Abstract:
Provided is a mobile charging system, e.g., implemented on a movable cart, that can be easily wheeled or carried to a location of a vehicle. The mobile charging system can be used to not only jumpstart or booster battery, but also to fully charge the battery. In this way, the mobile charging system eliminates the need to transport the vehicle to a service facility.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit of priority of U.S. provisional Patent Application Ser. No. 61/903,779, filed Nov. 13, 2013, entitled “Mobile Charger for 12 VDC Systems”, owned by the assignee of the present application and herein incorporated by reference in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    It is a common problem that automobile batteries discharge to the point where they are unable to start and automobiles engine, and this condition is commonly termed a “dead battery”. In order to charge the battery, the vehicle must be towed to a service facility. Complicating this is that most modem day vehicles require an adequate power source to deactivate the lock safety of the transmission park and neutral positions for the purpose of moving or towing the vehicle. If the battery is dead, not only will the car not start, but the same can no longer be moved or towed without risking serious damage to the automobile. 
       SUMMARY 
       [0003]    Present principles include a mobile charging system, e.g., implemented on a movable cart, that can be easily wheeled or carried to a location of a vehicle. In this way, the mobile charging system eliminates the need to transport the vehicle to a service facility. One of the main functionalities of certain implementations of present principles includes the ability to fully charge a dead or a discharged battery, allowing the vehicle to be started and driven. As a result the mobile charging system provides significant efficiencies for businesses that deal with automotive services such as mechanics shops, dealerships, body shops, auction yards, auto wrecking yards, and any businesses with large parking lots or multi level parking buildings. 
         [0004]    In addition, the mobile charging system according to present principles may in some implementations enjoy a significant advantage over existing battery boosters. In particular, automobile manufacturers recommend charging the battery fully before driving the vehicle. In fact in many cases the same do not recommend driving the vehicle with a discharged battery after a jump start, because it may permanently damage electrical and electronic components. 
         [0005]    Advantages of the invention may include one or more of the following. The mobile charging system can be easily wheeled to and throughout large parking lots and structures and between tight places. The mobile charging system may contain circuitry that protects itself and the vehicle electrical system from reverse polarity that may be potentially damaging and caused by human error. The mobile charging system may include an indicator, e.g., a green light indicator, to alert the operator when the system is interfaced correctly to the vehicle. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  illustrates an exemplary schematic diagram for one implementation of a mobile charging system according to present principles. 
           [0007]      FIGS. 2A-2D  illustrate a circuit which may be employed for an implementation of a mobile charging system according to present principles 
       
    
    
     DETAILED DESCRIPTION 
       [0008]    An exemplary mobile charging system or device  100  is illustrated in  FIG. 1 . The system  100  includes a housing  102  which may be carried or rolled on optional wheel assemblies  112 A and  112 B. In many cases three or four wheel assemblies will be included. 
         [0009]    Coupled to the housing may be a rechargeable source of energy  105 , which is in many cases a plurality of battery cells which may be charged, e.g., from a wall or other outlet source. The mobile charging system further includes an indicator  108  to indicate to the user various aspects, including whether the system is ready to charge a dead or insufficiently charged battery, whether the device has been hooked up properly to the dead or insufficiently charged battery, or the like. 
         [0010]    The mobile charging system  100  further includes at least two types of circuits, including a jump start and boost circuit  104 , and the charging circuit  106 . The jumpstart and boost circuit  104  may be employed to provide an immediate jumpstart to a battery. However, in many cases such jump starts are harmful to the battery, and for this reason the charging circuit  106  may be employed to fully charge a battery in a rapid manner. By fully charging the battery, the deleterious effects of the jumpstart procedure are avoided. 
         [0011]    While clearly present principles are more general than a specific implementation, for purposes of discussion, a specific implementation is illustrated by the circuit diagram shown in  FIG. 2A-2D . In particular, it is noted that variations in values of voltages and currents may be employed in given implementations, and that certain circuit components may be combined in various ways or implemented with different circuitry, including microprocessors. Accordingly, equivalent circuit configurations are also intended to be encompassed by the scope of present principles. 
         [0012]    Table I below provides a list of circuits within  FIG. 1  and exemplary voltage values. 
         [0000]    
       
         
               
             
               
               
             
               
             
           
               
                 TABLE I 
               
               
                   
               
             
             
               
                 C1 = 0.0 volts, common ground. battery 1 negative, 0.0 volts reference 
               
               
                 to all other circuits. 
               
