Guidelines about onboarding, configuring, integrating, and testing the EV charging infrastructure with the central management system of Tridens EV Charge.
Table of contents
The article guides EV charging infrastructure operators to onboard, configure, and test the EV charger with the central management system of Tridens EV Charge. It’s intended to improve understanding of the concepts and strongly advised to verify the operations before introducing and utilizing them on the production environment. Interoperability between the charger and the central system is ensured by both sides supporting the common communication protocol named Open Charge Point Protocol (OCPP). Not necessarily all the features are required to be verified, as business cases vary and use a limited amount of them.
Chapters are distributed in the following manner:
- Onboarding the Charging Infrastructure on Tridens EV Charge: Describing the configuration of the area, charging station, charger, and connector on Tridens EV Charge dashboard to reflect an actual charging infrastructure installation on location.
- Charging Infrastructure Management: Operations to manage charging infrastructure by using Tridens EV Charge dashboard.
- Operations Configuration: Instructions about the settings on the charger side and on the side of the central system, which need to be consistent for reliable operations and charging experience.
- Charging Sessions Management: Instructions about the operations of charging sessions, including reservations, session initiation options, consumption control, end customer rating and charging, session termination options and limitations.
- Testing: The step-by-step list and description of test scenarios with instructions.
Onboarding Charging Infrastructure on Tridens EV Charge
Once the Tridens EV Charge environment is ready for use, operators can proceed to set up the EV charging infrastructure on the dashboard. According to the physical charging infrastructure setup and capabilities, the charging operator needs to populate an area, charging station, charger and connector structure on the central system of Tridens EV Charge, by which the system allocates a connection URL with credentials for the charging device, so the charging device can start communicating with the central system of Tridens.
To onboard an area, please refer to the Tridens EV Charge – Areas; meanwhile, for onboarding the charging station, charger, and connector, please refer to the Tridens EV Charge – Stations web documentation for the explanation and guidance.
Figure: Onboarding an area
Figure: Onboarding the charging station, charger and connector with the connection settings allocation
Connectivity and communication configuration on the central system side for the specific charging station can be managed on the station’s connectivity settings, covering values of communication protocol, connection policy, and connection identifier. To find out how to manage these, see Tridens EV Charge – Stations – Connectivity Configuration.
Following the configuration settings, the charger is the side that initiates the connection to the central system. The operator needs to configure the charger with the central system’s allocated connection settings and credentials. How this configuration is done on the charger side depends on the charger’s manufacturer-specific implementation, usually done by its web dashboard interface, mobile interface, or directly on the charger’s screen.
Figure: Charging station’s connection settings
Having issues on establishing the connection between the two sides? Here is the list of tips when troubleshooting:
- Using the suitable security profile (WSS and authentication).
- Configuring the charger with the authentication token or authentication ID/pass is not the same:
- Does the charger accept an authorization token? Use the charger’s allocated token of Tridens EV Charge.
- Does the charger accept ID and password? Use the charger’s allocated connection id and password of Tridens EV Charge.
- Ensure that the charger is configured to automatically reconnect to the central system if disconnection occurs.
- Charger’s on-site configuration if the settings have been reset due to firmware upgrade or other reasons.
- Charger’s network stability.
Charging Infrastructure Management
Charging infrastructure operators require control over the set of operations by which they can manage their charging infrastructure, including configuration settings, availability, monitoring, and troubleshooting. These operations can be manageable from the Tridens EV Charge’s central system dashboard by standardized way of OCPP protocol or, alternatively by other ways, as the charger manufacturers may provide their own interface to manage these operations – it depends on the charger’s manufacturer implementation.
Figure: Charging infrastructure management operations
Infrastructure Status
Charging infrastructure has status indicators that represent the operational availability on three-tier levels of charging station, charger, and connector. Statuses are populated based on the communication connection and reports from the physical charging infrastructure.
The charging station can possess the statuses of operative and inoperative. Operative status indicates that the charging station is connected to the central system of Tridens EV Charge by the communication protocol (OCPP). Meanwhile, the charger and connector have a wider range of statuses, which can indicate available, reserved, occupied, charging, suspended, finishing, and faulted, to name a few.
