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Engineer analysing a charging session with a comemso charging analyzer at a public charging station

Charging interoperability analysis

Find out why a vehicle and a charger don't work together.

EVCA records messages, voltage and current of the real vehicle and the real station on one timeline, shows the first deviation and lets you confirm the cause by simulation – instead of swapping parts until the fault disappears.1

One EVSE manufacturer had searched for seven months. The recording pointed to the precharge response; the analysis took about three minutes.

Request a 15-minute demo Find your test system
Real pairStarts with the EV and EVSE that actually interacted
One timelineYou see communication, signals, states and measurements side by side
Verified causeThe hypothesis tested before either product changes
Reusable resultsThe case kept for regression
In 30 seconds
What for
Teams who must find out why a specific vehicle and charger don’t work together.
What it does
Messages, voltage and current of the real pair on one timeline; a seven-month search ended after about three minutes of analysis.
Not for
Release testing of a single product against the standard – that is EVSE testing or EV testing.

Every unexplained charging failure leaves a driver at the station – and sends a ticket to your support team.

The interoperability investigation, planned

Start with the real charging pair.

First, you identify the EV and EVSE involved. The documented diagnosis case shows the method; the measurements follow what your charging pair needs.

1 · Suitable systemEVCA InteropInterop observes the real vehicle and real charging station together, without replacing either side with a simulation.View EVCA Interop →
2 · Project examplesPrecharge field reportThe field report shows how the customer’s engineers used the measurement finding for a targeted correction and verified it with the real charging pair.Follow the diagnostic steps →
3 · Next stepThe setup for the charging pairWe specify interfaces, failure symptom, required measurements and the intended reproduction for the concrete pair.Discuss the test task →
Test scenario: Start with the precharge mismatch

In the documented customer case, the voltage requested by the vehicle did not match the charging station’s measured precharge response. Precharge prepares the voltage before the main power connection closes. The test compares request, measured voltage and next state together; after you correct the control parameters, the charging attempt runs again.

Compare the timing with the measured voltage.

In an anonymised EVSE (electric vehicle supply equipment, or charging station) case, the requested battery voltage and measured precharge response did not match. Reviewing communication and electrical signals together made the mismatch visible.

See the diagnostic sequence

Tracing charging interoperability failures

Bring vehicle and charging-station records onto one timeline.

Charging failure analysis follows the sequence across communication, low-level control and electrical behaviour. Separate PCAP files, vehicle logs and charger traces may show the final error while leaving the first deviation unclear.

All clocks run on one time base

Vehicle, charging station, backend and laboratory tools often use different time bases. When records are aligned manually, the apparent order of events can change.

You compare all relevant signals

You check decoded messages against low-level states, voltage, current and the expected charging phase. Messages alone cannot show that these stayed consistent.

You confirm the suspected cause before anyone changes software

The same conditions test the suspected cause before any software changes. This gives both teams a basis for discussing symptoms that appeared in separate exports.

Comparison of isolated charging logs with synchronized engineering evidence
From fragments to causality.

Passive Man-in-the-Middle measurement

Record the real vehicle and charging station together.

Passive Man-in-the-Middle measurement records the relevant layers at the physical charging interface on one time base. Both real partners stay connected, so the interaction that produced the problem is preserved.

First you record the real event, then you confirm the cause – by changing the live session or by simulation in the lab.

Method stepsField capture documents the original pair. Controlled validation tests a suspected cause. Laboratory reproduction preserves the relevant partner behaviour for a new test.
Real EV and real EVSE connected during an interoperability measurement
Begin with the actual EV-to-EVSE interaction before reproducing it in the laboratory.
Man-in-the-middle measurement of DC power, CP and PLC communication, and PP between a real charging station and vehicle.
Passive man-in-the-middle measurement records power and communication between a real vehicle and charging station.

Cross-layer charging analysis

Check the charging process across messages and measurements.

