EVCI Global recently researched charging points in the United Kingdom, and the published findings were eye-opening. The research revealed that as many as 31.5% of the charging points examined fell outside the accepted accuracy range. Even more worrying is that 15% showed a deviation of more than ±5%, with cases where the charges were 37% too low or 30% too high. Although metering inaccuracy may seem like a technical detail, even small deviations can have major consequences in a charging ecosystem where every transaction depends on the number of kilowatt hours consumed.
For EV drivers, inaccurate metering breaks trust. If billed energy does not match supplied energy, faith in public charging infrastructure erodes, particularly in a market that is not yet widely established. For industry stakeholders, such as EVSE manufacturers, charging point operators, service providers and fleet managers, the consequences reach further. Metering errors cause revenue loss, customer disputes, compliance problems, and reputational harm. At scale, small errors become systemic risks.
The real costs of an error of ‘just a few %’
Measurement errors in EV charging quietly affect margins, trust, and decision-making. For EVSEs, a small under-measurement of 1% in DC fast charging can trigger extra tests or warranty claims. If a meter falls outside the permitted MID accuracy class, the result may be not just technical fixes but also recalls, recertification, or even sales halts.
Charging service providers face different but equally costly risks. A 1–2% billing error, scaled across thousands or millions of sessions, leads to customer complaints, refund requests, and reputational harm that is harder to fix than the technical problem itself. A network supplying ten million kilowatt-hours a year could lose or refund tens of thousands of euros, often without knowing the source. Fleet managers rely on accurate energy data to manage costs per kilometre; small errors can disrupt their entire financial model. For fleets that charge a large number of vehicles, even minor errors can result in losses of hundreds of thousands of euros per year. What may seem insignificant at the device level can develop into a significant, structural financial problem, which underlines the importance of accuracy.
Understanding EV charging metering
During charging, the electricity meter determines exactly how much electrical energy is flowing from the grid to a vehicle and, ultimately, what is billed. This may sound straightforward, but the reality is considerably more dynamic. Charging electric vehicles involves rapidly fluctuating loads, wide power ranges, electrical noise, and even bidirectional energy flows when vehicles feed energy back into the grid. To record this accurately, highly advanced metering systems are required, based on precision components and rigorous calibration, all working together to ensure that what is measured matches what is supplied.
In Europe, this is regulated by the Measuring Instruments Directive (MID), which creates the legal basis for billing-grade electricity meters. Under MID, meters must meet strict standards for accuracy, consistency, traceability, and tamper resistance to keep energy transactions fair and verifiable. Accuracy classes define maximum allowable errors: Class A allows ±2%, Class B narrows this to ±1%, and Class C allows just ±0.5% for demanding EV charging. These classes form the basis for accurate billing, consumer protection and trust as the electric vehicle charging ecosystem continues to develop.
Protect your kWh's with precision tools
Metering testing solutions deliver what is rare in the EV ecosystem: true confidence in measurements. Instead of relying on assumptions or waiting for audits, operators and manufacturers can validate meter accuracy in real time. On-site verification catches measurement errors early, reducing regulatory non-compliance risk under the MID, and prevents small inaccuracies from escalating into larger financial or operational issues. In a sector where every kilowatt-hour matters, such devices quietly ensure trust, accuracy, and financial integrity across the EV charging landscape.
inepro Metering offers portable metering testing solutions, designed for fast, reliable on-site accuracy testing. Would you like to find out more? Then visit our dedicated product Tunkia TE1000 and T1100 pages.
