Showing papers on "State of charge published in 1991"

Apparatus and method for calorimetrically determining battery charge state

Abstract: The present invention is an apparatus and a method for determining the state of charge of a rechargeable battery (300). It comprises a means (350) for charging the battery (300), current sensors (305), heat detectors (301, 302) for detecting the heat emanating from the battery (300) during charging, with the heat being the complement of the charge acceptance percentage, and a processor (360) for storing a mathematical charge acceptance model for providing the relationship between the charge acceptance percentage and the state of charge of the battery (300), and for calculating the state of charge of the battery (300) from the heat detected by the heat detectors (301, 302) and the charge acceptance model. An accurate measure of battery charge state is produced while the battery (300) is being charged. The present invention is adaptable to existing battery power systems without the need for significant additional components and is applicable to any system utilizing rechargeable batteries.

Method and apparatus for detecting the state of charge of a battery

Abstract: A method and apparatus for detecting the state of charge of a battery during charging or discharging thereof. Voltage levels across the battery are measured during battery charging or discharging, and compared with preset values representative of a normal battery characteristic charge or discharge curve. The normal charge or discharge curve is modified responsive particular battery characteristics indicated by measured battery voltage levels, and, preferably, also responsive to measured battery temperature levels to form a modified normal battery charge or discharge curve. The modified normal battery charge or discharge curve is divided into curve portions defined by voltage levels and rates of changes of the voltage levels. Each curve portion defines a particular state of charge of the battery. Measured voltage levels and rates of changes thereof may then be associated with a modified normal battery charge or discharge curve portion and a particular state of charge or discharge curve portion and a particular state of charge defined thereby.

Sec. cell battery charge state measurement circuit - has up=down counter operating at different count rates for charging and discharging

Abstract: The state of charge measurer contains an electronic counter whose count state, corresp. to the state of charge, varies in a first direction when a load connected to the battery is operated. A pulse generator (16) varies the count state proportionately in the opposite direction when the battery (11) is being charged. Different count rates are used during charging and discharging. USE/ADVANTAGE - Esp. for use with Nickel-Cadmium batteries. State of charge is indicated independently of battery voltage and partial charging can be taken into account.

Ladezustandsanzeige einer batterie

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.

Battery discharging and charging

Abstract: A storage battery is first substantially fully discharged before it is charged. A load impedance is first connected across the battery to receive current from the battery and develop a signal representative of the state of charge of the battery. Sensing this signal provides an indication of when the battery becomes substantially fully discharged. The load impedance is then disconnected, and the battery then receives charging current. A full-wave rectifier couples the battery to an LED that may be coupled to the battery to provide the indication of when the battery becomes substantially fully discharged. This indication may be used to operate relays to disconnect the load impedance from across the battery and charge the battery.

Use of the Modeling of Lead-Acid Battery Operation for the Development of a State of Charge Meter

Abstract: The lead acid battery remains the most widespread type of electrochemical storage. Nevertheless, the diversity of the phenomenon taking place during charging or discharging, and their complexity makes it very difficult to determine the battery state of charge.

Method and device for testing the charge-condition of car-batteries

Abstract: To determine the state of charge of a car battery, the no-load voltage of the battery is measured at a given time. If the voltage is measured after the battery has been charged and before the electrochemical equilibrium is reached with onset of the open-circuit voltage, the relationship between voltage value and state of charge is established by applying a correction to the measured voltage which is calculated from the highest polarisation voltage of the charged battery and an approximately logarithmic function of time. The measured voltage is corrected by means of suitable devices by mechanical or electrical means and indicated as the corresponding state of charge.

Method and apparatus for controlling the tension in dependence of the state of charge of the battery

Abstract: A method and an apparatus for voltage regulation are proposed, by means of which the battery charge state and the loads from the on-board network are determined and suitable measures to improve this charge state are initiated if the battery charge state is poor. The on-board network load is determined during a first period (t1) from the switched-on duration of the switching transistor (18) of the voltage regulator (12) and the speed of the generator. In a second period (t2), the charge state of the battery is determined from the behaviour of the battery voltage at a reduced regulation voltage. … …

Battery Control Unit with State of Charge Indicator

Abstract: A new kind of Battery Control Unit (BCU) has been developed for a 160 Wp stand alone PV model plant. This plant uses a lead acid storage battery. The BCU is based on a 8051 microcontroller and includes a dc/dc converter. The features of the BCU are MPP — tracking, overcharge-and underdischarge protection, real — time simulation of the state of charge and display of all relevant system data.

Einrichtung zur symmetrierung der ladespannung eines bordnetzes

Abstract: The proposal is for a device for making the charging voltage of a vehicle power supply system symmetrical in which two batteries providing said power supply are charged in such a way that the one in a lower state of charge is given priority during charging. Here, the voltage is regulated in the prior art manner by switching the generator exciting current on and off. An additional circuit detects the current state of charge of the batteries and at the same time ensures that the one with the lower charge is given priority.

Battery state of charge indicator system

Abstract: An electric storage battery having a container (22) and a cover (23), and having a plurality of walls for enclosing the electrolyte and other electrochemical components of the battery, has a state of charge indicating device for monitoring the concentration of the electrolyte during the charge and discharge cycles of the battery. The indicating device is made of a porous solid support (31) and an acid concentration sensitive dye which exhibits a change in colour in accordance with the acid concentration of the electrolyte. The indicating device also includes a viewport located in one of the walls of the battery for viewing the colour of the dye. The colour may then be correlated to a reference scale to determine the state of charge of the battery.

Optimum matching of a photovoltaic array to a storage battery

Abstract: A detailed mathematical analysis that combines the model of the battery, the solar cell array, the insolation, and the temperature profiles in a nonlinear optimization formulation to maximize system performance is presented. The analysis is extended to determine the optimum sizing of the array needed to supply the storage battery load. Different models of the battery are studied. The results indicate that the simple linear model of the battery can be used to yield a good estimate of the sizing of the array. Results show that in order to raise the state of charge of a battery from 0.25 to 1.0 in one day, the battery open-circuit voltage at full charge is 75% of the array maximum power point voltage at standard conditions. >