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Charging Technology

OCPP and ISO 15118: What is the Difference Between Dynamic or Scheduled Control Mode?


April 25, 2023

As more people start using electric vehicles (EVs), it's important to know how the charging process works and how it can be improved. This article helps make sense of EV charging by explaining ISO 15118 and OCPP in relatively simple terms. You’ll also find out some of the different methods used in smart charging technology to make the process more efficient.

Whether you're an EV owner, a fleet manager, or a charging point operator, or just curious about this technology, this article will help you understand how EV charging is becoming smarter and more efficient. After this article, be sure to check out our report, "What Is OCPP and How to Use It for Smart Charging."

What is ISO 15118?

The International Organization for Standardization (ISO) developed ISO 15118, which outlines a communication protocol that promotes secure communication between electric vehicles (EVs) and electric vehicle supply equipment (EVSE), commonly known as charging stations. 

The primary aim of this protocol is to enable safe and efficient charging of the EV battery by facilitating secure communication between the EV and the charging point.

ISO 15118 is a critical standard that creates interoperability between various EV and EVSE manufacturers. It provides a common language for communication between these devices. It also allows for a more efficient and secure charging experience for EV owners and improved efficiency with reduced billing and authentication costs for EVSE operators.

What is OCPP?

OCPP stands for Open Charge Point Protocol. It is a communication protocol used in the electric vehicle (EV) charging infrastructure industry to facilitate communication between electric vehicle supply equipment (EVSE) and central management systems (CMS).

OCPP was developed as an open-source protocol that enables seamless interoperability between different manufacturers' EVSEs and CMSs.

The primary objective of OCPP is to establish a standard communication interface between EVSEs and CMSs, ensuring that they can interact efficiently and securely. Standardizing EV charging station networks enables the integration of charging stations from different manufacturers, allowing EV owners to charge their vehicles at any station, regardless of the brand, without any compatibility concerns.

Additionally, OCPP enables real-time monitoring and control of EV charging infrastructure. This allows operators to track and manage charging station usage, optimize energy consumption, and perform remote diagnostics and firmware updates.. This capability is crucial for EV charging infrastructure providers because it ensures efficient system operation, reduces operational costs, and improves customer service for EV owners.

Overall, OCPP is a critical protocol that drives the interoperability and efficiency of the EV charging infrastructure industry, ultimately contributing to the wider adoption of electric vehicles and the development of a more sustainable transportation system.

For more information on OCPP, check out our comprehensive OCPP guide.

What is smart charging?

Normal or traditional charging is a simple process of plugging in and charging until the battery is full. The charge point uses maximum charging power until the EV battery reaches 100% SoC, at which point the charging process stops automatically. 

Smart charging uses a central system to manage the power output from charging stations, taking into account real-time information about the EVs being charged, the available electricity supply, and the local grid infrastructure.

The central system controls the charging process and applies intelligent decision-making to coordinate EV charging across a whole fleet. In contrast to normal charging, which charges all vehicles at the maximum capacity of the charging station, smart charging is more dynamic. The power output of the station is adjusted depending on factors such as the time of day, the expected length of charging, the state of the EV battery, and the grid's overall demand.

Smart charging can also be used to balance the load on the grid. Since there are often spikes in electricity usage during peak hours, smart charging can spread out the EV charging load more evenly throughout the day. This reduces strain on the grid and prevents blackouts. To learn more about how smart charging and OCPP work together to help you optimize your charging efforts, read our report, "What is OCPP and How to Use It For Smart Charging."

Difference Between Dynamic or Scheduled Control Mode

ISO 151118 allows for distinguishing between Scheduled and Dynamic control modes in electric vehicle charging.

  • Scheduled Control: In this mode, the Electric Vehicle Supply Equipment (EVSE), or charging point, and the electric vehicle negotiate energy supply. Both parties agree upon a charging power, taking into consideration the energy needed by the vehicle and the intended departure time.
  • Dynamic Control: This mode relies on an external system, not the vehicle itself, for smart charging decisions. The energy management system fully delegates the charging limit to the charge point. The external "off-board" system ensures timely departure. Ampcontrol primarily utilizes this approach for "behind-the-fence" fleets, where the software is aware of departure times and required energy. For instance, the system can connect to scheduling or telematic systems.

Dynamic control is typically used for behind-the-fence fleet depots, where one system coordinates with other assets to make dynamic decisions.

Scheduled control, on the other hand, is commonly implemented in public or semi-public charging locations. In these situations, vehicles are not predetermined, and the optimization process negotiates with the vehicle to make decisions.


The four key takeaways from this article are:

  • ISO 15118 and OCPP are communication protocols that ensure efficient and secure EV charging.
  • Smart charging optimizes power output from charging stations, balancing grid load.
  • Scheduled Control mode is where the EV and charging point negotiate energy supply.
  • Dynamic Control mode is where an external system makes smart charging decisions. 

If you're interested in exploring smart charging solutions for your EV fleet or charging infrastructure, contact Ampcontrol, a leading smart charging software provider. Contact us to find out more about how Ampcontrol can optimize your EV charging experience and contribute to a more sustainable transportation future.

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