Patent Publication Number: US-2023155399-A1

Title: Methods and systems for charge control

Description:
RELATED APPLICATION(S) 
     This application is a divisional application and is being filed during the pendency of related U.S. Application No. 17/102,583 having a filing date of Nov. 24, 2020 and having “METHODS AND SYSTEMS FOR CHARGE CONTROL” as a title, the contents and teachings of which are herein incorporated by reference in their entirety. 
     U.S. Application No. 17/102,583 is also a divisional application and was filed during the pendency of U.S. Application No. 16/105,296 having a filing date of Aug. 20, 2018, and having “METHODS AND SYSTEMS FOR CHARGE CONTROL” as a title, the contents and teachings of which are herein incorporated by reference in their entirety. 
     U.S. Application No. 16/105,296 is a regular utility application of U.S. Application No. 62/549,241 having a filing date of Aug. 23, 2017, and having “METHODS AND SYSTEMS FOR CHARGE CONTROL” as a title, the contents and teachings of which are herein incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     A conventional lithium-battery powered vehicle includes rechargeable lithium battery packs which discharge while energizing loads such as an electric motor of the vehicle. The lithium battery packs are then recharged from the electric grid. 
     To recharge the lithium battery packs of the vehicle, a human operator typically parks the vehicle next to a charging station, attaches a plug from the charging station to an electrical socket of the vehicle, and actuates a charge-enable switch that electrically connects the lithium battery packs to the electrical socket so that the lithium battery packs receive charge from the charging station through the electrical socket. 
     SUMMARY 
     It should be understood that there are deficiencies to the above-described conventional lithium-battery powered vehicle. Along these lines, the human operator may not have confidence that the equipment is correctly set up so that the charging station is now properly charging the conventional lithium-battery powered vehicle. For example, the human operator may not be sure that the plug from the charging station is properly attached to the electrical socket of the vehicle. As another example, the human operator may wonder whether the charge-enable switch is set to the correct position for charging. Accordingly, the human operator may spend additional time and effort unnecessarily reviewing and double checking the equipment. Moreover, if the human operator is tasked with charging multiple conventional lithium-battery powered vehicles (e.g., a fleet of golf cars), the extra time and effort placed on each vehicle may lead to excessive inefficiency and performance. 
     In contrast, improved techniques are directed to charge control that enhances the user experience. Along these lines, a human user is able to initiate pre-charging evaluation of a lithium battery by simply connecting an external charger to a utility vehicle. Shortly after the user connects the external charger to the utility vehicle and prior to the vehicle providing direction to the external charger to adjust the amount of charge stored by the lithium battery, the utility vehicle performs a set of pre-charging assessment operations to determine whether charge adjustment should commence. Upon a successful pre-charging assessment, the utility vehicle automatically provides a user notification indicating that the utility vehicle is properly setup for charge adjustment. Such notification may be in the form of one or more audio signals (e.g., one or more buzzes, beeps, bell tones, other distinctive noises, combinations thereof, etc.) and/or one or more video signals (e.g., one or more solid or blinking lights, output on one or more segmented displays, output on a graphical screen or monitor, combinations thereof, etc.). Additionally, such notification may be through one or more devices of the utility vehicle, through the external charger, through one or more separate devices (e.g., a smart phone, a tablet, a computerized workstation, a server, etc.), or combinations thereof, and so on. 
     For example, circuitry of the utility vehicle may output a “success” signal which causes one or more user output devices selected by the user to provide the notification. Along these lines, the success signal may include a particular value in a predefine field, may be in a particular format, etc. indicating a successful outcome from the set of precharge assessment operations. Additionally or alternatively, the success signal may include a series of instructions that control the operation of the user device. In response, the user device provides the notification. 
     Accordingly, the user is able to proceed elsewhere (e.g., perform other useful work, etc.) with confidence that subsequent charge adjustment will proceed properly. Such operation thus eliminates the need for the user to double check or closely inspect charger connection, etc. Rather, the user may simply connect the charger, receive the notification shortly thereafter, and then proceed to another task (e.g., connect another charger to another vehicle), and so on. In some fleet management arrangements, a fleet of utility vehicles is managed concurrently to further inform the user (or a team of users) as to which utility vehicles of the fleet possess acceptable/unacceptable lithium battery health conditions, etc. before, during and/or after charge evaluation and/or adjustment. 
     One embodiment is directed to a charge control system that includes a lithium battery configured to provide lithium battery power to a set of electrical loads, a user signaling device, and control circuitry coupled with the lithium battery and the user signaling device. The control circuitry is operative to:
     (A) detect availability of charge from an external charger,   (B) in response to detection of the availability of charge from the external charger and prior to controlling the external charger to adjust the amount of charge stored by the lithium battery, perform a set of pre-charging assessment operations, and   (C) based on the set of pre-charging assessment operations, provide a user notification via the user signaling device, the user notification indicating whether the lithium battery is properly setup for charge adjustment.   
When the user signaling device generates the user notification, the user is informed that the utility vehicle is properly connected to the external charger.
     In some arrangements, the lithium battery, the user signaling device, and the control circuitry are components of a utility vehicle. In certain arrangements, the control circuitry is further operative to, in response to a successful result from the set of pre-charging assessment operations, provide a control signal that adjusts the amount of charge stored by the utility vehicle’s lithium battery. 
     In some arrangements, the control circuitry is further operative to detect an external charger connection event in which the external charger connects to a connector of the utility vehicle (e.g., a male plug, a female receptacle, etc.). In these arrangements, the external charger connection event indicates availability of charge from the external charger. 
     In some arrangements, the control circuitry, when providing the control signal that adjusts the amount of charge stored by the lithium battery, is operative to output a charger signal to the external charger through the connector. The charger signal causes the external charger to charge the lithium battery through the connector. 
     In some arrangements, the control circuitry, when performing the set of pre-charging assessment operations, is operative to test whether any of a plurality of battery management system (BMS) protection fault conditions exist, and generate a pre-charging assessment indication based on whether any of the plurality of BMS protection fault conditions exist. In some arrangements, testing whether any of the plurality of BMS protection fault conditions exist includes reading lithium battery temperature and voltage measurements from the lithium battery, and comparing the lithium battery temperature and voltage measurements to a set of predefined thresholds to determine whether any of the plurality of BMS protection fault conditions exist. 
     In some arrangements, the control circuitry, when performing the set of pre-charging assessment operations, is operative to test whether the lithium battery is to receive charge from the external charger, and generate a pre-charging assessment indication based on whether the lithium battery is to receive charge from the external charger. In some arrangements, testing whether the lithium battery is to receive charge from the external charger includes ascertaining a current amount of charge stored by the lithium battery, and comparing the current amount of charge to a predefined target charge range to determine whether the lithium battery is to receive charge from the external charger. 
     In some arrangements, the control circuitry, when performing the set of pre-charging assessment operations, is operative to test whether the external charger is operative to provide a predefined voltage to charge the lithium battery, and generate a pre-charging assessment indication based on whether the external charger is operative to provide the predefined voltage to charge the lithium battery. In some arrangements, testing whether the external charger is operative to provide the predefined voltage to charge the lithium battery includes measuring a current supply voltage provided by the external charger, and comparing the current supply voltage to a predefined supply voltage threshold to determine whether the external charger is currently operative to provide the predefined voltage to charge the lithium battery. 
     In some arrangements, the control circuitry, when performing the set of pre-charging assessment operations, is operative to:
     (i) test whether any of a plurality of battery management system (BMS) protection fault conditions exist,   (ii) test whether the lithium battery is to receive charge from the external charger,   (iii) test whether the external charger is operative to provide a predefined voltage to charge the lithium battery, and   (iv) generate a pre-charging assessment indication based on (a) whether any of the plurality of BMS protection fault conditions exist, (b) whether the lithium battery is to receive charge from the external charger, and (c) whether the external charger is currently operative to provide the predefined voltage to charge the lithium battery.   

     Another embodiment is directed to a utility vehicle which includes a utility vehicle body, a set of electrical loads supported by the utility vehicle body, and a charge control system supported by the utility vehicle body and coupled with the set of electrical loads. The charge control system includes a lithium battery configured to provide lithium battery power to the set of electrical loads, a user signaling device, and control circuitry coupled with the lithium battery and the user signaling device. The control circuitry is operative to:
     (A) detect availability of charge from an external charger,   (B) in response to detection of the availability of charge from the external charger and prior to controlling the external charger to adjust the amount of charge stored by the lithium battery, perform a set of pre-charging assessment operations, and   (C) based on the set of pre-charging assessment operations, provide a user notification via the user signaling device, the user notification indicating whether the lithium battery is properly setup for charge adjustment.   

     Another embodiment is directed to a charge control method which includes detecting availability of charge from an external charger and, in response to detection of the availability of charge from the external charger and prior to controlling the external charger to adjust the amount of charge stored by the lithium battery, performing a set of pre-charging assessment operations. The charge control method further includes providing, based on the set of pre-charging assessment operations, a user notification via the user signaling device, the user notification indicating whether the lithium battery is properly setup for charge adjustment. 
     Another embodiment is directed to a fleet management client device which includes a communications interface configured to communicate with a fleet management server apparatus, a utility vehicle interface configured to communicate with utility vehicle control circuitry that controls operation of a utility vehicle, and control circuitry coupled with the communications interface and the utility vehicle interface. The control circuitry is operative to: 
     (A) monitor a set of utility vehicle events through the utility vehicle interface and store a set of utility vehicle event entries in a buffer, the set of utility vehicle event entries identifying the set of utility vehicle events,   (B) establish a network connection between the fleet management client device and the fleet management server apparatus through the communications interface, and   (C) after the network connection between the fleet management client device and the fleet management server apparatus is established through the communications interface, convey the set of utility vehicle event entries from the buffer to the fleet management server apparatus via the network connection.   

     In some arrangements, the control circuitry, when storing the set of utility vehicle event entries in the buffer, is operative to record, as at least some of the set of utility vehicle event entries, a series of lithium battery conditions captured over time. 
     In some arrangements, the control circuitry, when detecting establishment of the network connection, is operative to automatically sense that the utility vehicle has entered a local wireless network location of the fleet management server apparatus. The set of utility vehicle event entries is communicated from the buffer to the fleet management server apparatus via the network connection in response to automatically sensing that the utility vehicle has entered the local wireless network location. 
     In some arrangements, the utility vehicle is an electric golf car constructed and arranged to transport a golfer among locations on a golf course. In some such arrangements in which the utility vehicle is an electric golf car, the fleet management client device further includes location identification circuitry coupled to the control circuitry, the location identification circuitry being configured to provide, to the control circuitry, a location signal that identifies a current geolocation of the electric golf car on the golf course. The fleet management client device may further include a touch screen coupled to the control circuitry. The touch screen is configured to receive golf course data that is based on the current geolocation of the electric golf car from the control circuitry and visually display the golf course data concurrently while the control circuitry records the series of lithium battery conditions captured over time. 
     Another embodiment is directed to a method of managing utility vehicle event entries which is performed in a fleet management client device of a utility vehicle. The method includes:
     (A) monitoring a set of utility vehicle events through a utility vehicle interface of the fleet management client device of the utility vehicle and storing a set of utility vehicle event entries in a buffer, the set of utility vehicle event entries identifying the set of utility vehicle events;   (B) establishing a network connection between the fleet management client device and a fleet management server apparatus through a communications interface of the fleet management client device, and   (C) after the network connection between the fleet management client device and the fleet management server apparatus is established, conveying the set of utility vehicle event entries from the buffer to the fleet management server apparatus via the network connection.   