Figure: Charging infrastructure status
The closed status of the area, station, charger, or connector indicates that the charging infrastructure is not in use anymore. The area, charging station, charger, and connector structure is never completely deleted but instead, only transition to the closed state and become generally hidden. The reason is due to historical backtracking reference requirements, as the charging infrastructure can be referenced to past charging sessions.
Refer to Tridens EV Charge – Stations – Charging Infrastructure Status for more information on this topic.
Configuration
Chargers shall be configured to fulfill the expected behavior and operate consistently to the central system’s settings. This can be achieved by either using Tridens EV Charge system’s dashboard, which communicates with the charger, or the charger manufacturer’s own configuration interface. Please note that in the first case, the charger’s connection to the Tridens EV Charge central system is required, so the operator can instruct the charger with the desired settings from the dashboard.
Figure: Charging station configuration
List of standardized settings can be found in the communication protocol specification, whether OCPP 1.6 or 2.0.1. Commonly used settings are already provided in the dashboard configuration dialog of Tridens EV Charge, meanwhile for the rest the custom configuration dialog can be used. In addition to the standardized values, the charger manufacturers may provide their own extended list of custom configuration settings and to manage them, operators can use the custom configuration dialog of Tridens EV Charge dashboard for that purpose as well.
We strongly advise charging operators to always check the charger’s manuals and consider all the available configuration options. It is important that operators are aware of how the charger operates in different situations and that the charger needs to be configured to fulfill the desired business scenarios and driver experience. More about these scenarios can be found in the upcoming paragraphs, where the testing phase is described.
See Tridens EV Charge – Station – Configuration section of web documentation to find instructions on how to manage the charger settings from the central system.
Availability Control
The operator of the charging infrastructure can use the Tridens EV Charge dashboard to manage the availability of the connected charging station’s charger or connector. Useful for the case when an operator wants to switch the charger or connector to unavailable due to maintenance purposes. After the work is done, the charger/connector can be switched back to available.
Find instructions on how to navigate to the availability change operations by following the Tridens EV Charge – Operations – Availability.
Reboot
Operators can request the charging station, which is connected to the central system of Tridens EV Charge, to reboot by following the instructions of Tridens EV Charge – Operations – Stations – Reboot.
Connector Unlock
As the charger’s connector is plugged into the vehicle, occasionally, it happens that the connector gets stuck in the vehicle due to an electromechanical lock. Connectors may provide the mechanism which tries to detach the connector from that position on the remote command. The command can be executed by the operator on the Tridens EV Charge dashboard by following the unlocking instructions on Tridens EV Charge – Operations – Connector Unlock.
However, the remote unlock action is not guaranteed to resolve an issue and it happens that the detaching needs to be done physically.
Firmware
It is advised to always use the latest stable available firmware of the charging device. The way of obtaining and installing the new firmware depends on the charger manufacturer’s implementation. They may provide their own interface for the customers to do it, or alternatively, they may follow the OCPP standardized approach, which requires and utilizes a file location from which the firmware is to be downloaded. Tridens EV Charge dashboard provides the dialog to execute the standardized instructions to the charger about the firmware file location and date-time of an update to be executed.
Guidelines on how to instruct the charger to gain the firmware update can be found in Tridens EV Charge – Operations – Stations – Firmware Update.
Diagnostics
Tridens EV Charge provides the OCPP standardized way of instructing the charger about where to upload the diagnostic log file. Chargers may support the standardized feature or provide alternative ways of obtaining the diagnostics, usually by their own interface dashboard.
The feature becomes useful when operators want to investigate the behavior of the charger, especially when there are operational issues and they would like to do troubleshooting.
Figure: Diagnostics request
Follow the instructions in Tridens EV Charge – Operations – Stations – Diagnostics for more details.
Operations Configuration
The operations configuration section contains instructions about the settings on the charger side and on the side of the central system, which need to be consistent for the reliable operations and charging experience.
Session and Meter Values Reporting
The charger needs to be configured to report meter values on a regular interval, so the charging session’s progress will keep being updated on the Tridens EV Charge’s central system and displayed accordingly to the system operators and the drivers. We advise using a 15 second interval. You can usually configure this on the charger’s own configuration dashboard, or use Tridens EV Charge dashboard, which can do it by OCPP communication protocol.
