Electricity: battery or capacitor charging or discharging – One cell or battery charges another – Vehicle battery charging
Reexamination Certificate
2001-01-24
2001-11-20
Tso, Edward H. (Department: 2838)
Electricity: battery or capacitor charging or discharging
One cell or battery charges another
Vehicle battery charging
C320S136000
Reexamination Certificate
active
06320351
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to switches and, more particularly, to battery disconnect switches for preventing undesirable discharge of a battery.
2. Description of the Related Art
A rechargeable battery for use in providing initial energy for starting a motor of a vehicle, such as an automobile, a truck, a bus, a boat and most lawnmowers, is well known. As also well known, once the engine of the vehicle begins to run, an electrical generator provides power to recharge the battery and to energize an electrical load of the vehicle. The electrical load typically includes electrical appliances such as various lights, including safety and illumination lights, power accessories such as power door locks and power windows, and a radio. When the engine of the vehicle is not running, the electrical generator produces no power and the battery becomes the sole source. As most operators have experienced, a substantial risk of over discharging the battery arises when the engine is off and the load has not been disconnected from the battery such as in the case of an automobile where the headlights are left on after the engine has been shut off. In such a case, the battery may be discharged to a level where insufficient power exists to restart the engine of the vehicle—possibly causing the operator to be stranded. In addition, over discharging a battery will shorten the battery life because sulphuration may occur. Sulphuration involves an abnormal sulfate formed on the surface of the battery plates which hinders the battery plate from receiving and accepting a charge because of an increased resistance thereof.
Currently, disconnect switches are available for monitoring the state of the battery and disconnecting the battery from the electric load of the vehicle when the battery is discharging at a high rate or low rate after the engine has been shut off. However, these devices suffer from the draw back that once the battery has been disconnected from the electric load of the vehicle, they must be manually reset by the operator in order to start the engine.
SUMMARY OF THE INVENTION
Briefly stated, the invention in a preferred form is an intelligent switch for preventing undesirable discharge of a battery of a vehicle. The intelligent switch includes a switch connected in circuit with the battery that is configured to toggle between a first state for preventing current flow from the battery and a second state for allowing current flow from the battery. A voltage monitor is connected to the battery and is configured to provide a voltage signal indicative of the voltage level of the battery. A vibration sensor is configured to detect vibration of the vehicle and provide a vibration signal indicative thereof. A controller is connected to receive the voltage signal and the vibration signal and generate a control signal for toggling the switch to the first state when no vibration of the vehicle is detected and the voltage level of the battery falls below a predetermined voltage threshold and to the second state when vibration is detected regardless of the voltage level of the battery.
In a particular aspect of the invention, the voltage monitor is configured to output the voltage signal when the voltage from the battery falls below the predetermined voltage threshold, the voltage signal being detected by the controller.
In other aspects of the invention, the controller comprises a central processing unit, in particular, a microprocessor and a timer circuit for providing a predetermined delay between when the voltage level falls below the predetermined threshold value and the output of the control signal from the controller so that should vibrations be detected the control signal will not be output from the controller.
The battery may include a first part primarily for starting the engine of the vehicle and a second part primarily for supplying power to electrical load of the vehicle and connectable in parallel with the first part, to which battery parts the voltage monitor is connected. An intelligent switch configured for use in conjunction with such a battery includes first and second said switches connected in circuit with the first and second battery parts respectively. The controller is configured to generate a first control signal for toggling the first switch to the first state when no vibration of the vehicle is detected and the voltage level of the battery parts connected in parallel falls below a first predetermined voltage threshold. The controller generates a second control signal for toggling the second switch to the first state when no vibration of the vehicle is detected and the voltage level of the second battery part falls below a second, relatively lower predetermined voltage threshold.
To protect the battery against over discharge in different current drain situations, the controller is configured with at least two predetermined voltage thresholds. The intelligent switch includes at least two said timers associated with said predetermined voltage thresholds. A first of said timers counting a relatively longer predetermined period of time corresponding to the predetermined voltage threshold that is relatively higher, and a second timer being for counting a relatively shorter predetermined period of time corresponding to the predetermined voltage threshold that is relatively lower, etc.
A controller equipped with multiple voltage thresholds and multiple timers has the capability to more accurately measure the discharge condition of the battery. According to one aspect of the invention, the controller is configured with five said predetermined voltage thresholds. The intelligent switch includes a timer associated with each predetermined voltage threshold for counting respective predetermined periods of time the lengths of which increase or decrease with the levels of the corresponding voltage thresholds.
Advantageously, the timer is configured to stop counting when the voltage level of the battery rises back above the predetermined voltage threshold and to continue to count when the voltage level of the battery falls below the predetermined voltage threshold again for the uncounted part of the predetermined period of time. The controller is configured to generate said control signal for toggling the switch to the first state at the time when any one of the predetermined periods is counted to an end.
In another aspect of the invention, a method of preventing undesirable discharge of a battery for a vehicle, comprises the steps of: monitoring a voltage level of the battery and providing a voltage signal indicative of the voltage level; detecting vibration of the vehicle and providing a vibration signal indicative thereof; receiving the voltage signal and the vibration signal; generating a control signal based on the voltage signal when the voltage level from the battery falls below a predetermined threshold voltage level and based on the vibration signal when no vibration of the vehicle is detected, the control signal toggling a switch to a first state for preventing current flow from the battery; and generating another control signal for toggling the switch to a second state for allowing current flow from the battery when vibration is again detected.
The method further comprises the step of starting to count a first, relatively longer predetermined period of time when the voltage level from the battery falls below a first, relatively higher predetermined threshold voltage level, and the step of starting to count a second, relatively shorter predetermined period of time when the voltage level from the battery falls below a second, relatively lower predetermined threshold voltage level, prior to the generation of the control signal. The control signal is generated when any one of the predetermined periods is counted to an end.
An object of the present invention is to provide a new and improved intelligent switch that prevents over discharge of a battery.
Another object of the invention is to provide a new and improved int
Choi Kong Fan
Ng Wai Man
Alix Yale & Ristas, LLP
Sunlite Trading Limited
Tso Edward H.
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