Abstract:
A tester connects with the connector of electrical vehicle service equipment (EVSE). The tester simulates the battery supply of an electric vehicle to test whether the EVSE is properly operating without requiring that the electric vehicle be present. In one embodiment LEDs are employed to indicate whether the EVSE meets specifications. In a second embodiment various measurements of voltage levels and signals are provided to allow for a more detailed analysis of the performance characteristics of the EVSE. Ground fault, proximity sensor, and re-closure tests are also undertaken.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority of U.S. Provisional Patent Application No. 61/539,682 filed on Sep. 27, 2011, the disclosure of which is incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     This disclosure relates generally to electric vehicle service equipment (EVSE) employed for charging the battery power supply of an electric vehicle. More particularly, this disclosure relates to devices and methods for installing EVSE in connection with residential installations. 
     The increased popularity of electric vehicles has been coupled with the increased numbers of installations of EVSE to provide charging terminals. The installation of EVSE typically requires the services of an electrician to ensure that the EVSE is operating properly and that the EVSE installation is safe. 
     Standards have been adopted by The Society of Automotive Engineers (SAE) and various governmental and professional organizations for providing a standard electrical connection and protocol between the land based electrical power supply and the battery charging unit of the electrical vehicle. This is typically implemented in the form of J1772 connectors. 
     When installing an EVSE, it is necessary to test the unit, to ensure its proper performance, before connecting to an electric vehicle. An installer typically will not have access to an electric vehicle, and it is recommended to use the electric vehicle as a tester. Therefore, there is a need for an EVSE tester that is portable and easy to use that tests all operating and safety functions of a newly installed EVSE. There is also a need for a tester that not only tests the operation and safety functions, but will also display the various performance values when the EVSE fails the “go/no go” requirements. 
     This disclosure pertains to two such tester devices. The first device is a go/no go tester to simply determine if the EVSE is performing within specifications. The second device is not only used to test the EVSE, but to display the values of each test to better determine the root cause of a failure. 
     SUMMARY 
     Briefly stated, a tester for electric vehicle service equipment (EVSE) for charging the battery power supply of an electric vehicle comprises a housing with control panel at an exterior location of the housing. The control panel comprises a switch and a plurality of indicators. An EVSE connector inlet is disposed for access exteriorly of the housing. Circuitry comprising a microprocessor is disposed in the housing and in communication with the inlet, the switch and the indicators. Upon connecting an EVSE connector to the inlet and activating the switch to an “On” mode, the circuitry simulates the battery power supply of an electric vehicle and activates indicators indicative of performance characteristics of the EVSE. 
     The performance characteristics comprise at least one characteristic selected from the group consisting of a signal level, a voltage level and a pulse width. The control panel is disposed generally opposite the inlet. A label with instructions is fixed to a third side of the housing. The control panel comprises a ground fault test switch. The tester also comprises circuitry for testing the ground fault safety of the EVSE. An indicator denotes the presence and performance level accuracy of an incoming pilot signal. An indicator indicates the presence and performance level of an incoming proximity signal. 
     At least one indicator and indicia indicate the range of current that may be supplied from the EVSE under test when powered by a 220 VAC source. In addition, at least one indicator and indicia indicate that the range of current that may be supplied from the EVSE under test from a 110 VAC source. At least one indicator denotes the maximum current that, under test, the EVSE is capable of supplying to an electric vehicle. The indicators are preferably LEDs. The LEDs are activated to indicate whether or not the performance characteristics meet the corresponding specification. At least some of the indicators indicate approximate measured values of performance characteristics. 
     A tester for EVSE for charging a battery power supply of an electric vehicle comprises a housing with a control panel at an exterior location of the housing. The control panel has an electronic display and a plurality of switches. The EVSE connector inlet is disposed for access exteriorly of the housing. Circuitry comprising a microprocessor is disposed in the housing and is in communication with the inlet, the display and the switches. Upon connecting an EVSE connector to the inlet and selectively activating various switches, the circuitry simulates the battery power supply of the electric vehicle, and the display presents measurement values indicative of performance characteristics of the EVSE. The control panel is disposed opposite the inlet. The control panel comprises a ground fault test switch. The circuitry tests the ground fault safety of the EVSE. The circuitry is employed to measure quantitative characteristics of an incoming pilot signal. The circuitry is also employed to measure quantitative characteristics of an incoming proximity signal. The display indicates a range of current that may be supplied from the EVSE under test when powered from an AC power source. 
     A tester for EVSE for charging the batter power supply in an electric vehicle comprises a control panel accessible exteriorly of the housing. The control panel has a plurality of switches and an electronic alphanumeric display. An EVSE connector inlet is disposed for access exteriorly of the housing. Circuitry comprising a microprocessor is disposed in the housing in communication with the inlet, the switches and the display. Upon connecting an EVSE connector to the inlet and selectively activating switches, the circuitry simulates a battery power supply of an electric vehicle and activates a display to indicate various tests and to display performance characteristics of the EVSE which result from the tests. The performance characteristics comprise at least one characteristic selected from the group consisting of a signal level, voltage level and a pulse width. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an EVSE tester; 
