How many kWh to charge an electric car?

Understanding the energy consumption of an electric car

The energy consumption of an electric car, expressed in kilowatt-hours (kWh), varies depending on several factors. To fully understand this concept, it’s essential to consider the battery capacity, the vehicle’s usage conditions, and the efficiency of the charging system.

↪️ Read more about: the ABC of EV charging

Battery capacity and driving range

Battery capacity, which is measured in kilowatt-hours, represents the maximum energy the battery can store. Each electric car model is equipped with a battery whose capacity typically ranges from 20kWh for small city cars to over 100 kWh for high-end models or utility vehicles.

This capacity directly determines the vehicle’s range, meaning the distance it can travel on a full charge. For example, an electric car with a 52kWh battery can cover approximately 400 kilometres, depending on its energy efficiency (average consumption in kWh/100km).

However, this range is influenced by several factors ⬇️.

Factors influencing energy consumption

Several factors can affect the energy consumption of an electric vehicle:

• Driving speed: driving at high speeds consumes more energy
• Weather conditions: cold temperatures reduce battery efficiency, while using air conditioning or heating increases energy consumption
• Driving style: aggressive or sporty driving puts more strain on the battery
• Weight onboard: a car loaded with passengers or luggage consumes more energy
  

Usable capacity vs total capacity

It is also important to differentiate between the total battery capacity (the one advertised by the manufacturer) and the usable capacity (the amount actually available for driving). A portion of the capacity is reserved to protect the battery and prevent it from being fully discharged, which could damage its cells.

Therefore, understanding these factors is essential for accurately estimating the number of kWh needed to charge your electric car.

The cost of charging an electric car

The cost of charging an electric car varies depending on the charging location, particularly between home and public charging stations. Here’s an overview of the main differences:

Home charging

Charging your electric car at home is often the most convenient and cost-effective solution. By using a heavy-duty power socket or a home charging station, you can control your budget more appropriately. It also allows you to take advantage of special electricity tariffs, such as off-peak hours. However, it’s essential to ensure your electrical installation is compliant and safe.

Public charging stations

Public charging stations offer valuable flexibility, especially on long trips. However, the costs are generally higher, particularly for rapid or ultra-rapid charging stations. These stations enable quick charging but include additional costs associated with infrastructure and maintenance.

Before using a public charging station, it’s advisable to compare network rates as well as station types to avoid unpleasant surprises.

Find tariffs for public charging points directly on the Chargemap application
Download the app.

Check out our comprehensive guide to understanding all aspects relative to the cost of charging an electric car. Drive with peace of mind while keeping your budget under control.

Tips to optimise charging and reduce costs

Optimising how you charge your electric car not only helps lower expenses but also extends the lifespan of your battery. Here are a few practical tips to apply on a daily basis:

Charge at home during off-peak hours

Electricity providers often offer discounted off-peak tariffs, typically at night. For instance, in the UK, the Economy 7 tariff provides seven hours of cheaper electricity, usually between midnight and 7am, making it an ideal option for overnight EV charging. Another option, Economy 10, extends the discounted hours to include additional off-peak periods during the afternoon and evening.

Many home chargers are equipped with smart scheduling features that allow you to set charging sessions during off-peak hours automatically. By using these tariffs, you can significantly reduce your charging costs while ensuring your car is ready for the day ahead.

Don’t hesitate to explore the plans offered by electricity providers to find the one that best suits your charging habits and budget!

Use charging stations suited to your vehicle’s capacity

Each electric car has a maximum power rating it can handle. If you use a charging station with a power rating, which is higher than your car’s limit, the system will automatically regulate itself to adapt to this threshold. This means the vehicle will only draw the amount of power it can safely cope with.

However, using a charging station with a power rating, which is significantly lower than what your car can handle will extend the charging time. To optimise your charging sessions, it’s recommended to choose a station whose power rating matches the maximum charging capacity of your vehicle.

Maintaining the battery to maximise efficiency

Proper battery maintenance is essential to preserve its energy efficiency. Here are some key tips:

• Avoid frequent full charges: opt for charging up to 80% instead of 100% to prolong the battery’s lifespan
• Minimise exposure to extreme temperatures: both extreme heat and extreme cold can degrade battery performance
• Prioritise slow charging: while slower, it is gentler on the battery in the long run
• Avoid fast charging in extreme heat without preconditioning: preconditioning allows the car’s thermal management system to cool the battery in advance, enabling it to handle higher charging rates without overheating
• Precondition the battery before fast charging in cold weather: simply driving for a short distance before initiating a fast charge will help warm up the battery, making charging more efficient

By adopting these best practices, you can not only save money on charging but also reduce long-term maintenance costs for your electric car.

FAQs

What is the lifespan of an electric car battery?

The average lifespan of an electric car battery is 8 to 10 years or more, depending on its usage and maintenance. Battery size also plays a role: smaller batteries require more frequent charging, which can impact their longevity. Moderate use and proper charging habits help slow down degradation.Manufacturers typically guarantee EV batteries for 8 years or up to 160,000km (about 100,000 miles), usually when the battery’s range drops below 70%. The term SOH (State of Health) is often used to indicate the battery’s condition and is expressed as a percentage.

💡Tip: If you’re considering buying a second-hand electric car, make sure to ask about the battery’s SOH. 

Is it better to charge up to 100% or to maintain a partial charge?

It’s generally recommended to avoid charging to 100%, except for long trips. For everyday use, keeping the battery charge between 20% and 80% helps preserve its lifespan.

↪️ Read more about: Should you charge your electric car every day?

Do fast charges affect the lifespan of an EV battery?

Frequent use of fast charging can accelerate battery ageing. However, occasional fast charging, especially if you primarily use standard home charging, has minimal to no impact on battery lifespan.

↪️ Read more about: 6 Things to know about fast charging

To sum it all up

Charging an electric car requires a clear understanding of energy consumption and associated costs. Depending on battery capacity, energy losses, and charging locations, the number of kWh needed and the overall cost can vary. By adopting optimised practices, such as charging during off-peak hours or properly maintaining your battery, not only can you lower your expenses but you can also extend the lifespan of your vehicle.