The Anatomy of an EV Charger Infographic
06Sep, 23 September 6, 2023
  • By evcharger

Electric vehicles have been gaining immense popularity as an eco-friendly transportation option compared to gas-powered cars. But to keep these green EVs running, their batteries must be regularly recharged using a special device – the EV charger. EV chargers are smart, interactive devices that supply electrical energy to replenish the battery packs that power electric vehicles. 

They provide the crucial link between the EV and the electrical grid to ensure the batteries stay juiced up and ready to transport you everywhere you need to go. Understanding how EV chargers work their technical magic helps drivers make the switch to emission-free electric mobility.

This comprehensive guide will dissect the anatomy of EV chargers by exploring their main components and inner workings.

EV Charging Diagram

EV Charging

Introduction to EVSE 

Before diving into EV charger components, it is important to understand EVSE. EVSE stands for Electric Vehicle Supply Equipment. This term refers to the entire charging equipment setup that links the power source to the EV battery for delivering electricity.

EVSE consists of the charging station, connectors, cable, control box, software, and all other components needed for power transfer between the grid and the vehicle. The charger unit itself is only one part of EVSE. 

Now let’s examine what’s inside these intelligent chargers that make EV refueling possible.

1. Power Supply – The Heart 

The power supply is the most vital internal component that makes up the core of an EV charger. It converts the high-voltage alternating current (AC) electricity from the electrical grid into lower-voltage direct current (DC) power suitable for charging EV batteries.

The power supply consists of:

  • Transformer: Steps down grid AC voltage to lower AC voltage for conversion to DC.
  • Rectifier: Converts AC into DC using diode or thyristor rectifiers. EV batteries run solely on DC.
  • Filtering Capacitors: Smooth out ripples in the DC output.
  • Control Circuitry: Regulates voltage and current to match EV battery needs.

Level 1 and Level 2 EV chargers use AC power supplies. In contrast, high-powered level 3 fast chargers use DC power supplies that deliver up to 350 kW for ultra-fast charging. The power rating determines charging speed and is the most important specification for an EV charger’s power supply. Higher power means faster charging.

Power Supply

Power Supply

2. Connector – The Bridge 

The connector is the crucial physical link between the EV charger and the vehicle’s charging port, allowing electricity to flow safely into the battery system. When plugged in, the connector’s multiple pins fit snugly into the port to complete the charging circuit.

A few main connector types are used to charge electric vehicles:

  • The Type 1, or SAE J1772, is a common connector that you’ll find in North America and Japan. It’s easy to recognize by its 5 pins and provides charging capabilities up to 16 amps, making it well-suited for slower, everyday charging.
  • You’ll often see the Type 2, or IEC 62196, connector in Europe and Australia. It contains 7 pins and can supply more power – up to 43 kilowatts, enabling faster charging.
  • The CHAdeMO connector, shaped distinctively like a gun, is popular in Japan for DC fast charging. It can deliver a powerful 62.5 kilowatts to charge compatible electric vehicles ultra-fast.
  • Finally, the Combined Charging System, or CCS, combines the best features of AC and DC charging. By integrating the Type 2 connector with 2 extra DC pins, CCS supports both slower AC and ultra-fast 350 kilowatt DC charging. 

Therefore, the connector plays a vital role in EV-charger communication. Durability, temperature resistance, and ease of connecting to the EV inlet are key requirements for the connector component.

EV charger connectors

EV charger connectors

3. Charging Cable – The Energy Transmission Line 

The charging cable is a flexible bridge carrying electric power between the EV inlet and the connector attached to the charger. Cables for EV charging services must have high conductivity to transmit energy with minimal losses.

Copper and aluminum are excellent conductors employed inside EV charging cables. These metals have the right electrical and thermal conductivity balance, flexibility, and ampacity or current carrying capacity.

Insulation surrounding the internal conductor prevents current leakage and overheating. Cables for outdoor EVSE require weatherproof jacketing to protect against environmental factors like moisture and UV radiation.

Longer cables allow charger placement farther from the parking spot. Having flexible, easy-to-handle cables improves usability and safety during operation.

Connector alongside charging cable

Connector alongside charging cable

4. Control Board – The Brains 

The control board is an EV charger’s central controller and intelligence hub. It consists of:

  • Microcontroller – Runs firmware that controls all charger functions.
  • Sensors – Monitor temperature, voltage, and current to detect issues.
  • Relays – Switch power on/off during charging session.
  • Communication Interfaces – Allow information exchange with the EV.

The control board performs some key functions, including:

  • Authenticating the EV – Identifying the vehicle to customize charging parameters.
  • Managing charging current and voltage – Varying levels based on battery needs.
  • Monitoring safety – Sensors continuously feed data about component temperature, moisture, voltage spikes, ground faults, etc. The controller prevents damage in case any hazard is detected. 
  • Communicating status – Indicates charging status clearly through indicator lights, display screens, smartphone apps, and vehicle dashboards.
  • Enabling smart charging V2G technology allows the charger to intelligently coordinate the bi-directional energy flow between the EV and the grid.

In a nutshell, the control board handles all the critical thinking needed to deliver efficient, safe, and smart EV charging tailored precisely to the vehicle’s needs.

