Charging batteries of electric vehicles

• US 5,598,084 A
• Filed: 06/07/1995
• Issued: 01/28/1997
• Est. Priority Date: 04/19/1993
• Status: Expired due to Fees

• Current Assignee: Arlie L. Keith
• Original Assignee: Arlie L. Keith
• Inventors: Keith, Arlie L.
• Primary Examiner(s): Hecker, Stuart N.
• Assistant Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US08/473,849
• Time in Patent Office: 601 Days
• Field of Search: 320/2, 320/48, 320/10, 320/54, 439/34, 439/246-248, 439/378-381, 180/65.1, 180/274, 180/275, 180/279, 307/10.1
• US Class Current: 320/109
• CPC Class Codes: B60L 1/08 Methods and devices for control or regulation
• CPC Class Codes: B60L 1/12 Methods and devices for control or regulation
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 53/16 Connectors, e.g. plugs or sockets, specially adapted for charging electric vehicles
• CPC Class Codes: B60L 53/305 Communication interfaces
• CPC Class Codes: B60L 53/64 Optimising energy costs, e.g. responding to electricity rates
• CPC Class Codes: B60L 53/65 involving identification of vehicles or their battery types
• CPC Class Codes: B60L 53/665 Methods related to measuring, billing or payment
• CPC Class Codes: G07F 15/005 dispensed for the electrical charging of vehicles electrical charging as such, B60L50/00
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 2220/20 Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/0045 concerning the insertion or the connection of the batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 : Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing
• CPC Class Codes: Y10S 320/12 : Precharging analysis, e.g. determining presence of battery
• CPC Class Codes: Y10S 320/13 : Fault detection
• CPC Class Codes: Y10S 320/19 : Charger status, e.g. voltmeter
• CPC Class Codes: Y10S 320/28 : Regulating transformer, e.g. high leakage, ferro-resonant

Abstract

An electric vehicle having a computer for controlling the charging of its battery includes a probe adapted to connect with a receptacle on a charging station which has a computer for controlling the charging voltage provided over the connection to the vehicle. In response to the vehicle announcing its presence with a broadcast signal, the charge station receptacle may be raised until it senses a laser signal presented by the vehicle to indicate alignment of the receptacle with the vehicle probe. The vehicle and station communicate over a current loop to establish battery type and voltage, method of payment and credit card number, as well as the cost basis for the power. When communications are complete, the system switches over to utilize the same connections for the charging current. The computers include stop modes which they rest in, and to which they return if performance of vehicle and station diagnostics (respectively) indicate inoperability or if other faults occur. The vehicle charges the battery in a short program triggered by a AC voltage zero crossing interrupt, the background program of which determines when charging should cease because the battery is full, a switch has been operated, or because excessive voltage or current has been sensed. The charged voltage is adjusted by motor driven autotransfer in response to a computer servoprogram. Many probe, receptacle and operational details assure safe, easy, automated operation.

Claims

1. A system for charging the batteries of electric vehicles, comprising:

a charge station to which a vehicle may be presented to receive an electric charge, said charge station including a station computer and a source of charging voltage;

a vehicle charging system including a vehicle computer and charge control circuits disposed on an electric vehicle that has a battery for supplying motive energy to the vehicle, said vehicle computer including manifestations identifying battery parameters including at least the nominal charging voltage thereof;

apparatus for establishing a connection between said charge station and said charging system employing a medium suitable for transferring electric power therebetween; and

selection means connecting both of said computers to said connection medium for transfer of signals therebetween, said vehicle computer sending signals to said station computer indicative of said battery manifestations, and said computers thereafter exchanging ready signals indicating that each is ready to commence battery charging, said computers responding to said ready signals to cause said selection means to disconnect said computers from said connection apparatus and to connect said source of charging voltage and said charge control circuits to said connection medium.

2. A system according to claim 1 wherein:

said station computer sends one of said ready signals over said connection medium to said vehicle computer and said vehicle computer thereafter sends one of said ready signals to said station computer.

3. A system according to claim 1 wherein:

said vehicle computer provides a start time signal indicative of time of day when charging of the battery should begin; and

said station computer sends one of said ready signals over said connection medium to said vehicle computer and in response thereto said vehicle computer thereafter sends one of said ready signals to said station computer after said start time signal indicates that charging of said battery should begin.