     Another embodiment is directed to a fleet management server apparatus which includes a communications interface configured to communicate with respective fleet management client devices of a fleet of utility vehicles, a utility vehicle database configured to store utility vehicle information from the fleet of utility vehicles, and control circuitry coupled with the communications interface and the utility vehicle database. The control circuitry is operative to:
     (A) establish network connections between the fleet management server apparatus and the respective fleet management client devices of the fleet of utility vehicles through the communications interface,   (B) after the network connections between the fleet management server apparatus and the respective fleet management client devices are established, collect respective sets of utility vehicle event entries from the fleet of utility vehicles through the communications interface and store the respective sets of utility vehicle event entries in the utility vehicle database, and   (C) based on the respective sets of utility vehicle event entries stored in the utility vehicle database, perform a set of utility vehicle conditioning activities that conditions the fleet of utility vehicles.   

     In some arrangements, the fleet of utility vehicles is a plurality of electric golf cars. Each electric golf car is constructed and arranged to transport a golfer among locations on a golf course. In these arrangements, performing the set of utility vehicle conditioning activities based on the respective sets of utility vehicle event entries stored in the utility vehicle database includes performing, for each electric golf car of the plurality of electric golf cars, a lithium battery health assessment on a lithium battery of that electric golf car, and identifying a current set of health conditions of the lithium battery of that electric golf car. 
     Another embodiment is directed to method of managing a fleet of utility vehicles. The method includes:
     (A) establishing network connections between the fleet management server apparatus and respective fleet management client devices of the fleet of utility vehicles through a communications interface,   (B) after the network connections are established, collecting respective sets of utility vehicle event entries from the fleet of utility vehicles through the communications interface and storing the respective sets of utility vehicle event entries in a utility vehicle database, and   (C) based on the respective sets of utility vehicle event entries stored in the utility vehicle database, performing a set of utility vehicle conditioning activities.   

     Other embodiments are directed to higher and lower level systems, assemblies, apparatus, processing circuits, etc. Some embodiments are directed to various processes, electronic components and circuitry which are involved in adjusting an amount of charge stored by a lithium battery of a utility vehicle. 
     This Summary is provided merely for purposes of summarizing some example embodiments so as to provide a basic understanding of some aspects of the disclosure. Accordingly, it will be appreciated that the above described example embodiments are merely examples and should not be construed to narrow the scope or spirit of the disclosure in any way. Other embodiments, aspects, and advantages will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features and advantages will be apparent from the following description of particular embodiments of the present disclosure, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of various embodiments of the present disclosure. 
         FIG.  1    is a perspective view of an example utility vehicle which controls electrical access to a lithium battery. 
         FIG.  2    is a block diagram of particular systems and components of the utility vehicle of  FIG.  1    in accordance with some example embodiments. 
         FIG.  3    is a block diagram of additional details of the utility vehicle of  FIG.  1    in accordance with some example embodiments. 
         FIG.  4    is a block diagram of particular details of a wakeup circuit of a battery management system of the utility vehicle of  FIG.  1    in accordance with some example embodiments. 
         FIG.  5    is a block diagram of a first arrangement of particular user controls that provide input to the wakeup circuit of  FIG.  4    in accordance with some example embodiments. 
         FIG.  6    is a block diagram of a second arrangement of particular user controls that provide input to the wakeup circuit of  FIG.  4    in accordance with some example embodiments. 
         FIG.  7    is a flowchart of a procedure which is performed by the battery management system of the utility vehicle of  FIG.  1    in accordance with some example embodiments. 
         FIG.  8    is a block diagram of particular charging circuitry of the utility vehicle of  FIG.  1    in accordance with some example embodiments. 
         FIG.  9    is a sequence diagram illustrating particular charging activities that occur during lithium battery charging in accordance with some example embodiments. 
         FIG.  10    is a flowchart of a procedure which is performed by circuitry of a utility vehicle during lithium battery charging in accordance with some example embodiments. 
         FIG.  11    is a flowchart of a procedure which is performed by circuitry of a utility vehicle when an external charger is connected to the utility vehicle in accordance with some example embodiments. 
         FIG.  12    is a block diagram of an electronic environment which includes multiple utility vehicles equipped with respective fleet management client devices and a fleet management server apparatus in accordance with some example embodiments. 
         FIG.  13    is a block diagram of a fleet management client device in accordance with some example embodiments. 
         FIG.  14    is a flowchart of a procedure which is performed by a fleet management client device in accordance with some example embodiments. 
         FIG.  15    is a block diagram of a fleet management server apparatus in accordance with some example embodiments. 
         FIG.  16    is a flowchart of a procedure which is performed by a fleet management server apparatus in accordance with some example embodiments. 
         FIG.  17    is a flowchart of a procedure for optimizing lithium battery charge integrity on a utility vehicle in accordance with some example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Overview 
     An improved technique is directed to charge control that enhances the user experience. Along these lines, a human user is able to initiate pre-charging evaluation of a lithium battery by simply connecting an external charger to a utility vehicle. Shortly after the user connects the external charger to the utility vehicle and prior to the vehicle providing direction to the external charger to adjust the amount of charge stored by the lithium battery, the utility vehicle performs a set of pre-charging assessment operations to determine whether charge adjustment should commence. Upon a successful pre-charging assessment, the utility vehicle automatically provides a user notification indicating that the utility vehicle is properly setup for charge adjustment. Such notification may be in the form of one or more audio signals (e.g., one or more buzzes, beeps, bell tones, other distinctive noises, combinations thereof, etc.) and/or one or more video signals (e.g., one or more solid or blinking lights, output on one or more segmented displays, output on a graphical screen or monitor, combinations thereof, etc.). Additionally or alternatively, such notification may be through any of a variety of devices of the utility vehicle, through the external charger, through one or more separate devices (e.g., a smart phone, a tablet, a computerized workstation, a server, etc.), or combinations thereof, and so on. For example, circuitry of the utility vehicle may output a “success” signal which causes particular output devices selected by the user to provide the notification. 
     Thus, the user is able to proceed elsewhere (e.g., perform other useful work, etc.) with confidence that subsequent charge adjustment will proceed properly. Such operation eliminates the need for the user to double check or closely inspect charger connection, etc. Rather, the user may simply connect the charger, receive the notification shortly thereafter, and then proceed to another task (e.g., connect another charger to another vehicle), and so on. In some fleet management arrangements, a fleet of utility vehicles is managed concurrently to further inform the user (or a team of users) as to which utility vehicles of the fleet possess acceptable/unacceptable lithium battery health conditions, etc. before, during and/or after charge evaluation and/or adjustment. 
     The various individual features of the particular arrangements, configurations, and embodiments disclosed herein can be combined in any desired manner that makes technological sense. Additionally, such features are hereby combined in this manner to form all possible combinations, variants and permutations except to the extent that such combinations, variants and/or permutations have been expressly excluded or are impractical. Support for such combinations, variants and permutations is considered to exist in this document. 
       FIG.  1    shows an example utility vehicle  20  which controls electrical access to a lithium battery. The utility vehicle  20  includes a utility vehicle body  22  (e.g., a chassis, a frame, etc.), a set of tires (or wheels)  24 , and a motion control system  26 . It should be understood that the utility vehicle  20  has the form factor of a golf car by way of example only and that other form factors are suitable for use as well such as those of personal transport vehicles, food and beverage vehicles, hospitality vehicles, all-terrain vehicles (ATVs), utility task vehicles (UTVs), motorcycles, scooters, vehicles for specialized applications, as well as other lightweight vehicles and utility vehicles. In embodiments, such as the example of  FIG.  1   , in which the utility vehicle  20  is a golf car, the golf car may include an operator seating area covered by a canopy supported by a plurality of struts. The golf car may further comprise a rear bag well area disposed rearward of the operator seating area and configured to carry one or more golf bags and/or other cargo. In some embodiments, the rear bag well area may support a rear facing seat for carrying additional passengers and/or a convertible rear seat kit configured to convert to a cargo deck for carrying cargo, such as E-Z-GO Rear Flip Seat Kit Item # 750265PKG. 
     The motion control system  26  controls vehicle movement such as drive provided by the set of tires  24 , speed control, braking, and so on thus enabling the utility vehicle  20  to perform useful work. The motion control system  26  of the illustrated embodiments includes, among other things, a motor system  30 , a lithium battery system  32 , and additional components  34  such as a set of user controls  36  (e.g., a foot pedal, a keyed switch, a maintenance switch, etc.) and cabling  38 . As will be explained in further detail below, the utility vehicle  20  runs on power from a lithium battery and is equipped with a sleep/wakeup feature that automatically disconnects the lithium battery in response to certain timeout conditions thus preventing the lithium battery from further discharging. Additionally, in accordance with certain embodiments, the utility vehicle  20  is operative to generate a user notification to inform a user that a charger has been properly connected to the utility vehicle. Furthermore, in accordance with certain embodiments, the utility vehicle  20  is equipped with a fleet management client device to enable conveyance of operational information to a fleet management server apparatus for robust and reliable utility vehicle fleet management. Further details will now be provided with reference to  FIGS.  2  and  3   . 
       FIGS.  2  and  3    show particular details of the motion control system  26  of the utility vehicle  20  ( FIG.  1   ) of some example embodiments.  FIG.  2    shows certain general components of the motion control system  26  of some embodiments and how these components are related.  FIG.  3    shows particular lower level details of the motion control system  26  in accordance with some embodiments. 
     As shown in  FIG.  2   , the motor system  30  includes a motor controller  40 , an electric motor  42  which is linked to the set of tires  24  ( FIG.  1   ), and an electric brake  44  coupled with the electric motor  42 . The motor controller  40  of some embodiments controls delivery of stored electric power from the lithium battery system  32  to the electric motor  42  which ultimately turns at least some of the tires  24  to move the utility vehicle  20 . Additionally, the motor controller  40  of some embodiments controls delivery of regenerative power from the electric motor  42  to recharge the lithium battery system  32  (e.g., during braking, while the utility vehicle  20  coasts downhill without any pedal depression, etc.). 
     The electric brake  44  is constructed and arranged to provide mechanical resistance which inhibits turning of the electric motor  42  when the electric brake  44  is unpowered, and remove the mechanical resistance to release the electric motor  42  thus allowing the electric motor  42  to turn when the electric brake  44  receives power. Accordingly, in some embodiments, when the utility vehicle  20  sits idle (i.e., the utility vehicle  20  is awake but a user is not pressing on the accelerator pedal, the utility vehicle  20  is turned off, etc.), the electric brake  44  remains engaged and the utility vehicle  20  sits in a parked state. 
     The lithium battery system  32  includes a battery management system (BMS)  50  and a lithium battery  52 . The BMS  50  controls electrical access to the lithium battery  52 . Additionally, as will be explained in further detail shortly, the BMS  50  of some embodiments responds to various events such as sleep events (e.g., timeouts) to prevent excessive discharging of the lithium battery  52  thus safeguarding the lithium battery  52  from becoming over discharged. In some embodiments, the BMS  50  responds to other events as well such as wakeup events (e.g., actuation of the user controls  36 ), charging situations, fault conditions, and so on to properly and safely control charging and discharging of the lithium battery  52 . 