         FIG. 2A  is a front view and  FIG. 2B  a side view, partly in diagram form, of the EVSE tester of  FIG. 1  disposed in side-by-side relationship; 
         FIG. 3  is a block diagram illustrating the EVSE tester of  FIG. 1  and the EVSE, including a J1772 connector; 
         FIG. 4  is an enlarged view of an instruction plate which may be mounted to the side of the tester of  FIG. 1  to aid in the usage of the tester by an electrician; 
         FIG. 5  is a perspective view schematically illustrating the connection of a representative J1772 connector for an EVSE installation and the EVSE tester of  FIG. 1 ; 
         FIG. 6  is an enlarged annotated end view illustrating connections for the J1772 connector; 
         FIG. 7  is an exploded perspective view of the EVSE tester of  FIG. 1 ; 
         FIG. 8  is a table illustrating the 110 VAC current displayed on an EVSE tester and the minimum breaker size required for the electrical supply system for the EVSE; 
       Table  9  is a table illustrating the 220 VAC current displayed on an EVSE tester and the minimum breaker size required for the EVSE electrical supply system for the EVSE; 
         FIG. 10  is an operational flow diagram of the EVSE tester of  FIG. 1 ; 
         FIG. 11  is a perspective view of a second embodiment of an EVSE tester; 
         FIG. 12  is a perspective view of the EVSE tester of  FIG. 11  taken from a generally opposite position thereof; 
         FIG. 13A  is a front view and  FIG. 13B  a side view, partly in diagram form, of the EVSE tester of  FIG. 12  disposed in side-by-side relationship; 
         FIG. 14  is a block diagram illustrating the EVSE tester of  FIG. 12  and the EVSE, including a J1772 connector; 
         FIG. 15  is a perspective view schematically illustrating the connection of a representative J1772 connector for an EVSE installation and the EVSE tester of  FIG. 12 ; 
         FIG. 16  is an enlarged view of an instruction plate which may be mounted to the side of the tester of  FIG. 12  to aid in the usage of the tester by a technician; 
         FIG. 17  is an exploded perspective view of the EVSE tester of  FIG. 12 ; 
         FIG. 18  is a generally bottom perspective view, partly in phantom, of the EVSE tester of  FIG. 12  showing the location of the internal battery; and 
         FIG. 19  is an operational flow diagram of the operation of the EVSE tester of  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference to the drawings wherein like numerals represent like parts throughout the Figures, an EVSE electrician tester is generally designated by the numeral  100  ( FIG. 1 ) and an EVSE technician tester is generally designated by the numeral  300  ( FIG. 11 ). The testers  100  and  300  are each a hand held test unit that simulates the battery power supply of an electric vehicle, and is used to test the operation and safety features of installed electric vehicle service equipment (EVSE). 
     Each tester evaluates compliance with applicable safety and performance standards and preferably, all of the standards specified by the Society of Automotive Engineers, J1772 publications. The testers  100  and  300  are designed to test any EVSE model that complies with the SAE J1772 standards. A representative EVSE is designated by the numeral  200  in  FIGS. 3 and 14 . 
     The testers  100  and  300  measure signal levels, pulse widths, and voltage levels generated by the EVSE  200  under test. The tester  100  indicates to the operator (electrician) the results of the measurements, using high intensity LEDs. The tester  300  indicates to the technician the results of various measurements, preferably using an alphanumeric display. Both testers  100  and  300  is a more sophisticade vice which the operator to test the important safety features, such as ground fault protection circuit, equipment grounding and the reclosure function. 
     Each tester is a hand held electric vehicle simulator designed to provide an efficient and user-friendly means of testing electric vehicle service equipment (EVSE) safety and operation or performance features without the presence of the electric vehicle. 
     The electrician tester  100  is powered when the EVSE applies power during the charge mode and requires no batteries. The technician tester  300  is powered by an internal battery  366  which is charged by either an external power pack or by the AC voltage present during the charge mode. 
     Each tester  100  and  300  (see  FIGS. 1 and 11 ) employs a rugged sealed high impact plastic hand held enclosure  10  with a functionally downwardly protruding handle  12 . A rear panel  14  is equipped with a rearward protruding SAE J1772 electric vehicle inlet  20 . The battery  366  is mounted in the handle  12  of tester  300  and secured by an access cap  368  ( FIG. 17 ). 
     With additional reference to  FIGS. 2A and 5 , a frontal, readily accessible control panel  30  on the tester  100 , interfaces with the electrician and has the following items:
         A charge on/off toggle switch  32  activates the EVSE under test.   LED indicator  34  denotes when the input voltage is between 95 and 125 VAC.   LED indicator  36  denotes when the input voltage is between 185 and 250 VAC.   Pilot status LED indicator  38  denotes the presence and lower range accuracy of the incoming pilot signal.   Proximity switch status LED indicator  40  denotes the presence and lower range accuracy of the incoming proximity signal.   Column  42  indicates the range of currents that may be supplied to the electric vehicle from the EVSE under test, when powered from a 220 VAC source.   Column  44  indicates the range of currents that may be supplied to the electric vehicle from the EVSE under test when powered from a 110 VAC source.   Indicator set  50  of seven LED indicators  51 - 57  denotes the maximum current that the EVSE under test is capable of supplying to the electric vehicle. The value of this current is determined by the pulse width of the pilot signal received from the EVSE under test.   Ground fault (GFCI) momentary switch  60 , which applies a  20  milli-amp leakage path from line 1 to ground, tests the ground fault safety feature of the EVSE under test.       