               
                 C2 = 12 V, Battery 1 Positive, series connection to battery 2 negative, 
               
               
                 12 V power source for MCS internal components. 
               
               
                 C3 = 24 V, battery 2 positive, series connection to battery 3 negative. 
               
               
                 C4 = 36 V, battery 3 positive, 36 V power source for MCS charging 
               
               
                 system components. 
               
               
                 C5 = 36 V, Fuse No. 7 power source “+Vin” to component 3a. 
               
               
                 C6 = 36 V, Fuse No. 6 power source “+Vin” to component 3b, 
               
               
                 power source for battery fuel gauge. 
               
               
                 C7 = Charge cycle off = ON = 0.0 V 
               
               
                 C8 = 13.8 to 14.3 VDC, charge cycle output to Fuse No. 4. 
               
               
                 C9 = 13.8 to 14.3 VDC, charge cycle output to Fuse No. 2. 
               
               
                 C10 = 0.0 V, charge output common ground to Fuse No. 3. 
               
               
                 C11 = 0.0 V, charge output common ground to Fuse No. 1. 
               
               
                 C12 = 1.5 V, voltage trim input 
               
               
                 C13 = Output current trim (Itrim) input, Selector switch positions as 
               
               
                 follows 
               
             
          
           
               
                   
                 10 amp = 0.44 V 
               
               
                   
                 20 amp = 0.78 V 
               
               
                   
                 40 amp = 1.46 V 
               
             
          
           
               
                 C14 = 12.0 VDC, Fuse No. 5 output power source for MCS internal 
               
               
                 components. 
               
               
                 C15 = not used. 
               
               
                 C16 = 2.0 to 14.3 VDC, vehicle battery input to MCS internal 
               
               
                 components. 
               
               
                 C17 = Boost cycle control, OFF = 0.0 V, ON = 12.0 VDC. 
               
               
                 C18 = 0.0 V during boost or charge cycle, 12.0 V during reverse polarity 
               
               
                 detection and enable. 
               
               
                 C19 = 13.8 to 14.3 VDC charge cycle output from Fuse No. 2 and 4 to 
               
               
                 Amp Meter. 
               
               
                 C20 = 13.8 to 14.3 VDC charge cycle output from Amp Meter to N.C. 
               
               
                 Contactor. 
               
               
                 C21 = Boost cycle = 12.0 VDC, charge cycle = 0.0 V reverse 
               
               
                 polarity detection = 12.0 V 
               
               
                 C22 = 12.0 V during charging and boost cycle, 0.0 V during reverse 
               
               
                 polarity condition. 
               
               
                 C23 = 12.0 V during reverse polarity condition only, others 0.0 V. 
               
               
                 C24 = 12.0 V during forward polarity condition only, others 0.0 V. 
               
               
                 C25 = 12.0 V during forward polarity condition only, others 0.0 V. 
               
               
                   
               
             
          
         
       
     
         [0013]    Table II provides an exemplary list of components. 
         [0000]    
       
         
               
             
           
               
                 TABLE II 
               
               
                   
               
             
             
               
                 1 = 12 V three bank battery charger (Delta Volt), professional series 
               
               
                 Model No. XXXX 
               
               
                 2a, 2b, 2c = each 12 V Lead Acid Battery, AC Delco No. XXXX or 
               
               
                 equivalent. 
               
               
                 3a, 3b = DC/DC converter by SynQor, Inc. Part number 
               
               
                 NQ40W40QGV30NRC-G 
               
               
                 4 = Fuse Box 
               
               
                 5 = Voltage Trim 
               
               
                 6 = 120 Minutes Timer Switch 
               
               
                 7 = Selector Switch by Electroswitch Inc. part number 7108Z. 
               
               
                 8 = Amp Meter, by Shurite, part number 7207Z 
               
               
                 9 = 36 V Battery Fuel Gauge (Delta Volt Model No. BFG36V) 
               
               
                 10 = Polarity indicator lights and buzzer. 
               
               
                 11 = 2 Minute timer switch. 
               
               
                 12 = Volt Meter, by shurite, part number 7108Z. 
               
               
                 13 = Reverse polarity sense circuit 
               
               
                 14 = Relay 1 
               
               
                 15 = Relay 2 
               
               
                 16 = Contactor N.O. 
               