     It should be understood that a variety of form factors are suitable for the lithium battery  52 . For example, the lithium battery  52  may include multiple lithium battery cells, a single battery pack, combinations thereof, and so on. 
     The additional components  34  may, for example, include the set of user controls  36  (e.g., pedals, switches, etc.), the cabling  38 , a charging connector  60 , and perhaps other electrical components  62  (e.g., lights, a global positioning system (GPS), specialized equipment, etc.). In some arrangements, the cabling  38  includes a communications bus, such as, for example, a controller area network (CAN) bus through which the motor system  30  and the lithium battery system  32  exchange communications  70  such as electronic CAN messages in accordance with the CAN protocol. In some arrangements, the other electrical components include one or more user signaling devices such as a backup/reverse buzzer, one or more lights, and so on to provide distinctive user notifications. 
     As shown in  FIG.  3   , in accordance with some example embodiments, the battery management system (BMS)  50  of the lithium battery system  32  includes a power delivery interface  100 , a lithium battery interface  102 , a wakeup circuit  104 , a contactor  106 , and a charge regulation circuit  108 . These components may reside together as a single assembly or unit (e.g., within the same enclosure) or in a distributed manner among different locations on the utility vehicle body  22  (also see  FIG.  1   ). 
     The power delivery interface  100  couples with the motor system  30 . Similarly, the lithium battery interface  102  couples with the lithium battery  52 . The wakeup circuit  104  controls closing and opening of the contactor  106  to electrically connect the motor system  30  to the lithium battery  52  and disconnect the motor system  30  from the lithium battery  52 , respectively. During such operation, the charge regulation circuit  108  controls signal conditioning during discharging and charging of the lithium battery  52 . 
     As further shown in  FIG.  3   , the contactor  106  includes a set of target contacts  120  that couple with the power delivery interface  100 , a set of source contacts  122  that couple with the lithium battery interface  102 , and an electromagnetic actuator  124 . Although  FIG.  3    shows the contactor  106  controlling two signal paths between the motor system  30  and the lithium battery  52  by way of example (i.e., there are two source contacts  122  and two target contacts  120 ), other arrangements include different numbers of contacts and signal paths (e.g., one, three, four, etc.) depending on the particular application/electrical needs/etc. (e.g., DC power signals at different voltages, AC power signals in different phases, ground, etc.). 
     The wakeup circuit  104  includes control logic  130  and a timer  132  which operate to manage access to the lithium battery  52 . As will be explained in further detail shortly, such operation may be based on a variety of inputs  134  from the motor system  30 , from the user controls  36  (directly or indirectly), and so on. Along these lines, in response to a wakeup event (e.g., a user turning on the BMS  50 ), the wakeup circuit  104  outputs an actuator signal  136  that actuates the electromagnetic actuator  124  in a first direction  140  from a first position to a second position that connects respective source contacts  122  to corresponding target contacts  120  to electrically connect the motor system  30  to the lithium battery  52 . Along these lines, the electromagnetic actuator  124  may be provisioned with a solenoid or coil that closes the contactor  106  in response to the actuator signal  136 . 
     Additionally, in response to a sleep event (e.g., encountering a predefined time period of non-use while the BMS  50  is awake), the wakeup circuit  104  terminates output of the actuator signal  136  which releases the electromagnetic actuator  124 . In particular, the electromagnetic actuator  124  is spring biased in a second direction  142  which is opposite the first direction  140 . Accordingly, termination of the actuator signal  136  enables the electromagnetic actuator  124  to return back from the second position to the first position thus automatically separating the source contacts  122  from the target contacts  120  when the wakeup circuit  104  terminates output of the actuation signal  136  thus disconnecting the motor system  30  from the lithium battery  52 . As a result, there are no parasitic loads placed on the lithium battery  52  that could otherwise further discharge the lithium battery  52  to an over-depleted state. 
     In other embodiments, the wakeup circuit  104  does not need to constantly maintain the actuator signal  136 . Instead, the wakeup circuit  104  controls engagement and disengagement of the contactor  106  using discrete engagement and disengagement signals. With such use of a dedicated release signal, maintenance of a signal and termination for release is not required. 
     Wakeup/Sleep 
       FIGS.  4  through  6    provide particular details of how the battery management system (BMS)  50  responds to wakeup and sleep events in accordance with some embodiments.  FIG.  4    shows example details of wakeup circuitry  200  which is suitable for the wakeup circuit  104  (also see  FIG.  3   ) in accordance with some embodiments.  FIG.  5    shows a first arrangement of particular user controls  36  that couple with the inputs  134  and control operation of the wakeup circuit  104  ( FIG.  3   ) in accordance with some embodiments.  FIG.  6    shows a second arrangement of particular user controls  36  that couple with the inputs  134  and control operation of the wakeup circuit  104  ( FIG.  3   ) in accordance with some embodiments. 
     As shown in  FIG.  4   , the wakeup circuitry  200  controls access to the lithium battery  52  ( FIG.  3   ) in response to various events, situations, faults, etc. As shown in  FIG.  4   , the wakeup circuitry  200  includes, in an example embodiment, a communications interface  202 , memory  204 , processing circuitry  206 , and additional circuitry  208 . Such components form the control logic  130  and the timer  132  of the wakeup circuit  104  ( FIG.  3   ). 
     The communications interface  202  is constructed and arranged to connect the wakeup circuitry  200  to one or more communications media such as a controller area network (CAN) bus (also see the cabling  38  in  FIG.  1   ). Such communications may include different media such as copper-based (e.g., USB, RJ45, etc.), fiber optic communications, wireless communications (i.e., WiFi, cellular, Bluetooth, etc.), infrared, combinations thereof, and so on. 
     The memory  204  stores a variety of memory constructs  220  including an operating system  222 , specialized battery management code  224 , configuration data  226  (e.g., identification data, predefined timeout settings, charging settings, version data, model data, etc.), and other software constructs, code and data  228  (e.g., activity/event logs, utilities, tools, etc.). Although the memory  204  is illustrated as a single block in  FIG.  4   , the memory  204  is intended to represent both volatile and non-volatile storage (e.g., random access memory, flash memory, etc.), and may, in some embodiments, include a plurality of discrete physical memory units. 
     The processing circuitry  206  is configured to run in accordance with instructions of the various memory constructs  220  stored in the memory  204 . In particular, the processing circuitry  206  runs the operating system  222  to manage various computerized resources (e.g., processor cycles, memory allocation, etc.). Additionally, the processing circuitry  206  runs the specialized battery management code  224  to electronically control access to the lithium battery  52  ( FIGS.  2  and  3   ). The processing circuitry  66  may be implemented in a variety of ways including via one or more processors (or cores) running specialized software, application specific ICs (ASICs), field programmable gate arrays (FPGAs) and associated programs, microcontrollers, discrete components, analog circuits, other hardware circuitry, combinations thereof, and so on. In the context of one or more processors executing software, a computer program product  240  is capable of delivering all or portions of the software to the wakeup circuitry  200  (e.g., also see the memory constructs  220  in  FIG.  4   ). The computer program product  240  has a non-transitory (or non-volatile) computer readable medium which stores a set of instructions which controls one or more operations of the wakeup circuitry  200 . Examples of suitable computer readable storage media include tangible articles of manufacture and other apparatus which store instructions in a non-volatile manner such as flash memory, a magnetic storage medium (e.g., various disk memories such as a hard drive, floppy disk, or other magnetic storage medium), tape memory, optical disk (e.g., CD-ROM, DVD, Blu-Ray, or the like), and the like. It will be appreciated that various combinations of such computer readable storage media may be used to provide the computer readable medium of the computer program product  240  in some embodiments. 
     The additional circuitry  208  represents other circuitry of the wakeup circuitry  200 . Such circuitry may include hardware counters, signal drivers, connectors, sensors, and so on. In some arrangements, where the utility vehicle is specialized equipment (e.g., a food and beverage vehicle, an ATV, etc.) the additional circuitry  208  may represent other components such as an electronic thermostat, lighting control, and so on. 
     With reference to  FIG.  5    and in accordance with some embodiments, a first arrangement of the user controls  36  includes a maintenance switch  260 , a keyed switch  270 , and an accelerator (or throttle) pedal  280  which are electrically connected in series to the other circuitry of the motion control system  26  (also see  FIG.  2   ). Such user controls  36  may communicate with the BMS  50  via the inputs  134  ( FIG.  3   ). Other user controls  36  may be electrically connected to the motion control system  26  as well such as a brake pedal, a forward/reverse switch, and so on. In some arrangements, one or more of the user controls  36  connect directly to the motor system  30  and input signals are sensed by the BMS  50  from the motor system  30 . 
     With reference to  FIG.  6    and in accordance with some embodiments, a second arrangement of the user controls  36  includes a keyed switch  270 , and an accelerator (or throttle) pedal  280 , and a park brake release switch  290  (e.g., a switch which energizes and releases an electric brake to enable towing) which are electrically connected in parallel to the BMS  50  (also see  FIG.  2   ). Such user controls  36  may communicate with the BMS  50  via the inputs  134  ( FIG.  3   ). Other user controls  36  may be electrically connected to the motion control system  26  as well such as a brake pedal, a forward/reverse switch, a tow switch which is different from the park brake release switch, and so on. 
     In some embodiments, the park brake release switch  290  is formed by an actual physical switching device that a user can move to different positions. In other embodiments, the park brake release switch  290  is formed by a set of jumpers (e.g., connectors, cables, etc.) that are switchable or arrangeable into different connecting configurations (e.g., a normal configuration, a tow configuration, etc.). 
     It should be understood the control logic  130  and the timer  132  of the wakeup circuit  104  ( FIG.  3   ), which are formed by the wakeup circuitry  200  ( FIG.  4   ), operate to monitor user activity of the utility vehicle  20  as well as transition the BMS  50  from a sleeping state to an awake state and vice versa. Further details of such operation will now be provided. 
     During operation, the wakeup circuit  104  monitors operation of the user controls  36  to determine whether to electrically connect the lithium battery  52  to the motor system  30  or electrically disconnect the lithium battery  52  from the motor system  30 . For example, suppose that a human operator (or user) wishes to operate the utility vehicle  20  after an extended period of non-use such as a 24-hour period. In such a situation, the utility vehicle  20  is initially in a sleep (or unawake) mode or state in which the wakeup circuit  104  ( FIG.  3   ) is completely unpowered and the contactor  106  is open (i.e., where there is no circuit formed between the lithium battery  52  and the motor system  30 ). Accordingly, there are no electrical loads on the lithium battery  52  that could otherwise drain charge from the lithium battery  52 . 
     Further details of wakeup/sleep operation will now be provided with reference to some embodiments in connection with  FIG.  5   . Suppose that the user turns the maintenance switch  260  to an ON position (e.g., by simply transitioning the maintenance switch  260  from an OFF position to the ON position, by cycling the maintenance switch  260  from the ON position to the OFF position and back to the ON position, etc.). In such a situation, the wakeup circuit  104  of the BMS  50  turns on and responds by outputting the actuation signal  136  to close the contactor  106  ( FIG.  3   ). As a result of such a wakeup event, the contactor  106  connects the source contacts  122  to the target contacts  120  thus connecting the lithium battery  52  to the motor system  30  and waking the motor system  30 . 
