Charging, Roaming, and Commercial Model¶

Charging has three linked records:

a physical energy-transfer episode
an operational session used for readiness, control, and support
a commercial record used for billing, settlement, and reporting

Those records often share identifiers, timestamps, meters, charger references, and vehicle references, but they answer different questions.

In the two-axis model:

problem coordinate: Roaming & Shared Charging -> Network Access & Interoperability or Roaming & Shared Charging -> Commercial Settlement & Shared Charging
physical coordinate: location, charger, EVSE, connector, driver or fleet user, vehicle, token, meter, session, tariff, CDR, payment rail, and time

Physical Session¶

A physical session begins when an EV connects to a charger and energy can flow. Its evidence includes:

station, EVSE, and connector identity
plug-in and unplug events
transaction or transaction-event identifiers
meter values and sampled measurements
SoC when available
status and fault changes
power limits or charging profiles applied during the session

Operational Session¶

The operational session explains why the physical session matters:

which vehicle or driver is involved
which work, route, block, job, or shift the energy supports
which readiness target applies
which priority or policy drove charging allocation
which incidents or degraded states affected the outcome
whether the session met the operational need before the deadline

Commercial Session¶

The commercial session explains access and money:

who was allowed to start the session
which token, user, contract, or roaming group authorised it
which tariff applied
what the billable meter delta was
which taxes, fees, and currency apply
which CDR is sent to which party
who invoices whom

flowchart TB
  Physical["Physical session<br/>energy transfer and meter evidence"]
  Operational["Operational session<br/>readiness and control meaning"]
  Commercial["Commercial session<br/>access, tariff, CDR, settlement"]

  Physical --> Operational
  Physical --> Commercial
  Operational --> Commercial

  Physical --> P1["OCPP transaction / meter values"]
  Operational --> O1["vehicle readiness / dispatch confidence"]
  Commercial --> C1["OCPI/OICP CDR / invoice / payout"]

Commercial Actors¶

Actor	Problem coordinate	Physical coordinate	What they do	Typical evidence
CPO	Roaming & Shared Charging -> Network Access & Interoperability	charging location, EVSE, connector, session, tariff, time	owns or operates charging infrastructure and exposes charger availability, sessions, tariffs, and CDRs	locations, EVSEs, connectors, tariffs, sessions, CDRs, invoices
eMSP / EMP	Roaming & Shared Charging -> Commercial Settlement & Shared Charging	user, token, contract, session, invoice, time	owns the driver or fleet charging contract and gives users a way to find, authorise, and pay for charging	tokens, app users, contracts, invoices, receipts
Roaming hub	Roaming & Shared Charging -> Network Access & Interoperability	partner, credential, EVSE data, CDR, time	brokers network access and data exchange between CPOs and eMSPs	partner IDs, routing, credentials, EVSE data, status, CDR flow
Fleet operator	Operations & Dispatch -> Fleet & Vehicle Management	vehicle, depot, route, schedule, readiness target, time	owns the work and vehicle-readiness problem	schedules, vehicles, depots, readiness targets, operational reports
Site owner	Energy & Cost Management -> Site Energy & Infrastructure	site, grid connection, circuit, tariff, access rule, time	owns or controls the physical site and electrical constraints	site capacity, circuits, tariffs, access rules
Payment provider	Roaming & Shared Charging -> Commercial Settlement & Shared Charging	payment intent, invoice, receipt, session, time	captures or settles payment for a charging session	pre-authorisations, payment intents, captures, refunds

The same organisation can hold more than one role. For example, a depot operator may act as a private CPO for its own fleet, a shared-charging CPO for visiting fleets, and an eMSP-like access manager for its own drivers.

Roaming Flow¶

sequenceDiagram
  participant User as Driver or visiting fleet user
  participant EMSP as eMSP / EMP
  participant Hub as Roaming hub (optional)
  participant CPO as CPO platform
  participant Charger as Charging station

  EMSP->>CPO: exchange credentials or route via hub
  CPO->>EMSP: publish locations, EVSEs, connectors, tariffs
  User->>EMSP: request charging with token or app
  EMSP->>CPO: authorize or remote start command
  CPO->>Charger: start charging through charger protocol
  Charger->>CPO: session and meter evidence
  CPO->>EMSP: session updates and CDR
  EMSP->>User: bill, receipt, or account charge

Tariffs, CDRs, And Settlement¶

A tariff defines how price is calculated. It may include:

energy price per kWh
time price per minute or hour
parking or idle fees
start fees
tax rules
currency
validity periods
public, private, or group-specific access rules

A CDR records the charge detail after the session. It usually includes who charged, where they charged, when they charged, how much energy was delivered, which tariff applied, and what the cost was.

Settlement is the business process that turns one or more CDRs into invoices, payouts, or ledger entries. The settlement actor depends on the commercial arrangement. Peer-to-peer OCPI may settle directly between CPO and eMSP. Hub-centered OICP may route through Hubject products and agreements.

BetterFleet Interpretation¶

In BetterFleet:

OCPP evidence usually enters through bf-manage-connect
operational charging, vehicle, depot, reporting, and tariff meaning usually lands in Manage domain services
roaming user journeys sit in bf-manage-roaming and related Manage configuration
OCPI and OICP concepts map to Roaming & Shared Charging and Commercial Settlement
reporting must keep physical meter evidence, operational vehicle meaning, and commercial tariff meaning traceable