Abstract:
A multiple battery system for a vehicle comprises a primary battery; a reserve battery electrically connectable to the primary battery; and a control unit with a relay switch electrically connected between the primary and reserve batteries. The relay switch is operable to close upon actuation and connect the reserve battery to the primary battery. The control unit also has a receiver electrically connected to the relay switch and is adapted to receive a control signal for actuating the relay switch. A wireless transmitter has a manually actuable switch for sending the control signal to the receiver. With this arrangement, actuation of the transmitter switch causes the control signal to be transmitted to the receiver and actuate the relay switch to connect the reserve battery to the primary battery.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/296,349 filed on Jun. 6, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to multiple battery systems, and more particularly to rechargeable vehicle battery systems with a primary battery and a reserve or emergency battery that is connectable to a vehicle electric circuit in the event of primary battery failure. 
     Vehicle battery systems including a primary battery and a reserve battery for starting a vehicle in the event of primary battery failure are known. One such battery system disclosed in U.S. Pat. No. 5,108,848 includes a primary battery and a reserve battery disposed within a common housing. The reserve battery is selectively connectable in parallel with the primary battery through a manually operable switch or relay. A unidirectional charging circuit connects the reserve battery in parallel with the primary battery, permitting charging current to flow into the reserve battery, but preventing drain of the reserve battery during normal vehicle operation. When the primary battery output is insufficient to start a vehicle, the switch is manually operated to connect the reserve battery in parallel with the primary battery. The reserve battery provides sufficient power for the operator to start the vehicle. When the vehicle has been started, the switch is operated to disconnect the reserve battery from the battery circuit. The primary battery is charged in a conventional manner and the reserve battery is recharged through the unidirectional current circuit. 
     One drawback of prior art manually switched devices is that the reserve battery is engaged and remains engaged even after the vehicle is running if a user does not switch the reserve battery out of the circuit. Consequently, it is difficult for the user to determine whether or not the reserve battery is switched in with the vehicle electrical circuit or switched out. Thus, the originally isolated reserve battery is now subject to the same conditions as the primary battery and may fail along with the primary battery. Accordingly, the reserve battery may not be available to provide the needed starting capacity should the primary battery fail. 
     Another problem associated with such multiple battery systems involves the location of the manual switch. Typically, the manual switch is either located in the engine compartment or in the passenger compartment of the vehicle. Location of the manual switch in the engine compartment is disadvantageous, especially during inclement weather, or with persons not familiar with the engine compartment and its various components. Location of the manual switch in the passenger compartment can require extra wiring between the engine compartment (where the reserve battery is located) and the passenger compartment. This approach may not be practical in vehicles where the integrity of the firewall between the engine compartment and passenger compartment must be maintained. Accordingly, such hardwired systems may not be easy to retrofit into vehicles that have already been manufactured. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, a multiple battery system comprises a primary battery, a reserve battery electrically connectable to the primary battery, and a control unit with a relay switch electrically connected between the primary and reserve batteries. The relay switch is operable to close upon actuation and connect the reserve battery to the primary battery. The control unit also has a receiver electrically connected to the relay switch for receiving a control signal for actuating the relay switch. A transmitter is provided for sending the control signal to the receiver. With this arrangement, actuation of the transmitter causes the control signal to be transmitted to the receiver and actuate the relay switch to thereby connect the reserve battery to the primary battery. 
     According to a further aspect of the invention, a multiple battery system comprises a primary battery, a reserve battery electrically connectable to the primary battery, and a relay switch electrically connected between the primary and reserve batteries. The relay switch is operable between a closed position wherein the reserve battery is connected to the primary battery and an open position wherein the reserve battery is disconnected from the primary battery to prevent discharge of the reserve battery. A manually actuable switch is operably connected to the relay switch for moving the relay switch to the closed position upon actuation of the manually actuable switch. A timer circuit is operably connected to the relay switch for moving the relay switch to the open position after a predetermined time period. 
