What is EV Charger? How Does EV Charging Work?

EV Charger is a device which transfers electric power from the power source to your Electric Vehicle battery. It is technically called Electric Vehicle Supply Equipment (EVSE).

Charging an electric vehicle is a simple process, just like charging your phone.

EVSE consists of multiple components, it includes an external charging unit (actually that’s the device people call as EV charger), charging cable & connector, adapter (if needed), vehicle onboard charger or internal charger and Vehicle’s Battery Management System (BMS).

Both EV charger and Electric Vehicles runs on software which remains the key in all electronic communications while charging, it is also called firmware. The software also includes a User Control mechanism.

Now, let’s see how EV charging happens looking at the function of each component of the system.

EV Charging Working Mechanism

External Charger or EV Charger:

An external charger often called EV charger is a device which draws the power supply and curates it with appropriate voltage and current that is compatible with your EV.

EV Charging Cable:

The power supply is then transferred with a cable to your EV. The charging cable remains a link connecting the EV charger and Electric Vehicle. At one end the charging cable is connected to external EV charger – from where it receives the power – and at another end there is charging connector or charging plug – where it will flow the power… Now let’s what happens next.

EV Charging Connector:

The connector is at one end of the charging cable which is also called the charging plug. Electric Vehicles have a charging port where the connector has to be plugged in to start charging, just like how you plug in your phone for charging.

There are various types of connectors like J1772 type1 and type2, CCS, CHAdeMo, ChaoJi, GB/T and NACS. Here is the detailed table showcasing the features of all these connectors.

Not every Electric Vehicle comes with a standard charging port. The majority of the EVs come with Type 1/2, CCS, and NACS port currently. However, the standard is shifting towards NACS in the USA and other countries.

EV Charging Adapter:

A charging adapter is a device which acts as a converter to charge with one connector type to another. The adapter fits upon the cable charging connector.

e.g. If the charger has a J1772 connector and you have NACS port in your EV. Then with J1772 to NACS adapter – (which fits upon J1772 charging cable connector converting it to NACS and then NACS will be plugged in to your EV) – you can charge your EV.

Internal Charger or Onboard Charger:

Now once you plug the connector to the charge port of your EV the power starts to flow to the EV’s battery. EV battery always stores electricity in DC form so EVs have an onboard charger built within the vehicle – a part of vehicle’s BMS – which accepts the necessary power supply in AC and converts it to DC to charge the battery. If charging with direct DC power then the onboard charger will be bypassed.

Vehicle Battery Management System (BMS):

While BMS controls the whole vehicle’s internal charging system including the whole charging process with protection and safety measures.

This onboard charger and vehicle BMS combined form the vehicle’s charging system.

Firmware & User Control Interface:

And there is software or firmware which is a set program for the electronic components in the EV charger and EV to conduct charging. It facilitates all electronic communications between EV charger and vehicle to conduct the charging process.

This firmware is installed separately in EV charger and EV (which is installed by default when you buy) and has separate functions for each to facilitate the charging process.

It also includes a user control mechanism like a dashboard screen and phone app for the car & phone app for the EV charger. It is used to facilitate the initial setup for charging and to control the charging process.

Your EV and EV charger also receive over-the-air firmware updates to enhance the control features or to remove any technical glitch.

However, not all EV chargers or EVs provide a full user interface. It may be totally absent or come with just a couple of options. But mostly all EVs & EV chargers come with a user interface.

In a Nutshell

So when you undock and lift the charging cable from (external!) EV charger and plug in to your Electric Vehicle’s charge port, the power flows from EV charger to your EV’s battery and you see.. ohh EV is charging! And It will be ready to shoot on the road once charged.


So Charged-up drivers OR Future EV owners, I hope now you have sufficient understanding about EV Charging. Let me know in the comments if you have any doubts.

See you in the next!


An engineer turned entrepreneur, being a Tech-enthusiast I am passionate about helping people understand and embrace the potential of technology in an insightful manner. At EV Chargers Guide, I help EV owners to navigate the Electric Revolution by providing in-depth guides to overcome their EV charging challenges and helping to make the Best choice selecting Charging Equipment for their EVs.

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  1. So it’s like charging our phone huh.. not that difficult

  2. Well informed guide. I am new to EV world and I just don’t know much about EV charging. But I now getting point of all these things.

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