Showing papers on "State of charge published in 1974"

Device for determining the state of charge in batteries

Abstract: A device for determining the state of charge in batteries. The battery un test is discharged to its maximum capability by controlling the discharge current in a linear manner. The product of the current and battery voltage is recorded until the battery power reaches maximum at the maximum power point. The readings, peak power and the potential of the battery at the peak power, are held on meters by peak read and hold and track and hold circuits, respectively. From the readings obtained the state of charge can be determined by using a calibration curve for the type of battery being tested.

Apparatus for determining the state of charge of storage batteries

Abstract: An apparatus responsive to the current supplied to and by a storage battery, together with various charge, temperature and discharge rate factors, for calculating and displaying a value of the total charge presently in a storage battery as an accurate prediction based upon factors which affect that charge. The calculations are partially performed on a hybrid analog-digital integrator including entry points for several compensation factors.

Hysteresis battery charger

Abstract: A charging network is described having a series pass element for delivering charging current to a battery, means for sensing the state of charge of the battery, and control circuitry for regulating battery charging A non-linear voltage reference element operatively associated with the control circuitry enables the battery to be charged to a predetermined relatively high voltage cut-off level at which time positive latch-out of charging occurs Charging is reinitiated only after the battery voltage level has dropped to a predetermined level below the initial charge cut-off level This hysteresis effect (loop width) may be selectively controlled

Battery charging circuit

Abstract: A battery charging circuit for effecting efficient charging of a battery by a solar energy source is provided. A voltage detecting circuit is coupled in parallel with a battery for detecting each state of charge of same, the detecting circuit including a constant voltage element. Transistor by-pass circuitry includes first and second current path electrodes connected in parallel with the battery. The transistor by-pass circuitry further includes a third control electrode coupled to the detecting circuit, and in response to the state of charging of the battery detected thereby, respectively effects one of an increase and decrease in the current carried by said current path electrodes.

Electronic control system for battery chargers

Abstract: An electronic control system for battery chargers in which the charging current is switched on and off at predetermined intervals of time, and the magnitude of the charging current during the ON periods is controlled from a signal produced from the electronic control system On switching OFF the charging current at each cycle of operation, the rate of decay of battery voltage is utilized to form a control signal, having first removed the voltage drop on switch off due to the ohmic resistance of the battery, known as the ''''IR Drop'''' Having extracted the ''''IR Drop,'''' the remaining rate in decay in voltage representing the ''''Gas Drop'''' due to potential changes in the layer of gas on the active surfaces of the electrode, is compared with a standard reference voltage, the result of said comparison being utilized to vary the magnitude of the charging current in accordance with the state of charge of the battery as determined by the rate of decay of battery terminal voltage, due to the ''''Gas Drop

State-of-charge indicator for voltage-regulated battery charger

Abstract: A signaling circuit is connected across the output terminals of a voltage-regulated battery charger that also has a.c. input terminals, an SCR connected between one input terminal and an output terminal, and a regulating circuit connected with the gate of the SCR and comprising a zener diode. The signaling circuit comprises a small lamp bulb connected in series with another zener diode, the latter having a zener voltage such as to pass current through the bulb only when voltage at the output terminals is at or above the value corresponding to a fully charged battery.

Experimental investigation and model development of the Skylab ATM secondary nickel-cadmium batteries

Abstract: The performance of a Ni-Cd battery was evaluated and the cyclic battery controls to be used on the ATM batteries were determined. Cell and battery performance models were developed which to predict the performance of the secondary Ni-Cd batteries on the ATM. Capacity degradation and charge acceptance characteristics were considered. Mathematical models for each of these operating areas were developed based on data from two separate test programs. The capacity degradation model describes the expected usable battery capacity as a function of time, temperature, and depth-of-discharge. The charge acceptance model describes the cell charge acceptance as a function of charge rate, temperature, and state of charge. The models were designed for computer use and to facilitate possible battery modification. They can be used to predict expected performance or to compare real time performance during flight.