Figure: Setting the interval in the charging station’s configuration form on Tridens EV Charge dashboard to the OCPP 1.6 charger
To show active power measurement in the mobile app, the operator needs to configure the charger to send the measurements in the scope of the charging session (usually at least kW for power and kWh for energy). Similarly, this is doable by the charger’s dashboard or by Tridens EV Charge dashboard, which can instruct the charger about the configuration by OCPP.
Figure: Setting measurands in the Charging Station’s configuration form on Tridens EV Charge dashboard to the OCPP 1.6 charger
There are two types of meter values that can be configured for reporting on the charger:
- Session Related Meter Values: Meter values which are related to the specific charging session and representing measurands related to it.
- General Meter Values: General meter values are reported independent of the session and may be required in the scenarios of the sessions which are being terminated by the final parking.
Tridens EV Charge checks the time of meter value reports and ignores the obsolete reports. Meter value report is obsolete when its reported time is older than the last successfully processed report’s time.
For more guidelines and instructions on configuring the meter values, refer to the Tridens EV Charge – Charging Session Integration – Meter Values Reporting.
Driver Authorization
As the drivers (customers) who intend to charge the vehicle may use the payment types of prepaid, postpaid or pay-now, each session charging needs to be first authorized by the Tridens EV Charge central system to verify the driver’s fund sufficiency for beginning the charging session. For the sessions which are started remotely by the mobile application, the driver sufficiency is thus checked prior the central system requests the charger for the session start, but for the means of the driver authorization at the charger side, either by swiping an RFID, NFC or by driver-vehicle contract verification by Plug & Charge of ISO 15118, to name a few, the charger needs to do the authorization by using the central system. Thus, charger’s local and offline authorization lists and caches need to be disabled, to propagate all the authorizations to the central system.
For the list of authorization settings, please check the Tridens EV Charge – Charging Session Integration – Driver Authorization. Note that the chargers may have their own customized list of configuration settings defined by the manufacturers, out of standardized scope of OCPP. As a CPO, please review the charger specific implementation for any additional settings that need to be managed.
Offline Sessions
The charger needs to be disabled to start the charging sessions without allowance of the central system, as it would result in non-customer public sessions. An example of such a scenario is when the charger is temporarily disconnected from the central system due to a network issue, and an unknown driver plugs into the vehicle and tries to start the charging.
Operators can prevent such scenarios by configuring the charger, as described in Tridens EV Charge – Charging Session Integration – Offline Sessions. Note that the CPO needs to review the charger specific implementation and configuration, as other settings out of standardized scope may apply.
Session Timeout
To avoid fraudulent usage, we suggest using preventive measures by configuring the charger’s timeout period in which the session is expected to start. It covers the time available to start the session, since the acceptance of remote start request or driver authorization at the spot.
Remote session start and authorization timeout on charger side represents the pending period to start the session upon the acceptance, after which session start confirmation is expected from the charger. If this time is breached, the charger should prevent any session from starting without the next session authorization acceptance, whether by mobile remote request or authorization at the charger.
Example:
The EV driver plugs the charger’s connector to the vehicle. Then the driver presses the session start request button on the mobile application, and at this point, session is ready. Ready session expiration time of 30 seconds starts ticking. If it reaches 30 seconds and the session has not started yet, then the session gets closed on the central system side and is not being tracked anymore. Charger needs to discard this session as well by using the compatible timeout period, which is advised to be shorter than the one of the central systems due to the time elapsed for the commands exchange.
Session timeout section is related to ready-session-expiration settings of the central system, as it closes inactive sessions based on the expiration settings and idle job configuration. Make sure to use the consistent ready-session-expiration time on the central system, so it works aligned with the charger.
For more technical details, please refer to the Tridens EV Charge – Charging Session Integration – Session Start Timeout and Tridens EV Charge – Idle Session Settings.
Session Expiration
Charging session on the central system of Tridens EV Charge is considered idle when not receiving charging event reports from the charger after a certain time threshold, configured on site or operator context level. Operator’s settings have higher priority, if set. When the session is detected as idle, the central system closes/completes it, which means that such session is not being tracked anymore and the driver is finally charged.
