Abstract: In estimating the residual capacity of a battery according to the maximum output estimating process, a reference point is established in advance at the intersection of a plurality of current/voltage characteristic linear curves corresponding to various residual capacities of the battery or in an area in the vicinity of the intersections of the curves. A current/voltage characteristic linear curve is determined so as to pass through the reference point and a measured operating point of the battery which corresponds to the present discharging current and output voltage values measured when the battery is discharged. Then, a maximum transfer power value of the battery is determined from the current/voltage characteristic linear curve thus determined, and the present residual capacity of the battery is estimated from the maximum transfer power value.

Abstract: The present invention provides an aqueous gel comprising a polymer of (meth)acrylamide or particular (meth)acrylamide derivative(s), particulate metal oxide(s) and an aqueous medium, a process for producing said gel, and products utilizing said gel.This aqueous gel can be produced so as to have transparency, has fire resistance and can prevent the spreading of flames, and is highly elastic. The aqueous gel, when produced as a transparent gel, becomes cloudy when heated or cooled and is useful for the shielding of heat rays or cold radiation.

Abstract: A cell/battery is excited by a time-varying signal that is characterized by periodically making step transitions between discrete levels. The immediate change in a responsive signal is determined by a circuit that is only enabled during a brief "window" of time encompassing a step transition, and which employs a "holding capacitor" to store dynamic conditions existing at the instant of enablement. Action of this "holding capacitor" causes the circuit to only respond to changes in noise signals occurring during the enablement "window" and not to the actual level of the noise itself. By making the "window" sufficiently narrow, noise signals can change by only an acceptably small amount and can be removed by synchronously detecting the response to the step excitation and averaging the result over time. Two embodiments are disclosed. A first embodiment utilizes a step current-signal excitation and a voltage-signal response to directly determine a particular component of incremental resistance.

Abstract: Three embodiments of an improved electronic device for testing or monitoring storage batteries that may be only partially charged are disclosed. The device determines the battery's small-signal dynamic conductance in order to provide either a proportional numerical readout, displayed in appropriate battery measuring units, or a corresponding qualitative assessment of the battery's relative condition based upon its dynamic conductance and electrical rating. Without additional user intervention, the device also determines the battery's terminal voltage in an essentially unloaded condition and utilizes this information to automatically correct the measured dynamic conductance. By virtue of this automatic correction, the quantitative or qualitative information displayed to the user conforms with that of a fully-charged battery even though the battery may, in actual fact, be only partially charged. If the battery's state-of-charge is too low for an accurate assessment to be made, no information is displayed.

Abstract: A thermal runaway detection apparatus is provided for use during charging of a battery. The thermal runaway detection apparatus includes circuitry for determining internal resistance (impedance) or conductance (admittance) of the battery under charge. Detection circuitry detects an increase in internal battery conductance or a decrease in internal battery resistance and provides an output. The output is indicative of a thermal runaway condition in the battery. The circuitry can be used to provide feedback which controls charging of the battery.

Abstract: A method of monitoring the internal impedance of an accumulator battery in an uninterruptible power supply, and a UPS. In accordance with the invention, during the discharge of the battery to the load, the load current induced by the load and passing through the battery is measured or calculated, and the corresponding AC voltage component obtained on the battery voltage is measured, the value for the internal impedance of the battery being calculated from these values. The obtained impedance value is compared to a predetermined reference value to determine the condition of the battery.

Abstract: A method and apparatus for estimating the remaining capacity of a lithium-iodine battery through the nomographic analysis of two or more measurements of battery impedance. In a preferred embodiment, a pacemaker or other implantable medical device is provided with circuitry for periodically measuring the internal impedance of its battery. Each measurement of impedance is stored along with an indication of when such measurement was made. Nomographic analysis, based upon the rated capacity of the battery and the expected internal impedance at various stages of depletion, allows for two or more time-stamped impedance measurements to serve as the basis for an extrapolation to estimate the remaining service life of the implantable medical device. Nomographic analysis may be performed by circuitry contained in the implanted device itself; in the alternative, periodic impedance measurements may be communicated to external processing circuitry via a telemetry channel.