5. User Interface – The Window to Charging

The user interface provides a window into the charging process for the EV driver. It consists of visual displays, controls, and payment options:

  • Display screen – Shows charging status parameters like estimated time remaining, elapsed time, energy consumed, voltage, current, cost, etc.
  • Buttons and switches – Allow starting, stopping, and configuring charging sessions. 
  • LED indicators – Display charging status and alerts using colored lights. Blue, green, amber, and red are commonly used.
  • Payment terminal – Accepts credit cards and mobile payments to pay for charging service. Enables payment pre-authorization in public EVSE.
  • RFID/Bluetooth reader – Allows secure authentication via RFID cards or a smartphone app before starting charging.
EV Charging mobile app user interface

EV Charging mobile app user interface

The user interface complexity ranges from an LED status indicator to an interactive touchscreen loaded with data.

6. Ground Fault Circuit Interrupter (GFCI) – The Safety Net

The risk of lethal electric shocks is significant since EV charging systems operate at high DC voltages. For maximum safety, the electrical code requires all single-phase electric vehicle charging receptacles of 150 volts or less to ground, and 50 amps or less, to have ground-fault circuit interrupter (GFCI) protection. 

This important protection shuts off power instantly if any electric current is detected leaking through the ground wire. GFCIs prevent lethal electric shocks that could otherwise occur during EV charging by quickly cutting power at the first sign of a ground fault. 

Safety is essential, so GFCIs are mandated for all residential and commercial EV charging stations within these common voltage and current levels.

7. Surge Protection – The Power Spike Shield

Voltage spikes are momentary surges in voltage that can damage charger components. Causes include lightning strikes, grid fluctuations, and turning high-voltage EV chargers on and off. EV chargers incorporate surge protective devices (SPDs) to protect from such hazardous spikes. 

SPDs divert any excess surge currents safely into the grounding wire. Common SPD strategies include metal oxide varistors (MOVs), gas discharge tubes, and zener diodes.

SPDs are mandatory to minimize downtime and replacement costs related to charger parts being destroyed by unsuppressed voltage surges. They shield the sensitive transformer and capacitor and shield electronics from damage.


Now that we’ve explored the anatomy of EV chargers, let’s recap the key components that enable these devices to safely and smartly charge EVs:

Power supplyConverts grid AC to charging DC voltage
ConnectorLinks the EV to the charger for power transfer
Charging cableConduit for electricity between EV and charger
Control boardManages all charging functions intelligently
User interfaceProvides charging status and control ability
GFCIProtects against lethal electric shocks
Surge protectionShields against hazardous voltage spikes

Now let’s look at the different levels and types of EV chargers.

Types of EV Chargers

Here are the types of EV chargers used for charging light-duty passenger EVs:

Level 1 AC Charger

  • Power Supply: 120V AC single-phase
  • Max Current: 12A-16A
  • Output: 1.4 kW – 1.9 kW
  • Charging Time: ~3-5 miles of range per hour
  • Connector: J1772
  • Location: Home

Level 1 works well for overnight home charging to cover daily commute needs. It is the most economical EVSE option.

Level 2 AC Charger

  • Power Supply: 208V or 240V AC single-phase
  • Max Current: 30A or up to 80A
  • Output: 3.3kW – 19.2kW+
  • Charging Time: ~10-60 miles of range per hour
  • Connector: J1772, Tesla
  • Location: Home, workplace, public

Level 2 AC chargers add 10-60 miles of added range per hour of charging—ideal for daily commuting and public charging. Home installation requires an upgraded electrical circuit. The J1772 connector is standard, with Tesla using a proprietary plug. 

DC Fast Charger

  • Power Supply: 480V AC 3-phase
  • Max Current: 400A
  • Output: 50kW – 350kW+
  • Charging Time: ~180 miles in 30 minutes
  • Connector: CCS, CHAdeMO, Tesla
  • Location: Public charging, highways

Businesses and highway corridors use DC fast chargers to serve heavy traffic. However, they require expensive high-voltage electrical upgrades. So, Level 2 AC units are more economical for lower-traffic locations.

Understanding the charger types assists in selecting the optimal EVSE based on charging location, vehicle, and grid capacity. Light home use needs only basic Level 2, while DC fast units support commercial heavy use. 

Comparative Analysis of Components by Charger Level

ComponentLevel 1 ChargerLevel 2 ChargerDC Fast Charger
Power Supply120V AC, single-phase, 12A208-240V AC, single-phase, up to 80A480V AC, 3-phase, up to 350A
ConnectorJ1772J1772, TeslaCCS, CHAdeMO, Tesla
Charging CableBasic plug-in cordHardwired or NEMA 14-50Long, liquid-cooled hardwired
Control BoardBasic controlAdvanced controlHighly advanced V2G capable
User InterfaceBasic single LED displayAdvanced touchscreen displayLarge touchscreen + apps
FlexibilityFixed powerMax 80A current; flexible powerUp to 350 kW power


This guide provides a comprehensive look at the components and types of EV chargers and the devices that connect electric vehicles to power. Understanding charger anatomy empowers EV owners, fleets, and charging networks to select the optimal EVSE solutions tailored to their specific charging needs.

Whether slow overnight charging or ultra-fast highway refueling, the capable EV charger delivers through its power electronics, safety mechanisms, connectivity, and user-friendly interfaces. Going forward, smart charger design and seamless user experience will continue to accelerate the EV revolution.