     At this time and in accordance with some embodiments, both the BMS  50  and the motor system  30  perform various self-tests. For example, the BMS  50  checks the amount of charge remaining in the lithium battery  52  and, if the amount of charge is below a predefined minimum charge threshold, the BMS  50  terminates (e.g., immediately terminates) the actuation signal  136  to electrically disconnect the lithium battery  52  from the motor system  30 . Such operation prevents the lithium battery  52  from becoming over-discharged. It should be understood that, while the BMS  50  remains awake, the BMS  50  continues to monitor charge remaining in the lithium battery  52  and terminates the actuation signal  136  to disconnect the lithium battery  52  from the motor system  30  if the remaining charge reaches (or falls below) the predefined minimum charge threshold to safeguard the battery against becoming over-discharged. In particular, there is still safety margin between the predefined minimum charge threshold and an over-discharged level. 
     In some embodiments, after passing their respective self-tests, the BMS  50  and the motor system  30  communicate with each other (e.g., exchange communications  70  such as CAN messages) to verify configuration information (e.g., model numbers, versions, status, etc.). In some arrangements, the motor system  30  may be one of multiple models and the wakeup circuit  104  operates using different configuration settings depending on the particular model identified via communications with the motor system  30 . 
     Also, at this time, the control logic  130  of the wakeup circuit  104  starts the timer  132  ( FIG.  3   ) which counts or tracks time until the timer  132  reaches a predefined idle time threshold (i.e., a maximum idle time limit). In accordance with some embodiments, example values that are suitable for use for the predefined idle time threshold include time amounts within the time range of 10 hours to 14 hours (e.g., 11 hours, 12 hours, 13 hours, etc.). In accordance with other embodiments, example values that are suitable for use for the predefined idle time threshold include time amounts within the time range of 2 hours to 6 hours (e.g., 3 hours, 4 hours, 5 hours, etc.). If the timer  132  counts from an initial time value to the predefined idle time threshold (a sleep event), the timer  132  outputs a sleep event signal to the control logic  130  of the wakeup circuit  104  which causes the control logic  130  to terminate output of the actuation signal  136  thus disconnecting the lithium battery  52  from the motor system  30 . Such operation prevents the lithium battery  52  from unnecessarily succumbing to parasitic loads from the motor system  30 , from the contactor  106  (i.e., the coil maintaining the contactor  106  in the closed position), and perhaps from elsewhere in the utility vehicle  20 . 
     However, after BMS  50  has woken up, suppose that the user inserts a physical key into the keyed switch  270  and moves the keyed switch  270  from the OFF position to the ON position before the timer  132  reaches the predefined idle time threshold. In response to this sensed user activity, the control logic  130  restarts the timer  132  to the initial time value. Accordingly, the timer  132  is prevented from reaching the predefined idle time threshold and expiring. 
     Likewise, suppose that the user actuates the accelerator pedal  280  (e.g., moves the pedal  280  from its non-depressed position) before the timer  132  reaches the predefined idle time threshold. In response to this sensed user activity, the control logic  130  restarts the timer  132  to the initial time value. Again, the timer  132  is prevented from reaching the predefined idle time threshold and expiring. It should be understood that moving the accelerator pedal  280  may further signal the motor system  30  to operate the motor  42  (e.g., rotate the motor  42  in a particular direction and at a particular speed based on other factors). 
     However, if the user leaves the utility vehicle  20  unattended and the timer  132  reaches the predefined idle time threshold, the timer  132  expires (a sleep event) and sends a sleep event signal to the control logic  130 . In response to the sleep event signal, the control logic  130  terminates output of the actuation signal  136  thus opening the contactor  106  to disconnect the lithium battery  52  from the motor system  30  ( FIG.  3   ) and protecting the lithium battery  52  against further discharge. 
     In accordance with some embodiments, if the BMS  50  has fallen asleep and the maintenance switch  260  ( FIG.  5   ) remains in the ON position, the user is able to wake the BMS  50  by moving the keyed switch  270  to the ON position (another wakeup event). Likewise, in accordance with some embodiments, if the BMS  50  has fallen asleep and the maintenance switch  260  and the keyed switch  270  are both in the ON position, the user is able to wake the BMS  50  by actuating the pedal  280  (yet another wakeup event). 
     In some embodiments and with reference to  FIG.  5   , the series configuration of the maintenance switch  260 , the keyed switch  270 , and the accelerator pedal  280  enables the maintenance switch  260  to disable sensing of the keyed switch  270  and the accelerator pedal  280 . In particular, when the maintenance switch  260  is in the OFF position, the keyed switch  270  and the accelerator pedal  280  are unable to provide input to the control logic  130  of the wakeup circuit  104  thus preventing the user from waking up the BMS  50  via the keyed switch  270  or the pedal  280  while the maintenance switch  260  is in the OFF position. 
     Similarly, when the keyed switch  270  is in the OFF position, the accelerator pedal  280  is unable to provide input to the control logic  130  of the wakeup circuit  104 . Accordingly, the user cannot wake up the BMS  50  simply by pushing on the accelerator pedal  280  while the keyed switch  270  is in the OFF position. 
     In some embodiments, while the maintenance switch  260  is in the ON position and the BMS  50  is awake, the motor system  30  and the BMS  50  operate to provide a walkaway protection feature that prevents the utility vehicle  20  from inadvertently rolling away at a high rate of speed. Along these lines, suppose that the user forgets to mechanically engage a brake to hold the utility vehicle  20  in place. If the utility vehicle  20  is perched on a hill and begins to roll, the motor system  30  senses that the utility vehicle  20  is moving but that the user is not pressing on the accelerator pedal  280 . Accordingly, the motor system  30  of such embodiments provides proactive speed control and regenerative power. The proactive speed control maintains motor rotation at a low speed thus enabling the user to walk up to and stop the utility vehicle  20 . Furthermore, the regenerative power recharges the lithium battery  52  thus improving efficiency. 
     Additional Details 
       FIG.  7    is a flowchart of a procedure  400  which is performed by the battery management system (BMS)  50  of the utility vehicle  20  to control access to the lithium battery  52  in accordance with some example embodiments. 
     At  402 , the BMS  50  mechanically disconnects a lithium battery interface from a power delivery interface in response to a sleep event. The lithium battery interface couples with a lithium battery supported by the utility vehicle, and the power delivery interface couples with a set of loads of the utility vehicle. For example, a timer of the wakeup circuit may expire after a period of non-use thus indicating that the BMS  50  may disconnect the lithium battery  52  without interfering with a user of the utility vehicle  20 . Such disconnection prevents parasitic loads from further draining the lithium battery  52 . 
     At  404 , after the lithium battery interface is mechanically disconnected from the power delivery interface, the BMS  50  mechanically reconnects the lithium battery interface to the power delivery interface in response to a wakeup event. For example, in accordance with some embodiments and in response to certain conditions, the user may press an accelerator pedal or cycle a keyed switch to wakeup the BMS  50 . 
     At  406 , after the lithium battery interface is mechanically reconnected to the power delivery interface, the BMS  50  maintains connection between the lithium battery interface and the power delivery interface to convey power from the lithium battery  52  to the set of loads of the utility vehicle through the lithium battery interface and the power delivery interface. In particular, the BMS  50  may start a timer to measure a period of non-use and maintain lithium battery access as long as the timer does not expire and as long as the lithium battery does not discharge below a predefined safe level. 
     As described above, improved techniques are directed to controlling electrical access to lithium batteries  52  on utility vehicles  20 . Such techniques provide the ability to automatically disconnect the lithium batteries  52  from loads in response to timeout or sleep events. Such operation prevents the lithium batteries  52  from discharging even due to parasitic loads while the utility vehicles  20  are idle. Accordingly, the lithium batteries  52  will not discharge to unnecessarily low levels (e.g., safeguard levels). As a result, such operation robustly and reliably prevents the lithium batteries  52  from being recharged after being over-discharged and thus safeguards the lithium batteries  52  against becoming unstable. 
     Charging 
       FIG.  8    shows particular details of an external charger  300  and a charging system  500  of the utility vehicle  20 . The external charger  300  includes a first plug  302 , a charger (or adaptor)  304 , and a second plug  306 . The first plug  302  is constructed and arranged to connect the charger  304  to an external power source  310  such as an AC outlet. The second plug  306  is constructed and arranged to connect the charger  304  to the charging connector  60  of the utility vehicle  20  (also see  FIG.  2   ). The charger  304  is constructed and arranged to convert and condition a power signal from the external power source  310  for use by the utility vehicle  20 . 
     In some embodiments, the charger  304  includes a display  312  to display information to a user. Along these lines, the display  312  may include light emitting diodes (LEDs) of different colors (e.g., green, red, etc.). 
     As shown in  FIG.  8    and in accordance with some embodiments, the charging system  500  of the utility vehicle  20  is formed by the connector  60  (e.g., a receptacle or plug), the lithium battery  52 , and control circuitry  502 . Furthermore, the control circuitry  502  is formed by the BMS  50  and at least a portion of the motor controller  40 . 
     Although some of the connecting pathways may have been mentioned and/or illustrated earlier, the various components of the charging system  500  couple via a variety of pathways  510 , including any combination of multiple types of pathways  510  (also see the cabling  38  in  FIG.  1   ). In some embodiments, the connector  60  couples with the motor controller  40  and the BMS  50  via a power bus  512 . In some embodiments, the motor controller  40  and the BMS  50  communicate over a communications bus  514 . In some embodiments, the connector  60  further couples with motor controller  40  via an interlock signal pathway  516 . In some embodiments, the connector  60  further couples with BMS  50  via a control signal pathway  518 . 
     Additionally, in some embodiments, the BMS  50  couples with the lithium battery  52  via a power pathway  520 , and a set of communications pathways  522 . The power pathway  520  carries power to and from the lithium battery  52 . The set of communications pathways  522  enables the BMS  50  to receive information (e.g., battery status such as voltage and temperature measurements) from the lithium battery  52 . 
     As further shown in  FIG.  8    and in accordance with some embodiments, the lithium battery  52  includes multiple lithium modules  530 . Each lithium module  530  may include several lithium cells as well as circuitry to output individual status such as that module’s minimum and maximum voltage, that module’s minimum and maximum temperature, etc. 
     In some embodiments, the connector  60  includes a display  540  to indicate charging information to a user. In certain embodiments, the display  540  includes an LED that provides status to the user via different blinking or flashing patterns. In accordance with some embodiments, in response to different charging commands that the external charger  300  receives from the utility vehicle  20 , the external charger  30  may flash or not flash the LED at different rates (e.g., a first speed to indicate charging at a normal rate, a second speed to indicate charging at a slow rate, and no flashing to indicate that the external charger  300  is not charging the lithium battery  52 , etc.). 
     In some embodiments, the motor controller  40  includes detection circuitry  550  and electric brake control circuitry  552 . The detection circuitry  550  is configured to detect connection between the external charger  300  and the connector  60  and convey such connection status to the BMS  50 . The electric brake control circuitry  552  is configured to control power to the electric brake  44  ( FIG.  2   ). Further charging details will be provided with reference to  FIGS.  8  and  9   . 
       FIG.  9    shows a sequence diagram  600  showing particular charging activities that occur during lithium battery charging in accordance with some embodiments. Suppose that a user wishes to charge the lithium battery  52  of the utility vehicle  20 . In particular, the user may be ready to connect the external charger  300  to the connector  60  of the utility vehicle  20 . 
