EV Charger Maintenance: A Practical Guide to Reliable Charging Infrastructure

Installing and commissioning EV charging infrastructure is not the end of the project. It marks the beginning of its operational life.

For a business, it is not enough for EV chargers simply to be installed. They need to be available when vehicles or users need them. Achieving this requires more than responding when something fails.

The reliability of a charging point depends on the charger itself, the electrical supply and protection systems, communications, configuration, software connectivity, and the way technical issues are identified and resolved.

EV charging infrastructure maintenance should therefore be treated as an ongoing process: prevention, monitoring, diagnostics, technical intervention and continuous oversight throughout the system lifecycle.

At Qerra, this approach begins before the maintenance phase itself. When one contractor is responsible for the design, electrical infrastructure, charging equipment, configuration and subsequent technical operation within the agreed scope, there is a much clearer starting point when an incident occurs: who understands the system and who is responsible for restoring it.

What Does EV Charging Infrastructure Maintenance Mean?

When we talk about EV charger maintenance, the charger is the most visible component. In practice, however, it is only one part of a wider system.

Several interconnected elements need to function correctly for a charging session to succeed:

• charging equipment;
• electrical supply and protection systems;
• communications connectivity;
• charger configuration;
• connection to the charging management system;
• software components and integrations;
• identification, access or payment mechanisms where applicable.

For this reason, “the charger is not charging” does not necessarily mean that the charger itself has failed. The cause may be related to the power supply, electrical protection, communications, configuration, the central management system or another component in the chain.

This is the difference between repairing a device and maintaining EV charging infrastructure as a system.

With a system-level approach, the first question is not “what component should we replace?” but:

Where is the problem, what is causing it, and who has technical responsibility for the affected part of the system?

This is why Qerra treats maintenance as a continuation of design and construction rather than as an isolated repair service. When the infrastructure has been designed and delivered by a single contractor, diagnostics can start with a known architecture, documented design decisions and existing technical documentation instead of reconstructing how the system was built every time an incident occurs.

What Does EV Charger Maintenance Include?

The exact scope depends on the equipment, utilisation, operating environment and agreed service level. In practice, reliable maintenance combines several related processes.

Preventive Maintenance

Preventive maintenance is planned and carried out before a specific failure occurs.

Its purpose is to identify signs of wear, deviations or developing issues before they result in a more serious fault or unplanned downtime.

Inspections may cover the condition of the charging equipment, cables and connectors, electrical components, protection devices, communications, configuration and other elements depending on the specific system and agreed technical scope.

There is no single maintenance interval that applies to every EV charger. The schedule should reflect the equipment, manufacturer recommendations, utilisation and operating conditions.

Monitoring and Remote Diagnostics

With connected charging infrastructure, part of the technical condition can be monitored remotely.

When the charging station and central system communicate via OCPP, status information and other operational data can be exchanged. The exact capabilities depend on the protocol version, the charging equipment and its implementation. OCPP 1.6, for example, provides status and diagnostic functionality, while OCPP 2.0.1 extends device-management and monitoring capabilities.

This means that some issues can be identified or initially localised without an immediate site visit.

However:

Monitoring shows what is happening. Diagnostics investigates why it is happening. Maintenance determines what needs to be done.

A structured process therefore looks like this:

monitoring → issue detection → diagnostics → decision → technical intervention where required

Remote diagnostics does not eliminate the need for physical inspection. For some faults, remote information may be sufficient for corrective action or for a better-prepared site visit. Other faults still require physical inspection and intervention.

Corrective Maintenance and Repair

Once a fault has been identified, corrective maintenance begins.

This may involve a configuration change, resolution of a communications or software issue, repair, component replacement or another technical intervention.

The important principle is that repair should follow diagnosis, not the other way around. The same symptom — for example, a charging session that cannot be started — may have several different causes.

After the intervention, the objective is not simply to confirm that a component has been replaced. The required functionality must be verified as restored.

Technical Inspections and System History

Periodic technical inspections allow the condition of the infrastructure to be assessed before a visible problem develops.

Equally important is maintaining a technical history that records:

• incidents;
• identified causes;
• completed maintenance activities;
• repaired or replaced components;
• recurring faults;
• technical recommendations.

This turns individual service interventions into useful information about how the infrastructure behaves throughout its lifecycle.

What Happens When an EV Charger Fails?

Effective incident response starts with a process, not simply with sending a technician to site without prior information.

1. Issue Detection

An incident may be reported by a user or operator or detected through monitoring.

2. Initial Assessment

The affected part of the system and the operational impact are identified.

3. Remote Diagnostics

Where the equipment and connectivity allow it, available status, event and diagnostic information is reviewed.

4. Prioritisation

The incident is handled according to its criticality and the agreed service level.

5. On-Site Intervention

If the issue cannot be resolved remotely, the necessary technical intervention is organised.

6. Repair or Correction

The cause may require a repair, component replacement, correction of an electrical or communications connection, configuration change or another technical action.

7. Verification

The required functionality is checked to confirm that it has been restored.

8. Documentation

The incident and actions taken become part of the system's technical history.

This process demonstrates why repair speed depends on more than how quickly a technician can arrive. Diagnostics, spare-parts availability, equipment access and the nature of the fault also affect restoration.

AC and DC EV Charger Maintenance

The fundamental maintenance logic is similar, but the technical scope can differ.

DC chargers generally contain more power electronics and additional subsystems within the charging equipment itself. Depending on the model, these may include active cooling, modular power architecture and more complex internal diagnostics.

With AC charging infrastructure, part of the power conversion takes place inside the vehicle, but this does not make maintenance insignificant. Cables, connectors, contactors, protection devices, communications, configuration and power supply remain part of the system.