     According to an even further aspect of the invention, a method for temporarily providing reserve battery power to a vehicle having a primary battery and an electrical system connected to the primary battery is provided. The method comprises providing a reserve battery, providing a relay switch between the primary battery and the reserve battery, providing a manually actuable momentary contact switch in communication with the relay switch, actuating the momentary contact switch for a period of time to thereby connect the reserve battery to the primary battery for the period of time, and releasing the momentary contact switch at the end of the period of time to disconnect the reserve battery from the primary battery. Preferably, the electrical system comprises a starter motor, a starter solenoid and an ignition switch adapted for electrical connection to the primary battery. The ignition switch is actuated during the time period to thereby engage the starter solenoid and starter motor. In this manner, the reserve battery can start a vehicle with a discharged main battery. 
     According to an even further aspect of the invention, a method of conveying a battery back-up system to a customer is provided. The battery backup system has a reserve battery, a control unit connected to the reserve battery and a transmitter for actuating the control unit. The method comprises installing the reserve battery and the control unit in a vehicle to be conveyed, such that the reserve battery is connectable to a main battery of the vehicle through actuation of the control unit, offering the customer an option of purchasing the vehicle battery back-up system, giving the customer the transmitter for actuating the control unit if the customer desires the option, and keeping the transmitter from the customer if the customer refuses the option. In this manner, the reserve battery can only be accessed when the customer buys the option. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The preferred embodiments of the present invention will hereinafter be described in conjunction with the appended drawings, wherein: 
     FIG. 1 is an exploded isometric view of a multiple battery system according to one embodiment of the present invention; 
     FIG. 2 is a diagrammatic illustration of electrical circuitry of the multiple battery system according to an embodiment of the invention; and 
     FIG. 3 is a schematic illustration of a portion of the electrical circuitry of FIG. 2 in greater detail. 
    
    
     Embodiments of the invention will now be described in greater detail with reference to the drawings, wherein like parts throughout the drawing figures are represented by like numerals. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and to FIG. 1 in particular, a multiple battery system  10  includes a primary battery  12 , an auxiliary or reserve battery  14 , and a control unit  16  electrically connected between the primary battery  12  and reserve battery  14 . A portable transmitter  18  is preferably provided for activating and/or deactivating the control unit  16 , as will be described in further detail below. 
     The primary battery  12  is preferably of the lead-acid type and includes a housing  20  with well-known internal components that produce a voltage across a positive terminal post  22  and a negative terminal post  24  that extend out of the housing. For passenger-type vehicles, the primary battery  12  normally produces about twelve volts across the posts and may have a starting power rating from about 300 cold cranking amps (CCA) to 900 CCA or more. The primary battery  12  is connected to electrical circuitry (not shown) of the vehicle through electrical battery cables  30  and  32  that mount to the positive and negative terminal posts  22  and  24 , respectively, for providing electrical power to the vehicle electrical circuitry The electrical circuitry may include a starter motor, a starter solenoid, an ignition switch for engaging the starter motor and solenoid with the primary battery, and various vehicle accessories, such as a radio, lights, windows, door locks, and so on, that are connectable to the primary battery through well known switches or other control means. 
     For top-mounted posts as shown, each cable  30 ,  32  has a terminal connector  34  with bifurcated arms  36 ,  38  that define an opening  40  for receiving the battery post therebetween. A threaded bolt  42  extends through openings in the outer free ends of the bifurcated arms  36 ,  38 . A nut  44  threads onto the bolt  42  and forces the arms  36 ,  38  together for clamping the post between the arms in a well-known manner. For batteries with side posts or other connecting means, it will be understood that different configurations and/or adapters can be provided. 
     The reserve battery  14  is preferably of the sealed lead-acid type and includes a housing  50  with well-known internal components that produce a voltage across a positive terminal tab  52  and a negative terminal tab  54  that extend out of the housing. For passenger-type vehicles, the reserve battery  14  preferably produces about twelve volts across the posts  52  and  54  for starting the vehicle engine when engaged with the vehicle&#39;s electrical circuitry, as will be described in greater detail below. According to one embodiment of the invention, the reserve battery is approximately eight inches wide by six inches high by one inch thick, to give a total reserve battery volume of approximately 48 cubic inches. This relatively small size is ideal for installation in engine compartments of newer vehicles or the like where extra space is limited. It is contemplated however, that a reserve battery with a total volume of approximately 200 cubic inches or less can be used in many vehicles. 
