What is the difference between slow, fast and rapid charging?

Figures show the UK had 30,000 public electric car chargers at the end of 2019. Of these, around 20 percent were slow chargers, 55 percent were fast, and the remaining were rapid or ultra-rapid.

Historic data reveals the past few years have seen increased investment in fast and rapid charge units, which is helping to accelerate the growth of the electric car industry. But what is the difference between slow, fast and rapid charging? Allow us to explain.

Essentially, they all do the same thing – charge an electric car – but as the names suggest, the speed of charging varies according to the connector type.

Electric cars require a direct current (DC). If you’re charging using a domestic socket, the alternating current (AC) will be converted to DC by the car. Fast chargers do the same thing, while rapid chargers (with one exception) also supply DC current straight to the car, speeding up the charging time.

Slow charging

Charging an electric car at home

As recently as 2012, slow chargers dominated the public charging network. Today, you’re more likely to find them in home or workplace locations, where the car can be left to charge for a longer period.

The majority of slow charging points are rated at 3kW (3.6kW) and will recharge an electric car in around eight to 12 hours. This makes them perfect for overnight charging or when you’re in the office.

Although it’s possible to slow-charge an electric car using a domestic three-pin plug socket, we’d strongly recommend the installation of a wallbox. Not only is this safer, you’ll also see faster charge times.

Alternatively, some lamp-post installations will charge at 6kW, which could be useful if you don’t have off-street parking at home.

There are four slow charger connector types:

  • Three-pin domestic plug socket (3kW)
  • Type 1 (3-6kW AC)
  • Type 2 (3-6kW AC)
  • Commando (3-6kW AC)

You can expect to pay up to £500 for a 3kW home charger, after the OLEV (Office for Low Emission Vehicles) grant has been deducted.

Fast charging

Fast chargers are the most common connectors in the UK, accounting for more than half of the charging network. The vast majority of fast chargers are rated at 7kW, but 22kW chargers are also available.

These tend to be found in locations where vehicles are parked for longer periods of time, such as car parks, supermarkets, leisure centres and retail outlets. A 7kW home charger will deliver charging speeds three times faster than a domestic plug, while a 22kW charger will be 10 times faster.

Charging times vary depending on the unit and electric car in question, but a 7kW charger should deliver a full charge in four to six hours. A 22kW unit will complete the task in between one and two hours. The network features both tethered (cable attached) and untethered (use your own cable) units.

Bank on spending between £350 and £600 (after the grant) on a 7kW unit, or £1,000 to £1,500 on a 22kW charger.

There are three fast charger connector types:

  • Type 1 (7kW AC)
  • Type 2 (7-22kW AC)
  • Commando (7-22kW AC)

Rapid charging

Rapid chargers are the fastest way to charge an electric car. You tend to find them at motorway service areas or locations close to major roads. They can deliver up to 80 percent charge in just 20 minutes, but an hour is a more realistic figure.

A rapid charger will provide power at 43kw to 50kW, while an ultra-rapid charger delivers either 100kW, 150kW or 350kW. The most common rapid charger in the UK is the 50kW unit.

Manufacturers often refer to an ‘80 percent’ charge in sales material and literature. The reason is that rapid chargers have an automatic cut-off at this point to protect the life of the battery.

The cable is tethered to the charging unit and only cars with rapid-charging functionality can use the machines. Rapid chargers cannot be installed at home.

There are four types of rapid charger connector types:

  • Type 2 (43kW AC)
  • CHAdeMO (50kW DC)
  • CCS (50-350kW DC)
  • Tesla Type 2 (150kW DC)

Click here to find out how to locate your nearest charging station.

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