Sessions
Topics in this document:
- Sessions Overview
- Session Status
- Session Actions on the Dashboard
- Idle Session Control
- Session Rating Settings
- Requesting the Session to Start
- Duration Scopes
- Requesting the Session to Stop
- Payment Authorization Policy
- Termination Strategy
- Session Retry Rating
- Session Retry Billing
- Idle Session Settings
- View Logs
- Limitations
Sessions Overview
To access this section in EV Charge, from the Menu, click Sessions. A paginated list of all sessions from a specific period is shown in a tabular format.
To produce charging sessions, please refer to Charging Sessions Integration, to find the guidelines.
To generate the sessions list in a spreadsheet, click CSV. To print, click Print, and to copy, click Copy.
Note:
They are generated, printed, and copied per paginated page.Information:
You can filter for a session by date-time, customer ID, or/and status.The session list will be empty if no active charging session has been made on the charging network.
Note:
A charging session is started by end users in the EV Charge - Mobile App. For more information, see Starting a charging session.For all charging sessions, it shows:
- the charger and connector used to charge the vehicle
- the date-time the session started and ended
- session duration scopes (charge time, park time)
- the customer ID
- the total energy (kWh) consumption from the session
- the monetary amount
An ongoing session (a session in progress) will be shown with a Status flag as In progress. Also, the consumption and amount of the active session will be updated in EV Charge as any live update occurs.
Information:
You can forcefully stop an ongoing session under Actions.Note:
Clicking the customer ID on a session will take you to Monetization, where the customer information resides.Session Status
Represents the latest status of the session.
| Session status | Description |
|---|---|
| Ready | Session was requested to start by the driver. Central system is waiting for the charger to start the charging process. |
| Refused | Session refused to start. Reason could be insufficient driver’s resources, configuration issue or other failure. |
| Reserved | Session is reserved for the driver. Only the driver which reserved the charger can proceed to charging until reservation expires.Reserved session can transition to an actual charging or expires and closes otherwise. |
| In progress | Session is charging. |
| Limit reached | Indicates that session has reached one of the configured limits:- Monetary limit- Energy limit- Charge time limit- Not able to authorize additional driver’s resources |
| Closing | Session is in the closing process.Triggered when force session stop is triggered by the Tridens EV Charge. |
| Closed | Final stage when session is completed and driver’s resources are spent.Final stage of session depends on the session settings configuration, whether it ends by the charging end or by parking end.See “Session settings”. |
| Rating failed | Indicates that session is over regarding the session settings, but the driver was not monetarily rated.Retry operation can be used on domand or by an automated job execution. |
| Billing failed | Indicates that session is over regarding the session settings, but the pay-now driver was not billed.Retry operation can be used either on demand or by an automated job execution. |
Session Actions on the Dashboard
| Session action | Description |
|---|---|
| Force close | While session is ready/in-progress, system operator may demand to forcefully close the session by using the EV Charge dashboard, by clicking the close button on the right side.This operation requests the session to stop on the charging infrastructure, but if the infrastructure is not responding for any reason, session is forcefully closed.Driver is rated, session closes. See more details of this status in Requesting the Session to Stop. |
| Retry rating | While session is in rating failed status, retry rating button is available for use.When triggered, session rating is retried. See more details of this status and possible actions in Retry Session Rating. |
| Retry billing | While session is in billing failed status, retry billing button is available for use.When triggered, session billing is retried. See more details of this status in Session Retry Billing. |
Idle Session Control
The pre-configured recurring background job checks for idle ready/ongoing sessions and also closes any expired reservations. The session is idle, regarding the Site/Operator settings. See Idle Session Settings.
Session Rating Settings
These are settings which apply for the rating of session, considering different metric types.
Rating settings are determined on the following levels:
- Site (lowest priority)
- Operator
- Charger (highest priority)
Settings are overridable, meaning the settings of the highest priority level are used.