               
                 17 = Contactor N. C. 
               
               
                 18 = Positive Output to vehicle 
               
               
                 19 = Negative Output to vehicle 
               
               
                 20 = Forward Polarity Sense Circuit 
               
               
                 21 = Relay 3 
               
               
                   
               
             
          
         
       
     
         [0014]    a particular implementation, a greater or lesser number of circuits and components may be employed, and the type, structure, configuration, and values of components within may vary. 
         [0015]    Referring to  FIGS. 2A-2D , a mobile charging system may include apparatus to contain stored energy, e.g., in a chemical form, such as a series of batteries  2   a,    2   b,  and  2   c  shown in the figure. In the figure, three 12 VDC batteries are connected in series to form a 36 VDC battery pack. 
         [0016]    The batteries may be lead acid, absorption glass mat (AGM), lithium ion, or the equivalent, in their particular electrical specifications can vary. In one implementation, the mobile charging system may employ three deep cycle lead acid batteries with ampere hour ratings of 95 ampere-hours. 
         [0017]    In order to ensure that the batteries are fully and equally charged, the mobile charging system may use a battery charger  1  with three independent and isolated charging banks that is connected to a 120 VAC source during the charging phase when the mobile charging system is not being used. When the 36 VDC battery pack is fully charged, charger  1  may be configured to automatically shut off and a green light may illuminate on battery fuel gauge  9  when the test switch  20  is pressed, indicating that the mobile charging system is ready to be used. Then the same can be disconnected from the 120 VAC source and rolled or carried to a location of a vehicle that has a dead or a discharged battery. The mobile charging system may be connected to the electrical system of that vehicle via battery cables  18  and  19  and clamped onto each terminal of a dead battery. 
         [0018]    When a technician is physically connecting the mobile charging system to a vehicle with a discharged battery, two possible operational conditions may ensue. 
         [0019]    Condition 1: the mobile charging system may be connected correctly when the positive cable  18  is connected to the vehicle battery positive post and the negative cable  19  connected to the vehicle battery negative post. This condition is referred to as a forward polarity connection. 
         [0020]    Condition 2: on occasion, due to technician error, the mobile charging station may be connected incorrectly, e.g., when the positive cable  18  is connected to the vehicle battery negative post and the negative cable  19  is connected to the vehicle battery positive post. This condition referred to as a reverse polarity connection. 
         [0021]    Operational descriptions of these two conditions are now described. 
       Condition 1: 
       [0022]    When the mobile charging system is correctly connected to a vehicle with a discharged battery, the green warning light  10  will illuminate, indicating proper connection. Component  18  with circuit C 16  will have positive voltage and component  19  with circuit C 1  will have negative voltage. C 16  and C 1  circuits are monitored by component  20  (forward polarity sense circuit), and this component includes three resistors with ratio values biased for low voltage detection. When circuit C 16  voltage value is 2 or more volts more positive than circuit C 1 , the operational amplifier L2722 will conduct and switch its output circuit C 25  to 12V positive to energize component  21  (Relay 3). When relay 3 N.O. (normally open) contacts are closed, 12V power from circuit C 14  will connect with circuit C 24  to turn green light on in component  10 , indicating the correct and safe hook-up of the mobile charging system. 
         [0023]    Properly hooked up, the mobile charging system in certain implementations provides two independent functions as follows. 
       Function 1: Jump-Start and Boost 
       [0024]    This function is commonly used in the automotive industry. The mobile charging system contains this feature because of convenience and necessity specifically in automotive repair facilities. The jump-start and boost functions can be activated with, e.g., a two-minute timer switch  11 . The switch dial can be rotated manually clockwise and set up to a maximum time of 2 minutes (and thus other times are also possible). Once the switch is set to the desired time, then the dial may automatically rotate counter-clockwise and shuts off when it reaches 0. 
         [0025]    When switch  11  is set, the internal electrical contacts are closed, and when switch  11  shuts off, the contacts are open. In this way, the mobile charging system allows a maximum of a 2 minute window for each intervals of boost function. 