Abstract: A pacemaker having a fault-tolerant elective replacement indicator (ERI) triggering scheme in which transient excursions of parameters used as criteria for triggering ERI are rejected as triggering events. Periodic assessments of certain indicia of battery depletion are made, and subjected to a long-term low-pass filtering operation in order to reduce the effects of transient excursions of the indicia which result from non-ERI conditions. Over a long period of time (e.g., a day) predetermined threshold values of the indicia of interest must be exceeded a predetermined number of times in order for the device to issue an ERI. In one disclosed embodiment of the invention, the battery's loaded terminal voltage and internal impedance are used as indicators of the battery's depletion level. Periodically, these values are measured and converted to digital values.

Abstract: A method and apparatus for measuring the depletion level (depth of discharge) of a lithium-iodine battery in an implantable medical device. A first set of measurements are made to determine the internal impedance of the battery, and a second set of measurements are made to determine the geometric capacitance of the battery, which has been found to correlate closely to the depth of discharge of the battery. The measurements are all made while the pacemaker is first temporarily decoupled from the medical device circuitry. The first measurements are made during a time window following a known change in resistive load across the terminals of the battery, and are capable of being correlated with 1-kHz qualification testing data made on the battery at the time of manufacture. The second measurements are made when the known load is periodically coupled and decoupled to the terminals of the battery at a rate of 80-kHz.

Abstract: A system for accurately predicting impending battery failure in battery powered electronic and electrical devices. The system continually monitors changes in battery voltage responsive to load changes and calculates a ratio of the change in voltage to the change in load. When the ratio exceeds a certain threshold value, indicating that the impedance of the battery has risen to near its final value, a user warning indication is generated.

Abstract: Method and apparatus for accurately determining the charge state of a battery is disclosed. The charge state is derived from the battery voltage, which is corrected for errors introduced by temperature and series resistance. Error from series resistance is minimized by either making an open circuit voltage measurement, or by making a plurality of voltage measurements under known load conditions, calculating the series resistance from these measurements, and calculating an equivalent open circuit voltage, compensating for the voltage drop caused by the series resistance of the battery. Errors introduced by temperature induced shifts in battery voltage are corrected by reading the battery temperature and correcting the battery voltage to a reference temperature. The battery voltage corrected for temperature and series resistance effects is used to compute charge state by table look up or algebraically.

Abstract: A battery monitoring method and apparatus are used for monitoring the charge level of a rechargeable electric storage battery, for example a lead acid battery. The counter-voltage of the battery is monitored by continuously monitoring the actual terminal voltage of the battery. When the battery is fully charged, the monitor provides a "DO NOT CHARGE" signal, for example a green light. When the charge level has dropped to a point that there may be some value in recharging the battery, the "DO NOT CHARGE" signal is replaced with an "OK TO CHARGE" signal, for example a yellow light. When the battery has discharged to the point where the battery must be recharged in order to avoid damage, the "OK TO CHARGE" signal is replaced with a "MUST CHARGE" signal, for example a red light. Audible signals may accompany the "OK TO CHARGE" and "MUST CHARGE" signals. The monitor is self-testing when turned on. It automatically recognizes the charge level of a battery to which it is connected.

Abstract: An electronic device for monitoring the charge state of a rechargeable battery comprising a voltage sensor, a current sensor, a microprocessor, and a display. The voltage sensor is operatively connected to the microprocessor to provide to the microprocessor an electronic signal indicative of the voltage appearing across the terminals of the battery. The current sensor is operatively connected to the microprocessor to provide to the microprocessor an electronic signal indicative of the current between the terminals of the battery. Based on the signals received from the voltage and current sensors, the microprocessor calculates the total current discharge capacity of the battery and the present level of charge contained within the battery, and delivers electronic signals indicative of the total current discharge capacity and the present level of charge contained within the battery to the display means.

Abstract: The invention continuously monitors the current drawn from the on board battery system of a recreational vehicle or marine vessel. The device calculates and displays the energy remaining as a portion of the total capacity by accumulating over time the net energy drawn out of the battery. The device accurately accounts for the known effect of effectively lower battery capacities at higher current draws, and also allows the user to re-initialize the battery system capacity to reflect either degradation of the battery capacity with time or upgrades to the battery system.

