Abstract: A lightweight, efficient, transformerless battery-charging system especially for use with electric vehicles, wherein a switching regulator stores only a fraction of the energy in each charging pulse, and much of the charging energy is supplied directly from the powerline and never stored in the charger. Major components include an overload and ground-fault protective current interruptor, an RF interference filter and line rectifier, and a switching regulator capable of maintaining a constant-current constant-voltage output, providing controlled input current throughout the AC cycle and including means for external shutdown.

Abstract: A battery cell controlled charging system, consisting of a display unit, battery cell probes, a battery charger and circuitry for controlling the charger, monitors the specific gravity, electrolyte level and temperature control of each cell in a multi-cell lead-acid battery and uses the information to automatically charge the battery when a cell or cells become out of specification while restricting overcharging which is damaging to cells.

Abstract: A transducer and battery performance indicator which senses various levels of specific gravity and other conditions of a liquid or electrolyte of varying degrees of translucency and converts the measurements into electrical analog signals which are fed to an indicator read-out. The device may include temperature and level sensors, as well as an agitator for circulating electrolyte, and a number of them are used remotely to monitor a bank of batteries.

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 system for automatically monitoring a plurality of parameters of a plurality of cells in a lead-acid storage battery system. A transponder means responsive to a frequency pattern corresponding to a digital command is located at each cell to be monitored and includes a plurality of sensors which provide analog signals having an amplitude related to the value of the parameters being monitored. In a remote scanner/display means, a microprocessor generates a digital interrogation command (containing a transponder address, sensor selection, and reply duration commands) which is converted to a frequency pattern and coupled to the transponder. In response to the command, the transponder couples the analog signal from the selected sensor to a voltage-controlled oscillator and the output of the oscillator is coupled for the selected reply duration to the scanner/display means where the frequency of the signal is determined under the control of the processor.