4. A system according to claim 1 wherein:

said selection means connects said charge control circuits to said connection medium a few seconds before said selection means connects said source of charging voltage to said connection medium.

5. A system according to claim 4 wherein said station comprises:

selectively actuatable main power means for connecting said source of charging voltage to electric power lines;

means for providing a current signal indicative of the magnitude of current flow between said source of charging voltage and said connection medium; and

wherein said station computer actuates said main power means to connect said source of charging voltage to the electric power lines after said selection means connects said source of charging voltage to said connection medium only if said current signal indicates that said current flow is negligible.

6. A system according to claim 5 wherein:

after said main power means is actuated, said station computer provides a bad connection signal indicative of a bad connection if said current signal indicates that said current flow is less than a threshold magnitude.

7. A system according to claim 6 wherein:

in response to said bad connection signal, said station computer disactuates said main power means to thereby disconnect said source of charging voltage from the electric power lines.

8. A system according to claim 5 wherein:

said station comprises selectively actuatable main power means for connecting said source of charging voltage to electric power lines;

wherein said station computer actuates said main power means to connect said source of charging voltage to the electric power lines after said selection means connects said source of charging voltage to said connection medium;

said station includes means for providing a voltage signal indicative of the magnitude of charging voltage provided to said connection medium by said source of charging voltage; and

said station computer disactuates said main power means to disconnect said source of charging voltage from the electric power lines in response to said voltage signal indicating a voltage in excess of a threshold magnitude.

9. A system according to claim 5 wherein:

said station comprises selectively actuatable main power means for connecting said source of charging voltage to electric power lines;

said station computer actuates said main power means to connect said source of charging voltage to the electric power lines after said selection means connects said source of charging voltage to said connection medium;

said station includes means for providing a current signal indicative of the magnitude of charging current flowing between said connection medium and said source of charging voltage; and

said station computer disactuates said main power means to disconnect said source of charging voltage from the electric power lines in response to said current signal indicating a current in excess of a threshold magnitude.

10. A system according to claim 1 wherein:

said vehicle charge system includes means for providing a charge voltage signal indicative of the magnitude of voltage provided to the vehicle by said source of charging voltage; and

said vehicle computer causes said selection means to disconnect said battery charge circuitry from said connection medium in response to said charge voltage signal indicating a voltage outside a predetermined set of voltage limits.

11. A system according to claim 10 wherein:

said vehicle computer selectively provides an operator induced override signal in response to a corresponding operator input thereto; and

said vehicle computer causes, only in response to the absence of said override signal, said selection means to disconnect said battery charge circuitry from said connection medium in response to said charge voltage signal indicating a voltage outside a predetermined set of voltage limits, and does not cause such disconnect in the presence of said override signal.

12. A system according to claim 1 wherein said conductive medium comprises electrically conductive contacts.

13. A system according to claim 12 wherein said medium includes a probe and a receptacle disposed so that said probe makes electrical contact with said receptacle when the vehicle is presented to the station for a charge.

14. A system according to claim 13 wherein said probe is disposed on said vehicle and said station includes said receptacle.

15. A system according to claim 12 wherein:

said conductive medium comprises a pair of station contacts on said station connecting with a pair of vehicle contacts on said vehicle charge system to provide a feed circuit and a return circuit; and

said selection means comprises a pair of station switches connected to said station contacts and a pair of vehicle switches connected to said vehicle contacts.

16. A system according to claim 15 wherein said switches comprise relays.

17. A system according to claim 15 including:

a current generator connected between said station computer and one of said station switches in said feed circuit and operable to generate current in response to signals from said station computer;

a current receiver connected between one of said vehicle switches in said feed circuit and said vehicle computer, and operable to provide signals to said vehicle computer in response to current received thereat;

a current switch connected to said vehicle computer and connected between said current receiver and one of said vehicle switches in said return circuit for selectively passing current in response to signals from said vehicle computer; and

a current receiver connected between one of said station switches in said return circuit and said station computer for providing signals to said station computer in response to current received thereby.

