초록 ▼

An electric battery, such as that of an automotive vehicle, is continuously tested for its state of charge by a bridge circuit in parallel with a voltage stabilizer such as a Zener diode which forms part of a voltage divider connected across the battery terminals, the other part of that divider bein

An electric battery, such as that of an automotive vehicle, is continuously tested for its state of charge by a bridge circuit in parallel with a voltage stabilizer such as a Zener diode which forms part of a voltage divider connected across the battery terminals, the other part of that divider being a resistance circuit. The bridge circuit has an output diagonal with one corner connected to the battery terminal which is tied to the resistance circuit so that a reduction of battery voltage unbalances the bridge in one sense, a compensatory change in the opposite sense being brought about by a sensor responsive to the load current drawn from the battery. The current sensor may be a small resistor inserted between two adjoining bridge arms. An integrating operational amplifier connected across the output diagonal of the bridge controls a pulse generator which steps an associated pulse counter whenever the amplifier output passes a threshold indicating a predetermined degree of depletion of the battery; the counter, after measuring a cumulative time interval during which this depletion condition is present, triggers a switch which generates an alarm signal, e.g. by eliminating certain options in the operation of the vehicle. The operational amplifier and/or pulse generator also work into visual charge indicators. The resistance circuit of the voltage divider may include a transistor designed to compensate changes in battery current due to the de-energization of a switching relay. A feedback connection between the counter and the pulse generator causes continuing stepping of the counter after the switchover to maintain the alarm signal until the counter resets itself after an extended period, such resetting also occurring upon reclosure of the load circuit after a prolonged interruption.

대표청구항 ▼

A charge monitor for an electric battery provided with a first and a second terminal and with a load circuit connected across said terminals, comprising: a voltage divider with a voltage-stabilized first section and a resistive second section serially connected across said terminals, said first sect

A charge monitor for an electric battery provided with a first and a second terminal and with a load circuit connected across said terminals, comprising: a voltage divider with a voltage-stabilized first section and a resistive second section serially connected across said terminals, said first section extending between said first terminal and a junction point, said second section extending between said junction point and said second terminal; a resistive bridge circuit connected between said first terminal and said junction point, said bridge circuit having an output diagonal with a corner tied to said second terminal via a resistive connection for tending to unbalance said bridge circuit in one sense upon a decrease in the potential difference between said terminals; current-sensing means coupling said bridge circuit with said load circuit for tending to unbalance said bridge circuit in an opposite sense upon an increase in current flow through said load circuit; amplifier means differentially connected across said output diagonal for generating a test voltage representative of the state of charge of said battery; and dectector means connected to said amplifier means for establishing an alarm condition upon said test voltage passing from a normal range to an off-normal range indicative of a predetermined state of depletion of said battery.