     At  610 , the user connects the external charger  300  to the connector  60  of the utility vehicle  20 . In some embodiments, it does not matter whether the user plugs the external charger  300  into the external power source  310  (e.g., an AC outlet) before or after the user engages the plug  306  with the connector  60 . Rather, the external charger  300  is considered properly connected to the connector  60  of the utility vehicle  20  once both events have occurred, i.e., the user has plugged the external charger  300  into the external power source  310  and the user engaged the plug  306  with the connector  60  (also see  FIG.  8   ). 
     At  620 , in response to the user plugging the external charger  300  into the external power source  310  and engaging the plug  306  with the connector  60 , the external charger  300  outputs (i) an initial power signal  622  and (ii) an interlock signal  624  to the utility vehicle  20  ( FIG.  8   ). In some embodiments, the initial power signal  622  is a temporary pulse (e.g., a 48 Volt power signal for a duration of six seconds). If the motor controller  40  and the BMS  50  are initially asleep, this initial power signal  622  wakes the motor controller  40  and the BMS  50  (e.g., the motor controller  40  and the BMS  50  power up and perform self-tests, the motor controller  40  and the BMS  50  perform sensing, etc.). 
     At  630 , with the interlock signal  624  from the external charger  300  present at the connector  60  due to connection of the external charger  300  with the connector  60 , the motor controller  40  detects the presence of the interlock signal  624  via the interlock signal pathway  516 . In some embodiments, the detection circuitry  550  of the motor controller  40  tries to raise the interlock signal pathway  516  to a predefined voltage and a transistor in the connector  60  pulls that predefined voltage on the interlock signal pathway  516  low (e.g., to ground) in the absence of the external charger  300 . When the user connects the external charger  300  to the connector  60 , the transistor in the connector  60  stops pulling the predefined voltage on the interlock signal pathway  516  low in response to the interlock signal  624  from the external charger  300 . As a result, the detection circuitry  550  detects that the external charger  300  is connected to the connector  60 . 
     At  640 , in response to detecting connection of the external charger  300  with the connector  60 , the control circuitry  550  of the motor controller  40  sends a communication  642  ( FIG.  8   ) to the BMS  50  informing the BMS  50  that the external charger  300  is connected to the connector  60 . In some embodiments, the communication  642  is a CAN message that the motor controller  40  sends to the BMS  50  via a CAN bus (also see communications  70  in  FIG.  2   ). 
     At  650 , in response to the communication  642 , the BMS  50  closes its contactor  106  ( FIG.  3   ) and ascertains the current charge state of the lithium battery  52 . In some embodiments, the BMS  50  routinely samples a current set of operating conditions  652  ( FIG.  8   ) from the lithium battery  52  such as minimum and maximum voltage, minimum and maximum temperature, etc. 
     At  660 , based at least in part on the current set of operating conditions  652 , the BMS  50  provides a control signal  662  ( FIG.  8   ) on the control signal pathway  518  to the external charger  300 . In some embodiments, the control signal  662  informs the external charger  300  of what the lithium battery  52  requires for proper charging based on the condition of the lithium battery  52 . 
     At  670 , if the lithium battery  52  requires charging, the external charger  300  provides a proper power signal  672  ( FIG.  8   ) to the lithium battery  52  based on the control signal  662 . Additionally, in some embodiments and at  680 , the external charger  300  provides a status signal  674  to the display  540  of the connector  60  to inform the user of the charging status (e.g., a slow blinking LED for a slow charge rate, a fast blinking LED for a normal charge rate, a solid LED for no charging due to the lithium battery being at full capacity, etc.). In some embodiments, the control signal  662 , the interlock signal  624 , and the status signal  674  are multiplexed through a cable connecting the charger  304  to the connector  60 . 
     This above-described operation may continue until the lithium battery  52  is fully charged (e.g., repeating  630  through  670 ). In some embodiments, the BMS  50  is configured to routinely monitor the current charge state of the lithium battery  52  over time. If the BMS  50  determines that the lithium battery  52  requires different charging, the BMS  50  provides an appropriate control signal  662  to the external charger  300  causing the external charger to provide a proper power signal  672 . It will be appreciated that such routine monitoring may encompass monitoring the current charge state of the lithium battery  52  over any of a variety of time intervals, including, for example, monitoring at various periodic intervals, monitoring at aperiodic intervals of varying time length, and/or in some embodiments, constant monitoring during one or more time periods. If the BMS  50  determines that the lithium battery  52  is fully charged, the BMS  50  provides an appropriate control signal  662  informing the external charger  300  to stop providing the power signal  672 . 
     In some embodiments, the BMS  50  routinely samples, from all of the lithium modules  30 , a current overall minimum voltage and a current overall maximum voltage. The BMS  50  compares these samples to a set of predefined voltage thresholds to determine whether the lithium battery  52  requires further charging or if the lithium battery  52  is fully charged. It will be appreciated that such routine sampling may encompass sampling over any of a variety of time intervals, including, for example, sampling at various periodic intervals, sampling at aperiodic intervals of varying time length, and/or in some embodiments, constant sampling during one or more time periods. 
     Additionally, in some embodiments, the BMS  50  routinely samples, a respective minimum temperature and a respective maximum temperature from each module  530 . It will be appreciated that such routine sampling may encompass sampling over any of a variety of time intervals, including, for example, sampling at various periodic intervals, sampling at aperiodic intervals of varying time length, and/or in some embodiments, constant sampling during one or more time periods. 
     The BMS  50  further determines an overall current minimum temperature and an overall current maximum temperature for the lithium battery  52  as a whole from all of the respective module measurements. The BMS  50  compares these overall measurements to a set of predefined temperature thresholds to determine an appropriate rate of charge if any (also see the configuration data  226  in  FIG.  4   ). For example, in accordance with some embodiments, the BMS  50  considers the lithium battery  52  ready to receive charging from the external charger  300  at a normal rate if the temperatures reside within a temperature range of 5° C. to 45° C. Additionally, in accordance with some embodiments, the BMS  50  considers the lithium battery  52  ready to receive charging from the external charger  300  at a slow rate (i.e., a rate which is slower than the normal rate) if the temperatures reside within a defined suboptimal temperature range, which in some embodiments may include a defined suboptimal temperature range of -10° C. to 5° C. and/or within a suboptimal temperature range 45° C. to 60° C. (i.e., outside the range of 5° C. to 45° C. but within the range of -10° C. to 60° C.). It will be appreciated that such suboptimal temperature ranges may be selected and defined based on characteristics and tolerances of the lithium battery  52 . Thus, alternative optimal and suboptimal ranges may be used in accordance with various embodiments. Furthermore, in accordance with some embodiments, the BMS  50  considers the lithium battery  52  not ready to receive charging from the external charger  300  (i.e., a fault situation) if the temperatures reside outside a defined temperature range, such as the temperature range of -10° C. to 60° C. 
     In some embodiments, the control signal  662  takes the form of a pulse width modulation (PWM) signal to imitate electrical behavior of a thermistor. Here, the BMS  50  outputs signals of different pulse widths to convey, as commands to the external charger  300 , the different charging requirements of the lithium battery  52  (e.g., full, charge at a slow rate, charge at a normal rate, or fault). 
     In some embodiments, if the charging criteria changes over time and the external charger  300  updates the power signal  672 , the external charger  300  also updates the status signal  674  to the display  540  of the connector  60 . Accordingly, the user is able to identify whether the lithium battery  52  is charging and, if so, at what current rate. 
     When the BMS  50  informs the external charger  300  that the lithium battery  52  should not be charged, the external charger  300  terminates the power signal  672  and sets its display  312  accordingly. In some embodiments, when the BMS  50  informs the external charger  300  that the lithium battery  52  is fully charged, the external charger  300  terminates the power signal  672  and provides a visual indication (e.g., lights a green LED) to inform the user. In some embodiments, when the BMS  50  informs the external charger  300  that the lithium battery  52  should not be charged due to a fault condition (e.g., a temperature reading outside a predefined temperature range), the external charger  300  terminates the power signal  672  and provides a visual indication (e.g., lights a red LED) to inform the user. 
     In response to determining that the lithium battery  52  is fully charged, the BMS  50  notifies the external charger  300  and goes to sleep by opening the contactor  106  ( FIG.  3   ). In some embodiments, the BMS  50  may remain awake for a short time after the lithium battery  52  is fully charged. Along these lines, the control logic  130  of the BMS  50  may use the timer  132  ( FIG.  3   ) to monitor inactivity time and then go to sleep if there is no further sensed electronic activity by the utility vehicle  20  before the timer  132  times out. That is, in response to expiration of the timer  132 , the BMS  50  opens the contactor  106  and goes to sleep. 
     It should be understood that the various timeout times imposed by the timer  132  may be of different lengths depending on the particular circumstances. For example, the amount of time used by the timer  132  to monitor inactivity after lithium battery charging may be different from the amount of time used by the timer  132  to monitor inactivity after other events such as after the user has cycled the keyed switch  270  and/or after the user has let up on the accelerator pedal  280  after driving the utility vehicle  20 . In some embodiments, the timer  132  uses a shorter timeout period to monitor inactivity in response to the lithium battery  52  being charged to full capacity. 
     In some embodiments, the pull-down transistor feature of the connector  60  operates as a safeguard in the event that the connector  60  is damaged and disconnects from the motor controller  40 . In such a situation, the detection circuitry  550  of the motor control  40  will detect a high signal on the interlock signal pathway  516  since the detection circuitry  550  raises the voltage to a predefined level and the transistor in the connector  60  is unable to pull that signal down due to disconnection. 
     In some embodiments, when the detection circuitry  550  of the motor controller  40  detects connection between the external charger  300  and the connector  60  (e.g., due to the presence of the interlock signal  624  on the interlock signal pathway  516 ), the detection circuitry  550  causes the electric brake control circuitry  552  to prevent the electric brake  40  from energizing (also see  FIG.  8   ). Accordingly, the utility vehicle  20  remains stationary. Further details will now be provided with reference to  FIG.  10   . 
       FIG.  10    is a flowchart of a procedure  700  which is performed by circuitry of a utility vehicle during lithium battery charging in accordance with some example embodiments. In some embodiments, the procedure  700  begins simply in response to a human user connecting an external charger to a charging connector of the utility vehicle. 
     At  702 , the circuitry detects connection between an active external charger and a connector of the utility vehicle (e.g., a connection event). In some embodiments, a motor controller of the utility vehicle provides a communication (e.g., a CAN message) to a BMS of the utility vehicle informing the BMS that the utility vehicle’s charging connector is connected to the external charger. 
     At  704 , in response to detecting connection between the external charger and the connector, the circuitry ascertains a charging state of the lithium battery. In some embodiments, the circuitry samples maximum and minimum voltages and temperatures from individual lithium modules that form the lithium battery and compares these samples to a set of predefined thresholds to determine the current charging state of the lithium battery. 
     At  706 , based at least in part on the charging state, the circuitry provides a control signal to the external charger through the connector. The control signal is configured to control charging output from the external charger to charge the lithium battery. In some embodiments, the external charger provides one of multiple different responses based on the control signal (e.g., terminate the charging signal due to the lithium battery being fully charged, provide a charge signal at a slow charge rate, provide a charge signal at a normal rate, terminate the charging signal due to a fault, etc.). 
     If the external charger is providing a charge signal to charge the lithium battery, the circuitry repeats  704  and  706 . It will be appreciated that repetition of operations  704  and  706  may be performed at any of a variety of time intervals, including, for example, various periodic intervals, aperiodic intervals of varying time length, and/or in some embodiments, constant sampling during one or more time periods. As a result, the external charger continues to provide a charge signal and the lithium battery continues to charge. 
