Protective circuit for battery powered engine ignition system
First Claim
1. A protective circuit for battery discharge circuit protection in a battery-powered engine ignition electrical system for a vehicle, boat, aircraft or hovercraft wherein said circuit is an entirely solid state circuit comprising a switching transistor means (Q2) to control connection between a battery terminal (T4) and an electrical load means (e.g.4), means (9) for manually switching said switching transistor means to open or close said connection between the battery terminal and said load means, means (T4, R1, R2, T3, R3, R5) for automatically switching the said switching transistor means to open or close the said connection between said battery terminal and the said load in relation to a predetermined battery discharge condition, and a voltage multiplier (M, DP or IC2a, DP) for maintaining a sufficient stable voltage to control said switching transistor means irrespectively of varying load currents and battery voltage.
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Accused Products
Abstract
A battery protection circuit for an engine ignition system comprises first and second terminals for connection in series with a discharge circuit of the battery and normally ON switching means connected between said terminals. If the battery voltage falls below a predetermined level, for example, as a result of leaving the headlights on in a parked motor vehicle, incorporating the circuit in its ignition system, the switching means turns OFF and isolates the battery, so as to prevent further discharge of the battery. The switching means can be reset by the user, for example, by means of a signal from a handheld I.R. transmitter on returning to the vehicle, enabling the ignition coil to be energized from the battery and the engine to be started. Thus the circuit can be used to prevent a vehicle battery from going flat when the vehicle is parked.
34 Citations
10 Claims
- 1. A protective circuit for battery discharge circuit protection in a battery-powered engine ignition electrical system for a vehicle, boat, aircraft or hovercraft wherein said circuit is an entirely solid state circuit comprising a switching transistor means (Q2) to control connection between a battery terminal (T4) and an electrical load means (e.g.4), means (9) for manually switching said switching transistor means to open or close said connection between the battery terminal and said load means, means (T4, R1, R2, T3, R3, R5) for automatically switching the said switching transistor means to open or close the said connection between said battery terminal and the said load in relation to a predetermined battery discharge condition, and a voltage multiplier (M, DP or IC2a, DP) for maintaining a sufficient stable voltage to control said switching transistor means irrespectively of varying load currents and battery voltage.
Specification