18. A system according to claim 1 wherein:

said station includes a current generator for providing electric current signals to said selection means in response to signals from said station computer;

said vehicle includes a vehicle current receiver for providing signals to said vehicle computer in response to current conducted thereto through said selection means and said connection medium;

said vehicle includes a current switch connected in series with said vehicle current receiver for selectively conducting current therefrom to said selection means, or not, in response to signals from said vehicle computer; and

said station includes a station current receiver for providing signals to said station computer in response to current conducted thereto through said selection means and said connection medium.

19. A system according to claim 18 wherein said station includes monitor means for monitoring current in said connection and for providing a bad connection signal if current interruptions do not occur at regular short intervals.

20. A system according to claim 19 including a display for indicating that said connection is faulty in response to said bad connection signal.

21. A system according to claim 19 wherein:

said station computer has a stop mode in which the only function it can perform is to respond to an external interrupt to leave said stop mode and resume operation; and

said station computer is placed in said stop mode by said bad connection signal.

22. A system according to claim 19 wherein said monitoring means comprises a retriggerable monostable multivibrator.

23. A system according to claim 1 wherein said vehicle computer includes manifestations identifying a credit card with which payment may be made for a charge;

and

wherein said vehicle computer sends signals to said station computer indicative of said credit card manifestations before sending one of said ready signals.

24. A system according to claim 1 wherein said vehicle computer selectively provides an operator induced cash signal indicative of an operator'"'"'s intent to pay for a charge by cash;

and

said vehicle computer sends said cash signal to said station computer before sending one of said ready signals.

25. A system according to claim 1 wherein said vehicle computer includes manifestations identifying a credit card with which payment may be made for a charge;

said vehicle computer selectively provides an operator induced cash signal indicative of an operator'"'"'s intent to pay for a charge by cash; and

before sending one of said ready signals, said vehicle computer sends signals to said station computer indicative of said credit card manifestations in the absence of said cash signal or, alternatively, said vehicle computer sends said cash signal to said station computer before sending one of said ready signals.

26. A system for charging the batteries of electric vehicles, comprising:

a charge station to which a vehicle may be presented to receive an electric charge, said charge station including a source of charging voltage and a station computer for controlling the magnitude of voltage provided by said source;

a vehicle charging system disposed on an electric vehicle that has a battery for supplying motive energy to the vehicle, including charge control circuits and a vehicle computer for controlling with said charge control circuits the level and extent of charge provided to said battery; and

apparatus for establishing a connection between said charge station and said charging system when said vehicle is presented to said station to receive a charge;

said station computer when in operation, controlling the provision of charging voltage to said connection, said vehicle computer, when in operation, controlling the operation of said charge control circuits in applying electric power from said connection to said battery.

27. A system according to claim 26 wherein:

said computers each have a stop mode in which the computer consumes minimal power and in which the only function it can perform is to respond to an external interrupt to leave said stop mode and resume operation;

said vehicle charge system includes means for broadcasting an arrival signal to announce its arrival at said station;

said station includes means for responding to said arrival signal by providing a station external interrupt to said station computer to cause it to assume normal operation; and

said vehicle includes means for providing a vehicle external interrupt to said vehicle computer to cause it to assume operation and commence precharge procedures.

28. A system according to claim 27 wherein said vehicle external interrupt is initiated by the vehicle engine being turned on.

29. A system according to claim 27 wherein said station computer includes a program of station diagnostics which is performed immediately in response to said station external interrupt.

30. A system according to claim 29 wherein said station includes a display having indicia thereon indicative of the fact that said station is not available to have vehicles charged thereat, said display being operable by a power source independent of said station computer in response to a signal provided thereto by said station computer;

and

said station computer provides said signal to operate said display in response to performance of said program of station diagnostics indicating that said station is incapable of properly charging vehicle batteries.

31. A system according to claim 29 including a display for indicating that said station is open to charge vehicle batteries;

and

said station computer provides signals to operate said display in response to performance of said program of station diagnostics indicating that said station is capable of properly charging vehicle batteries.

32. A system according to claim 27 wherein said vehicle computer includes a program of vehicle charging system diagnostics which is performed immediately in response to said vehicle external interrupt.

