On-board battery supervisor

• US 20090212740A1
• Filed: 02/25/2008
• Published: 08/27/2009
• Est. Priority Date: 02/25/2008
• Status: Active Grant

• Current Assignee: Jimmie Doyle Felps
• Original Assignee: Jimmie Doyle Felps
• Inventors: Felps, Jimmie Doyle
• Granted Patent: US 7,898,219 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: H01M 10/06 Lead-acid accumulators semi-lead accumulators H01M10/20
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• 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
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An on-board battery supervisor that monitors the state-of-charge (SOC) of a lead-acid vehicle battery and automatically disconnects loads from the battery to prevent over-discharging of the battery, is disclosed. As the battery is being discharged, the on-board battery supervisor disconnects loads at an SOC level that leaves enough energy in the battery to reliably start the vehicle engine, while providing as much energy as possible to accessory loads. The loads are automatically reconnected as the battery is charged. Some preferred embodiments of the invention are designed specifically for use in watercraft and a dual output version of the invention simplifies the electrical system. All embodiments have circuit breaker outputs, high peak current capability, a low quiescent current drain and a dual timer that allows accurate determination of the SOC of the battery.

Claims

1. An on-board battery supervisor means for monitoring the state-of-charge (SOC) of a battery in a boat having an outboard motor (or other engine type), the on-board battery supervisor means comprising:

a voltage means for measuring the voltage of the battery through Kelvin connections;

a dual timer means for determining when the output of the voltage means is valid;

a current sensing means for measuring load current from the battery, excluding outboard motor current;

a compensation means for battery internal resistance;

an evaluation means for determining the state-of-charge (SOC) of the battery based on the relationship between the measured voltage, measured current, battery internal resistance compensation and the dual timer;

a first switching means for connecting and disconnecting loads connected to the battery;

a latching, adjustable, circuit breaker means that is integral to the first switching means;

a second switching means for manual control of first switching means and for resetting the latching, adjustable, circuit breaker means;

a first status means for indicating when the state-of-charge (SOC) level of the battery is above a level that allows for reliably starting the outboard motor; and

a second status means for indicating a fault.

2. The method of claim 1, wherein the said dual timer means is a 1-minute timer for load currents above approximately 2.75 A and a 10-minute timer for load currents below approximately 2.5 A.

3. The method of claim 1, wherein the said compensation means for battery internal resistance is based on the load current measured by said current sensing means and the marine cranking amp (MCA) rating of the battery. e.g. a battery with an MCA rating of 875 A has a typical internal resistance of 23 mΩ

when delivering 40 A of current.

4. The method of claim 1, wherein the said evaluation means switches the said first switching means off at a decreasing level of the state-of-charge (SOC) of the battery (typically 20%), leaving enough energy in the battery to reliably start the outboard motor (or other engine type).

5. The method of claim 1, wherein the said evaluation means switches the said first switching means on (after being off) as the level of the state-of-charge (SOC) of the battery increases (as a result of being charged) to approximately 30%.

6. The method of claim 1, wherein the on-board battery supervisor means has a low quiescent current, <

1 mA when off and typically 12 mA when on.

7. The method of claim 1, wherein the on-board battery supervisor means allows an operator to confidently use the same battery for starting the outboard motor (which replaces charge in the battery each time the outboard motor is running) and for powering the trolling motor and other accessories.

8. An on-board dual output battery supervisor means for monitoring the state-of-charge (SOC) of a battery in a boat having an outboard motor (or other engine type), the on-board dual output battery supervisor means comprising:

a voltage means for measuring the voltage of the battery through Kelvin connections;

a dual timer means for determining when the output of the voltage means is valid;

a current sensing means for measuring load current from the battery, excluding outboard motor current;

a compensation means for battery internal resistance;

an evaluation means for determining the state-of-charge (SOC) of the battery based on the relationship between the measured voltage, measured current, battery internal resistance compensation and the dual timer;

a first switching means for connecting and disconnecting a trolling motor connected to the battery;

a second switching means for connecting and disconnecting other accessory loads to the battery;

a latching, adjustable, circuit breaker means that is integral to the first switching means and to the second switching means;

a third switching means for manual control of first and second switching means and for resetting the latching, adjustable, circuit breaker means;

a first status means for indicating when the state-of-charge (SOC) level of the battery is above a level that allows for reliably starting the outboard motor; and

a second status means for indicating a fault.

9. The method of claim 8, wherein the said dual timer means is a 1-minute timer for load currents above approximately 2.85 A and a 10-minute timer for load currents below approximately 2.5 A.

10. The method of claim 8, wherein the said compensation means for battery internal resistance is based on the load current measured by said current sensing means and the marine cranking amp (MCA) rating of the battery. e.g. a battery with an MCA rating of 875 A has a typical internal resistance of 23 mΩ

when delivering 40 A of current.

11. The method of claim 8, wherein the said evaluation means switches the said first switching means off at a decreasing level of the state-of-charge (SOC) of the battery (typically 20%), leaving enough energy in the battery to reliably start the outboard motor (or other engine type).

12. The method of claim 8, wherein the said evaluation means switches the said first switching means on (after being off) as the level of the state-of-charge (SOC) of the battery increases (as a result of being charged) to approximately 30%.

13. The method of claim 8, wherein the on-board battery supervisor means has a low quiescent current, <

1 mA when off and typically 18 mA when on.

14. The method of claim 8, wherein the on-board battery supervisor means allows an operator to confidently use the same battery for starting the outboard motor (which replaces charge in the battery each time the outboard motor is running) and for powering the trolling motor and other accessories.

15. An on-board battery supervisor means for monitoring the state-of-charge (SOC) of a battery in a motor vehicle, the on-board battery supervisor means comprising:

a voltage means for measuring the voltage of the battery through Kelvin connections;

a dual timer means for determining when the output of the voltage means is valid;

a current sensing means for measuring load current from the battery, excluding outboard motor current;

a compensation means for battery internal resistance;

an evaluation means for determining the state-of-charge (SOC) of the battery based on the relationship between the measured voltage, measured current, battery internal resistance compensation and the dual timer;

a first switching means for connecting and disconnecting loads connected to the battery;

a latching, adjustable, circuit breaker means that is integral to the first switching means;

a control means using the accessory output from the vehicle ignition key to enable the on-board battery supervisor to be on and to keep it off (and also reset the latching, adjustable, circuit breaker means in the event it becomes tripped) when the vehicle ignition key is off.

16. The method of claim 15, wherein the on-board battery supervisor means has a low quiescent current, <

1 mA, when the ignition switch is off and typically 12 mA when the ignition switch is on.