Abstract: A vehicle storage battery is monitored to determine battery capacity, state of charge and certain fault conditions. The ambient temperature, battery voltage alternator/regulator output voltage and current to and from the battery are continuously measured. Current voltage (I-V) data is analyzed to determine the internal resistance and polarization of the battery. A determination is made regarding state of charge and fault conditions produced by corroded terminals and low electrolyte level. The low temperature starting limit is determined by comparing the battery's power output capability with starting power requirements of the vehicle. Data produced by the comparison are indicated on the dashboard of the vehicle.

Abstract: Impedance measurement of battery cells within a battery system comprising at least one string of battery cells is accomplished by dividing each of the strings into at least two portions. A loading current for measurement purposes is only imposed on a portion of one of the strings at any given time and battery cell voltage measurements are made only within this string portion.

Abstract: A battery and charging system tester includes an automatically-operated carbon pile for loading the battery, the pile having a shaft therethrough rotated by a stepper motor, and a compression nut threadedly engaged with the shaft for movement into and out of engagement with the carbon pile in response to rotation of the shaft for varying the compression of the pile and, thereby, the impedance thereof. Probes are provided for sensing battery load current and output voltage, and the output current of an alternator charging unit. A feedback control circuit including a microprocessor operating under stored program control converts the analog probe outputs to digital signals and compares the battery output voltage and load current to selectively variable references for controlling the stepper motor to vary the battery load so as to regulate either the battery load current or the battery output voltage to a predetermined reference value, depending upon the test being performed.

Abstract: A stationary battery testing device as provided for measuring imminent battery failure while the battery is in a float mode. The device includes a circuitry for measuring the internal resistance changes of a battery and then comparing them over a predetermined duration of time so as to provide audible or visual discernable signals to indicate an imminent battery failure after the expiration of said predetermined period of time. An additional temperature monitoring component may be provided for the device to monitor internal changes within the battery with respect to temperature. This can also be combined in a temperature compensated automatic adjustment of voltage and alarm thresholds in an active feedback loop to augment and broaden the basis of stationary battery applications where the battery testing device can be used.

Abstract: The remaining capacity of a storage cell, particularly a valve regulated lead-acid cell, is determined by measuring its impedance at typically two or three relatively low frequencies f, e.g., frequencies in the approximate range of 0.001 to 1.0 Hz. In one application, the imaginary part Z" of the complex impedance Z(=Z'+jZ") is plotted vs. f.sup.-1/2, whereby the intercept Z".sub.o (at f.sup.-1/2 =0) of the bestfitting straight line of the plot is a measure of the cell's remaining capacity. In another application, the slope (dZ"/dZ') of a plot of the imaginary part Z" vs. real part Z' of the complex impedance Z, again as measured at relatively low frequencies f, is a measure of the cell's remaining capacity.

Abstract: A self-contained electronic device instantaneously assesses the stored energy capacity of single, two-volt, lead-acid cells; or of batteries comprised of such cells. The testing device is electrically connected to the terminals of a cell or battery and measures its dynamic conductance with a small, time-varying signal. An internal conductance standard permits initial calibration of the device to assure accuracy of the cell/battery measurements. Means are provided for entering a "reference conductance", defined to be the dynamic conductance of an identically rated and constructed cell or battery having 100% energy capacity. The device displays either the test cell/battery's measured conductance in Siemens (mhos), or its "percent capacity" determined by appropriately scaling its measured conductance in accordance with the "reference conductance". When determining "percent capacity", an LED lights if the result is less than a preset threshold value.

Abstract: Apparatus for measuring the total internal resistance of a multicell battery having positive and negative terminals employs a first transistor device having an input and an output and having mutually exclusive conductive and non-conductive electric states. An arrangement of resistances is connected in series with the device to form a network. The network is connected between the positive and negative terminals. An operational amplifier has an output connected to the input of the device and first and second inputs. The first input is connected to the network at a point connected to both of the device and the arrangement. A square wave signal alternating between a positive voltage and ground on alternate half cycles is applied to the second input. The device is in the conductive state when the alternating voltage is positive and is in the non-conductive state when the alternating voltage is at ground.