33. A system according to claim 32 wherein said vehicle includes a display for indicating that said vehicle charging system is inoperable;

and

said vehicle computer provides signals to operate said display in response to performance of said program of vehicle charging system diagnostics indicating that said vehicle charging system is incapable of properly charging the vehicle'"'"'s battery.

34. A system according to claim 32 wherein said vehicle includes a display for indicating that said vehicle charging system is operable;

and

said vehicle computer provides signals to operate said display in response to performance of said program of vehicle charging system diagnostics indicating that said vehicle charging system is capable of properly charging the vehicle'"'"'s battery.

35. A system according to claim 26 wherein said station comprises:

selectively actuatable main power means for connecting said source of charging voltage to electric power lines;

means for providing a current signal indicative of the magnitude of current flow between said source of charging voltage and said connection; and

wherein said station computer actuates said main power means to connect said source of charging voltage to the electric power lines only if said current signal indicates that said current flow is negligible.

36. A system according to claim 35 wherein:

after said main power means is actuated, said station computer provides a bad connection signal indicative of a bad connection if said current signal indicates that said current flow is less than a threshold magnitude.

37. A system according to claim 36 wherein:

in response to said bad connection signal, said station computer disactuates said main power means to thereby disconnect said source of charging voltage from the electric power lines.

38. A system according to claim 26 wherein:

said station comprises selectively actuatable main power means for connecting said source of charging voltage to electric power lines;

said station computer actuates said main power means to connect said source of charging voltage to the electric power lines;

said station includes means for providing a voltage signal indicative of the magnitude of charging voltage provided to said connection by said source of charging voltage; and

said station computer disactuates said main power means to disconnect said source of charging voltage from the electric power lines in response to said voltage signal indicating a voltage in excess of a threshold magnitude.

39. A system according to claim 26 wherein:

said station comprises selectively actuatable main power means for connecting said source of charging voltage to electric power lines;

said station computer actuates said main power means to connect said source of charging voltage to the electric power lines;

said station includes means for providing a current signal indicative of the magnitude of charging current flowing between said connection and said source of charging voltage; and

said station computer disactuates said main power means to disconnect said source of charging voltage from the electric power lines in response to said current signal indicating a current in excess of a threshold magnitude.

40. A system according to claim 26 wherein:

said vehicle charge system includes means for providing a charge voltage signal indicative of the magnitude of voltage provided to the vehicle by said source of charging voltage; and

said vehicle computer disconnects said battery charge circuitry from said connection in response to said charge voltage signal indicating a voltage outside a predetermined set of voltage limits.

41. A system according to claim 40 wherein:

said vehicle computer selectively provides an operator induced override signal in response to a corresponding operator input thereto; and

said vehicle computer disconnects, only in response to the absence of said override signal, said battery charge circuitry from said connection in response to said charge voltage signal indicating a voltage outside a predetermined set of voltage limits, and does not disconnect in the presence of said override signal.

42. A system according to claim 26 wherein said medium includes a probe and a receptacle disposed so that said probe makes electrical contact with said receptacle when the vehicle is presented to the station for a charge.

43. A system according to claim 42 wherein said probe is disposed on said vehicle and said station includes said receptacle.

44. A system according to claim 26 wherein said vehicle computer includes manifestations identifying a credit card with which payment may be made for a charge;

and

wherein said vehicle computer sends signals to said station computer indicative of said credit card manifestations.

45. A system according to claim 26 wherein said vehicle computer selectively provides an operator induced cash signal indicative of an operator'"'"'s intent to pay for a charge by cash;

and

said vehicle computer sends said cash signal to said station computer.

46. A system according to claim 26 wherein said vehicle computer includes manifestations identifying a credit card with which payment may be made for a charge;

said vehicle computer selectively provides an operator induced cash signal indicative of an operator'"'"'s intent to pay for a charge by cash; and

said vehicle computer sends signals to said station computer indicative of said credit card manifestations in the absence of said cash signal or, alternatively, said vehicle computer sends said cash signal to said station computer.

47. A system according to claim 26 wherein:

said vehicle charge system includes means for broadcasting an arrival signal to announce its arrival at said station;

said apparatus for establishing a connection includes a probe on said vehicle and a receptacle having a selectively operable closure on said station; and

said station computer responds to said arrival signal to cause said closure to open.