Charging interoperability analysis compares protocol messages, timing, low-level states, voltage, current and both partners’ reactions. Reviewed against the charging phase, they reveal the first technically meaningful deviation.

Original comframe view · EVCA
  1. Partner request: charging-message sequence.
  2. Device response: synchronised voltage and current traces.
  3. Result record: decoded messages and event data.
Original comframe view · EVCA

Messages, states and measurements are checked for agreement.

1
Communication

Message direction, sequence, content and timing.

2
Low-level state

Connection, control, signaling and stop conditions.

3
Electrical behaviour

Voltage, current, power transition and physical reaction.

4
Expected context

Charging phase, permitted combination and identified deviation.

Automated Standards Analysis can add normative or configured expectations where released. Cross-Layer State Monitoring is implemented for applicable DC CCS, CHAdeMO and DC China / GB/T DC configurations.

One charging interoperability method

CCS interoperability testing: from failed charge to root cause

  1. 1
    Connect

    Connect to the real EV and EVSE at the charging interface.

  2. 2
    Capture

    Capture the relevant charging layers on one synchronised time base.

  3. 3
    Decode

    Decode messages and identify state transitions, signals and timing.

  4. 4
    Correlate

    Compare communication with low-level signals and electrical behaviour.

  5. 5
    Analyse

    Find the first deviation from the expected charging state.

  6. 6
    Validate

    Change one controlled condition to test the suspected cause.

  7. 7
    Reproduce

    Reproduce supported partner behaviour in a repeatable laboratory test.

  8. 8
    Reuse

    Keep the case for supplier discussions, regression tests and documentation.

Field capture, analysis and validation, laboratory reproduction, and reuse of charging tests for regression

The cause validated, the field case reproduced

Check cause and effect before changing the product.

Once the first deviation is isolated, change one condition to test its effect. The live gateway keeps both real partners connected.

Both real partners stay connected during the test

Where released, Manipulating Gateway shows whether a selected value, message or timing condition changes the result.

Manipulating Gateway

The partner behaviour, repeated in the laboratory

Where released, Charge Playback presents recorded EV-side or EVSE-side behaviour to the device under test again.

Charge Playback
Vehicle and charging test equipment in a laboratory validation setup
The recorded field case stays linked to the controlled validation test.
Man-in-the-middle setup with a Manipulation Gateway between the vehicle and charging station for targeted CP and PLC changes.
Manipulating Gateway introduces targeted communication changes to test the response of the real charging pair.

Recording and test conditions stay together

Record the case, repeat the conditions and verify the correction.

Save the synchronised measurement with the expected behaviour, observed deviation, validation condition and decision. The link to the original event stays, so others can follow how you reached the conclusion.

  • Communication and measurements on one synchronised time base
  • Expected state, observed behaviour and deviation shown together
  • Documented conditions for the controlled validation test
  • Shared records for development, suppliers and laboratories
  • A reusable case for release regression and variant testing
Reusable evidence package containing measurement, expectation, validation and decision
Measurement + expectation → validation → reusable result.

Use the same case in development, supplier discussions and field support.

Where to use charging interoperability analysis

Development

Resolve integration failures before release

You investigate the interaction while changes to vehicle and charging-station software can still be planned and tested.

Field

The charging pair, recorded on site

You capture the event while both implementations are still on site and their original interaction is observable.

Supplier alignment

Give both teams the same recording

Vehicle and charging-station teams review the same time base, event sequence and tested hypothesis.

Regression

Verified cases repeated after updates

The relevant partner behaviour repeats after software, parameter or hardware changes.

Choose the next test step.

From method to implementation

Next tasks: record a real charging pair, reproduce partner behaviour, configure faults or select a complete test system.

Product
EVCA Interop

EVCA Interop records communication and measured signals from the real vehicle and charging-station pair.

Adjacent product
EVCA Multi Mobile

Broader portable measurement, simulation and multi-standard field work.
Capability
Automated Standards Analysis

See the released standards-aware evaluation and timing analysis functions, with examples from the user interface.