     When the lithium battery is fully charged, the circuitry detects this situation (e.g., based on monitoring the charging state of the lithium battery), and causes the external charger to terminate the charging signal. Additionally, the circuitry goes to sleep (e.g., after a short period of time) to prevent unnecessary discharging of the lithium battery. 
     As described above, improved techniques are directed to charging a lithium battery  52  of a utility vehicle  20  where a human user is able to initiate charging by simply connecting an external charger  300  to the utility vehicle  20 . Such techniques do not require further human user input. Rather, the utility vehicle  20  is able to automatically respond by conveying charge from the external charger  300  to the lithium battery  52  and disconnecting the lithium battery  52  once the lithium battery  52  is fully charged. Accordingly, the human user does not need to remember to actuate a charge-enable switch and does not need to receive special training on how to operate such a switch. 
     In accordance with some embodiments, a charging system controls charging of a lithium battery powered car. Various features include charging initiation by plugging in charger only, dynamic charge rate adjustment based at least in part on battery temperature, and communication of status, control, and fault conditions between the BMS and charger. 
     In some embodiments, the components of the charging system include an off board battery charger, charger plug, charger receptacle, and BMS. The lithium battery couples with the BMS which disconnects the pack from the car when the car is not being used. 
     Conventional lithium battery powered vehicles require the operator to actuate a switch that tells the BMS to reconnect to the vehicle electrical system for charging. If the operator forgets to actuate the switch then the batteries won’t charge. 
     However, in accordance with certain embodiments disclosed herein, the charge sequence is initiated by connecting the external charger to the charging connector of the utility vehicle. No other operator input is required. To accomplish this, the charger may sense a plug being plugged into a receptacle. The charger then applies a 6 second, 48 volt pulse to power the entire vehicle electrical system. This wakes up the BMS and the motor controller. 
     In some embodiments, the BMS does not have a direct input from the charger or connector indicating whether the charger is plugged in. Rather, the motor controller senses that the charger is plugged in through an interlock signal from the connector. The motor controller sends a message (e.g., a CAN message) to the BMS that the charger is plugged in. When the BMS receives this signal it closes its contactor to reconnect the batteries to the vehicle electrical system. As long as this signal is valid, the BMS will remain connected. Charging can then take place. 
     For some lead acid battery powered vehicles, the lead acid battery charger uses a thermistor on the batteries to sense battery temperature. Battery temperature is used to adjust certain charge parameters in the charger. The thermistor is connected to the charge connector which multiplexed the thermistor reading, the connector LED control, and charger interlock signals onto a single wire to the charger. For the lithium batteries, the thermistor signal may be repurposed into a charge control signal. A transistor can be added to the BMS which imitates a thermistor by using pulse width modulation (PWM). In some embodiments, the PWM duty cycle is divided into 4 distinct levels that represent Charger Full, Charging Allowed at a Slow Rate, Charging Allowed at the Normal Rate, and Fault. In some embodiments, the BMS allows full charge rate within a normal range of battery cell temperatures (5 to 45° C.). In some embodiments, the slow charge rate is allowed over a slightly wider cell temperature range (-10 to 5, and 45 to60° C.). No charging is allowed outside of the wide temperature range. The system dynamically adjusts charge rates based on temperature with no operator input. When charging is complete, the BMS signals Charger Full to the charger, which terminates charging. The charger responds to a fault signal by lighting a fault indicator LED on the charger. 
     In accordance with some embodiments, system components include the charger, charger plug, charger receptacle, BMS, motor controller, and vehicle switches. The BMS and the motor controller communicate over the CAN bus. In some embodiments, the BMS monitors the status of 3 switch inputs: key switch, pedal switch, and park brake release switch. In some embodiments, the motor controller monitors the status of a Run/Tow switch. In some embodiments, the BMS sends a PWM signal to the charger via the charger plug and connector. The connector drives a charger interlock signal that is monitored by the motor controller. An LED on the connector is controlled by the charger and indicates charge status. The LED, interlock, and PWM signals are all multiplexed onto a single wire from the charger to the charger plug and connector. Circuits inside the charger and connector encode and decode the signals. For lithium, a lead acid battery temperature signal was not needed and was replaced by the PWM signal which relays status information from the BMS to the charger. 
     In accordance with some embodiments, when the charger is plugged into the car, charging initiates regardless of whether the BMS is asleep or awake. If the BMS is awake, plugging in the charger asserts the charger interlock signal from the charge connector to the motor controller. In some embodiments, the motor controller informs the BMS that the charger is plugged in via a status bit in a message (e.g., a CAN message). The BMS then sets the PWM signal appropriately (when not charging, the BMS sets the PWM signal to the Fault mode as a failsafe). Charging can then take place. The BMS stays awake until charging is complete, and goes to sleep shortly after charging is complete. Accordingly, the BMS knows that the charger is plugged in and can monitor for fault and warning conditions. If the charger is plugged into a vehicle where the BMS is asleep, then the charger provides power to the vehicle’s electrical system. This wakes up the BMS and the motor controller. If the BMS receives a message (e.g., a CAN message) from the motor controller with the charging status bit set, then it will close its contactor and set the PWM signal appropriately. Charging then commences. 
     Additionally, it should be understood that the keyed switch was described above as being used in certain example embodiments. It will be appreciated that the keyed switch is just one example of an ignition switch that may be used in various embodiments. For example, in other example embodiments, the vehicle uses a keyless, push-button ignition rather than a keyed switch. Such ignition is enabled when an “electronic key” (e.g., an RF device) on the passenger’s person is within range of a wireless sensor of the vehicle. Here, an actuation of the switch occurs through presence of the electronic key in combination with physical actuation of the button. 
     Furthermore, in some embodiments, the BMS  50  utilizes an inactivity timer that measures inactivity time based on current (also see the timer  132  in  FIG.  3   ). For example, the inactivity timer starts timing inactivity when current sensed from the lithium battery falls below a predefined current threshold (e.g., 3 amps). As long as the current remains below this predefined current threshold, the inactivity timer continues to measure time. However, if the current rises above the predefined current threshold, the inactivity timer is cleared (or reset) because this rise in current above the predefined current threshold is considered detected activity. The inactivity timer then starts counting again when current falls below the predefined current threshold. If the inactivity timer ever reaches a timeout value, the inactivity timer is considered to have expired (i.e., detected an inactivity timeout event). 
     User Notification 
     In accordance with some embodiments, the utility vehicle  20  generates a user notification when an external charger has been properly connected to the utility vehicle  20  (e.g., see the external charger  300  in  FIG.  8   ). The user notification may be distinctive to particularly inform the user that the external charger has been properly connected to the utility vehicle  20  so that the user is able to move on to other tasks rather than place further time and effort into monitoring or double checking the equipment in order to make sure the external charger and the utility vehicle are connected and operating properly. 
     The operation of determining whether the external charger is properly in place is performed by circuitry of the utility vehicle  20  in accordance with some embodiments. Such circuitry may be formed by a portion of the motor system  30 , the lithium battery system  32 , and/or the additional components  34  (also see  FIG.  2   ). Alternatively, some or all of the circuitry may reside elsewhere such as within the external charger, within an external server, and so on. 
     In some arrangements, the circuitry of the utility vehicle provides a notification signal to an external user device (e.g., a smart phone, a tablet, an external computer, etc.). Such communications may take place via a cable or wirelessly. In some arrangements, such communications take place through an intermediate external server that also logs and processes the notification signal. 
     Moreover, such communications may take the form of push notifications to inform the user (e.g., via a phone app, via a text message, etc.) that provides utility vehicle information such as lithium battery charge integrity verification status resulting from a pre-charge test routine. Along these lines, the user device may receive notification for a single vehicle or for multiple vehicles (e.g., in a fleet management scenario). Such operation may be performed in addition to or in lieu of a user notification that is directly output from the utility vehicle  20 . 
       FIG.  11    shows a procedure  800  which, by way of example, is performed by the circuitry of the utility vehicle  20  to provide the user notification as well as adjust the amount of charge stored by the lithium battery  52  (e.g., to charge the lithium battery  52 , also see  FIG.  2   ) when the external charger is connected to the utility vehicle  20  ( FIG.  8   ). As part of this process, the circuitry provides the user notification when the external charger is properly connected. 
     At  802 , the circuitry detects availability of charge from the external charger. For example, such detection may occur when a user connects the external charger to a connector of the utility vehicle  20 . 
     At  804 , in response to detection of the availability of charge from the external charger and prior to controlling the external charger to adjust the amount of charge stored by the lithium battery, the circuitry performs a set of pre-charging assessment operations. In some embodiments, the detection circuitry  550  is operative to detect connection between the external charger  300  and the connector  60  and convey such connection status to the BMS  50  (also see  FIG.  8   ). Moreover, the BMS  50  and the motor controller  40  are able to coordinate their operation and determine a result the set of pre-charging assessment operations indicating either that the lithium battery  52  should be charged (i.e., a successful result) or not charged (i.e., an unsuccessful result). 
     In some embodiments, when the circuitry detects connection of the external charger, the circuitry tests whether any of a plurality of BMS protection fault conditions exist and then generates a pre-charging assessment indication based on whether any of the plurality of BMS protection fault conditions exist. Here, the circuitry evaluates aspects such as current lithium battery temperature and voltage measurements from the lithium battery by reading such measurements and comparing them to a set of predefined thresholds, status flags, warning signals, etc. to determine whether any of the plurality of BMS protection fault conditions exist. For example, the circuitry may determine that the lithium battery  52  is too cold or too warm (i.e., fault conditions) to safely receive a charge. As another example, the circuitry may determine that the lithium battery  52  has been extremely undercharged (i.e., another fault condition) and is no longer safe to receive a charge, and so on. 
     In some embodiments, when the circuitry detects connection of the external charger  300 , the circuitry tests whether the lithium battery  52  is to receive charge from the external charger, and generate a pre-charging assessment indication based on whether the lithium battery  52  is to receive charge from the external charger. Here, the circuitry ascertains a current amount of charge stored by the lithium battery  52 , and compares the current amount of charge to a predefined target charge range to determine whether the lithium battery is to receive charge from the external charger. If the amount of charge is already within the predefined target charge range, the circuitry does not charge the lithium battery because there is no need to charge the lithium battery  52 . However, if the amount of charge is below the predefined target charge range, the circuitry determines that the lithium battery is ready for charging. 
     In some embodiments, when the circuitry detects connection of the external charger, the circuitry tests whether the external charger is operative to provide a predefined voltage to charge the lithium battery  52 , and generate a pre-charging assessment indication based on whether the external charger is operative to provide the predefined voltage to charge the lithium battery  52 . Here, the circuitry measures a current supply voltage provided by the external charger, and compares the current supply voltage to a predefined supply voltage threshold. If the external charger does not provide the predefined voltage, the circuitry determines that the external charger is not ready to charge the lithium battery  52 . However, if the external charger is currently operative to provide the predefined voltage, the circuitry concludes that the external charger is ready to charge the lithium battery  52 . 
     In some arrangements, the circuitry does not charge the lithium battery  52  unless multiple conditions described above are in place before charging the lithium battery  52 . In certain embodiments, the circuitry does not charge the lithium battery  52  unless no BMS protection fault conditions exist, the BMS outputs a signal indicating that the lithium battery  52  is ready to receive charge from the external charger, and the external charger  300  has demonstrated that the external charger  300  is prepared to provide the predefined voltage. 