     A label  62  ( FIG. 4 ) containing concise operating instructions is mounted to one side  18  of the housing  10 . 
     With reference to  FIG. 3  and  FIG. 14 , the EVSE testers  100  and  300  employ a transformer  70  and use an advanced microprocessor  80  and  380 , respectively, developed for the automotive industry. 
     The microprocessor  80  of tester  100  performs the following functions:
         Measures incoming line voltage from 0 to 250V AC.   Measures incoming pilot signal amplitudes up to +/−15V DC with 0.1% accuracy.   Measures pilot signal frequency (I kHz) with 0.1% accuracy.   Measures pilot signal pulse width, 0 to 95% duly cycle with 0.1% accuracy.   Measures the proximity switch  42  resistor with 0.1% accuracy.   Controls the 110V AC and 220V AC indicator LEDs  34  and  36 .   Controls the pilot and proximity switch indicator LEDs  38  and  40 .   Controls the seven current range indicator LEDs  50 .       

     The microprocessor  380  of tester  300  performs the following functions:
         Measures incoming line voltage from 0 to 250 VAC.   Measures incoming pilot signal amplitudes up to +/−15 VDC with 0.1% accuracy.   Measures pilot signal frequency (I kHz) with 0.1% accuracy.   Measures pilot signal pulse width, 0 to 95% duly cycle with 0.1% accuracy.   Measures the proximity switch  42  resistor with 1.0% accuracy.   Is controlled by the up and down sequence switches  324  and  326 .   Senses when the charge switch  32  is on or off.   Measures the voltage of battery  366 .   Indicates when the battery  366  is low.   Senses when a ground fault has occurred.   Turns off battery  366  power after a period of inactivity.   Displays sequentially all instructions, measurements, and status.       