         [0026]    Component  11  receives 12V power from component  14  Relay N.C. (normally closed) contacts, from circuit C 14  through circuit C 22 . When component  11  internal contacts are closed, 12V power is switched to circuit C 17 , energizing contactor  16  (Normally Open). Closing internal contacts results in a high current connection between circuit C 2  and C 16  that provides a direct connection between battery  2   a  and positive circuit C 2  and vehicle battery positive post  18 . This allows for the high current transfer needed to jump start a vehicle. 
         [0027]    During the boost function, component  15  is also energized, closing internal contacts and transferring 12V power from C 14  to C 21 , for the purpose of energizing contactor  17  N.C.to break open internal contacts that will disconnect circuit C 20  from C 16 . Component  17  acts as an isolator between the boost function and charging function of the MCS. It is also energized during reverse polarity conditions. 
       Function 2: Charging 
       [0028]    Automotive battery boosters are very common in the industry and the same are used only to jump start vehicles, but they lack the ability to charge the vehicle battery. The mobile charging system according to present principles allows an on-board charging system, along with the boost capability described above. This feature is enabled only when the mobile charging system is connected correctly to a vehicle battery. The charging function utilizes the full 36 VDC power of the battery pack  2   a,    2   b  and  2   c.  The output from battery  2   c  positive terminal goes through circuit C 4  to fuse number  6  and  7 . The 36V power output from Fuse No.  6  and  7  flows through circuit C 5  and C 6  to provide positive power input to component  3   a  and  3   b.    
       Description of Components  3   a  and  3   b      
       [0029]    Components  3 A and  3 B are DC/DC converters that are used to regulate output voltage and current. Each converter is capable of a maximum output current of 30 amps. The mobile charging system circuitry may in some cases limit each converter maximum output to 20 amps to prevent overheating. 
         [0030]    In one implementation, the mobile charging system can charge a vehicle battery at a maximum rate of 40 amps. Therefore, component  3   a  and  3   b  may be connected in a parallel configuration and may share their inputs and outputs, resulting in a combined output maximum current rate of 40 amps, 20 amps from converter  3   a  and 20 amps from converter  3   b.  Both converters&#39; output voltages may be regulated between 13.8 to 14.3 VDC. 
       Charging Function Controls 
       [0031]    The mobile charging system may contain in one implementation five primary components used to regulate the output voltage and current to properly recharge a discharged vehicle battery, and these are components  3   a,    3   b,    5 ,  6  and  7 . Components  3   a  and  3   b  are as noted above, e.g., switching regulator DC to DC converters. In one specific implementation the same are identical in model and part numbers, with the same electrical characteristics and specifications. Because of their configuration, they share the same inputs and outputs and are connected (wired) in parallel; therefore, the shared output current will max out at 40 amperes. 
       Turning ON Charge Feature 
       [0032]    The charge cycle may be initiated by activating component  6  which is a 120 minute rotary timer that contains internal contacts. When the desired time is set, the contacts will close allowing circuit C 1  to connect with C 7 , applying 0 volts to pin # 2  for each DC/DC Converters  3   a  and  3   b  allowing the same to turn on or otherwise be enabled. 
         [0033]    When components  3   a  and  3   b  are enabled, then current may flow through their pins numbered  1  for a positive VIN and Pin  2  for a negative VIN. 
       Power Regulation 
       [0034]    Component  3   a  and  3   b  power regulation is a voltage and current calibration and is accomplished as follows. 
       Voltage Regulation 
       [0035]    Using component  5  voltage trim (DC/DC converter input Pin No. 6 ) to adjust output voltage between a minimum 13.8 volts to a maximum of 14.3 volts. This value is chosen as an ideal voltage range to recharge a battery. This component consists of one resistor and one potentiometer. It uses circuit C 1  0.0 volts and circuit C 12  that connects to Pin No.  6  of component  3   a  and  3   b.    
       Current Regulation 
       [0036]    Using component  7  selector switch, DC/DC converter input Pin No. 5  may be employed to set the desired current output of component  3   a  and  3   b.  This switch has three positions that represent the charging rate of the mobile charging system. These include a slow charge rate, e.g., 10 amperes, a medium charge rate, e.g., 20 amperes, and a fast charge rate of, e.g., 40 amperes. The slower the charge rate, the longer the time required to recharge a battery. The faster the charge rate, the shorter the time to recharge. It will be understood that other implementations may include more or fewer positions and selectable charging rates. 
         [0037]    Component  7  is connected to C 1  0.0 volts and includes three resistors with pre calculated values that create a desired output voltage drop to circuit C  13  that is connected to Pin  5  (Itrim) of component  3   a  and  3   b.    
       Output 