Table: Session expiration settings
| Setting name | Description |
|---|---|
| Ready session expiration | Allowed inactivity in seconds for a ready charging session. When background job detects a ready session’s inactivity exceeding this time, it finalizes it (rating and closing). |
| Ongoing session expiration | Allowed inactivity in seconds for an ongoing, in-progress charging session. When background job detects an in-progress session’s inactivity exceeding this time, it finalizes the session (rating and closing). |
Consider these effects in scope of ready-session-expiration:
- Session requested to start by mobile application (operated by central system), charger is not responding with acceptance. Session will be closed after ready-session-expiration time.
- Session requested to start by mobile application (operated by central system), charger accepting the request. Central system is waiting for the session’s start event. If not started, session will be closed after ready-session-expiration time.
- Session requested to start by mobile application (operated by central system), charger responds with rejection, session is closed immediately.
- Session requested to start by mobile application (operated by central system), charger accepting the request. Central system is waiting for the session’s start event. Charger responds with a start event before the ready-session-expiration time and session proceeds for charging.
Consider these effects in scope of ongoing-session-expiration:
- Session is in progress and charging. Charger stops sending the session update reports and once inactivity time breaches ongoing-session-expiration time setting, session is detected as idle by the central system. System thus requests the charger to stop the session and closes/completes it, which means not tracking it anymore.
More technical explanations about the session expiration configuration and its impacts can be found in Tridens EV Charge – Sessions – Idle Session Settings.
Charging Rate Limiting
The power rate utilized for the EV charging sessions is manageable by using the limiting configurations, either by a static charging profiles approach or by using the dynamic load balancing for the group of chargers.
The first option of the charging profiles enables configuring the charging profiles and applying them to the specific chargers. Charging profiles can be set as one-time occasions for the limit changes on holidays or promotions, or they can be set as recurring on the daily/weekly basis for the desired time range, providing on-peak and off-peak power limiting management. Profiles can overlap and stack by priority, where the highest valid applies. Technical details on applying the charging profiles can be found in Tridens EV Charge – Charging Profiles.
A more advanced way of charging rate power limiting is configurable on the area level, covering a group of chargers on the common electricity grid. The feature is called dynamic load balancing (DLB) and consists of several rules, as applied by the charging infrastructure operator. Total area’s power supply limit can be determined by using the reports of the live power meter asset, limiting periods by the energy forecasting of energy management system or using the general limit. The distribution strategy can be selected, providing an option of equal power supply distribution among all the drivers who are charging at the moment in time or, alternatively to allow maximum available charging to the drivers who started charging earlier. Based on the limiting rules and strategies, the available power supply is dynamically distributed among the active charging sessions on the charging infrastructure of the area. Find more technical configuration details in Tridens EV Charge – Areas.
Figure: Daily charging profile
Charging Sessions Management
The central system and charger configuration done until this point is made for the reason to provide a desired functional experience for the EV charging sessions, which is required to provide transparent management and monitoring to the charging infrastructure operators and reliable charging experience to the drivers which are using the charging infrastructure and charging their electric vehicles.
Figure: Sessions overview
Reservation Phase
Prior to charging, the driver may instantly reserve the connector for a limited amount of time by using the mobile application. Reservation duration is configurable on the levels of site or operator, so it is up to the charging infrastructure operator to decide about the acceptable allowed time range for the reservation. Once connector is reserved, it appears as such in the Tridens EV Charge dashboard interface, on mobile application to other drivers and charger screen/light indication. For the reservation time, only the driver who reserved the connector can start the session on that connector. Reservations in future are not supported due to current communication protocol limitations.
The following transitions are possible for the reserved sessions:
- Driver who reserved the connector, comes to the spot and starts charging. Reservation goes into the charging session.
- Reservation expires.
- Reservation is canceled by user/operator.
For more about the reservation topic, check out Tridens EV Charge – Reservations.
Reservations can be monetarily charged based on Tridens Monetization configuration, by which the flat fee, full length fee or used length fee can apply.