     With additional reference to  FIGS. 12 ,  13 A and  15 , a frontal, readily accessible control panel  330  interfaces with the technician and has the following items:
         A power on toggle switch  64  activates the tester  300 .   A charge on/off toggle switch  32  activates the EVSE  200  under test.   A ground fault (GFI) momentary switch  60 , which applies a 20 milli-amp leakage path from line 1 to ground, tests the ground fault safety feature of the EVSE under test.   An alphanumeric display  322  indicates voltages, frequencies, resistance, currents measurements as well as in or out of tolerance boundaries.   The tester  300  has a label  362  ( FIG. 16 ) containing concise operating instructions. The label  362  is mounted to one side  18  of the housing  10 .       

     The tester  300  has an internal battery  366  ( FIG. 18 ) used to power the tester when no AC power is supplied from the EVSE. 
     Operation of Electrician Tester  100   
     An EVSE  200  is tested by inserting the J1772 connector  210  of the EVSE  200  under test into the J1772 inlet  20  on the EVSE tester  100  (see  FIG. 3 ). 
     When the J1772 connector  210  is inserted into the inlet  20 , the pilot voltage on Pin 4 is reduced from +12 VDC to +9 VDC with respect to ground on Pin 3. This reduction in voltage, signals the EVSE, “under test”, that the tester is connected. The EVSE in return will convert the +9 VDC signal to a +9 VDC/−12 VDC, 1 kHz, square wave signal. Some manufacturers supply EVSE without the −12 DCV bias, which “will be out of spec”, but will still work with some electric vehicles. The pulse width of this square wave will vary, from 10% to 95%, depending on the amount of current that the EVSE can supply to the electric vehicle. 
     In addition, a 150 ohm resistor to ground, Pin 3, is connected to the proximity input, Pin 5, signaling to the tester  100  that the J1772 connector  210  is attached and locked. The EVSE tester  100  is now ready to test the EVSE  200 . 
     When the charge switch  32 , is toggled to the “On” position (closed contact), the pilot signal will decrease to +6 VDC peak. This action will signal the EVSE to close Relay  1   230  and apply either 120 VAC or 220 VAC to Pins 1 and 2 on the EVSE tester  100 . 
     When AC power is applied to Pins 1 and 2 on the EVSE tester  100 , the microprocessor  80  is activated and, as a self test, will sequentially light all of the status LEDs. 
     The microprocessor  80  will then measure the voltage on Pins 1 and 2 and depending on the amplitude, illuminate either the 110 VAC status LED  34  or the 220 VAC status LED  36 . When the AC voltage is between 185 VAC and 250 VAC, the 220 V status LED  36  is turned on steady. When the AC voltage is between 95 VAC and 125 VAC, the 110 V status LED  34  is turned on steady. When the voltages are outside these ranges, the voltage LEDs  34  and  36  will flash (see fault conditions). The microprocessor  80  will also measure the amplitude and pulse width of the pilot signal. If the amplitude is within acceptable range, the maximum AC current available is determined by the microprocessor  80  and displayed by the current status LED indicators  51 - 57 . 
     Based on the maximum current displayed on the tester  100 , the electrician should ensure that the rating of the service breaker (not illustrated) is 1.25× the maximum current, i.e., 30 A displayed should be protected with a non GFCI, 40 A breaker (see the tables of  FIGS. 8 and 9 ). The maximum current displayed by the tester  100  should never exceed the rating displayed on the EVSE name plate. The breaker rating should comply with all local and state electrical codes. 
     When the pilot signal is within the required J1772 specification, the pilot OK status LED  38  is turned on steady. Should the pilot signal not comply with the J1772 specification, the pilot LED  38  will flash indicating a problem (see fault conditions). 
     When the voltage, pilot and proximity status LEDs  34 ,  36 ,  38  and  40  are on steady, the last two tests may be completed. 
     The release latch  220  on the J1772 connector  210  (connector should not be removed from inlet on tester.) is activated at release button  222 . The proximity OK status LED  40  should turn off when the release button is pressed (If not, see fault conditions.). 
     Next, the GFCI test monitoring toggle switch  60  is pressed to create a 20 ma leakage current to ground. This should cause the EVSE under test to drop AC power and indicate a ground fault condition (If not, see fault conditions.). All status LEDs on the EVSE tester  100  will then turn off. 
     Most EVSE manufacturers provide an automatic time-delayed reclosure after a ground fault interception. After the specified time delay, the EVSE  200  should once again supply voltage to the EVSE tester  100  (If not, see fault conditions.). 
     The EVSE test is now completed. 
     A summary of fault conditions for the EVSE Tester  100  is set forth in Table I. 
                             TABLE I               Action   Response   Problem                   Press Charge   No status LED   Check EVSE breaker       Switch “On”       Check EVSE power               Check EVSE ground               Check Pin 4 to ground Pin               3. Should be between +11 to +13               VDC           110 V status LED   Line voltage less than 95           flashes   VAC           220 V and 110 V   Line voltage between 125 to           LED flash   185 VAC           220 V status LED   Line voltage above 250           flashes   VAC           Pilot status LED   Pilot frequency outside           OFF   specification           Pilot status LED   Pilot voltage outside           flashes   specification           (note 1)   Check Pin 4 to ground Pin               3. Should be between +11 to +13               VDC       Press locking   Proximity status   Locking latch not fully       latch   LED flashes   engaged               Measure resistance               between Pin 5 and ground Pin 3.               Should be 150 ohms and change               to 480 ohms when lock latch is               pressed                    
Operation of the Technician Tester  300 
 