       [0038]    The regulated voltage and current of component  3   a  and  3   b  is output using pin  4  for negative voltage through circuit C 11  to fuse  1  and circuit ClO to fuse  3 . 
         [0039]    Output pin  8  is for positive voltage through circuit C 9  to fuse  2  and circuit C 8  to fuse  4 . 
         [0040]    These fuses are used to protect the output drivers of components  3   a  and  3   b  in the event of a reverse polarity condition due to technician error. 
         [0041]    The negative output of fuse  1  and  3  is combined and connected to negative common circuit C 1  that is equal to 0.0 volt. The positive output of fuse  2  and  4  is also combined and connected to circuit C 19  that feeds component 8 Amp Meter for current measurement and display. Current flows through the meter to circuit C 20  and then to component  17  contactor N.C. When component  17  is de-energized, current flows through it from circuit C 20  to circuit C 16  and then to component  18  to the vehicle battery. 
         [0042]    Component  17  acts as an isolator between charging and boost cycles. As such, the same is de-energized during a charging cycle of the mobile charging system, and energized during jump start or “boost” function and during reverse polarity detection condition. During the charging cycle of the mobile charging system, the voltage output will vary between 13.8 to 14.3 volts, depending on the condition of the vehicle discharged battery. 
       Condition 2: Reverse Polarity Connection 
       [0043]    This condition occurs when a technician connects the mobile charging system cables components  18  and  19  in reverse order to the vehicle battery. This condition can create an electrical short or over load that causes damage to internal components of the mobile charging system. The amount of damage is relatively proportional to the condition of the vehicle battery and the amount of power it can deliver. The mobile charging system on board batteries also have a considerable amount of power and are capable of causing damage to vehicle electrical systems in the event that the boost cycle is energized. 
         [0044]    During the reverse polarity condition, circuit C 1  becomes positive in its polarity and circuit C 16  becomes negative. 
         [0045]    This reverse source of voltage originates from the vehicle battery. Component  13  is a reverse polarity sense circuit that uses circuit C 1  and C 16  for input signals. It also uses circuit C 14  from fuse No. 5  for a 12 voltpower source that originates from battery  2   a.    
         [0046]    The reverse polarity sense circuit  13  includes in one implementation three resistors with ratio values biased for low voltage, e.g., approximately negative 2 volts or greater at circuit C 16 . An operational amplifier L2722 may be configured as a voltage comparator. This component will output positive 12 volts through circuit C 23  when its negative input is more negative than its positive input with approximately 2 volts or greater. This only occurs in reverse polarity connection to vehicle battery. 
         [0047]    The reverse polarity sense circuit is designed and configured in this manner to have the ability to detect reverse polarity condition even if the vehicle battery is discharged from 12 volts to as low as 2 volts. 
         [0048]    Once the reverse polarity sense circuit detects reverse polarity, it will conduct current and switch output circuit C 23  to positive 12 volts energizing component  14  relay  1  that will result in the enabling of the reverse polarity protection feature of the mobile charging system, and the disabling of the boost cycle power source to component  11 . 
       Components and Circuits States During Reverse Polarity Enable 
     Component  14   
       [0049]    When component  14  is energized, normally open relay  1  contacts will close, connecting circuit C 14  (+12V source) with circuit C 18  that feeds component  10  (polarity indicator) red warning light and buzzer in the instrument panel to warn the technician of the incorrect connection of the mobile charging system to the vehicle battery. Circuit C 18  also feeds component  15  (Normally Closed) relay  2  contacts that connect to circuit C 21 . 
         [0050]    Component  15  may be de-energized during a reverse polarity condition and may act as an interrupt during boost cycle. When circuit C 21  has +12 Volts it will energize component  17  (Normally Closed) Contactor resulting in a circuit break between circuit C 16  vehicle battery and circuit C 20  that controls the mobile charging system output, thus providing protection to amp meter  8  and fuse box  4  and other internal mobile charging system components. In addition, it also prevents the mobile charging system boost and charge functions from causing electrical damage to the weak or discharged vehicle battery and electrical system by isolating the same from the mobile charging system internal power source. 
         [0051]    It will be appreciated that elements or components shown with any embodiment herein are merely exemplary for the specific embodiment and may be used on or in combination with other embodiments disclosed herein. 
         [0052]    While the invention is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the scope of the appended claims.