Abstract: An aircraft storage battery is monitored to determine battery capacity, state of charge and certain fault conditions. The ambient temperature, battery voltage on-board charger output voltage and current to and from the battery are continuously measured. Current voltage (I-V) data is analyzed to determine the internal resistance and polarization of the battery. A determination is made regarding state of charge and fault conditions produced by corroded terminals and low electrolyte level. The low temperature starting limit is determined by comparing the battery's power output capability with starting power requirements of the aircraft. Data produced by the comparison are indicated on the dashboard of the vehicle.

Abstract: A method for charging and simultaneously testing the condition of a nickel-cadmium accumulator wherein the charging cycle includes intervening measuring phases with discharging phases of relatively short duration. During the measuring phases, the internal resistance of the accumulator is measured under different charging and discharging conditions. The measured internal resistances are interrelated and additionally compared to internal resistances determined during successive measuring phases. The thus found relationships are used to derive therefrom a comprehensive spectrum of informations relating to various states of the accumulator, these informations being used for controlling the charging operation and permitting the state of usefulness of the accumulator to be assessed.

Abstract: A vehicle storage battery is monitored to determine battery capacity, state of charge and certain fault conditions. The ambient temperature, battery voltage alternator/regulator output voltage and current to and from the battery are continuously measured. Current voltage (I-V) data is analyzed to determine the internal resistance and polarization of the battery. A determination is made regarding state of charge and fault conditions produced by corroded terminals and low electrolyte level. The low temperature starting limit is determined by comparing the battery's power output capability with starting power requirements of the vehicle. Data produced by the comparison are indicated on the dashboard of the vehicle.

Abstract: There is disclosed a battery monitor for monitoring a plurality of conditions of a battery utilized within a system as the primary or auxiliary power source of the system. The battery monitor includes a voltage measuring means for measuring the voltage of the battery and a processor coupled to the voltage measuring means. The processor utilizes the voltage measurement of the voltage measuring means to determine the presence or the absence of the battery, whether the battery voltage is equal to or greater than a nominal voltage level, and whether the discharge rate of the battery is greater than a selected discharge rate.

Abstract: Methods and circuits are provided for monitoring a battery with the monitored battery electrically connected in an operating system. A dynamic impedance characteristic of the monitored battery is identified and compared with a predefined value. An alarm signal is generated responsive to the compared values to predict a degraded battery capacity. A leakage current value through the monitored battery is detected. An alarm signal is generated responsive to the detected leakage current value to predict a short life expectancy for the monitored battery. Visual and audible alarms are generated responsive to either of the generated alarm signals after the monitored battery has been fully charged. An alarm signal is immediately generated responsive to a detected charging current value above a predetermined value.

Abstract: A self-contained electronic device for testing storage batteries that may be partially discharged is disclosed. The testing device performs small-signal measurements of the battery's dynamic conductance and provides either a proportional numerical readout, displayed in appropriate battery measuring units, or a corresponding qualitative assessment of the battery's relative conduction based upon its electrical rating. In addition, the testing device measures the battery's open-circuit (unloaded) voltage and provides adjustable means for correcting the dynamic conductance test result in inverse correspondence with the battery's open-circuit voltage relative to its fully-charged value. By virtue of this correction, the quantitative or qualitative information displayed to the user in the dynamic conductance test is adjusted to comport with that of a fully-charged battery even through the battery may, in actual fact, be only partially charged when tested.

Abstract: A novel automotive battery life diagnosis apparatus is disclosed, in which the terminal voltage, charge-discharge current and the temperature of a battery are detected, output signals from the detectors are applied to and processed in a predetermined manner by a control unit, and a life alarm is displayed on a display unit. Further, the control unit has the functions to calculate a value representing the life of the battery from the detection signals of the detectors before and after cranking of an internal combustion engine and to store an initial value of a parameter representing the battery life in the initial stage of battery operation. The initial value of the parameter is compared with the present value thereof to forecast and indicate the life of the battery on the display unit from a predetermined relationship formed by life curves between the initial value and the present value of the parameter.

