Battery charge monitor

• US 5,321,389 A
• Filed: 11/27/1992
• Issued: 06/14/1994
• Est. Priority Date: 11/27/1992
• Status: Expired due to Fees

• Current Assignee: Echlin, Inc.
• Original Assignee: Echlin, Inc.
• Inventors: Meister, Jack B.
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): TONG, NINA C
• Application Number:
  US07/982,707
• Time in Patent Office: 564 Days
• Field of Search: 340/636, 340/455, 340/663, 320/13, 320/38, 320/40, 320/48, 307/10.7, 362/92, 290/38 R, 335/177, 335/178, 335/179
• US Class Current: 340/455
• CPC Class Codes: B60R 16/03 for supply of electrical power to vehicle subsystems or for circuit arrangements for charging batteries H02J7/00
• CPC Class Codes: H02J 2310/46 for ICE-powered road vehicles
• CPC Class Codes: H02J 9/002 in which a reserve is maintained in an energy source by disconnecting non-critical loads, e.g. maintaining a reserve of charge in a vehicle battery for starting an engine

Abstract

A battery charge monitor for automotive vehicles that includes electronic circuitry for connection to the vehicle battery and responsive to battery voltage to provide a first electrical signal when battery voltage decreases to a selected threshold level. A latching relay includes relay contacts for connection between the vehicle battery and vehicle battery loads, including the starter. A first relay coil is operatively coupled to the relay contacts and responsive to the first signal from the electronic circuitry to open the relay contacts and disconnect the battery from the battery loads including the starter. A second relay coil is operatively coupled to the relay contacts and responsive to a second electrical signal from an operator reset switch for reclosing the relay contacts and connecting the battery to the loads. Thus, when battery charge reaches a level below which starting may be difficult, the electronic circuitry cooperates with the latching relay to disconnect the battery from the loads. When the vehicle is to be started, the battery is reconnected to the loads, including the starter, by operation of the reset switch before energizing the starter.

Claims

1. A battery charge monitor for automotive vehicles having a vehicle battery, a starter and an ignition, said monitor comprising:

electronic circuit means for connection to the vehicle battery and responsive to the battery voltage to provide a first electrical signal when said battery voltage decreases to a selected threshold level,

latching relay means including relay contact means for connection between the vehicle battery and vehicle battery loads including the starter, first relay coil means operatively coupled to said relay contact means and responsive to said first signal to open said relay contact means and disconnect the battery from the battery loads, and second relay coil means operatively coupled to said relay contact means and responsive to a second electrical signal for closing said relay contact means and connecting the battery to the loads,

said latching relay means including first means for holding said relay contact means in a first position closing said relay contact means in the absence of said first signal, and second means for holding said relay contact means in a second position opening said relay contact means in the absence of said second signal and

first switch means responsive to an operator to provide said second electrical signal to said second relay coil means.

2. The monitor set forth in claim 1 wherein said relay contact means includes a fixed contact and a movable contact carried by a resilient contact arm, said first means comprising resiliency of said arm urging said movable contact against said fixed contact, said second means comprising detent means on said arm, said first coil means moving said arm to separate said contacts and engage said detent means to hold said arm and said movable contact spaced from said fixed contact, said second coil means moving said arm to disengage said detent means such that resiliency of said arm closes said movable contact against said fixed contact.

3. The monitor set forth in claim 2 wherein said detent means comprises a fixed ledge and a protrusion on said arm, resiliency of said arm urging said protrusion toward said ledge.

4. The monitor set forth in claim 1 further comprising second switch means responsive to an operator for providing said first signal to said first relay coil means independent of said electronic circuit means.

5. The monitor set forth in claim 4 wherein said first and second switch means comprise a single center-open toggle switch.

6. The monitor set forth in claim 1 wherein said electronic circuit means further includes means responsive to the vehicle ignition for inhibiting provision of said first signal independent of battery voltage.

7. The monitor set forth in claim 6 wherein said electronic circuit means further includes means for delaying application of said first signal to said first relay coil means so as to isolate said first relay coil means from transient changes in battery voltage.

8. The monitor set forth in claim 1 wherein said electronic circuit means including means for varying said selected threshold.

9. The apparatus set forth in claim 8 wherein said threshold-varying means comprises means for automatically varying said threshold as a function of temperature.

10. A latching relay that includes,

a pair of terminals for connection to an external circuitry, a pair of contacts, one of said contacts being operatively coupled to one of said terminals,

a resilient contact arm operatively coupling the other of said contacts to the other of said terminals, resiliency of said arm urging said other contact toward a first predetermined position with respect to said one contact,

detent means on said arm for holding said arm in a second predetermined position with respect to said one contact, one of said predetermined positions being with said contacts in electrical engagement and the other of said predetermined positions being with said contacts spaced from each other, and

a pair of solenoid coils having plungers for operative engagement with said arm, each of said solenoid coils being responsive to an electrical signal for moving the associated plunger and said arm to said first and second positions respectively.

11. A battery switch system for automotive vehicles having a vehicle battery comprising:

latching relay means including relay contact means for connection between the vehicle battery and vehicle battery loads including the starter, first relay coil means operatively coupled to said relay contact means and responsive to a first electrical signal to open said relay contact means and disconnect the battery from the battery loads, and second relay coil means operatively coupled to said relay contact means and responsive to a second electrical signal for closing said relay contact means and connecting the battery to the loads, and

switch means responsive to an operator to provide said first electrical signal to disconnect the battery and said second electrical signal to reconnect the battery.

12. The system set forth in claim 11 wherein said switch means comprises a single center-open toggle switch.