Session Initiation
As mentioned in the previous sections, the drivers who intend to charge their electric vehicle need to introduce themselves to the charger and the central system, so the system executes the necessary verification, whether the driver is allowed to start charging based on the session settings, as described in Charging Sessions Management – Session Rating Configuration.
There are two ways of initiating the driver verification. The first is when the driver uses a mobile application and initiates the charging session request. Meanwhile, the second one is authorization at the charger side.
Mobile Application
Once the driver requests to start the charging session by the mobile application, the central system of Tridens EV Charge executes the necessary customer verification, based on the configuration. Usually, the monetary sufficiency is checked, and monetary authorization of the resources is made. Proceeding, the session is prepared and ready to track by the central system, which requests the charger to start the session and waits for the charger to confirm the session start request and then start the charging process.
Authorization at the Charger
For the means of the driver authorization at the charger side, either by swiping an RFID, NFC or by future proof and user-friendly driver-vehicle contract verification by Plug & Charge of ISO 15118, the charger forwards authorization request to the Tridens EV Charge central system. Based on the session rating configuration, the central system executes necessary verification and responds to the charger, whether the authorization succeeded or failed. In a successful case, the system prepares a session ready for further tracking and is expecting the session events from the charger.
Configure your charger consistently to desired operation requirements, by following Charger Operations Configuration – Driver Authorization. Driver identification device setup instructions can be found in Tridens EV Charge – Integration – Charging Identification Device Setup.
Session Energy Consumption
System is using meter values detection, as there are different varieties of reporting by chargers:
- Chargers reporting an absolute energy meter values at session start, intermediate, stop. Energy of all the sessions on the charger so far.
- Chargers reporting the session relative energy meter values at session start, intermediate, stop. Energy of the latest session.
- Chargers reporting an absolute energy meter value at the start and stop of session, but in the intermediate time, they are sending relative session values.
Note that Tridens EV Charge also checks the time of meter value reports and ignores the obsolete reports. Meter value report is obsolete when its reported time is older than the last successfully processed report’s time.
Figure: Session consumption and duration scopes
Duration Scopes
While the charging session is in progress, the applicable charger’s connector status impacts how the session is being tracked by the Tridens EV Charge central system and thus how it appears to the drivers on mobile application. Session duration is being separated into the scopes of charge time, park time, reservation time and fault time.
Which connector statuses apply for the session’s specific duration scope can be found in Tridens EV Charge – Sessions – Duration Scopes.
Session Rating Configuration
To configure a set of session settings which are important in the scope of session initiation and tracking, Tridens EV Charge provides session settings which can be applied on the levels of general site, operator context or the specific charger.
There, the charge quantity steps can be determined based on the desired business model, e.g. for monetary authorizations per energy quantity step (kWh), charge and park time quantity step (seconds) and by providing the payment authorization policy, energy limit, charge time limit, monetary limit, termination strategy, session start restrictions and simple pricing.
More technical details can be found in the Tridens EV Charge – Sessions – Session Rating Settings.
Figure: Session settings
Termination Strategy
Once the stop session event comes from the charger, it depends on the Tridens EV Charge’s configuration of session termination strategy (see Session Rating Settings) how the event impacts the session. If desired, the session can be completed at that point, or alternatively the session can continue to be tracked for the idle/park time, until the connector remains connected to the vehicle. Park time termination detection may be different based on the charger implementation by the manufacturer, as different actions may indicate when the charging session is over, as it can be by unplugging the connector, or until leaving the parking spot completely. So, this can be configurable on the charger side.
Check out the Tridens EV Charge – Sessions – Termination Strategy for more technical details.
Limitations
The section contains a list of limitations that currently apply for the EV charging sessions on Tridens EV Charge:
- One active session per customer (driver) at once.
- Customer is not allowed to make another session, including reservation, until an active session is closed.
Testing
Tridens provides a comprehensive list of test scenarios which are advised to be precisely reviewed and executed by the charging infrastructure operators and mobility service providers as well for the sake of the stability of operations. It is not necessary to fulfill all the tests on the list, as the operators might not utilize all the features for their business case. Tests for the features which are not planned to be used can be exempted.
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