Below are the rating settings available:
Table 1: Description of session rating settings
| Setting name | Unit/value | Description |
|---|---|---|
| Energy step | kWh | Energy step for rating authorization control (kWh). |
| Charge time step | seconds | Charge time step for rating authorization control (seconds). |
| Park time step | seconds | Park time step for rating authorization control (seconds). |
| Park time threshold | seconds | Defines seconds threshold, as point in park time duration at which parking becomes ratable.Difference between the total park time and threshold (park_time minus park_time_threshold) is ratable quantity. Rating authorizations start executing once threshold breaches. |
| Reservation | true / false | Indicating whether the charging reservations are being authorized by rating. |
| Termination | Applicable values of: - Session end - Park time end | Indicating which action stops the charging session on the server side. See termination strategy for further explanations. |
| Monetary limit | Site currency | Max. monetary amount allowed for a session.Empty value represents no limit.When the central system of Tridens EV Charge detects that the charging session’s used monetary amount is above the configured Monetary limit value for the charging session, it requests the charger to stop that charging session. In order for a session to actually end as closed and rated on the central system, charger needs to report the final stop event or if session is detected as idle. Final used amount is persisted on the session based on the charger’s reports, as it needs to track the actual consumption reported. |
| Energy limit | kWh | Max. energy amount to be consumed for a session.Empty value represents no limit.When the central system of Tridens EV Charge detects that charger’s reported energy is above the configured Energy limit value for the charging session, it requests the charger to stop that charging session. In order for a session to actually end as closed and rated on the central system, charger needs to report the final stop event or if session is detected as idle. Energy (kWh) is persisted on the session based on the charger’s reports, so if the energy limit is set 50 kWh and the charger reports 57 kWh, the system is going to use 57 kWh, as it needs to track the actual consumption reported. |
| Charge time limit | seconds | Max. duration allowed for a session to charge.Empty value represents no limit.When the central system of Tridens EV Charge detects that the charging session’s elapsed charge time is above the configured Charge time limit value for the charging session, it requests the charger to stop that charging session. In order for a session to actually end as closed and rated on the central system, charger needs to report the final stop event or if session is detected as idle. Final charge time is persisted on the session based on the charger’s reports, as it needs to track the actual consumption reported. |
| Payment auth. policy | Applicable values: - None - Initial auth only - Auth control | Payment authorization policy which applies for pay-now customers and defines how charging session is controlled by payment provider’s authorizations. See payment authorization policy for further explanations. |
| Payment auth. amount | Site currency | Amount used for session’s payment authorizations. See payment authorization policy for further explanations. |
| Charge time price | Site currency | Price per hour of charging time.Used in scope of simple pricing. |
| Park time price | Site currency | Price per hour of parking time.Used in scope of simple pricing. |
| Energy consumed price | Site currency | Price per kWh of energy consumed.Used in scope of simple pricing. |
| Home roaming energy price | Site currency | Home roaming energy price (per kWh).Applies for monetary amount calculation, if session is in roaming on CPO of Tridens EV Charge, but customer/driver is of third-party roaming eMSP. |
| Home roaming charge time price | Site currency | Home roaming charge time price (per hour).Applies for monetary amount calculation, if session is in roaming on CPO of Tridens EV Charge, but customer/driver is of third-party roaming eMSP. |
| Home roaming park time price | Site currency | Home roaming park time price (per hour).Applies for monetary amount calculation, if session is in roaming on CPO of Tridens EV Charge, but customer/driver is of third-party roaming eMSP. |
| Home roaming reservation time price | Site currency | Home roaming reservation time price (per hour).Applies for monetary amount calculation, if session is in roaming on CPO of Tridens EV Charge, but customer/driver is of third-party roaming eMSP. |
| Home roaming reservation fixed price | Site currency | Home roaming fixed reservation price (flat fee).Applies for monetary amount calculation, if session is in roaming on CPO of Tridens EV Charge, but customer/driver is of third-party roaming eMSP. |
| Start Restriction - Connector Occupied | true / false | Indicates whether the connector/socket is required to be occupied (EV connected) for the charging session start request to proceed. |
Requesting the Session to Start
Sessions can be initiated in the following ways:
Driver as mobile user requests to start the charging session on the selected connector. The central system verifies that customer for the sufficient monetary resources and in case of success, it forwards the request to the charging infrastructure and requests it to start the charging process, upon which the charging session is expected to start.
