Auxiliary battery monitor
First Claim
1. A voltage differential monitor for use within a vehicle electrical system of the type which includes primary battery means and auxiliary battery means, the primary battery means functioning as an electrical power source for operating the engine of the vehicle and supplied with charging voltage by an alternator, the auxiliary battery means functioning as an electrical power source for accessories at least during downtime of the engine of the vehicle, said monitor comprising voltage sensing input means coupled respectively to said auxiliary battery means and to said primary battery means, voltage comparison means coupled to said input means, switch means coupled to said switch means, said voltage comparison means being constructed and arranged, when said charging voltage is present, to automatically direct an output signal to said switch means when the voltage of said primary battery means exceeds the voltage of said auxiliary battery means by a predetermined voltage differential and said switch means constructed and arranged to energize said alarm means upon receipt of said signal from said voltage comparison means whereby the operator of the vehicle is made aware of the existence of a specific voltage differential condition relative to said auxiliary battery means.
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Accused Products
Abstract
The electrical system of a vehicle includes a primary voltage source for starting and operating the engine of the vehicle and an auxiliary voltage source for operating the electrical accessories of the vehicle, particularly when the engine is not operating, and a voltage differential monitor circuit for warning the vehicle operator of the existence of a low voltage condition of the auxiliary battery, such as resulting from an auxiliary battery charging system failure which could result in the inability of an electrical accessory to operate even when the engine is operating. The voltage differential between the primary and auxiliary sources is measured by coupling same to a voltage comparison device, namely a pair of voltage dividing resistor pairs providing inputs to an operational amplifier in which an output is turned on when the voltage differential is above a predetermined value determined by the voltage division ratio of the resistors causing the amplifier to direct a signal to a switching device, a field effect transistor, which in turn completes a circuit to a lamp causing same to become illuminated, the illuminated lamp warning the operator of the system failure.
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Citations
14 Claims
- 1. A voltage differential monitor for use within a vehicle electrical system of the type which includes primary battery means and auxiliary battery means, the primary battery means functioning as an electrical power source for operating the engine of the vehicle and supplied with charging voltage by an alternator, the auxiliary battery means functioning as an electrical power source for accessories at least during downtime of the engine of the vehicle, said monitor comprising voltage sensing input means coupled respectively to said auxiliary battery means and to said primary battery means, voltage comparison means coupled to said input means, switch means coupled to said switch means, said voltage comparison means being constructed and arranged, when said charging voltage is present, to automatically direct an output signal to said switch means when the voltage of said primary battery means exceeds the voltage of said auxiliary battery means by a predetermined voltage differential and said switch means constructed and arranged to energize said alarm means upon receipt of said signal from said voltage comparison means whereby the operator of the vehicle is made aware of the existence of a specific voltage differential condition relative to said auxiliary battery means.
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8. A voltage differential monitor for use within a vehicle electrical system of the type which includes primary battery means and auxiliary battery means, the primary battery means functioning as an electrical power source for operating the engine of the vehicle and supplied with charging voltage by an alternator, the auxiliary battery means functioning as an electrical power source for accessories at least during downtime of the engine of the vehicle, said monitor comprising voltage sensing input means coupled respectively to said auxiliary battery means and to said primary battery means, voltage comparison means coupled to said input means, switch means coupled to said voltage comparison means and alarm means coupled to said switch means, said voltage comparison means constructed and arranged to direct an output signal to said switch means when the voltage of said primary battery means exceeds the voltage of said auxiliary battery means by a predetermined voltage differential and said switch means constructed and arranged to energize said alarm means upon receipt of said signal from said voltage comparison means whereby the operator of the vehicle is made aware of the existence of a specific voltage differential condition relative to said auxiliary battery means;
- the voltage differential level at which the comparison means delivers an output signal to the switch means being determined by the voltage division ratios of resistor pairs disposed between said comparison means and respectively said primary battery means and said auxiliary battery means.
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10. In a vehicle electrical system of the type which includes primary battery means and auxiliary battery means, the primary battery means functioning through an ignition switch as an electrical power source for operating the engine of the vehicle and being supplied with charging voltage by an alternator, the auxiliary battery means functioning as an electrical power source for accessories during downtime of the engine of the vehicle, said auxiliary battery means including charging switch means connecting said auxiliary battery means to said alternator when said engine is operating, the improvement comprising a voltage differential monitor continuously coupled respectively to said auxiliary battery means and to said primary battery means upon said ignition being on, said monitor having voltage comparison means having a first auxiliary voltage sensing input and a second primary voltage sensing input, switch means coupled to said voltage comparison means and alarm means coupled to said switch means, said voltage comparison means being disposed to direct a signal to said switch means when said primary voltage input exceeds said auxiliary voltage input by a predetermined voltage differential, and said switch means being disposed to energize said alarm means upon receipt of said signal from said voltage comparison means whereby the operator of the vehicle is made aware of the existence of a low voltage condition of said auxiliary battery means.
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11. In a vehicle electrical system of the type which includes primary battery means and auxiliary battery means, the primary battery means functioning as an electrical power source for operating the engine of the vehicle and being supplied with charging voltage by an alternator, the auxiliary battery means functioning as an electrical power source for accessories during downtime of the engine of the vehicle, said auxiliary battery means including charging switch means connecting said auxiliary battery means to said alternator when said engine is operating, the improvement comprising a voltage differential monitor coupled respectively to said auxiliary battery means and to said primary battery means, said monitor having voltage comparison means having a first auxiliary voltage input and a second primary voltage input, switch means coupled to said voltage comparison means and alarm means coupled to said switch means, said voltage comparison means being disposed to direct a signal to said switch means when said primary voltage input exceeds said auxiliary voltage input by a predetermined voltage differential and said switch means being disposed to energize said alarm means upon receipt of said signal from said voltage comparison means whereby the operator of the vehicle is made aware of the existence of a low voltage condition of said auxiliary battery means;
- said voltage comparison means comprising a high gain operational amplifier and voltage dividing resistor pairs interposed between each of said inputs and said amplifier, each of said resistor pairs having a voltage division ratio which, upon said predetermined voltage differential being exceeded, produce respective input voltages at said amplifier means which trigger an output voltage therefrom to activate said switch means.
- View Dependent Claims (12, 13, 14)
Specification