     The reserve battery  14  is preferably mounted to the primary battery  12  through straps  60 , such as nylon ties, that extend horizontally and/or vertically around the batteries  12 ,  14 . Alternatively, the reserve battery  14  may be mounted to the primary battery  12  or vehicle structure with brackets, adhesive, or other mounting means. 
     The control unit  16  includes a housing  70  and electronic circuitry  72  (FIG. 2) located in the housing  70  for switching the reserve battery  14  into and out of the vehicle&#39;s electrical circuitry. A first set of electrical battery cables  74  and  76  extend from the electrical circuitry  72  in the housing  70  to the positive and negative terminal posts  22  and  24 , respectively, of the primary battery  12 . Preferably, the connection end of each cable  74  and  76  is terminated with a ring connector  78  that fits over one of the bolts  42  between the bolt or nut  44  and its associated terminal connector  34  for electrically connecting the control unit  16  to the primary battery  12 . A second set of electrical battery cables  80  and  82  extend from the electrical circuitry  72  in the housing  70  to the positive and negative terminal tabs  52  and  54 , respectively, of the reserve battery  14 . Preferably, the connection end of each cable  80  and  82  is terminated with a ring connector  84  for receiving a threaded bolt  86 . Each threaded bolt  86  extends through one of the ring connectors  84  and a corresponding opening  88  formed in the terminal tabs. A nut  92  is threaded onto each bolt to secure the cables  80  and  82  to the reserve battery  14  and electrically connect the control unit  16  to the reserve battery  14 . 
     Although the battery cables  74 ,  76 ,  80  and  82  are described as being connected to their respective batteries through particular connection means, it will be understood that other connection means can be used for mechanically and electrically connecting the cables. Moreover, although the control unit  16  according to the invention is shown with a separate housing, the control unit may alternatively be incorporated into the housing  50  of the reserve battery  14  or into the housing  20  of the primary battery  12 . 
     The provision of a separate housing  50  for the control unit  16  advantageously permits replacement of the primary battery and/or reserve battery should one or both batteries fail or reach the end of their service life. In addition, the separate control unit  16  and reserve battery  14  can be readily moved to another vehicle without modification to the vehicle, other than mounting the control unit and reserve battery as previously described. 
     The transmitter  18  is preferably a wireless transmitter of the radio frequency type for transmitting a control signal to the control unit  16 . The transmitter  18  includes a housing  100 , electrical circuitry (not shown) in the housing  100  and a manually actuable button or switch  102  extending out of the housing  100  and connected to the circuitry. Preferably, the switch  102  is a momentary push-button switch that is normally biased to an open position so that the transmitter will only transmit a control signal when the switch  102  is pressed or otherwise actuated. It will be understood that other momentary contact switches, such as rotational, toggle or slide switches, can be used. Actuation of the switch  102  causes one or more control signals to be transmitted via radio frequency from the transmitter  18  to the control unit  16  to thereby switch the reserve battery  14  into and/or out of the vehicle circuitry, as will be described in greater detail below. 
     According to a further embodiment of the invention, the transmitter  18  can be in the form of a satellite, pager, cellular or digital phone, or other wireless transmitter that is capable of transmitting a control signal to a suitable receiver  110  (FIG. 2) in the control unit. 
     According to an even further embodiment of the invention, the transmitter can be a hard-wired transmitter, such as a manually actuable switch that is hardwired into a multiplexed circuitry of a vehicle. Actuation of the switch can generate a protocol signal that is transmitted over the circuitry to a receiver  110  (FIG. 2) in the control unit. 
     With reference now to FIG. 2, the circuitry  72  located in the control unit housing  70  according to a preferred embodiment of the invention includes a receiver  110 , such as a radio frequency receiver, and an antenna  112  connected to the receiver for receiving a transmitted signal from the transmitter  18 . The transmitted signal is preferably a coded signal that can be generated in the transmitter through well known hardware and/or software encoding techniques to prevent unauthorized operation of the control unit. 