Abstract: A self-contained electronic device for testing disparate storage batteries having any one of a fixed plurality of possible nominal voltages is disclosed. The testing device performs small-signal measurements of a battery's dynamic conductance and provides either a proportional numerical readout, displayed in appropriate battery measuring units, or a corresponding qualitative assessment of the battery's relative condition. Special voltage-sensing circuitry within the testing device identifies the particular one of the possible nominal voltages possessed by the battery and scales the dynamic conductance measurements accordingly. As a result, the quantitative or qualitative information provided to the user is automatically adjusted to comport with the nominal voltage of the battery undergoing test without the user having to actually input the battery's nominal voltage to the testing device.

Abstract: A device for detecting the residual capacity of a battery comprises a battery current measuring circuit for measuring battery current, a battery voltage measuring circuit for measuring battery voltage, a converting circuit for converting the measured current into a voltage value, based on the internal impedance of the battery, and a comparator circuit for comparing the conversion voltage value with the measured voltage. When the measured voltage is smaller than the conversion voltage value, the comparator circuit operates a battery residual-capacity detect signal indicating that the residual capacity of the battery is small.

Abstract: A self-contained electronic device for testing disparate storage batteries having any one of a fixed plurality of possible nominal voltages is disclosed. The testing device performs small-signal measurements of a battery's dynamic conductance and provides either a proportional numerical readout, displayed in appropriate battery measuring units, or a corresponding qualitative assessment of the battery's relative condition. Special voltage-sensing circuitry within the testing device identifies the particular one of the possible nominal voltages possessed by the battery and scales the dynamic conductance measurements accordingly. As a result, the quantitative or qualitative information provided to the user is automatically adjusted to comport with the nominal voltage of the battery undergoing test without the user having to actually input the battery's nominal voltage to the testing device.

Abstract: An improved self-contained electronic device for testing storage batteries and other dc sources is disclosed. The testing device accurately performs small-signal measurements of the battery's dynamic conductance and provides for displaying either a numerical reading proportional to the battery's available power, or a qualitative assessment of the battery's condition. Special design features permit powering all active circuit elements by means of common power terminals and allow circuit implementation with medium scale integrated (MSI) circuits.

Abstract: A method is described of measuring the state of discharge of a battery, i.e. the ratio between the supplied capacity and the nominal capacity.The method consists in measuring a first internal impedance of the battery at a first frequency and a second internal impedance of the battery at a second frequency, then in determining the argument of the difference between the internal impedances, the resulting argument being representative of the state of discharge of the battery.The method can be used to advantage to check in a rapid, accurate and non-destructive way whether batteries to be used in portable appliances, e.g. electronic watches, are in good working order before being fitted into the appliances.

Abstract: A vehicular charging system is provided with a microcomputer for performing a diagnostic routine on the vehicle battery and charging system. The battery charging condition and internal resistance are monitored to determine the service life of the battery and the state of the battery charging system. The internal resistance is calculated by taking the difference between the voltage when the battery terminals are in an open circuit condition and the voltage when the battery terminals are in a closed circuit state and dividing this difference by the battery current. Also included in the charge condition measurement is the measurement of the specific gravity of the battery.

Abstract: A testing device measures the impedance of secondary cells that form a battery, such as a lead acid battery, while the battery is in a float charge condition and connected to an active electrical load. The impedance measurement is made at a frequency selected to be different from those frequencies otherwise present in the charger-load circuit. A first application of the testing device monitors the battery for a change in impedance that can signal a developing defect in one or more individual cells or intercell connections that can prevent the battery from delivering its stored energy to the load. In a second application, the testing device is used to compare the impedance of individual cells and electrical connections to locate faulty components.

Abstract: A battery condition monitor and monitoring method uses known relationships between battery impedance, remaining capacity and remaining service life at different frequencies to detect remaining capacity and remaining service life. The monitor includes a computer for computing internal impedances of the storage battery from different frequency components of voltage and amperage signals from the battery, a memory for storing predetermined relationships between the internal impedance, remaining capacity and remaining service life of the storage battery for each of the frequencies and a device for determining the remaining capacity and remaining service life values for the storage battery in agreement at both or all frequency values derives from the computed internal impedances. The exact remaining capacity and service life of the storage battery are continuously monitored.

Abstract: This invention relates to a device which when connected to a storage battery of a type which is a prime power source, such as a lead acid storage battery, measures the open circuit voltage condition of the battery to give a reading in increments of time of the remaining useful life of the battery for a given use up to the point of full discharge of the battery.