     At  806 , the circuitry provides a user notification via the user signaling device based on the set of pre-charging assessment operations, the user notification indicating whether the lithium battery is properly setup for charge adjustment. It should be understood that a variety of user output indicators are suitable for use. For example, such notification may be in the form of one or more audio signals (e.g., one or more buzzes, beeps, bell tones, other distinctive noises, combinations thereof, etc.) and/or one or more video signals (e.g., one or more solid or blinking lights, output on one or more segmented displays, output on a graphical screen or monitor, combinations thereof, etc.). For example, in some embodiments, notification may be provided via a backup/reverse buzzer, headlights, taillights, some combination thereof, and/or the like of the utility vehicle  20 . Moreover, the absence of a particular type of output (e.g., silence) may operate as an indicator (e.g., an indication of a fault situation, improper connection, etc.). 
     In some arrangements, the circuitry provides a particular user notification if the lithium battery is properly setup for charge adjustment, and a different user notification if the lithium battery is not properly setup for charge adjustment. The differences may be different sounds, noises, video indications, and so on. In some arrangements, silence and no video indicates that the lithium battery is not properly setup for charge adjustment. 
     Once the user receives a successful result as the user notification, the user knows that the external charger is properly connected and that the utility vehicle  20  has concluded that the lithium battery  52  is ready for charge adjustment based on the successful result from the set of pre-charging assessment operations. Accordingly, the user may move on to another task such as attending to another utility vehicle  20  if managing a fleet of utility vehicles  20 . 
     At  808  and in accordance with some embodiments, based on a successful result from the set of pre-charging assessment operations, the circuitry of the utility vehicle  20  provides a control signal that adjusts the amount of charge stored by the lithium battery  52 . For example, the circuitry may signal the external charger to provide charge in order to charge the lithium battery  52 . In response the external charger  300  provides charge (e.g., through the connector  60 , also see  FIG.  8   ) to charge the lithium battery  52 . 
     In some arrangements, the circuitry signals the external charger to provide charge at a particular charge rate (e.g., a full charge rate, a less than full charge rate due to sub-optimal temperature, etc.). In some arrangements, the circuitry notifies the external charger to provide no charge but instead allow the utility vehicle to discharge the lithium battery  52  for storage purposes. Other charge adjustment operations are suitable for use as well. 
     It should be understood that if the circuitry determines that the lithium battery is not properly setup for charge adjustment, (e.g., there is a fault condition), the set of pre-charging assessment operations provides an unsuccessful result (e.g., a different audio output, a different visual output, combinations thereof, silence, etc.) and the circuitry does not provide the control signal. 
     Fleet Management System Equipped With User Notification 
       FIG.  12    shows particular details of a fleet management system  900  that includes utility vehicles  20 ( 1 )( 1 ),  20 ( 1 )( 2 ),  20 ( 1 )( 3 ), ...,  20 ( 2 )( 1 ),  20 ( 2 )( 2 ), ...,  20 (X)(Y), ..., and so on (collectively, utility vehicles  20 ) which are equipped with fleet management client devices  910 ( 1 )( 1 ),  910 ( 1 )( 2 ),  910 ( 1 )( 3 ), ...,  910 ( 2 )( 1 ),  910 ( 2 )( 2 ), ...,  910 (X)(Y), ..., and so on (collectively, fleet management client devices  910 ), respectively, where X (e.g., the row of the utility vehicle  20 ) and Y (e.g., the position of a utility vehicle  20  within a row, etc.) are positive integers. Additionally, the fleet management system  900  includes a fleet management server apparatus  920  that is operative to assess and/or track various vehicle information (e.g., lithium battery status, etc.). 
     In some arrangements, the fleet management server apparatus  920  receives the results of the pre-charge assessment operations performed by each utility vehicle  20  of the fleet. Along these lines, the fleet management server apparatus  920  is then able to identify which utility vehicles  20  are not properly charged, cars with faulty lithium battery systems  32 , faulty external chargers  300 , and so on. 
     It should be understood that the fleet management system  900  includes a fleet management network environment  930  that facilitates communications  940  between the fleet management client devices  910  and the fleet management server apparatus  920 . Such communications  940  may occur through wires (e.g., copper-based, fiber-based, etc.), may be wireless (e.g., WiFi, cellular, Bluetooth, infrared, etc.), may involve further data communications devices (e.g., routers, firewalls, bridges, gateways, etc.), combinations thereof, and so on. 
     In some embodiments, users are able to drive the utility vehicles  20  into and out of the fleet management network environment  930  (see the double arrow  932 ). When a user drives a utility vehicle  20  from a location  934  which is outside a fleet management network environment  930  to a location  936  which is within the fleet management network environment  930 , the fleet management client device  910  of that utility vehicle  20  and fleet management server apparatus  820  are able to communicate with each other. For example, the user may be driving the utility vehicle  20  from a work site or field area (e.g., the location  934 ) back to maintenance or storage area (e.g., the location  936 ). To initiate such communications, the fleet management client device  910  may be able to auto detect a wireless network if the network environment  930  is equipped with wireless transceivers. Alternatively, a user may physically connect the fleet management client device  910  to the network environment  930  (e.g., via a plug, a jack, etc.). 
     As a utility vehicle  20  is driven around, the fleet management client device  910  of that utility vehicle  20  routinely monitors and collects activity information regarding that utility vehicle  20 . For example, the client device  910  stores (or logs) lithium battery information (e.g., charge levels, temperature levels, lithium battery fault conditions, lithium battery state transitions, etc.). The client device  910  may further store other information such as motor controller events (e.g., motor controller state transitions, motor controller fault conditions, etc.). 
     Additionally, when the fleet management client device  910  of a utility vehicle establishes a connection with the fleet management server apparatus  920 , the client device  910  delivers the collected activity information to the server apparatus  920 . Such a connection may be established when a user drives the utility vehicle  20  within range of a wireless network or when the user connects a network cable to the utility vehicle  20 . Other situations are suitable as well (e.g., cellular transmissions, longer range wireless metropolitan area network transmissions or WiMax, etc.). 
     Once a connection is established, the fleet management client device  910  of the utility vehicle and the fleet management server apparatus  920  are able to communicate with each other and the information may be transferred from the fleet management client device  910  to the fleet management server apparatus  920  at any time. In some embodiments, the client device  910  begins the information transfer process as soon as the client device  910  discovers (or handshakes with) the server apparatus  920 . Accordingly, the server apparatus  920  is able to obtain a record of activities for each utility vehicle  20  that connects to the network environment  930 . 
     One should appreciate that the fleet management network environment  930  is well-suited for certain applications such as a fleet of golf cars utilized by a golf course. In such a situation, human users may drive the golf cars (i.e., the utility vehicles  20 ) to a holding area (e.g., a barn or shed which enjoys coverage by the network environment  930 ) for overnight lithium battery recharging (e.g., at the ends rounds of golf, at the end of the day, etc.). While the golf cars reside in this holding area to recharge, the fleet management client devices  910  communicate their logged activities for the day to the fleet management server apparatus  920 . In turn, the fleet management server apparatus  920  may evaluate the logged activities as well as current charging behavior and provide extensive evaluation results (e.g., reports, analyses, diagnostics, notifications, alerts, etc.) for subsequent servicing by a human technician. Along these lines, during the next morning, the human technician may review the evaluation results to determine which golf cars have fully charged lithium batteries  52  and are available for use versus other golf cars that either don’t have fully charged lithium batteries  52  or perhaps require servicing for other reasons (e.g., faulted electrical systems, faulted external chargers  300 , etc.). Further details will now be provided with reference to  FIG.  13   . 
       FIG.  13    shows particular details of a fleet management client device  910  (also see  FIG.  12   ). The fleet management client device  910  includes a communications interface  1000 , a utility vehicle interface  1002 , and specialized control circuitry  1004  which couples with the communications interface  1000  and the utility vehicle interface  1002 . In some embodiments, the fleet management client device  910  includes other components  1006  such as a local power supply which is operative to receive charge from the BMS  50  (also see  FIG.  2   ) and/or an external charger (also see  FIG.  8   ), a touch screen or other user interface, and so on. 
     It should be understood that the fleet management client device  910  is supported by the utility vehicle body  22  and electrically couples with the motion control system  26  (also see  FIG.  1   ). In some arrangements, the fleet management client device  910  has the form factor of a tablet device (e.g., a regular-sized tablet, a mini tablet, etc.). In other arrangements, the fleet management client device  910  has the form factor of module or package which mounts to the utility vehicle body  22 . Other form factors are suitable for use as well. 
     The communications interface  1000  (e.g., a wireless transceiver, a physical communications port, combinations thereof, etc.) is constructed and arranged to connect the fleet management client device  910  to a communications medium that enables communications with other electronic components of the fleet management system  900 . Such communications may be IP-based, SAN-based, cellular-based, cable-based, fiber-optic based, wireless (cellular, RF, infrared, etc.), cloud-based, combinations thereof, and so on. Accordingly, the communications interface  1000  enables the fleet management client device  910  to robustly and reliably communicate with other external apparatus. 
     The utility vehicle interface  1002  (e.g., a wireless transceiver, a physical communications port, etc.) is constructed and arranged to connect the fleet management client device  910  to the motor control system  26  of a utility vehicle  20 . Again, such communications may be IP-based, SAN-based, cellular-based, cable-based, fiber-optic based, wireless (cellular, RF, infrared, etc.), combinations thereof, and so on. In certain embodiments, the utility vehicle interface  1002  includes a cable harness that enables the fleet management client device  910  connect to the cabling  38  ( FIG.  1   ), e.g., to monitor electronic CAN messages in accordance with the CAN protocol, etc. In some arrangements, the communications interface  1000  and the utility vehicle interface  1002  share the same hardware. 
     The specialized control circuitry  1004  is constructed and arranged to work in tandem with the circuitry of the motor control system  26 . Along these lines, the specialized control circuitry  1004  includes memory (or a buffer) which logs motor control system events during the course of utility vehicle operation. Then, when the utility vehicle  20  establishes a connection with the fleet management server apparatus  920 , the specialized control circuitry  1004  transmits (e.g., uploads) the collected events from the memory to the fleet management server apparatus  920  ( FIG.  12   ) for processing. In some embodiments, at least some of the specialized control circuitry  1004  is formed by memory that stores specialized instructions (e.g., code) and processing circuitry that operates in accordance with the specialized instructions. 
     The other circuitry  1006  refers to additional and perhaps optional components of the client device  910 . Along these lines, the client device  910  may be a modularized smart device that includes a local power supply, a user interface (e.g., a touchscreen), a camera, microphones and speakers, a set of accelerometers, a set of gyroscopes, an altimeter, global positioning system (GPS) circuitry, and so on. The local power supply enables the client device  910  even if the lithium battery  52  that drives the motor control system  26  of the utility vehicle  20  is unavailable. The user interface enables a user to perform other operations and useful work (e.g., determine a location on a golf course to distance to golf course landmarks, enter scores, contact the club house, access news or other services/information, etc.). 
     In some arrangements, the client device  910  includes location identification circuitry (e.g., GPS circuitry) which provides a location signal that identifies a current geolocation of the golf car on the golf course. A touch screen of the client device  910  is configured to receive golf course data that is based on the current geolocation of the electric golf car from the control circuitry and visually display the golf course data (e.g., how far the client device  910  is from a hole location) concurrently while the client device  910  contemporaneously records the series of lithium battery conditions captured over time. 