The maintenance plan should therefore be based on the specific equipment and operating conditions rather than simply on whether the charger is classified as AC or DC.

What Is an SLA for EV Charging Infrastructure Maintenance?

An SLA — Service Level Agreement — turns the expectation of “fast support” into measurable service parameters.

It is important not to confuse different time commitments.

Response time indicates how quickly the incident-handling process begins.

Diagnostic time defines the timeframe for technical assessment under the agreed conditions.

Technical intervention time may define when an on-site visit needs to be organised.

Restoration time also depends on the nature of the fault, required spare parts and other technical dependencies.

Therefore:

Response time ≠ resolution time.

An SLA should define more than a timeframe. It should establish who responds, under what conditions, for which part of the system and with what responsibility.

What Does Uptime Mean for EV Chargers?

Uptime indicates the operational availability of the charging infrastructure over a defined period.

Small differences in the percentage can translate into significant differences in actual time.

For a year of 8,760 hours:

99% uptime allows for approximately 88 hours of unavailability.

97% uptime allows for approximately 263 hours of unavailability.

A difference of only two percentage points represents approximately 175 hours — more than seven days.

The percentage alone is therefore not enough. It needs to be clear what is being measured and under which conditions.

There is another important distinction in EV charging infrastructure:

Online does not necessarily mean operational.

It is useful to distinguish between:

Connectivity — is the charging station communicating with the management system?

Functional availability — are the required functions available?

Successful charging — can the user actually complete a successful charging session?

A charging station may be communicating with the central system while a specific technical issue still prevents charging.

Uptime is therefore not simply a characteristic of the hardware. It is the result of the charging equipment, electrical supply, communications, configuration, software, diagnostics, spare-parts availability and the organisation of technical response.

Taking Over Charging Infrastructure Installed by Another Contractor

Changing the maintenance provider is possible, but the new contractor first needs to understand the system it is being asked to take responsibility for.

A technical assessment may include:

• documentation and as-built drawings;
• equipment manufacturer and model;
• current technical condition;
• electrical infrastructure;
• configuration;
• communications;
• integration with the central management system;
• technical access and credentials;
• fault and repair history;
• warranty status;
• spare-parts availability;
• existing boundaries of responsibility.

Taking on an SLA for a system with an unknown technical condition creates risk for both the customer and the new service provider.

For this reason, when Qerra Care takes over existing charging infrastructure, it is preceded by a technical assessment and approval of the scope.

This establishes what can realistically be taken over and where Qerra's responsibility begins.

How to Choose an EV Charger Maintenance Model

Not every charging infrastructure project requires the same maintenance model.

Reactive maintenance begins after a problem occurs. It may be sufficient for certain non-critical applications but provides less predictability.

Preventive maintenance adds planned inspections and activities designed to identify potential issues early.

SLA-based maintenance establishes defined service levels, time commitments and responsibilities.

Lifecycle maintenance connects prevention, monitoring, diagnostics, technical response, repair and reporting with the way the infrastructure was originally designed and built.

The appropriate model depends on the number and type of chargers, utilisation, geographic distribution, acceptable downtime, internal technical resources and the role charging plays in the organisation's operations.

How Do You Know Whether EV Charger Maintenance Is Working?

A maintenance contract alone does not show whether charging infrastructure is being managed effectively.

Depending on the project, useful indicators may include:

• uptime and downtime;
• number of technical incidents;
• recurring faults;
• response time;
• diagnostic time;
• time to restoration;
• preventive maintenance activities;
• technical intervention history;
• performance against agreed SLA parameters.

Trends are particularly important.

If the same charging station repeatedly develops a similar fault, closing each individual service case does not necessarily mean that the root cause has been resolved.

If response is fast but the system remains unavailable because a required part is not available, that is also an operational issue.

Maintenance quality should therefore be evaluated not simply by the number of site visits but by the resulting reliability and predictability of the charging infrastructure.

When Maintenance Becomes a Business Issue

For a single non-critical charging point, temporary unavailability may simply be an inconvenience.

For charging infrastructure supporting a corporate fleet, facility or customer service, the consequences can be different.

Downtime may mean vehicles that are not charged according to the operational schedule, an interrupted service or additional work for facility-management and operations teams.

A particularly revealing situation occurs when an incident requires the customer to determine which of several suppliers is responsible: the electrical contractor, charger supplier, software platform, communications provider or maintenance company.

At that point, a technical issue becomes an accountability issue.

This is where Qerra's approach to single-point technical accountability becomes important. When design, construction, charging equipment, system integration and subsequent technical maintenance form part of one continuous delivery model, the customer does not have to act as the system integrator between multiple suppliers every time an incident occurs.

Maintenance Starts at the Design Stage

The quality of maintenance is influenced by decisions made long before the first service case.

Cable routes and sizing, electrical panels, protection systems, communications architecture, charger selection and configuration determine not only how the infrastructure operates but also how effectively it can later be diagnosed and maintained.

When Qerra has designed and delivered the charging infrastructure, maintenance does not begin with an unknown system. The team has the project context and technical documentation and understands how the individual components were designed to work together.

This does not mean that technical issues will never occur. It means that when they do, diagnostics has context and accountability has an owner.

This is also the role of Qerra Care — to continue the infrastructure lifecycle after commissioning through preventive maintenance, monitoring, diagnostics, technical response and agreed service levels.

Already Have Existing EV Charging Infrastructure?

If the infrastructure was installed by another contractor, the first step should not be an SLA promise. It should be understanding the system.

Qerra can perform a preliminary technical assessment of existing EV charging infrastructure to establish its condition, technical dependencies and the scope that can realistically be taken over for ongoing maintenance.

Frequently Asked Questions