DC Chargers Decoded: Your Guide to Fast Charging Your EV


DC (Direct Current) chargers are heavy weight chargers and handy for quick charging of heavy vehicles including cars and buses. For example, a car like ZS EV can charge from 0-80% in less than 50mins using a 60kW DC charger. They are like a quick boost when you are low on power. With more and more Charge Point Operators (CPOs) expanding their network in India, it is further making public fast charging quick and convenient for the users.

The article addresses the futureproofing and upgrading of DC chargers and their integration with Charger Management Software, empowering individuals for a greener future.


Types of charger connectors

DC chargers convert grid AC (Alternating Current) to essential DC power. There are different types of DC charger connectors used to combine fast, slow, or moderate charging.

Episode 6 | Types of chargers




DC charger size and capacity

DC chargers are also known as off-board chargers and are available in various sizes. Their DC output ratings range from 30 to 240 kW with expandable options. When you plug your EV into a DC charger, the battery management system (BMS) takes over and eliminates the need for an onboard charger. 

Additionally, DC chargers are versatile, supporting multiple output connectors like CHAdeMO, CCS, and Type-2 AC (GBT optional). In today's evolving landscape, these chargers are getting smarter equipped with built-in safety features and vehicle compatibility checks. Some can even auto-detect the connected vehicle and can be  be operated using RFID, mobile apps, or a simple plug-and-play feature . Communication protocols like OCPP and OCPI further enhance their functionality.

The EV Charger Management System (CMS) underpins the seamless electric vehicle charging infrastructure operation. It ensures connectivity, monitors uptime, and guarantees charger availability. This software enables remote monitoring, fault diagnosis, and even firmware updates, optimising the performance of charging stations. Additionally, it plays a crucial role in managing user access, authentication, and payments, enhancing the user experience. The EV Charger Management System empowers operators to make informed decisions by providing real-time data on charging sessions and station status, ensuring a reliable and efficient charging network for EV users.

The rectifier is the core of a DC charger and is crucial to ensure a steady supply of DC energy. There are rectifiers in various sizes, such as 7.5 kW, 15 kW, 20 kW, and 30 kW, offered by charger OEMs.

The charger sizing principles

Battery sizing
  • Battery manufacturer uses standard sizes.
  • Multiple cells are arranged in series and parallel inside modules that make up the battery
  • Total Capacity = n (number of cells used) x Single cell Capacity.
DC charger sizing
  • Battery manufacturer uses standard sizes.
  • Multiple cells are arranged in series and parallel inside modules that make up the battery
  • Total Capacity = n (number of cells used) x Single cell Capacity.

Charger OEMs consider the vehicle charging curve and various aspects before sizing the product.

Why does DC charger size matter?

The size of your DC charger directly influences the charging speed and accessibility to charging networks. Different configurations of DC chargers are available for EV users in a public charging station, and the charger's Capacity can impact the charging time accordingly.

Open Charge Point Protocol (OCPP) and Open Charge Point Interface (OCPI) are essential to achieving interoperability in EV charging. OCPP is a standard protocol that enables communication between charging stations and central management systems, allowing seamless integration and control. 

OCPI, on the other hand, facilitates communication between different charging networks, ensuring a consistent user experience across various providers. This interoperability allows drivers to use different charging networks without the hassle of multiple memberships, promotes a unified and accessible charging ecosystem, and accelerates the transition to sustainable transportation.

Making the most of DC chargers

DC chargers are the bridge that connects your EV to a cleaner, greener future. They manage the authorisation of your charging sessions through RFID, mobile applications, or password entry. They interact with Charger Management Software (CMS), diligently recording and sharing valuable data about your charging sessions, offering insights and convenience.

As you embark on your electric vehicle journey, understanding the vital functions of DC chargers empowers you to make informed choices. When considering an EV charger, ask if it can be upgraded to meet your future needs.

Best practices for DC charging

Follow the 80% rule (Source)
  • Fast charging slows significantly after reaching 80%. Unplugging them is efficient and courteous to others. Monitor your charge status with the ChargePoint app for optimal timing. Prioritise fast charging when you genuinely need it. (Check out this post to learn more about charging curves.)
Use fast charging judiciously
  • It is pricier than Level 2 charging due to higher installation and operational costs. Overuse may strain your battery, affecting efficiency and lifespan. Reserve it for essential situations. Remember, those without home or work charging rely more on fast charging. (there is a requirement of having mandatory AC charging after 3-4 cycles of DC charging…I think we need to mention that)
Points to remember while using DC chargers installed at public locations
  • It is advisable to use charging equipment recommended by the manufacturer
  • Ensure the location for charging the battery is dry, clean, safe, and dustproof.
  • Ensure proper connection of the charger output cable with the connector (DC Output) to the battery.
  • Do not leave the vehicle unattended for long hours.
  • Check the gun is not damaged or tampered with before plugging in the car.