Capability
Manipulating Gateway

Supported live changes, protocol scope, limits and validation conditions.

 Capability
Charge Playback

Active physical charging-partner reproduction, direction and release depth.
Formal verification
Conformance Test Libraries

Defined test cases, standard editions, DUT roles, verdicts and validation scope.

Conformance, interoperability and robustness

Choose the test discipline for the question.

1

Conformance

Does one implementation meet a defined requirement set and standardized test cases?

2

Interoperability

How do two specific implementations work together during a real charging session?

3

Robustness

How does an implementation respond to configured limits, timing changes and difficult partner behaviour?

Technical background

Frequently asked questions

Interoperability and charging analysis

What is charging interoperability testing?

Charging interoperability testing examines a specific real EV and EVSE during a charging session. It compares communication, low-level states, timing, electrical behaviour and both implementations’ reactions.

How does interoperability differ from conformance testing?

Conformance testing checks one implementation against defined requirements and test cases. Interoperability testing checks how two specific implementations interact. Both are needed to answer these different questions.

Why can individually compliant products still fail together?

Interpretations, optional behaviour, timing margins, certificate conditions, state transitions and error handling can differ. Their interaction may reveal a problem that a test of either implementation alone did not show.

Why is passive Man-in-the-Middle measurement useful?

Both real partners remain connected during the field capture. Passive Man-in-the-Middle measurement records the relevant layers on a common time base and preserves their actual interaction.

Why can communication traces alone miss an EV charging fault?

Compare a communication trace with measured voltage and current to check whether the electrical response matches the requested values. The trace alone cannot establish that match.

In the anonymised comemso precharge case, communication timing appeared unremarkable, while the measured EVSE voltage response did not match the requested battery voltage. An experienced product specialist identified this relationship by reviewing synchronised electrical and communication recordings. This was human analysis of one vehicle–charger pairing; the account does not establish that all faults have the same cause or diagnosis time.

Read the precharge diagnosis account

Can a suspected cause be tested before software is changed?

Yes, where a released live validation method supports the required controlled change. The purpose is to observe cause and effect before implementing a correction in the EV or charging station.

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Interoperability testing: turn the suspected root cause into a controlled check

It starts with the complete initial state: vehicle, charging station, firmware, interface, communication profile and boundary conditions. Interoperability testing asks whether the two partners reach the intended charging sequence together. One unsuccessful charge does not identify its root cause. Retain a suitable successful comparison and locate the first difference on the same timeline.

In a precharge case, compare the vehicle request, the actual voltage trace and each partner’s response. Distinguish a late response from one carrying an incorrect value. State the suspected root cause as a condition that a controlled repeat can confirm or disprove.

A defined EV tester or charging-station simulator can replace a real partner with a repeatable laboratory sequence. Preserve the limits of the evidence: correcting one case provides the starting point for further interoperability testing with the intended charging partners.

After the correction, repeat the original fault case and successful comparison. Check neighbouring states as well, so a timing change does not move an interruption elsewhere in the sequence. CCS interoperability depends on coordinated vehicle and charger behaviour. A shared record makes that behaviour testable and gives the two development teams common data when verifying the root cause.

CCS interoperability with EVCA Interop · You can reproduce a charging fault in the laboratory

Real-pair investigation

Prepare a repeatable charging interoperability test.

You identify the real vehicle and charging station and reproduce the reported condition. Before selecting hardware, define the synchronised signals and measurements needed to investigate the cause.

Find your test systemRequest a 15-minute demo
¹ Scope

Functions, charging standards, interfaces, power ratings and Test Libraries depend on the EVCA system, the software release and your project configuration. Automated standards analysis supports, but does not replace, formal conformance testing. The quotation confirms the scope for your project.

  • Start with the investigation method, then confirm supported directions, editable parameters, release limits and technical configuration on the relevant capability pages.