     With reference to  FIGS. 14 and 19 , when the power on switch  64  is pressed, the EVSE tester  300   FIG. 14 , DC voltage is applied to the microprocessor  380  and associated circuits. The microprocessor  380  will first measure the voltage level of battery  66  and present its value on the display  322 . When the voltage is nearing the discharged level, a low battery message is displayed. 
     When the battery voltage is adequate for operations, a sequence of identifying messages will be presented at display  322 . A prompt message will be displayed instructing the operator (technician) to plug in the J1772 connector  210  into the J1772 inlet  20  on the tester  300 . 
     When the J1772 connector  210  is inserted into the inlet  20 , the pilot voltage on Pin 4 is reduced from +12 VDC to +9 VDC with respect to ground on Pin 3. If the power is not on, then this voltage will turn on the tester  300 . This reduction in voltage signals the EVSE  200 , “under test”, that the tester  300  is connected. The EVSE in return will convert the +9 VDC signal to a +9 VDC/−12 VDC, 1 kHz, square wave signal. The pulse width of this square wave will vary, from 10% to 95%, depending on the amount of current that the EVSE can supply to the electric vehicle. 
     In addition, a 150 ohm resistor to ground, Pin 3, is connected to the proximity input, Pin 5, signaling to the tester  300  that the J1772 connector  210  is attached and locked. The EVSE tester  300  is now ready to test the EVSE  200 . 
     A prompt message is displayed at display  322  to press the latch lever on  222  ( FIG. 15 ), but not to remove the connector from the inlet. When the lever is pressed, a 330 ohm resistor  44  is connected in series with the 150 ohm resistor  43  which causes the pilot voltage to increase from 2.5 VDC to 4 VDC signaling that the latch  222  was pressed. This change in resistance and voltage level signals the electric vehicle to raise the voltage level of the pilot signal  201  which signals the EVSE  200  to open relay  230  which removes the voltage from connector  210 , Pins 1 and 2. 
     The tester  300  will measure the 150 ohm resistor when the latch is not pressed and display its results. The tester  300  will also measure the resistance when the latch is pressed and again this value will be presented in the display  322 . 
     To step to the next test, the operator uses the up arrow switch  324  on the tester  300 . The operator may also use the down arrow  326  to step back to a previous test. 
     When the proximity switch test is completed, the operator steps to the pilot voltage test. In this step, the microprocessor measures the positive peaks of the pilot signal and presents the value and status in the display  322 . 
     When the pilot plus voltage test is completed, the operator steps to the pilot negative voltage test by pressing the up switch  324 . In this test the negative peak of the pilot will be measured and the value and status will be presented in the display. 
     When the pilot negative voltage test is completed, the operator advances to the pilot charge voltage test by pressing the up switch  324 . The microprocessor will prompt the operator to press the charge switch  32  ( FIGS. 12 and 14 ). 
     When the charge switch  32  is pressed, a 1.3 K resistor, which is connected to the pilot input, will be connected to ground causing the pilot signal to drop from +9 VDC to +6 VDC. This value will be measured by the microprocessor  380 , and the voltage and its status presented on the display  322 . This reduction in pilot voltage will also cause the EVSE, under test, to close its relay  230  which will apply the charge voltage on J1772 connector ( 20 ) on Pins 1 and 2. 
     One preferred embodiment of EVSE tester  300  has the features set forth in Table II: 
     