48. A system according to claim 47 including:

means providing a signal to said station computer to indicate that said probe is in connection with said receptacle;

said station computer causing said closure to partially close in response to said signal.

49. A system according to claim 48 including a roller on said closure to permit said probe to be extracted from said receptacle with said closure partially closed against said probe.

50. A system according to claim 26 wherein:

said source of charging voltage includes a motorized autotransformer for connection to main power lines and adjustable in response to said computer to control the charge voltage provided to said connection.

51. A system according to claim 50 including:

a voltage sensor connected to said autotransformer for providing a voltage signal indicative of the actual magnitude of voltage provided by said autotransformer to said connection;

said computer providing a voltage target magnitude and comparing the actual magnitude indicated by said voltage signal to said target magnitude, and in the event that said actual magnitude exceeds said target magnitude by at least a first amount, setting the motor direction to reduce said actual magnitude but in the event that said target magnitude exceeds said actual magnitude by at least a second amount, setting the motor direction to increase said actual magnitude, and in the event that said actual magnitude differs from said target magnitude by at least a third amount greater than said first or second amount, providing power to the motor to cause said motor to provide an increment of adjustment to said voltage.

52. A system for charging the batteries of electric vehicles, comprising:

a charge station to which a vehicle may be presented to receive an electric charge, said charge station including a source of charging voltage having a motorized autotransformer connected to main power lines and adjustable to control the voltage provided by said source;

a vehicle charging system including charge control circuits disposed on an electric vehicle that has a battery for supplying motive energy to the vehicle; and

apparatus for establishing a connection between said charge station and said charging system when said vehicle is presented to said station to receive a charge.

53. A system according to claim 52 including:

a voltage sensor connected to said autotransformer for providing a voltage signal indicative of the actual magnitude of voltage provided by said autotransformer to said connection;

means for providing a voltage target magnitude and comparing the actual magnitude indicated by said voltage signal to said target magnitude, and in the event that said actual magnitude exceeds said target magnitude by at least a first amount, setting the motor direction to reduce said actual magnitude but in the event that said target magnitude exceeds said actual magnitude by at least a second amount, setting the motor direction to increase said actual magnitude, and in the event that said actual magnitude differs from said target magnitude by at least a third amount greater than said first or second amount, operating the motor to cause said motor to adjust said voltage.

54. A system for charging the batteries of electric vehicles, comprising:

a charge station to which a vehicle may be presented to receive an electric charge, said charge station including a source of charging voltage;

a vehicle charging system disposed on an electric vehicle that has a battery for supplying motive energy to the vehicle, including charge control circuits and a vehicle computer for controlling said charge control circuits; and

apparatus for establishing a connection between said charge station and said charging system when said vehicle is presented to said station to receive a charge;

said vehicle computer, when in operation, controlling the operation of said charge control circuits in applying electric power from said connection to said battery;

said computer has a stop mode in which the computer consumes minimal power and in which the only function it can perform is to respond to an external interrupt to leave said stop mode and resume operation;

said vehicle includes means for providing an external interrupt in response to the vehicle engine being turned on;

wherein said vehicle computer includes a program of vehicle charging system diagnostics which is performed immediately in response to said vehicle external interrupt;

said vehicle computer resuming said stop mode in response to performance of said program of vehicle charging system diagnostics indicating that said vehicle charging system is incapable of properly charging the vehicle'"'"'s battery.

55. A system according to claim 54 wherein said vehicle includes a display for indicating that said vehicle charging system is inoperable;

and

said vehicle computer provides signals to operate said display in response to performance of said program of vehicle charging system diagnostics indicating that said vehicle charging system is incapable of properly charging the vehicle'"'"'s battery.

56. A system according to claim 54 wherein said computer continuously performs said program of vehicle charging system diagnostics until either performance of said program indicates that said vehicle is incapable of properly charging the vehicle'"'"'s battery or said computer receives a signal indicating that the battery is to be charged.

57. A system according to claim 56 wherein said vehicle includes a display for indicating that said vehicle charging system is operable;

and

said vehicle computer provides signals to operate said display in response to performance of said program of vehicle charging system diagnostics indicating that said vehicle charging system is capable of properly charging the vehicle'"'"'s battery.

