Navigating the World of EV Charging Stations

Navigating the world of EV charging stations can be a daunting task for both new and experienced EV owners alike. With a diverse array of charging options, varying charging speeds, connector types, and pricing structures, understanding how to navigate this landscape is crucial for optimising the charging experience.

In this comprehensive guide, we delve into the intricacies of EV charging stations, providing valuable insights and practical tips to help you make informed decisions and navigate the evolving world of electric vehicle charging.

Whether you’re a seasoned EV driver or considering making the switch to electric, this article aims to equip you with the knowledge needed to confidently navigate the diverse ecosystem of EV charging stations.

But first…nerdy basics of electricity for EV charging

Voltage (V): This is the pressure from an electrical circuit’s power source that pushes charged electrons through a conducting loop, enabling them to do work such as powering an electric motor. In the context of EV charging, different charging levels provide different voltages. For example, standard home outlets in Europe provide about 230V, while fast-charging stations provide much higher voltages to charge the batteries more quickly.

Current (A): Current is the rate at which electric charge flows past a point in a circuit. In simple terms, it represents how fast the electricity is flowing. Charging stations are often rated by their maximum current output, which, combined with the voltage, determines how quickly they can charge an EV’s battery. The current can be alternating (AC) or direct (DC), with AC being the type of electricity supplied by most public and home electrical systems, and DC typically used for rapid charging.

Power (kW): Power is the rate at which electrical work is performed or energy is transferred. It is calculated as voltage multiplied by current (P = V * A). EV charging stations are often categorised by their power output in kilowatts (kW). For instance, Level 1 chargers might offer up to 2.3 kW, while Level 2 chargers can range from 3.7 kW to 22 kW, and DC fast chargers can exceed 50 kW, with some offering up to 350 kW or more.

So, how does EV charging work?

Connection:

When an EV is connected to a charging station, the vehicle communicates with the station to establish a connection and ensure compatibility. This includes verifying the type of current (AC or DC), the maximum power the vehicle can accept, and any safety protocols.

Charging process:

• For AC charging (Level 1 and Level 2), the electricity from the grid is AC and needs to be converted to DC to be stored in the battery. This conversion is done by an onboard charger within the vehicle. The charging speed is limited by the capacity of this onboard charger.
• For DC fast charging, the charging station converts AC electricity from the grid to DC before it reaches the vehicle, allowing for a much faster charging process as it bypasses the vehicle’s onboard charger limitations.

Battery management: Throughout the charging process, the vehicle’s battery management system (BMS) closely monitors the charging to ensure the battery is charged safely and efficiently. The BMS regulates the charging speed, temperature, and voltage to protect the battery’s health and optimise its lifespan. Generally, EV batteries tend to perform more efficiently in summer months because warmer temperatures allow the battery to operate within its optimal temperature range. Colder temperatures lead to decreased performance and range because the battery’s chemical reactions slow down in cold weather.

Optimal charging strategy for your EV

The frequency at which you should charge your electric vehicle (EV) and the optimal battery percentages can vary depending on several factors, including your driving habits, the type of EV you own, and your charging infrastructure.

Many EV manufacturers recommend maintaining the battery level between 20% and 80% for daily use. Keeping the battery within this range helps balance the trade-off between maximising driving range and prolonging battery life.

While charging to 100% occasionally for long trips is fine, maintaining a maximum charge level of around 80% for daily driving can help optimise battery longevity.

Types of EV charging stations

Charging stations are categorised based on their charging speed and the type of current they use.

Level 1 Charging (Slow Charging)

• Type of current: Alternating Current (AC)
• Charging speed: Typically up to 2.3 kW
• Charging time: It can take 8-12 hours or more to fully charge a typical EV battery.
• Range added per hour: Approximately 2.3 kW * 4 miles/kWh = around 9.2 miles per hour of charging.
• Common use: Mostly for overnight charging at home using a standard electrical outlet (230V in Europe).

