Showing papers on "State of charge published in 1977"

Device for controlling the charging and discharging of a storage battery

Abstract: A device for controlling the charging and discharging of a storage battery has an input to which there is applied an input voltage proportional to the magnitude and sign of the current flowing through the battery. The input voltage is amplified and integrated to provide an integral which is an image of the state of charge of the battery. In this invention the input voltage is converted to a pulse train whose frequency is proportional to the magnitude of the input voltage and the pulses are added or subtracted according to its sign. The pulse total forms the said image of the state of charge of the battery.

System and apparatus for monitoring or controlling secondary battery operation

Abstract: The terminal current of a main secondary battery is continuously monitored throughout charging and discharging by a system having a monitor cell, such as a metal gas battery, and having circuitry for conforming monitor cell terminal current in sense, and proportionally in magnitude, to the main battery terminal current. Apparatus responsive to the monitor cell state of charge may provide sensible output indication of main battery state of charge or control charging/discharging of the main battery.

Monitoring circuit for battery charge state - has several cells connected in series and uses series chain of transistors to balance cell loads

Abstract: A limit switch (T11-Tn1) is connected in parallel with each cell (B1-Bn) and controlled by the respective cell voltage. Switch outputs are connected to the inputs of a series AND gate (G) which operates a switch (T1) between the battery and load (RL). Threshold value transistors may be used as the limit switches (T11-Tn1). The base terminal of each of the latter is connected through a resistor (R12-RnZ) to a second set of transistors (T12-Tn2) which together form the series AND gate (G) with a coupling transistor (T2). The transistor chain enables the load on each cell to regulate itself in accordance with the state of charge.

Porous electrode primary battery having state of charge sensing electrode

Abstract: In a porous electrode primary battery a sensing grid is positioned in a cell on or near the surface of the porous cathode facing the separator and anode. The voltage measured between this sensing grid and the conventional cathode current collector grid is a function of the current distribution within the electrode which is continuously changing as the battery discharges, thus the measured voltage is indicative of the state of charge of the particular cell having the sensing grid and for a battery containing cooperatively connected cells, the state of the battery in general.

Standby emergency power source - is operated by storage battery and provides constant indication of charge state of battery and has two independent charging circuits

Abstract: A stably or auxiliary power source comes into operation if the primary source fails. The source is based on rechargeable batteries and includes a circuit which provides constant monitoring of the state of charge of the batteries regardless of this state when the batteries are first loaded into the unit. The circuit is based on the use of at least two batteries each of which has an independent charging circuit each of which is used alone to provide the emergency supply. There is a voltage sensitive relay which monitors each battery and switches it out and a further one in once its output level falls below a set threshold.

Battery charge indicator with magnetic floats - uses reed relay energised by floats to operate warning lamp on vehicle dashboard

Abstract: A group of lead acid batteries has a state of charge indicator placed such that the user, typically the driver of an electrically propelled vehicle, can maintain a constant watch on the state of the batteries. The charge indicator is based on the use of a suitable density float (7) acting as a hygrometer. The floats are either spherical or cylindrical and they are made of some magnetic material, the position of which activates some form of reed relay (10) in circuit with a warning lamp (13). The hygrometer position can either be a built-in compartment (4) on the side of the battery wall or in a position between the plates of the battery.

High frequency battery charging circuit

Abstract: 1421083 Battery charging systems using DCDC converters MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 17 Jan 1974 [19 Jan 1973 20 April 1973 16 May 1973 (2) 5 Dec 1973] 02163/74 Headings H2H and H2F [Also in Division H3] A system for charging a battery from an A.C. power supply by way of a transistor D.C. to D.C. converter comprises means for rendering the converter inoperative and thus to terminate charging when the battery reaches a predetermined state of charge. A battery B is charged from an A.C. source a, b by way of a rectifying diode D 1 , a converter comprising a transistor Tr 1 and a transformer T having a primary winding nc in the collector circuit of the transistor Tr 1 , a feedback winding nb connected to the base of the transistor and a secondary winding ns the output of which is rectified by a diode D 2 to charge the battery. When the battery B is sufficiently charged the potential at the mid-point of a divider R 2 , R 3 becomes such that transistor Tr 2 turns on so turning on transistors Tr 3 , Tr 4 , the turn-on of transistor Tr 4 connecting the base of transistor Tr 1 to its emitter whereby the transistor Tr 1 ceases oscillation so terminating the battery charging process. The turn-off of transistor Tr 1 may be enhanced by connecting a diode in its base or emitter circuit and the connection of a diode between the emitters of transistors Tr 1 , Tr 4 prevents interaction between the A.C. source and the secondary side of the transformer T. If desired the converter may comprise a pair of transistors operating in a push-pull blocking oscillator mode. In order to provide full electrical isolation between the secondary and primary sides of the transformer T the connection between the transistors Tr 4 and Tr 1 may include a photo-electric element, an electromagnetic relay or a thermo-electric element. An indicatoring lamp may be provided to indicate that charging is taking place.

In emergency dc power supplies

Abstract: 1516921 Standby supply systems; converters INTERNATIONAL STANDARD ELECTRIC CORP 28 Jan 1976 [6 Feb 1975] 03278/76 Headings H2H and H2F A standby supply system for supplying DC to a load 3 comprises a battery 2, a rectifier circuit 1 supplied from an AC source 9, and a DC to AC converter 4 controlled by the load current and/or the load voltage, the output of the converter being fed back to the AC source or to the rectifier circuit in dependence on the state of charge of the battery and the converter being controlled by the load current and/or the load voltage so that the load receives the correct supply voltage independent of the instantaneous state of the battery When the mains supply is present, the rectifier circuit 1, which includes thyristors T 1 , T 2 controlled by a circuit 15, charges the battery 2 and supplies DC to the load via a smoothing circuit 5, 6 The converter 4, which includes thyristors TA, TB controlled by a circuit 8 in dependence on the load voltage, feeds back to the supply 9 any voltage in excess of that required by the load If the mains supply fails, at least one of the thyristors TA, TB is held conductive so that the battery supplies power to the load A system for use with a three phase supply is also described

Electronic DC battery charger - has boost circuit and control circuit and sensors to detect battery voltage and temp. to indicate state of charge

Abstract: A, battery charger receives d.c. power from an external source through a power connector. Switch means receives the power from the power connector and supplies it to a boost circuit which is removably and conductively connected to a battery. A control circuit is connected to receive a battery voltage signal from the battery and a battery temp. signal from a sensor positioned to detect battery temp. The control circuit determines the state of charge of the battery from the voltage and temp. signals. The control circuit supplies (1) switching signals to the switch means to cause the switch to be conductive, and (2) boosting signals to the boost circuit to cause the boost circuit to charge the battery in accordance with a pre-selected charging program related to the state of charge of the battery.