     A decoder  114 , such as a radio frequency decoder, is connected to the receiver  110  for decoding the coded signal in a well known manner to thereby verify that the received signal is authorized. Once decoded, the signal is sent to a driver circuit  116  for controlling operation of a normally open relay switch  120 . 
     The relay switch  120  is preferably of the conventional solenoid type and includes an electric coil  122  with a positive terminal  123  and a negative terminal  125 . The coil  122  generates a magnetic field for driving a switch arm  124  toward an electrical contact  126  when actuated to thereby connect the positive terminal  52  of the reserve battery  14  to the positive terminal  24  of the primary battery. The negative terminal  54  of the reserve battery is preferably always connected to the negative terminal  22  of the primary battery. A voltage regulator  128  is preferably connected to the receiver  110 , decoder  114 , and output driver circuit  116 . 
     With the relay switch  120  in the normally open position, the positive terminal  52  of the reserve battery  14  is connected to the positive terminal  24  of the primary battery  12 , preferably through a pair of clamping diodes  130 . With the negative terminals of the battery continuously connected and the relay switch  120  in the normally open position, the reserve battery  14  can be charged by the vehicle&#39;s electrical system through the diodes  130 , which in effect bypass the relay switch  120 . When the primary battery  12  discharges to a voltage level lower than the voltage level of the reserve battery  14 , such as when lights or other vehicle accessories are left on without the motor running for an extending period of time, the diodes  130  prevent discharge of the reserve battery  14 . 
     When the relay switch  120  is actuated, the switch arm  124  is moved into contact with the electrical contact  126  (as shown in dashed line) to thereby connect the positive battery cables  74  and  80  and bypass the diodes  130  (due to the voltage drop across the diodes) so that the reserve battery  14  can be accessed for starting the vehicle and/or operating vehicle accessories. When the relay switch  120  is deenergized, the diodes  130  permit the reserve battery to recharge and prevent the reserve battery from further discharge. The use of two diodes in parallel is preferred, since it has been found that a single diode having the necessary power requirement (about three Amperes in the preferred embodiment) is more costly than two diodes sharing the same power requirement. 
     In another embodiment of the invention, the negative battery terminals may also or alternatively be normally disconnected and connected in the same manner as the positive battery terminals through a suitable relay. 
     With reference now to FIG. 3, the driver circuit  116  (shown in dashed line) includes a timer circuit  140  (shown in phantom line) connected to the decoder  114  through a resistor  142 , a diode  144 , and an NPN transistor  146 . An emitter of the transistor  146  is connected to ground, while a collector of the transistor  146  is connected to the negative terminal  125  of the relay coil  122 . A filtering capacitor  150  extends between the positive voltage output of the voltage regulator  128  and ground, while a filtering capacitor  152  extends between the positive voltage input of the regulator  128  and ground. 
     According to an embodiment of the invention, the timer circuit  140  includes a capacitor  160  connected between the base of the transistor  146  and ground, a diode  164  connected to the collector of the transistor  146  through a capacitor  162 , a first resistor  166  connected across the diode  164 , and a second resistor  168  connected between the first resistor  166  and the collector of a PNP transistor  170 . The values of the timer circuit components are preferably selected to create a predetermined time period during which the relay switch  120  remains closed. After the predetermined time period, the relay switch  120  returns to the normally open position to switch the reserve battery  14  out of the vehicle&#39;s electrical circuitry. In this manner, further discharge of the reserve battery is prevented. This feature is especially advantageous over the prior art relay switches that must be manually switched from an open position to a closed position prior to cranking the engine and switched again to the open position after the engine starts, since it is no longer necessary for the user to remember if the relay switch as been returned to the open position. In this manner, the reserve battery  14  is not subject to the same charge and discharge conditions of the primary battery  12 , and therefore will be ready for use when the primary battery is insufficient for starting the motor and/or operating vehicle accessories. 