Level 2 Charging (Fast Charging)

• Type of current: Alternating Current (AC)
• Charging speed: Ranges from 3.7 kW to 22 kW, with some stations offering up to 43 kW.
• Charging time: Can charge an EV battery from empty to full in 3-8 hours, depending on the vehicle’s acceptance rate and the charging capacity.
• For a 7 kW charger, as an example:
  • Range added per hour: Approximately 7 kW * 4 miles/kWh = around 28 miles per hour of charging.
• For a 22 kW charger:
  • Range added per hour: Approximately 22 kW * 4 miles/kWh = around 88 miles per hour of charging (though the actual rate can be limited by the EV’s onboard charger capacity).
• Common use: Suitable for home, workplace, and public charging. These stations are commonly found in public parking areas, shopping centres, and dedicated EV charging hubs.

DC Fast Charging (Rapid Charging)

• Type of current: Direct Current (DC)
• Charging speed: Typically starts at 50 kW, going up to 150 kW, with ultra-fast chargers offering up to 350 kW or more.
• Charging time: Can charge an EV from 20% to 80% in about 20-30 minutes for 50 kW chargers, and even faster for higher-capacity chargers.
• For a 50 kW charger:
  • Range added per hour: Approximately 50 kW * 4 miles/kWh = around 200 miles per hour of charging (for the first 20-80% of battery capacity, as charging tends to slow down as the battery gets fuller).
• For a 150 kW charger:
  • Range added per hour: Approximately 150 kW * 4 miles/kWh = around 600 miles per hour of charging (considering the same caveat as above).
• Common use: Ideal for quick top-ups during long-distance travel, found along highways and in strategic locations to facilitate long-distance EV travel.

Types of charging connectors in Europe

The type of connector is also an important aspect of EV charging in Europe. The most common connectors are:

Type 2 (Mennekes)

The standard connector for AC charging in Europe, used for both Level 1 and Level 2 charging.

CCS (Combined Charging System)

The standard for DC fast charging in Europe, compatible with most new EV models.

CHAdeMO

A DC fast-charging standard mainly used by some Japanese manufacturers, though it’s less common in Europe compared to CCS.

Cost of charging an electric vehicle

Calculating how much you could pay to charge your EV in Europe is extremely difficult because the price of electricity varies significantly across different countries and cities and some charging stations charge you for parking or service fees.

EV charging stations determine the cost of charging based on various factors, including electricity rate, charging speed, connection time, connection fees and dynamic pricing. The cost of charging is set by the charging station operator.

Please take this cost calculation example with a pinch of salt.

Average electricity prices

Let’s assume an average residential electricity price of €0.20 per kWh for home charging and a range of prices for public charging stations. Note that these rates can fluctuate widely:

• Level 1 and Level 2 charging at home or public places (without additional service fees): €0.20 per kWh
• Public Level 2 charging (with service fees): €0.30 per kWh
• DC Fast Charging: €0.35 per kWh (This can vary more significantly based on the provider and location)

Cost calculation for full charge (0% to 100%)

For a full charge of a 75 kWh battery:

Level 1 Charging (Slow Charging) and Home Level 2 Charging

• Cost for Full Charge: 75 kWh * €0.20 = €15

Public Level 2 Charging (Fast Charging)

• Cost for Full Charge (with service fees): 75 kWh * €0.30 = €22.5

DC Fast Charging (Rapid Charging)

• Cost for Full Charge: 75 kWh * €0.35 = €26.25

Cost calculation for typical daily use (20% to 80% charge)

For a more typical daily use scenario, charging from 20% to 80% (60% of battery capacity, or 45 kWh for a 75 kWh battery):

Level 1 Charging and Home Level 2 Charging

• Cost for 60% Charge: 45 kWh * €0.20 = €9

Public Level 2 Charging

• Cost for 60% Charge (with service fees): 45 kWh * €0.30 = €13.5

DC Fast Charging

• Cost for 60% Charge: 45 kWh * €0.35 = €15.75

Navigating the world of EV charging stations involves understanding the different types of charging stations, the basics of electricity for EV charging, and the cost considerations associated with charging an electric vehicle. By mastering these essentials, you can make informed decisions and optimise your EV’s charging experience.