     In accordance with some embodiments, at least some of the utility vehicle circuitry that performs pre-charge assessment and which is the source of various vehicle event information resides outside the client device  910  (e.g., see the lithium battery system  32  and/or the motor system  30  in  FIG.  2   ). In some arrangements, the client device  910  effectively relays this information (e.g., battery data, current utility vehicle settings, utility vehicle events, etc.) to the fleet management server apparatus  920  ( FIG.  12   ). In certain arrangements, the client device  910  enhances this information with additional information such as timestamps, vehicle geolocation, ambient temperature, etc. before conveying the information to the fleet management server apparatus  920 . 
     Furthermore, in some arrangements, the client device  910  provides the user notification. Along these lines, the client device  910  (e.g., in the form factor of a smart phone, a tablet, etc.) may output one or more sounds to the user via its speaker and/or one or more visual notifications via its screen or LED. Further details will now be provided with reference to  FIG.  14   . 
       FIG.  14    shows a procedure  1100  which is performed by the fleet management client device  910  of a utility vehicle  20 . In some embodiments, the client device  910  remains in operation at least as long as the utility vehicle  20  is awake. 
     At  1102 , circuitry of the client device  910  monitors a set of utility vehicle events through the utility vehicle interface  1002  and stores a set of utility vehicle event entries in a buffer. The set of utility vehicle event entries identifies the set of utility vehicle events. For example, in some embodiments, the set of entries includes a series of lithium battery conditions captured over time such as cell voltage and temperature measurements, captured fault conditions, state transitions such as transitions into or from sleep mode, storage mode, charging mode, and so on. Other information may be recorded as well such as motor controller status, towing status, and so on. 
     At  1104 , the circuitry of the client device  910  establishes a network connection between the client device  910  and a fleet management server apparatus  920  through a communications interface of the fleet management client device. For example, the client device  910  may have come with range of a wireless network, a user may have connected a network cable to the client device  910 , etc. 
     At  1106 , the circuitry of the client device  910  conveys the set of utility vehicle event entries from the buffer to the fleet management server apparatus via the network connection. Accordingly, charge verification determination is able to be sent (wirelessly or over wired network) to a fleet management system such that the system gathers charge verification data for all cars in the fleet, which can help identify cars that are not properly charged, cars with faulty BMS’s, faulty chargers, etc. 
       FIG.  15    shows particular details of a fleet management server apparatus  920  (also see  FIG.  12   ). The fleet management server apparatus  920  includes a communications interface  1200 , a utility vehicle database  1202 , and specialized control circuitry  1204  which couples with the communications interface  1200  and the utility vehicle database  1202 . In some embodiments, the fleet management server apparatus  920  includes other components  1206  such as a user interface, one or more external charging stations (also see the external charger  300  in  FIG.  8   ), and so on. 
     It should be understood that the fleet management server apparatus  920  may form part of an enterprise computer system such as standalone server equipment, a cluster of computers in a central office, and/or a cloud infrastructure. In some arrangements, the fleet management server apparatus  920  has the form factor of mainframe, a cluster of computers, a server farm, and/or a distributed computing system. Other form factors are suitable for use as well. 
     The communications interface  1200  (e.g., a wireless transceiver, a physical communications port, etc.) is constructed and arranged to connect the fleet management server apparatus  920  to a communications medium that enables communications with other electronic components the fleet management system  900  (also see  FIG.  12   ). Such communications may be IP-based, SAN-based, cellular-based, cable-based, fiber-optic based, wireless (cellular, RF, infrared, etc.), cloud-based, combinations thereof, and so on. Accordingly, the communications interface  1200  enables the fleet management server apparatus  920  to robustly and reliably communicate with other external apparatus. 
     The utility vehicle database  1202  is constructed and arranged to store utility vehicle information from a fleet of utility vehicles  20 . Along these lines, the utility vehicle database  1202  is able to access (i.e., store and retrieve) vehicle data for different utility vehicles  20  at the same time (e.g., save vehicle data from multiple vehicles concurrently, save vehicle data from one vehicle while concurrently reading and evaluating vehicle data from another vehicle, etc.). 
     The specialized control circuitry  1204  is constructed and arranged to perform a variety of monitoring and control activities. Along these lines, the specialized control circuitry  1204  detects establishment of network connections between the fleet management server apparatus  920  and the respective fleet management client devices  910  of the fleet of utility vehicles  20  through the communications interface  1200 , collect respective sets of utility vehicle event entries from the fleet of utility vehicles  20  through the communications interface  1200  and store the respective sets of utility vehicle event entries in the utility vehicle database  1202  and, based on the respective sets of utility vehicle event entries stored in the utility vehicle database  1202 , perform a set of utility vehicle conditioning activities. Further details will now be provided with reference to  FIG.  16   . 
       FIG.  16    shows a procedure  1300  which is performed by the fleet management server apparatus  920  of the fleet management system  900 . In some embodiments, the server apparatus  920  remains in operation even after the utility vehicles  20  have gone to sleep or have been turned off. 
     At  1302 , circuitry of the server apparatus  920  establishes network connections between the fleet management server apparatus  920  and the respective fleet management client devices  910  of the fleet of utility vehicles  20  through the communications interface  1200 . In some arrangements, as the utility vehicles  20  individually enter the network environment  930  ( FIG.  12   ), the server apparatus  920  and the client device  910  of that utility vehicle  20  communicate with each other (e.g., via WiFi, via a cable that a user connects from a data communications device to the client device  910 , etc.). 
     At  1304 , the circuitry of the server apparatus  920  collects respective sets of utility vehicle event entries from the fleet of utility vehicles  20  through the communications interface  1200  and stores the respective sets of utility vehicle event entries in the utility vehicle database  1202 . As mentioned earlier, each set of utility vehicle event entries from a utility vehicle  20  identifies a set of utility vehicle events over a period of operation for that utility vehicle  20 . In particular, in some embodiments, the set of entries includes a series of lithium battery conditions captured over time such as cell voltage and temperature measurements, captured fault conditions, state transitions such as transitions into or from sleep mode, storage mode, charging mode, and so on. Moreover, other information may be recorded as well such as motor controller status, towing status, and so on. 
     At  1304 , the circuitry of the server apparatus  920  performs, based on the respective sets of utility vehicle event entries stored in the utility vehicle database, a set of utility vehicle conditioning activities. In some embodiments, such activities include, for a utility vehicle  20 , performing a lithium battery health assessment on a lithium battery of that utility vehicle, and identifying a current set of health conditions of the lithium battery of that utility vehicle. In accordance with some embodiments, other activities include management of lithium battery charging operation and generation of lithium battery charging reports, and so on. 
     As described above, improved techniques are directed to charge control that enhances the user experience. Along these lines, a human user is able to initiate pre-charging evaluation of a lithium battery  52  by simply connecting an external charger  300  to a utility vehicle  20 . Shortly after the user connects the external charger  300  to the utility vehicle  20  and prior to the utility vehicle  20  providing direction to the external charger  300  to adjust the amount of charge stored by the lithium battery  52 , the utility vehicle  20  performs a set of pre-charging assessment operations to determine whether charge adjustment should commence. Upon a successful pre-charging assessment, the utility vehicle  20  automatically provides a user notification indicating that the utility vehicle  20  is properly setup for charge adjustment. Such notification may be in the form of one or more audio signals (e.g., one or more buzzes, beeps, bell tones, other distinctive noises, combinations thereof, etc.) and/or one or more video signals (e.g., one or more solid or blinking lights, output on one or more segmented displays, output on a graphical screen or monitor, combinations thereof, etc.). Additionally, such notification may be through one or more devices of the utility vehicle, through the external charger, through one or more separate devices (e.g., a smart phone, a tablet, a computerized workstation, a server, etc.), or combinations thereof, and so on. For example, circuitry of the utility vehicle  20  may output a “success” signal which causes one or more user output devices selected by the user to provide the notification. 
     Accordingly, the user is able to proceed elsewhere (e.g., perform other useful work, etc.) with confidence that subsequent charge adjustment will proceed properly. Such operation thus eliminates the need for the user to double check or closely inspect charger connection, etc. Rather, the user may simply connect the charger, receive the notification shortly thereafter, and then proceed to another task (e.g., connect another charger to another vehicle), and so on. In some fleet management arrangements, a fleet of utility vehicles is managed concurrently to further inform the user (or a team of users) as to which utility vehicles of the fleet possess acceptable/unacceptable lithium battery health conditions, etc. before, during and/or after charge evaluation and/or adjustment. 
     While various embodiments of the present disclosure have been particularly shown and described, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims. 
     For example,  FIG.  17    shows a flowchart of a procedure  1400  for maximizing charge integrity of a lithium battery  52  of a utility vehicle  20  in accordance with certain embodiments. Such a procedure  1400  is capable of being performed for each utility vehicle  20  of a utility vehicle fleet. 
     In some embodiments, electric vehicle charging is accomplished by a connection between the charger and the electric vehicle. This connection can be in the form of a physical charger plug inserted into a vehicle charging connector. Upon making this connection, a battery charger is able to provide power to the electric vehicle for charging the vehicle’s battery pack. In more advanced electric vehicles, the battery charging is managed by a battery management system (BMS). Indication that battery charging has begun is accomplished typically by visual indicators on either or both the battery charger and the electric vehicle. 
     In some embodiments, the improvement is composed of two parts. These parts are (1) a battery management system parameter check that will verify the entire system is fully prepared to accept charging current and (2) charge integrity displays available through fleet management equipment. 
     The battery management system check is responsive to connecting the charger in some embodiments. Along these lines, the vehicle traction controller (or motor control system) is powered from the charger and communicates with the Battery Management System to verify charge current can be accepted and activate an audible alarm to signal a user that the check has passed. 
     Conventional methods that involve charging of lead acid batteries have no Battery Management System available and therefore have little to no intelligence or vehicle integration. Rather, the convention methods require charging to actually begin and be confirmed by means of a measurement of increasing voltage of the battery pack. This type of conventional method is not useful for a vehicle with a Battery Management System as it does not have the ability to check battery conditions before the contactor is closed. 
     In contrast, the integration of the vehicle systems with a fleet management system introduces opportunity for several features which will help fleet operators understand and improve their vehicle availability in real time. A fleet management system is able to display charging conditions such as state of charge, estimated time to charge completion, charge rate, charging stage and charging related faults. 
     Additionally, the improved techniques are applicable to any utility vehicle which features a Battery Management System that is integrated with the Vehicle Traction Controller and has an audible alarm and fleet management integration. 
     Furthermore, it should be understood that portions of the fleet management client device  910  may be combined or share portions of the motor control system  26 . Along these lines, processing circuitry that forms some of the control logic for one portion (e.g., processing circuitry of the client device  910 ) may also form the control logic of another portion (e.g., processing circuitry of the BMS  50 , of the motor controller  40 , combinations thereof, etc.). 
     Additionally, it should be understood that the user notification may include any number and/or type of audio/visual indicators. Suitable audio signals include tones, noise patterns, voice, etc. Suitable visual indicators include lights (e.g., colored LEDs, dedicated dashboard lights/icons, headlights, parking lights, signal lights, etc.), touchscreen output, computerized displays, and so on. Other types of user I/O indicators are suitable for use as well. Such modifications and enhancements are intended to belong to various embodiments of the disclosure.