Driver swipes an RFID device, uses NFC, Plug & Charge or any other way to initiate the session authorization at the charger side. Charger uses the identification means and asks the central system to verify the customer, whether he/she has sufficient monetary resources to charge and in case of acceptance, the charging is expected to start.
Driver starts charging immediately on the charging station, without prior authorization. In this case, the session customer is not known and not charged.
When customer is detected, but is not successfully authorized for the charging session, the session is persisted as rejected. Otherwise no session is persisted.
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 scopes of charge time, park time, reservation time and fault time. See table below to see which status applies for the specific duration scope.
Table 2: Duration scopes and applicable Connector statuses
| Duration Scope | Applicable Connector Statuses |
|---|---|
| Charge time | Charging |
| Park time | Preparing, Occupied, Suspended EV, Suspended EVSE, Finishing, Available. |
| Fault time | Faulted, Unavailable |
| Reservation time | Reserved |
Requesting the Session to Stop
While session is ready/in-progress, system operator may demand to forcefully close the session using the Tridens EV Charge dashboard, by clicking the close button on the right side. This operation requests the charging session to stop on the charging infrastructure, but if the infrastructure is not responding for any reason, session is forcefully closed.
Driver is rated, and the session closes.
The table below shows how session stop requesting may reflect on the charging infrastructure.
Table 3: Charging infrastructure reflecting the session stop command
| Stop Response Type | Description |
|---|---|
| Accepted | Charging infrastructure accepted the stop request. It is expected that it will send the session stop event. |
| Rejected | Session is not being closed on the charging infrastructure. |
Force session close covers the following issues:
Remote stop request is accepted by the charge point, but no stop event confirmation comes from the charging infrastructure.
Remote stop requests are always rejected by the charging infrastructure.
Charging infrastructure is not responding due to lost connection to the central system, lost track of the session.
Payment Authorization Policy
Payment authorization policy applies for customers of pay-now type and defines how charging session is controlled by payment authorizations. The setting is used along with the payment authorization amount.
The following settings apply:
None: Charging session is not controlled by payment authorizations.
Initial authorization only: Charging session initialization depends on the success of the initial payment authorization.
Authorization control: Charging session progress depends on the continuous payment (re)authorizations.
Example with Initial authorization only policy:
When environment is configured for Initial authorization only for payment auth. amount of $10, it means the system will check for $10 on the payment card (authorize/lock the amount) at the beginning of the session, and if this operation is successful, then it will allow the user to charge as much as they like. At the end, the system will collect/capture the original authorized amount of $10, and if the total session price exceeds it, it will try to take the remaining funds as a direct card charge. This also comes with a risk of the user lacking the remainder of the funds and being unable to pay.
Our recommendation would be to raise the initial authorization amount to a value that will cover most of the sessions (like an average session price) in a single payment transaction. You may want to use the Authorization control policy instead. This policy will perform another authorization when the first one is fully consumed, ensuring that the user always has enough funds on the card to continue the session or stop it if no more funds are available.
Example with Authorization control policy:
Once Authorization control is configured for payment auth. amount of $5, the system will try to authorize $5 every time the previously authorized $5 is consumed. Then at the end of the session it will collect (capture) all of the authorizations. This way we are ensuring the user always has enough money on the card to continue the session. If we receive a negative response from the payment provider for authorization, then our system will stop the session and collect the amount the customer has authorized up to that point.
If the charging session would progress to the cost of $22.88, then the session would result in 5 x $5 authorizations, where 4 of them would be fully captured, and one would only capture for $2.88. This would also mean 5 payment gateway transactions, which is why we recommend raising the authorization amount in order to lower the number of necessary transactions, impacting the cost.
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 end 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.
Table 4: Session termination strategy
| Strategy name | Description |
|---|---|
| Charging end | At the session stop event from the charger, the central system stops tracking the session and applies the final session fees for the driver. Session gets closed. |
| Parking end | At session stop event from the charger, the central system keeps tracking the session in park time, until connector is released. At the time of connector’s final release, the central system stops tracking the session and applies the final session fees for the driver. Session gets closed. |
Session Retry Rating
Session in rating-failed status indicates that the charging session is over, but the driver was not monetarily rated. Thus, retry rating operation can be used to charge the driver/customer of the charging session. The driver’s payment type, billing and payment may also apply afterwards.