     By way of example, the capacitor  160  can have a value of approximately 47 μF, the capacitor  162  can have a value of approximately 220 μF, and the resistors  166  and  168  can each have a value of approximately 51 Kζ to create a predetermined time period of approximately 25 seconds during which the relay coil  122  is actuated and deenergized. When the capacitor  162  is selected to have a value of approximately 470 μF, the predetermined time period will be approximately 50 seconds. When the capacitor  162  is selected to have a value of approximately 100 μF, the predetermined time period will be approximately 12 seconds. 
     In use, when the user actuates the switch  102  on the transmitter  18 , a coded control signal is sent to the receiver  112 , which is in turn decoded in the decoder  114  and sent as a positive signal output to the output driver circuit  116 . The signal turns on the NPN transistor  146 , which in turn connects the negative terminal  125  of the relay coil  122  to ground, thereby causing current to flow through the coil and move the switch arm  124  to the closed position. In this manner, the reserve battery  14  is connected in parallel with the primary battery  12 . When the transmitter switch is released, current will continue to flow through the relay coil  122  for a predetermined time period, as established by the timer circuit  116 . In particular, a negative voltage will be present at the base of the PNP transistor  170  to turn on the transistor  170  and drive the current from the positive terminal of the voltage regulator  128  to the base of the NPN transistor  146  and the capacitor  160 . The amount of time that the transistor  146  remains on is directly dependent on the value of the capacitor  162 . With the transistor  146  turned on, the ground connection to the relay coil  122  is maintained for the predetermined time period. In this manner, momentary actuation of the transmitter switch  102  will cause the reserve battery  14  to be connected in parallel with the primary battery  12  for the predetermined time period, which is preferably greater than the momentary actuation time of the transmitter switch  102 , and which is preferably long enough to crank the engine a number of times to start the vehicle. 
     At the end of the predetermined time period, i.e. when the capacitor  162  is sufficiently discharged, the transistor  146  is turned off and the switch arm  124  is returned to the open position, thereby disconnecting the reserve battery from the vehicle&#39;s electrical circuitry. 
     Although a particular timer circuit has been shown and described, it is to be understood that other timer circuits can be used, such as timer circuits using the well-known 555 IC timer, and so on. 
     Although the transmitter  18  is a wireless transmitter according to one preferred embodiment of the invention, it will be understood that the timer circuit  116  can work equally as well with hard-wired transmitters or other switches where it is desirous to automatically disconnect the reserve battery from the vehicle circuitry. 
     According to a further embodiment of the invention, the timer circuitry can be eliminated and the button can be continuously actuated by a user during cranking of the engine. Thus, the user will hold the momentary contact switch while turning the vehicle&#39;s ignition switch to engage the reserve battery with the starter motor and starter solenoid. Once the vehicle&#39;s engine is running, the momentary contact switch can be released to open the relay switch and remove the reserve battery  14  from the vehicle&#39;s electrical circuit, with the exception of the charging connection as previously described. 
     When the timer circuit  116  is left out of the circuitry, release of the transmitter switch  102  causes the transistor  146  to turn off, which in turn causes the switch arm  124  to return to the open position and disconnect the reserve battery from the vehicle&#39;s electrical circuitry. In this manner, the user must keep the transmitter switch  102  actuated while cranking the engine of the vehicle. 
     The term “connect” and its derivatives as used throughout the specification, including the claims, may refer to elements that are directly joined together mechanically and/or electrically, or mechanically and/or electrically joined together through their common connection to something else. 
     The above-described multiple battery system can also be advantageous for particular business entities, such as car dealerships, where customers can be offered the option and security of an emergency start package, including the reserve battery  14  and control unit  16  when purchasing, leasing or otherwise obtaining a vehicle. Prior to obtaining the vehicle, the dealership can install an emergency start package in the vehicle. The customer can then be offered the option of whether to accept or reject the emergency start package. If the customer accepts the emergency start package, the customer pays a predetermined monetary amount and the transmitter  18  is given to the customer for controlling operation of the emergency start package, as previously described. However, if the emergency start package is refused, the transmitter is withheld so that the customer cannot control operation of the reserve battery. Alternatively, the emergency start package may be removed prior to conveying the vehicle to the customer. 
     While the invention has been taught with specific reference to the above-described embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and the scope of the invention. Thus, the described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.