       
         
               
               
             
           
               
                 TABLE II 
               
               
                   
               
               
                 Feature: 
                 Specification 
               
               
                   
               
             
             
               
                 Compatibility: 
                 Emulates all electric vehicles that comply with 
               
               
                   
                 SAE J1772 standards 
               
               
                 Inlet: 
                 J1772 Compatible 
               
               
                 Voltage Status: 
                 Measures 0 to 250 VAC 0.1% accuracy 
               
               
                 Pilot Signal: 
                 Measures Frequency 1 kHz 0.1% accuracy 
               
               
                   
                 Measures voltages +15 to −15 VDC 0.1% 
               
               
                   
                 accuracy 
               
               
                 Pilot Pulse Width: 
                 Measures 10 to 90% duty cycle 0.1% accuracy 
               
               
                 Proximity Signal: 
                 Measures Voltages 0 to +5 VDC 0.1% 
               
               
                   
                 accuracy 
               
               
                 Current Display: 
                 220 V range—10 A to 70 A 
               
               
                   
                 110 V range—6 A to 18 A 
               
               
                 Ground Fault Test: 
                 20 ma; Line 1 to ground 
               
               
                 Compliance: 
                 SAE J1772 
               
               
                 FCC Compliance: 
                 FCC part 1 Class A 
               
               
                 Line Safety: 
                 Internal fuse 
               
               
                 Environment: 
                 ROHS compliant 
               
               
                 Operating Temperature: 
                 0° to 122° F. (−20 C. ° to 50° C.) ambient 
               
               
                 Operating Humidity: 
                 100% 
               
               
                 NEMA Rating: 
                 4R 
               
               
                 Material: 
                 Bright yellow, high impact absorbent plastic 
               
               
                 Drop Test: 
                 3′ to hard surface 
               
               
                 Weight: 
                 3 lb. 
               
               
                 Size: 
                 3.37 ins. × 9.10 ins. × 5.94 ins. (FIGS. 
               
               
                   
                 13A and 13B) 
               
               
                   
               
             
          
         
       
     
     While preferred embodiments have been set forth for purposes of illustration, the foregoing description should not be deemed a limitation of the invention herein. Accordingly, various modifications, adaptations and alternatives may occur to one skilled in the art without departing from the spirit and the scope of the present invention.