Under kWh billing, only the meter matters: the bill follows the energy delivered, and when anything else happened changes nothing. Under time billing, the bill follows a clock — and that clock’s start and stop are defined by the operator’s tariff, not by physics. Two stations both priced “per minute” can count the same session differently, because one starts at plug-in and the other at first energy.
Key Takeaways
- Per-kWh billing follows the meter; time billing follows a clock whose start and stop the tariff defines.
- Connection, authorisation and first energy are all used as start points — there is no industry default.
- Grace periods, rounding and minimums are tariff definitions, confirmed by the session record.
- The charger records the events; the platform’s configuration decides which are billed.
The Difference, Stated Once
Per-kWh billing charges for energy measured by the charger’s meter; time billing charges for minutes or hours counted by the platform’s clock. The full comparison of the bases — metering, fairness, rules — is covered in our guide to how much charging stations charge. What it cannot show is the counting layer underneath the time basis: the events a tariff picks as its start and stop. That layer is where time bills are decided.
The Events Every Session Passes Through
| Event | What happens | Why a time tariff cares |
|---|---|---|
| Plug-in | The connector is seated in the car | Some tariffs start counting here — before any energy moves |
| Authorisation | The driver is identified and the session opened (app, card or RFID) | Other tariffs start here, when the session formally exists |
| First energy | Power starts flowing into the battery | The third possible start: counting only while charging is possible |
| Charge complete | The car stops taking power — full, or at its set limit | Some tariffs stop here; others keep counting |
| Unplug | The connector is removed and the bay released | The last possible stop — counting to here prices the parking, not the charge |
A per-kWh bill is indifferent to this whole table: energy delivered is the same whichever events a tariff names. A per-minute bill is built from it. The gap between plug-in and first energy — authorising, the car and charger handshaking — is billed time on a plug-in-start tariff and free time on an energy-start tariff.
How Operators Define the Start, the Stop and the Edges
- Start definitions vary. Connection, authorisation and first energy are all in use. None is the industry default; each is a line in the operator’s own tariff terms.
- Stop definitions vary the same way. Counting can end at charge completion or run until unplug — a tariff that runs to unplug is pricing occupancy as well as charging.
- Grace periods are a defined edge, not a courtesy. Some tariffs allow a set number of minutes after completion before any further time charge applies.
- Rounding is also a definition. Part-minutes or part-hours may be rounded up, counted exactly, or subject to a minimum session charge — again, tariff text, not physics.
Because all four are operator definitions, the check is documentary: the tariff terms for the exact station state them, and the session record afterwards shows the start and end the platform actually used. Whether a site charges money at all is a separate question from how its clock counts.
Hardware Records the Events; the Tariff Defines Them
The counting split mirrors the hardware split. A station such as the EV-AC03201T dual-connector AC station — two Type 2 connectors, up to 43 kW shared, OCPP 1.6J, RFID, IP54, its touchscreen a display rather than a payment terminal — records when a session starts and ends and how much energy it delivers, and reports that record to the operator’s platform. The EV-ACT3204PE 22 kW wallbox (three-phase, Type 2, RFID and app, IP66, CE) does the same at wall-mounted sites. Which events the platform bills on is a tariff configuration, not a hardware property — no EVDANCE listing states a billing platform or a counting rule. See our commercial charging range for the hardware side.
Frequently Asked Questions
Does time billing charge me for the minutes before charging starts?
Only if the tariff starts its clock at connection or authorisation. On an energy-start tariff, those minutes are not billed. The station’s tariff terms state which definition applies.
Why did my session show more minutes than I spent charging?
Because the clock and the charge are different measures. Setup time, and any time between charge completion and unplugging, sit inside the counted window on tariffs that start early or stop late. The session record’s start and end times show which window was billed.
Do these definitions affect per-kWh bills too?
Not the energy line: metered kilowatt-hours are identical under any start definition. They matter on a per-kWh tariff only where a time element rides on top — an idle or overstay component counting from charge completion.
Related Reading
- How Much Do EV Charging Stations Charge? Pricing Models Explained
- Do EV Charging Stations Cost Money? Free vs Paid Charging Explained
- How Do Commercial EV Charging Stations Work?
