator includes a compressible chamber such as a blister which is adapted to be installed in a battery as an assembly. The blister chamber is filled with a viscous gel and is exposed to the expandable cathode of the battery. As the battery discharges, the cathode expands thus causing the gel within the chamber to be extruded out through an outlet into a viewing channel in an overlying disk. The amount of gel flowing into the viewing channel is proportional to the amount of expansion of the cathode and, thus, indicates the amount of discharge and, conversely, the remaining life of the battery. A battery charge indicator is also disclosed in which the expansion of the cathode is adapted to apply localized pressure to a disk. The localized pressure applied to the disk causes stretching of the material of the disk, which causes a visual indication of the state of charge of the battery.

State of charge indicator for a battery or an accumulator in a remote control transmitter

Abstract: A state of charge indicator for a battery or an accumulator in a remote control transmitter for information-technology apparatuses, especially apparatuses for entertainment electronics, for example radios, television sets or video recorders which remote control transmitter conditions commands (which are entered by means of keys, analog-value setting devices or speech) in a command conditioning circuit and, in a transmitting circuit, transmits said commands using a carrier in a modulated or unmodulated manner to the apparatus to be controlled using a transmission medium such as infrared light, ultrasound or electromagnetic waves, having a monitoring device for monitoring the state of charge and/or the corresponding voltage of the battery or of the accumulator, which apparatus has a receiver circuit and demodulates the commands, conditions them or passes them directly to the function elements to be controlled in the apparatus, for control of the function, is distinguished in that the monitoring device generates adequate information material as a function of the state of charge of the battery or of the accumulator, which information material is transmitted from the remote control transmitter to the apparatus to be controlled, which apparatus contains a remote control receiver and an evaluation circuit for the information signal, and a display element having a driving circuit for displaying the state of charge.

Secondary power supply for in-car audio equipment - has capacitor pack across battery with discharge resistor and short circuiting switch, controlled by state of charge

Abstract: A secondary power supply for audio equipment in vehicles has a capacitor pack (23) between the main positive (16) and negative (19) rails, the terminals (17, 20) being directly adjacent to the pack to avoid resistive loss. The capacitance of the pack is between 0.6 and 1.2 farad, pref. 0.9. The negative rail is earthed to the chassis. The output terminals (21, 22) for the ancillary equipment are block terminals, the negative one being connected to a common earth rail. The positive one has separate fuses for each load circuit, joined at a subsidiary terminal. The capacitor pack is joined to the positive supply by a resistor (27) in parallel to a short circuiting switch (29), activated by control unit (25) according to its state of charge. ADVANTAGE - No long cable paths so no resistive drop.

Device for measuring the state of charge of an electrochemical generator

Abstract: The device uses op. amp. and transistor (11,13) which impose on the battery (10) a reference voltage (Vd) which is less than the batteries nominal voltage (Vb) so as to produce a discharge current, measured by current measuring instrument (15,16) to provide an indication of the charge state of the battery(10). Reference voltage correction circuit (50) corrects the reference voltage (Vb) as a function of the discharge current. This circuit produces a corrected reference voltage (Vs) which compensates for parasitic resistance in the battery.

Measurement and display system for vehicle battery - uses initialisation and control devices to measure voltage with open circuit and after loading to determine state of charge

Abstract: The system for monitoring a subassembly within the electrical circuit of a vehicle includes initialisation, monitoring and display circuitry for checking the state of the battery. The monitoring circuit measures the internal resistance of the battery, and/or the open circuit voltage. A specified current is then drawn for a given time, e.g. 10A for 100 mS, and the voltage is then measured again. These voltages are then compared, in order to evaluate a measurement of the state of charge of the battery. The circuit may take account of other factors, such as temperature. ADVANTAGE - Display of additional information to driver of vehicle, giving battery status.

Battery operated electric razor or hair clippers

Abstract: The battery powered electrical device has an electrical load of essentially constant current consumption supplied via an electronic switch. A display shows the state of charge of the battery, and a time element determines the time for which the battery is connected to the load. After a defined battery-load connection time has elapsed and when the display is indicating a null charge state, the timing element isolates the load from the battery by means of the switch.

A method for charging a rechargeable battery

Abstract: A rechargeable battery is charged by connecting the terminals of the battery to an electrical power source. In order to avoid overcharging and undue temperature increase in the battery cell, the course of a least one charging parameter, such as the increase rate of the voltage, is surveyed during at least part of the process of charging the battery. This charging parameter surveyed is compared with a number of reference parameter courses representing idealistic or desireable processes of charging the battery for different starting states of charge of the battery. Such comparisons may for example be made by means of a microprocessor, which may also select the reference course with a starting state of charge similar to the actual starting state of charge of the battery. Thereafter the process of charging the battery may be controlled so as to approximate the course of said charging parameter to the selected reference course. The charging voltage may be limited to a maximum value (Vmax). When such value has been reached the charging process may be terminated after a certain predetermined time period being one of the reference values.

Battery-operated device.

Abstract: In an electrical device, an electricity consumer (2) is powered by a battery (B) via an electronic switch (21). To indicate the state of charge of the battery there is a display (9) and a timer (5) ascertains the period for which the consumer (2) is connected to the battery. At the end of a given period of connection of the consumer to the battery (B), when the display (9) shows a zero state of charge, the timer (5) cuts the electricity consumer (2) from the battery (B) via the electronic switch.

Battery charge and discharge display circuit in two-engine mounted machine

Abstract: PURPOSE:To obtain a battery charge and discharge display circuit for displaying the state of a battery in a two-engine mounted machine through one charge lamp and for giving a warning at the time of an insufficient charge by providing a charge lamp for displaying the state of charge and discharge, an hour meter for integrating an operating time and a charge and discharge-displaying and hour meter-driving relay. CONSTITUTION:First, when first and second engines are not operated and a battery switch 2 is closed, a charge lamp 8 is lighted and an hour meter 14 does not operate. Then, when both first and second engines are operated, a first generator 5 and second generator 5' operate to start a power generation, the charge lamp 8 is not lighted to indicate that a battery 1 is charged with electricity by both generators 5, 5', and the hour meter 14 operates. When e.g. only the first engine is operated or only the second generator 5' gets out of order, the charge lamp is lighted to indicate that the battery 1 is placed in the state of an insufficient charge, and the hour meter 14 operates.

Controller of idle speed for car

Abstract: PURPOSE:To inhibit the change of idle speed at the time of the operation of intermittent electric load by monitoring the charge and discharge of a battery for a time set at a value longer than the duty cycle of intermittent electric load and deciding the change of idle speed on the basis of the result of the monitor. CONSTITUTION:When a battery 11 discharges electricity within a fixed time, idle speed is increased slightly. When the battery 11 discharges electricity within the next fixed time, idle speed is accelerated slightly again after a specified time passes. Consequently, idle rotational speed is gathered gradually at every specified time during a time when the state of the discharge of the battery 11 continues. When the battery 11 is overcharged within the fixed time, inversely, idle speed is decreased slightly. Idle speed is reduced gradually at every specified time during a time when the state of the overcharge of the battery 11 continues. When the battery 11 is brought to the proper state of charge, idle speed is maintained without change.