EV Charging Metering: A Guide for Charge Point Operators
News Details
EV charging metering answers a question that a building meter cannot. A site with four charge points and one utility meter can bill the total. It cannot bill the driver who plugged in at bay three. This guide covers the decisions that make per-session billing and load control possible.
Key Takeaways
- Meter each charge point when drivers pay; meter the feeder when the site only needs a total.
- Match the meter to the actual supply, because a single phase unit cannot serve a three phase point.
- Communication decides whether you bill remotely or send someone to read the unit.
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Why EV Charging Metering Differs From Building Metering
A building meter measures one supply for one bill. EV charging adds many short, heavy sessions across several points, and each session belongs to a different payer. One afternoon can move more energy through a single bay than an apartment uses in a week.
That pattern changes the requirement. The meter must resolve short intervals, hold the data when a link drops, and tie each record to one connector. Electric vehicle charging infrastructure also grows bay by bay, so the meter count rises with the site rather than all at once.
In short, ev charging metering is not a scaled-down version of building metering. It is a billing instrument that happens to sit on a car park.
Meter per Charge Point or per Feeder
Two layouts dominate, and the choice sets the meter count.
Meter per charge point gives an exact allocation. Each session lands on one account, and a dispute can be settled from the record. Meter per feeder is cheaper, and it suits staff car parks, depots and overnight fleet charging.
In practice, most operators meter each point and keep one feeder meter as a cross-check. The feeder total should match the sum of the points. As a result, a gap between the two points to a wiring fault or an unmetered socket.
For a site with several bays, a power data gateway terminal collects the meters over a local link and reports upstream in one stream.
Single Phase or Three Phase at the Charge Point
Most AC charge points draw single phase. A common AC point pulls 32 A at 230 V, which is roughly 7.4 kW. Faster AC points need three phases and reach 11 kW or 22 kW. A DC unit sits outside this discussion, because it meters on the DC side.
Therefore, confirm the service before ordering. A single phase electronic energy meter covers a 5(60) A single phase point with accuracy class 1. A three phase point needs a three phase unit. Because of that, mixing the two gives you either an unusable meter or a reading that misses two phases.
In addition, the current rating matters as much as the phase count. A point rated at 32 A leaves little headroom on a 40 A meter. Size for the continuous load, and check the ambient temperature inside your cabinet.
Who Reads the Meter: Local Bus, Cellular or Gateway
In addition, the reading path decides the operating cost. A meter with no link needs a person and a clipboard, which does not scale past a handful of bays.
Three options cover most sites. A wired RS485 bus suits a new build, where the contractor runs cable during construction. A cellular module inside the meter removes the local network, which suits a single remote bay. A gateway suits a cluster, because one device reads many meters and forwards the totals. The charge point operator still owns the data, so confirm who keeps the record.
Ev charger load management belongs in the same decision. A gateway can cap the total draw across a group of points, so the site stays inside its supply. That cap is the core of ev charger load management, and it protects your main breaker while postponing a costly upgrade.
Whichever path you choose, confirm what happens during an outage. A meter that buffers sessions and resends them protects the revenue. However, one that discards data turns a network fault into a billing dispute.
Billing Models the Meter Must Support
The tariff model shapes the data that ev charging metering must store, so settle it before the hardware.
Three models are common. Energy billing charges per kilowatt-hour and needs only a reliable total. Session billing charges per connection and needs a start and an end event. Time based billing charges for occupancy and needs the interval record, because a driver who stays parked still occupies the bay.
Many operators combine them, because electric vehicle charging infrastructure rarely fits one model across a site. They bill energy for the electricity and add a parking fee after a grace period. As a result, that mix requires interval data, and a meter with a rolling load profile earns its small extra cost. In practice, the same record supports ev charging energy billing across several sites from one platform.
Specifying Hardware for EV Charging Metering
- Supply type and current rating at each point.
- Accuracy class required by the local billing rule.
- Data retention, meaning how many days of interval records the meter holds.
- Communication link and the protocol the platform expects.
For three phase bays, a 4G three phase DIN rail energy meter packs the meter and the cellular link into one DIN rail unit. That removes a separate modem and shortens the panel build. It is one of several families covered in our review of smart energy meters.
Frequently Asked Questions
How accurate must an ev charging meter be? Match the local billing rule. Class 1 covers most public charging, and IEC 62053-21:2020 sets that class for static meters measuring AC active energy (IEC, published 17 June 2020).
Can one meter serve two charge points? It can measure both, but it cannot separate them. If two drivers pay separately, give each point its own meter.
Do I need a certified meter to bill drivers? In the European Union, active electrical energy meters used for billing fall under Directive 2014/32/EU as instrument category MI-003 (Directive 2014/32/EU, 2014). Confirm the national rule first.
What happens if the network drops mid-session? A meter with local storage keeps the session and resends it later. Confirm the buffer depth against your own outage pattern, because a long outage can exceed a shallow buffer.
Final Thoughts
EV charging metering succeeds on three choices: the meter count, the supply match and the reading path. Fix those in order, and the billing model follows.
Start with the bay layout. Decide who pays, then let that decide whether each point needs its own meter. Next, match the phase count and current rating to the actual service. Finally, confirm the interval record, because ev charging energy billing depends on it.
For the wider metering design behind the chargers, read our wider metering guide. Chargers are non-linear loads, so they also affect the site's power factor penalty exposure. Send us your site list and we will match models to both.