Abstract: A charge control system for a vehicle is provided with a microcomputer which calculates the most suitable battery charging value or voltage regulator set value on the basis of detected engine and charging system parameters. The microcomputer uses parameters such as the charging condition and service life condition of the battery, along with the instantaneous generated voltage, etc., and outputs the calculated set value to the voltage regulator of the charging system.

Abstract: The condition of a storage battery of an internal combustion engine powered vehicle is tested automatically, and an indication of battery condition is provided to the service technician. The battery testing apparatus is connected to the positive (+) and negative (-) terminals of the battery to measure battery voltage under several different conditions. In particular, the battery testing apparatus measures battery voltage under open circuit conditions, while subjecting the battery to a predetermined AC load, and while subjecting the battery to a predetermined DC load. The battery testing apparatus also includes a temperature probe which measures the temperature of the battery.

Abstract: A system and method for testing a battery having an internal impedance by generating digital battery parameter values corresponding to the battery parameters at different points in time by means of current, voltage and temperature measurement circuits and an analog-to-digital converter. An electrical load is periodically placed on the battery and the battery is also charged between loadings in order to provide battery parameter values during different battery conditions. A microprocessor coordinates the testing of the battery and the measuring of the battery parameter values, as well as the calculation of test criteria based on those values in order to quickly and accurately analyze the condition of the battery.

Abstract: Apparatus for indicating the level of the electrolyte in a battery cell. A three-electrode sensor probe having the electrodes partially embedded in an electrically insulating housing suspended in the electrolyte so that a portion of the probe is immersed in the electrolyte. The electrolyte provides the only conduction path between the electrodes so that the resistance between the electrodes varies according to the level of the electrolyte. An AC or pulsed DC sensing signal is applied between two of the electrodes and an output signal related to the level of the electrolyte is produced. A polarizing current is applied to the other electrode to prevent the buildup of surface contamination on the two sensing electrodes due to the sensing signal.

Abstract: A circuit is disclosed for providing automatic detection of end of life of a battery source, particularly a lithium iodine type battery source characterized by a sharply increased internal resistance characteristic near end of life. The circuit periodically samples the short circuit output current of the source, the sampling being done at a high switching speed and for an extremely short time duration so that power consumption is minimized and only the resistive component which causes the knee in the resistance characteristic is measured. In the embodiment as incorporated in a cardiac pacer device, detection of the internal resistance knee is utilized to cause a step change in an operating characteristic of the pacer, such as stimulus rate, whereby end of life can be accurately monitored.

Abstract: A battery monitoring means for an implantable living tissue stimulator system in which various battery voltages are telemetered to an external receiving means, these voltages being related to the internal impedance of the implanted battery. More specifically, a battery loading circuit is provided which incorporates a switch means for loading the battery in accordance with a predetermined sequence. In a specific embodiment, first and second resistors are sequentially connected across the battery. The battery output voltage is telemetered to an external receiving means during this sequential connection. By knowing the values of the two resistors, the internal impedance of the battery can be calculated, this impedance being related to the remaining life of the implanted battery.

Abstract: A method and apparatus for determining the condition or freshness of an electric battery. The battery is discharged with a load current having an amplitude increasing linearly with time. The battery voltage is measured as the battery is discharged and the amplitude of the load current is measured when the battery voltage decreases to a predetermined value. The measured amplitude of the load current is representative of the battery condition or freshness.

Abstract: Apparatus for automatically testing automotive-type, lead acid storage batteries are disclosed in which three separate tests are made and the results thereof compared to predetermined standards in a specified order to maximize the information obtained about the battery. The three tests measure (1) whether the battery meets its cold cranking rating by drawing a predetermined load current therefrom for a predetermined period of time and determining whether the battery terminal voltage is above a specified level at the end of that period, (2) whether the battery terminal voltage is above another specified level at the end of a predetermined period of time following the completion of the first test, and (3) whether the internal resistance is acceptably low. If the battery passes the first test, it is known to be acceptable. If the battery fails the first test and passes the second test, it is known to be unacceptable. If the battery fails the first and second tests, the third test is performed.