What is OCPP?

More and more EV charging stations are being installed all over the world, and with it come new technologies that bring their own terminology. One of the key ingredients to a successful deployment of electric vehicle charge points is the Open Charge Point Protocol, or OCPP for short.

What is Open Charge Point Protocol (OCPP)?

OCPP, the Open Charge Point Protocol, is the language that electric vehicle charging station management systems (CSMS) use to communicate with connected EV charge points, also known as EV supply equipment (EVSE), in order to manage charging sessions and enable remote diagnostics, all while ensuring a secure exchange of data.

We can identify three different players in the field of EV charging that need to cooperate well for a great end user charging experience:

1. EVSE Manufacturers: These are hardware companies that manufacture the chargers, which are also known as Electric Vehicle Supply Equipment (EVSE)
2. CSMS Software Providers: These are software companies that build Charging Station Management Systems (CSMS)
3. CPOs: The Charge Point Operators (CPOs) own the customer relationship and are the brands that EV drivers interact with

It is common for these three to be separate businesses, but in some cases, single companies choose to take the role of two or all three of the above.

In order for CPOs to be able to bill the driver for their use of electricity and manage the electrical load that the chargers have access to, the charger needs to be controllable through a central interface. These interfaces are typically Web-based administration portals that sit in the cloud and use the public Internet. They are built by the CSMS providers, and the OCPP as an open standard protocol is needed for chargers from different manufacturers to be able to speak to charging station management systems from different software providers. The OCPP ensures compatibility across systems, which in turn allows for more choice in both hardware and software for the consumer that buys home chargers, real estate companies that install chargers at apartment or office buildings, or other buyers of EV charge points.

Examples of OCPP in action

A typical sequence of events for EV drivers when requiring charging looks as follows:

1. Driver makes a reservation request for a particular charger prior to arriving at the station, typically through a mobile app, or through messaging
2. As the driver arrives, the driver identifies herself and the charger authorizes her
3. The charger physically unlocks the connector that the driver plugs into her car
4. The charger starts the charging sessions
5. The driver enters a nearby store for a cup of coffee and eventually receives a notification that the charging session has ended
6. The driver sets the connector back into the socket and the charger locks the socket
7. The charger triggers a billing event with the driver

Each of the above-mentioned steps utilizes a command/response that is exchanged between the EVSE and the CSMS via the OCPP protocol.

How to access OCPP-compliant chargers over the Internet?

For EVSE manufacturers, CSMS providers and CPOs to be able to function on their own and with each other, they need reliable connectivity in all the places they operate in or want to expand into. Luckily, such an infrastructure exists with the public wireless networks around the world. While many older chargers are still connected through Ethernet, cellular connectivity combines reach, availability, and security into a package that gives charge point operators the reliability they need.

However, OCPP does not offer a lot in terms of remotely accessing chargers to reconfigure them, troubleshoot for issues, or push firmware updates to remedy security issues or improve their functionality over time. While it exposes error codes when chargers malfunction, this is not sufficient to accomplish the above. Charge points, like any modern Internet-connected devices (IoT devices), need to allow remote access and the ability to update the firmware (software) that runs on them, in a way that guarantees stability.

Twilio supports OCPP-compliant chargers with two offerings:

1. Super SIM – a single SIM card that gives access to over 400 top-tier networks around the world, with automatic failover built in and local Internet breakouts for low latencies and high data sovereignty. Super SIM lets charge point operators, CSMS providers, and manufacturers turn their chargers into smart chargers and attain a high level of control over the cellular deployment, from choosing which networks to utilize and which to exclude, to getting a stream of SIM connection events that allows them to create additional revenue streams around access to premium network status visibility and more.
2. Microvisor – a managed service providing 24/7/365 remote device access as well as hardware-to-cloud security for the lifetime of connected devices such as EV chargers. Microvisor allows operators to continuously monitor, troubleshoot, and improve their chargers in the field, by offering unbreakable over-the-air firmware updates and secure live (line-by-line) remote debugging.

Have a look at IoT SIMs and Managed Connectivity for Smart EV Chargers for more information, and to sign up for a free Super SIM trial card or join the Microvisor beta program.