OCPP: The Protocol Your Chargers Run On

OCPP: The Protocol Your Chargers Run On

If you are thinking about operating chargers, or already operate them, the hardware you buy is only half the purchase. The other half is the conversation that hardware has with your software, every few seconds. When that conversation breaks, sessions fail, revenue goes missing, and the EV users blame you.

That is where OCPP comes into the picture. OCPP is the foundation everything else sits on. Yet public charger uptime is widely estimated at just 60–70%; and uptime is an OCPP problem long before it is a hardware problem.

The Open Charge Point Protocol connects your charger to your charging management system.

What is OCPP and why does it matter?

OCPP stands for the Open Charge Point Protocol, maintained by the Open Charge Alliance. It is the open standard that lets a charger and a charging management system talk to each other. Start a session, stop a session, report a meter value, push firmware, and raise a fault.

OCPP works inside one operator’s network, between the charger and their Charging Station Management System (CSMS). Open Charge Point Interface (OCPI) works between companies, connecting the Charge Point Operators (CPOs) with e-Mobility Service Providers (eMSPs).

But OCPP and OCPI are tightly linked. Every location status, meter reading, and session record an operator shares with a roaming partner over OCPI starts its life as an OCPP message. If the OCPP data is wrong, the OCPI data will be wrong too.

The Versions of OCPP Protocol

OCPP 1.6J introduced JSON over WebSockets (commonly called OCPP 1.6J), smart charging, and local authorisation list management. It is still the most widely deployed version, in India and worldwide. A later security extension added TLS, certificate management, and security event logging.

OCPP 2.0.1 is a genuine redesign, not an increment. It introduces a structured device model with variables and components instead of loose configuration keys, a cleaner transaction model built on TransactionEvent, real diagnostics, defined security profiles with TLS and certificate handling, and native support for ISO 15118 so Plug and Charge is possible rather than improvised. It is not backward compatible with OCPP 1.6.

OCPP 2.1 extends 2.0.1 into bidirectional power, V2X, control of distributed energy resources (DER), battery swapping, local cost calculation, and support for ad hoc and prepaid payments through payment terminals.

Should you migrate?

Honest answer: not automatically. Migration costs firmware work, CSMS work, and a revalidation of every site. The case is strong if you are procuring new hardware now, if you need Plug and Charge or if you are running smart charging against a constrained connection.

How does OCPP improve charger uptime?

At 60–70% estimated uptime, roughly one visit in three fails. OCPP 2.0.1’s device model shifts charging network troubleshooting from hands-on field maintenance to remote data analysis:

Registers and monitors every charger – When a charger powers up, it establishes a connection with the CSMS by sharing its make, model, firmware version, and serial number. From then on, it sends regular heartbeats and status updates, so the operator knows whether each connector is available, charging, faulted, or offline.

Authorizes Drivers - When a driver taps an RFID card or starts a session from an app, the charger checks with the CSMS whether that ID is allowed to charge. For sites with weak connectivity, OCPP supports a local authorisation list and an authorisation cache, so the charger can make the decision itself when the network is down.

Manages Charging Sessions - OCPP marks the start and end of every session and records who charged, when, and on which connector. In OCPP 1.6 this is handled through separate start and stop transaction messages; OCPP 2.0.1 replaces them with a single, richer transaction event.

Reports Meter Values - The charger sends energy readings at the start of a session, at intervals during it, and at the end. These readings are the basis for billing the driver and, through OCPI, for settling with roaming partners.

Enables Remote Operations - Operators can start or stop a session remotely, unlock a stuck connector, reboot a charger, change its configuration, pull diagnostic logs, and push firmware updates, all without sending a technician to site.

Supports Smart Charging - The CSMS can send charging profiles that cap the power a single charger or an entire site draw, by time of day or by available grid capacity. This is how operators share a limited grid connection across many chargers and avoid paying for peak demand.

Every downstream layer like roaming, aggregation, national interoperability; amplifies whatever your chargers do. Fixing uptime is precondition to enhance roaming for your network.

How ChargeIndia helps you get more from OCPP

The OCPP Compliance Test Tool (OCTT) developed by the Open Charge Alliance (OCA) is the industry reference platform for checking whether an OCPP implementation conforms to the specification. It supports both OCPP 1.6 and OCPP 2.0.1 and validates all three sides of protocol: Charging Station Management System (CSMS), Charging Station and Charging Station Software Stacks.

At ChargeIndia we will run your implementation through the OCTT to locate exactly where it deviates from the specification; before these deviations surface as failed interoperability and roaming issues. We will be bringing OCTT-based conformance testing to charger OEMs, CPOs, and CSMS developers.

What you will be getting:

OCTT test runs for OCPP 1.6 and OCPP 2.0.1

Testing for hardware chargers, firmware/software stacks, and backend CSMS platforms

Detailed failure analysis with specific references and guidance on how to remediate it

Re-testing support

This testing service will help charger OEMs prepare for OCPP certification or tender requirements, CSMS and software vendors to prove their interoperability with multiple charger brands and CPOs to validate their hardware before a large-scale deployment.

Clean OCPP data in, reliable roaming out. With interoperability at the core, ChargeIndia helps create a more connected, scalable, and dependable EV charging ecosystem.

India's charging networks, on one platform. Be part of what is next-

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