EV fast charging: All you need to know

In previous years, electric vehicles have faced some issues from critics due to their limited range and lack of charging points. Thankfully, electric car ranges are extending with every new release and rapidly advancing battery technology. But what about charging, and in particular, the amount of time it takes to charge your electric vehicle?

Deciding which electric vehicle to purchase can often be dependent on the length of time it takes for a vehicle to charge. There are a number of factors that can influence how long a vehicle takes to charge, and an EV can take anywhere from 30 minutes to 12 hours to charge, depending on the size of the battery and the speed of the charging port.

We’ve put together a comprehensive guide to EV fast charging, and all you need to know is detailed below.

What types of EV charging are there?

Electric vehicles use DC (direct current) to charge, but the national grid delivers AC (alternating current).

There are three different types of electric vehicle charging: rapid charging, fast charging, and slow charging. The three speeds represent the charging speeds available to charge your electric vehicle. Our guide focuses on EV fast charging.

EV fast charging is a reasonably simple invention, working similarly to a mobile phone charger. The charger has two connectors, one that plugs into the vehicle, and one into the charge point itself.

The type of connector you will need varies depending on the type of vehicle you have.

Electric vehicles will either have a type one or type two-socket for slow or fast charging, or a CCS for rapid charging. Most slow and fast charging points have a type two-socket, but occasionally will have a cable attached instead.

What’s the difference between AC and DC charging?

AC charging is the simplest and most common type of EV charging. AC charging outlets are generally found in shopping centres, motorway service stations and at home.

An AC charging port provides power to the onboard charger in the EV, then converts the AC power into DC in the battery.

An AC charging point supplies the vehicle’s onboard charger, which in turn converts the power to DC. The size of the onboard charging device is constrained by the space inside the vehicle, and the price of the vehicle, so generally speaking AC chargers are found in more reasonably priced vehicles. Because the onboard converter is small, the amount of power that they are able to deliver to the battery is typically low (6-22 kW).

What is DC fast charging?

DC fast charging is essential when undertaking long-distance journeys with high mileage, and will also work well for fleet vehicles. DC fast charging has a quick turnaround time, so enables drivers to recharge during the day or while taking a break from a long drive, as opposed to needing to be charged stationary overnight.

A DC fast charger supplies power directly and safely to the vehicle’s battery by bypassing the onboard charging device. A DC charger is external to your EV and not constrained in size or cost. This means that DC fast chargers can use 3-phase power and smart technology which enables the charge level to adjust to suit the battery state of charge (SOC). DC fast chargers have the ability to charge up to 50kw per hour depending on EV charge point capacity.

DC fast charging bypasses some of the limitations found with an on-board charger (size and power restrictions) instead providing DC power directly to the battery. This means that the charging speed has the potential to greatly increase. Charging times do vary based on several factors, including the battery size and output of the dispenser, but many vehicles are capable of reaching up to 80% charge in about an hour.

EV fast charging is typically rated at either 7 kW or 22 kW. Charging times will vary depending on the type of vehicle you have, but a 22kW charger will take between 1-2 hours to charge a compatible EV with a 40 kWh battery, whereas a 7kW will take a little longer at 4-6 hours.

Charging rates when using EV fast charging will depend on the car’s onboard charger, as not all EV models accept more than 7kW. These electric vehicle models can still be plugged into a fast charging port but will only accept the maximum charge level accepted by the onboard charger.

Will fast charging affect my battery life?

Just like any battery found in an electronic device, EV batteries deplete over time, but while laptop and phone battery charging can be damaged with consecutive charging, electric vehicle batteries won’t.

This is because electric vehicle manufacturers have built-in safety systems to prevent damage from frequent EV fast charging or top-up charging. Most electric vehicles are smart enough to acknowledge when too much power is being administered to the battery too often, so will lower the rate of charge.
Factors that affect charging speed

There are several factors that contribute to affecting charging speeds, regardless of what type of EV charger you have installed.

Battery size – The larger your vehicle’s battery is, the longer your EV will take to charge. Battery capacity is measured in kWh
The state of your battery at point of charge (empty v full) – If you’re topping up a battery that is charged to a percentage, charging will be much quicker than charging from empty.

The maximum charging rate of your vehicle – You can’t charge your vehicle any faster than the rate it allows you to. You won’t be able to charge an EV faster with a bigger charging point if your vehicle cannot reach the maximum charge rate
The maximum charging rate of the charge point – Similarly, the time it takes to charge your EV will depend on the maximum rate of the charging point

There are also environmental factors to consider when considering the time to charge your EV. Colder temperatures can have a slight impact on the speed of charging, and can mean that vehicles run less efficiently, so you may find that fewer miles are added to each journey when charging in colder climates.

In winter, it can be a good tip to regularly top up your vehicle, rather than relying on long charging, to get the most out of the mileage from each charge.

What is top-up charging?

For most EV drivers, it’s more important to know the range of miles they will get, as opposed to how long it will take them to reach full. This is often why fast charging and top up charging is more valuable to an electric vehicle owner than standard AC charging.

Most electric vehicles can charge where ever they are parked, whether that is at home, the shopping centre, the gym, or at work. This is commonly known as top-up charging.

Instead of letting the battery run empty, and waiting overnight or all day for the EV to charge, many drivers make use of charging stations each time they park and maintain a 90-95% level of charge at all times. This won’t affect the battery life and will keep your vehicle ready to drive at all times.

Combining top-up charging, EV fast charging and overnight charging can be the best way to keep your electric vehicle charged and ready to go at all times.

As we mentioned earlier, treating your EV like a mobile phone by giving your electric vehicle quick bursts of charge in the day, then charging fully overnight can be the most effective way to keep your EV in great charge.

If you’re starting your OLEV funding application, check out our range of DC charging and AC charging units.

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