Abstract: The voltage regulator includes a voltage regulation electric circuit stage, an output electric circuit stage and an optic coupler connecting but electrically isolating said stages. The input of the voltage regulation stage is connected to a battery and/or directly or indirectly to the power output terminal of a direct current alternator or generator and the output of the voltage regulation stage is connected to the light emitting diode of the optic coupler the phototransistor of which is connected to a transistor switch in the output electric circuit stage which functions to connect the field windings of the alternator or generator to the same battery or to another battery in series with said battery, and/or to the power output terminal of the alternator or generator. When employed with series-connected batteries and the dual voltage control described in applicant's earlier U.S. Pat. No.

Abstract: A voltage regulator includes a first normally closed switch arranged for releasably connecting the field coil terminal of an engine-driven DC alternator or DC generator to its appropriate positive or negative output terminal. The first switch is controlled by an electric actuator having an electric circuit arranged for connection across the output terminals of the alternator or generator and is operable at a predetermined lower level output voltage to open the first switch, whereby to limit the output charging voltage to said lower level which is predetermined to effect charging of the battery without significant consumption of water.

Abstract: A pair of batteries of equal voltage rating are connected together in parallel through isolation diodes and in series through a first silicon controlled rectifier, the gate electrode of which is connected to the positive terminal of the first battery through a second silicon controlled rectifier and the emitter-collector switch circuit of a switching transistor. The gate electrode of the second silicon controlled rectifier is connected to said positive terminal through a capacitor and said transistor switch.

Abstract: The electric potential output from a battery and generator assembly is monitored by three electric indicator circuits, one of which includes a first indicator which is activated to indicate excessively low battery voltage when the normally deactivated transistor switch in said circuit is activated by deactivation of a bias control transistor resulting from deactivation of a zener diode when the output voltage from the assembly drops below a predetermined minimum; a second indicator circuit of which includes a second indicator which is activated to indicate excessively low generator charging voltage when the normally activated transistor switch in parallel with said second indicator is deactivated by deactivation of a zener diode when the output voltage from the generator drops below a predetermined minimum; and a third alarm circuit of which includes a third indicator which is activated to indicate excessively high generator charging voltage when the normally deactivated transistor switch in said third circui

Abstract: Two series-connected batteries are connected across the power and ground terminals of an alternator and a silicon controlled rectifier selectively connects said power terminal to the junction between the batteries. A turn-on control circuit for the silicon controlled rectifier is connected across the battery providing the higher voltage output to effect conduction of the silicon controlled rectifier when the voltage drop across said battery reaches a predetermined value, whereby to direct charging current from the alternator only through the battery providing the lower voltage output.