58. Apparatus for charging the battery of an electric vehicle, comprising:

a charge control circuit for connection between a source of alternating charging voltage and a battery on the vehicle to be charged, said charge control circuit including a switch selectively operable in response to a control signal applied thereto for connecting said source to said battery, said charge control circuit including a zero crossing detector to provide a zero crossing signal each time said alternating voltage goes to zero;

a selectively operable switch for connecting said charge control circuit to said source;

a voltage sensor connected to said battery for providing a voltage signal indicative of the magnitude of battery voltage; and

a computer connected for response to said voltage signal and having an external interrupt connected for response to said zero crossing signal, and including a first program initiated in response to said interrupt to respond to said voltage signal by selectively providing said control signal to said switch to thereby provide some portion of said charging voltage to said battery in dependence upon said battery voltage.

59. Apparatus according to claim 58 including:

means for connecting said charge control circuit;

and wherein said computer includes a second program which functions as a background program for said first program, said interrupt causing a branch from said second program to the entrance point of said first program, completion of said first program causing return to the point of interruption in said second program, said second program including determination of whether or not charging of the battery should cease, and for causing said switch to disconnect said charge control circuit from said source in response to determination that charging should cease.

60. Apparatus according to claim 59 including a battery charge status indicator for providing a charge signal indicating the degree of charge of the battery;

and wherein said computer determines that charging should cease in response to said charge signal.

61. Apparatus according to claim 59 including an operator controlled switch for selectively indicating that charging is to occur or not, and said computer determines that charging should cease in response to said switch indicating that charging is not to occur.

62. Apparatus according to claim 59 including:

means for measuring the voltage of said source and providing a voltage signal indicative thereof; and

said second program determining that charging of said battery should cease in response to said voltage signal indicating that the voltage of said source is outside predetermined limits.

63. Apparatus according to claim 59 including:

means for measuring the charge current provided to the battery and providing a current signal indicative thereof; and

said second program determining that charging of said battery should cease in response to said current signal indicating that the current provided to the battery is outside predetermined limits.

64. Apparatus according to claim 59 wherein said computer provides operator induced manifestations of whether and when cabin heat is required in the vehicle;

and

said second program provides signals to control vehicle cabin heat in response to said manifestations.

65. Apparatus according to claim 58 including means to measure the temperature of the battery and to provide a temperature signal indicative thereof;

and wherein

said first program does not provide said control signal in the event of said temperature signal indicating that the temperature of the battery is in excess of a predetermined limit.

66. Apparatus according to claim 58 wherein said first program does not provide said control signal in the event of said voltage signal indicating that the voltage of the battery is high enough.

67. Apparatus according to claim 58 including:

a charge station;

apparatus for establishing a connection between said charge station and said charging system employing a medium suitable for transferring electric power therebetween; and

wherein said source of alternating charging voltage comprises a transformer disposed on said station.

68. The method of charging a variety of different types of batteries of electric vehicles at a charge station to which a vehicle is presented for charging of the battery thereof, comprising:

establishing a connection between the vehicle and the charge station;

providing over the connection to the vehicle AC charging voltage, the voltage magnitude of which is selectively adjusted on said charge station to correspond with the battery to be charged; and

rectifying said voltage on the vehicle and selectively applying the rectified voltage to the battery in response to the state of charge of the battery.

69. The method according to claim 68 including:

establishing communication between the vehicle and the charging station;

providing to the charging station a manifestation of the voltage rating of the battery on the vehicle; and

adjusting the magnitude of the AC voltage provided by the charging station to the vehicle in accordance with said manifestation.

70. A method according to claim 68 wherein said applying step comprises applying a portion of each half sine wave of rectified voltage to the battery in dependence upon the condition of the battery.

71. A method of charging the battery of an electric vehicle at a commercial battery charging station, comprising:

inserting an amount of cash in the station to pay for the charging power;

determining in said station the maximum amount of power which is paid for by the cash inserted;

providing charging voltage from said station to said vehicle;

terminating in said vehicle the charging of said battery as a result of said battery becoming fully charged; and

terminating in said station the provision of said battery charging voltage to said vehicle in the event that said maximum amount of power has been transferred to said vehicle.