Session’s rating-failed status may arise for the following reasons:
Invalid Monetization rating configuration, which causes that session can not be rated for the customer. This could be a configuration issue of rate plans, products, rating metrics or customer’s subscription-plan setup.
System maintenance work.
Session retry rating can be used in different modes to determine rating session identifier, used for Monetization charge event rating when session is in rating-failed status.
See the table below.
Table 5: Rating identifier modes of session retry rating
| Rating Identifier Mode | Description |
|---|---|
| Use existing | Existing session rating identifier is being used for Monetization rating. Default option. |
| Use existing, otherwise generate new | Existing session rating identifier is being used for Monetization rating. If rating fails, new rating identifier is auto-generated by the system and rating automatically retries. |
| Assign new | New explicit session rating identifier is assigned in the request and used for Monetization rating. |
| Generate new | New rating identifier is auto-generated by the system and used for Monetization rating. |
Notes:
Session’s retry rating is handled by the pre-configured automated execution job in 30 minutes interval, otherwise it can be triggered for the specific session on demand.Session Retry Billing
Session in billing-failed status indicates that the session is over regarding the session settings, but the pay-now driver/customer was not billed. Thus, retry billing operation can be used to retry billing and payment of a driver for the charging session.
Session’s billing-failed status may arise for the following reasons:
Invalid Monetization rating and billing configuration, which causes that session can not be rated for the customer. This could be a configuration issue of rate plans, products, rating metrics, customer’s subscription-plan or billing profile setup.
System maintenance work.
Notes:
Session’s retry billing is handled by the pre-configured automated execution job in 30 minutes interval, otherwise it can be triggered for the specific session on demand.Idle Session Settings
Session on the central system is considered as idle when not receiving event reports from the charging infrastructure after a certain configured time of Site or Operator. Operator’s settings have higher priority, if set.
When session is detected as idle, the central system closes/completes it, which means that such session is not being tracked anymore.
| 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). Setting impacts user’s experience. When user requests to start the new session by mobile application, the app uses this time for the countdown time display in which session is expected to transition into an active status. |
| 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). |
| Session closed verification time | Amount of seconds since the session stop request, after which session is verified to be closed. Used in scope of force stopping and idle sessions stopping.Limitation: This settings only applies for the Site currently. |
Table: Session expiration settings
Pre-configured idle sessions job operation is responsible for detecting idle sessions based on expiration settings of Site and Operator.
Job’s execution interval determines how often the central system checks for the idle sessions.
Notes:
- Consider setting the ready-session-expiration time setting of site/operator to the proper amount, regarding your chargers. For some AC chargers, time to start charging may be 5 seconds, meanwhile for DC it can take up to 20-40 seconds. Please consider it and adjust ready-session-expiration in your settings of the site/operator.
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.
View Logs
Logs of Open Charge Point Protocol (OCPP) communication exchanged between the central system of Tridens EV Charge and the charging station for the time of the specific charging session. Operators usually utilize them at onboard testing and for troubleshooting.
To view session’s OCPP logs, navigate to the sessions view, find the session of interest, move to the Actions column and hit the View Logs button. See Figure 1. Logs are filterable by the time range and can be exported by CSV or Print options which appear on the bottom of the tool. See Figure 2.
Figure 1: Sessions view and the navigation to view OCPP communication logs.
Figure 2: OCPP communication logs of the session.
Limitations
Session initiation limitations:
a) If requesting to start the session on connector A with customer A, session is prepared and charger is requested to start charging. If customer A tries to start the another session on connector A or any other connector, the request is rejected, as this customer already has an active session. There is a limitation of one active session per customer.
b) If requesting to start the session on connector A with customer A, session is prepared and charger is requested to start charging. If customer B tries to start the session on connector A, the request is rejected, as connector already has another active session assigned.
c) If customer A and customer B both want to start the session on connector A at the same time, the request that came in first will be proceed (access lock), meanwhile the other request will be rejected.
