How long does it take to charge an electric car?

Published: 11 November 2021

► How many hours or minutes does EV charging take?
► Why charging at home is slower but more convenient
► How battery tech will improve

Along with range, EV charging time is one the main barriers to stopping people moving from fossil fuel to electric. On this page, we’ll explain how long it realistically takes to re-energize electric cars these days, because it has changed quite a bit since the first-generation Nissan Leaf.

Calculating charging time

The time it takes to charge an electric car depends on two things: the size of the car’s battery, and the power output of the charger you’ve plugged into.

Calculating the charge time is very easy, and the equation looks like this:

Battery size ÷ charging power = charge time.

So, if you’re driving a Jaguar i-Pace and you stop at a 50kW charging point, the 90kWh battery should be topped up in under two hours.

 

 

Types of chargers

Throughout the UK’s public network of more than 27,000 chargers (and in excess of 46,000 connectors), there are three categories.

Rapid charging (up to 350kW)

The terminology isn’t official, but the term ‘rapid charger’ usually applies to a charging point capable of 50kW or more. Rapid chargers (including Tesla’s network of Superchargers) have their own tethers and can have an output of up to 350kW. The number of rapid chargers capable of over 100kW is growing too; these are often called ‘ultra-rapid’ chargers.

Most EVs use the rapid chargers via a Type 2 alternating current (AC) or CCS direct current (DC) plug, with a few models such as the Mitsubishi Outlander using a CHAdeMO connection that has largely been dropped by most other car manufacturers. At the time of writing the Tesla Supercharger network is exclusive to Tesla drivers, but this is set to change soon.

It’s worth remembering that most electric cars today have a limit to the amount of power they can receive when plugged in. So if you stop at a 350kW charger and your EV is capped at 100kW, then the latter is what you’ll get.

Fast charging (7kW and 22kW)

Used both at public charging points and at home, fast charging refers to chargers that provide between 7 and 22kW. A home charger tends to be the former because that’s all a regular single-phase domestic power supply can manage (we will cover charging at home in a moment). 

The majority of public chargers are classed as ‘fast’ and many of these are untethered, meaning you use your car’s supplied cable to plug in with. In terms of charging time, use the equation above. 

For example: 90kWh battery ÷ 22kW charger = four hours to fully charge your car.

Slow charging (5kW-3kW)

Slow charging is done with either a Type 1 or (more commonly these days) a Type 2 plug, both of which either plug into a dedicated EV wallbox or a typical, three-pin household socket. Public slow chargers might manage up to 5kW, but using a regular home plug you will only get 2-3kW. Slow chargers are mostly used at home by people who charge their small EVs overnight: although the power only trickles in, owners of smaller EVs can wake up to a full battery.

How much does it cost to charge an electric car?

Methods of charging

Top-up charging

This is what people generally do when using the public chargers. Sticking with the i-Pace and 50kW rapid charger scenario, let’s say you wanted to know how much range you would get from plugging in the Jag at a motorway service station for 30 minutes. In that time, using that charger, the i-Pace would gain about 90 miles of range. If using a 22kW fast charger, that would drop significantly to about 12 miles. 

Therefore, it largely depends on the charger. Unlike the earlier generation of plug-in cars, most modern EVs can cope with rapid charging.

Home charging

The overwhelming majority of EV owners charge their cars at home overnight. As we mentioned, the easiest but slowest means of domestic charging is by plugging an EV into a regular home socket. However, 7kW fast chargers are easy to get installed, and affordable thanks to the government’s Electric Vehicle Homecharge Scheme. The EVHS grant contributes up to £350 per charger installation, covering a maximum of two chargers per property. 

When charging an electric car at home, amps, volts and watts are useful in working out how long it takes to charge a car with a given charger. Chargers give you a power output figure, but it helps to understand how it has reached that figure.      

Amps (or Amperes) are a measure of electrical current, the amount of electricity flowing through a circuit. Voltage is the muscle; it determines how much current can be shoved through an electrical circuit. And Watts are the unit of measurement for the power that results. The relationship between these three is represented by this equation: 

Power = Current x Voltage

Therefore, a 7.4kW home charger has a voltage of 230V (standard home voltage) and current of 32 amps (230 x 32 = 7360 watts/7.4 kilowatts). 7.4kW chargers are ideal for overnight charging, even for EVs with big batteries. Plus they only require a single-phase power supply like domestic properties tend to have. 

You can upgrade to a 22kW charger at home if you really want to, but it means installing a three-phase power supply, which can be very expensive. The 3kW slow-charging method isn’t really feasible for high-mileage drivers: any EV with a large battery – such as a Ford Mustang Mach-E or an Audi e-Tron – will take days to charge rather than hours.            

There are a number of companies that offer home chargers such as Wallbox, Pod Point, BP, and Rolec. Additionally, car manufacturers such as Tesla and BMW offer their own domestic units, and some manufacturers will include installation within the purchase price.

While home chargers are undoubtedly useful and easy, they require a garage or a driveway. Those of us whose cars live outside our houses (sometimes a little down the street if a visitor has nicked our spot) struggle with practical issues of draping a charging cable out to the car. 

Watch out for the cold

The weather can seriously tamper with some of the maths above: colder temperatures can slow the charging rate and reduce the overall range of an EV. A study conducted in 2018 by the Idaho National Laboratory looked at the effects of temperature on a fleet of Nissan Leaf taxis. They found that the cars being charged at 25°C for 30 minutes gained 36% more charge than those being charged at 0°C for the same length of time.

 

The future of EV charging

While chargers are getting better, current battery tech is holding some EV buyers back. For many, it still takes too long to charge an EV compared to a petrol or diesel car. But things are changing.

Israeli company StoreDot has begun production of its extreme fast-charging (XFC) batteries. StoreDot’s aim is for these batteries to be able to gain 100 miles worth of charge in five minutes by 2025 – that’s twice as fast as a 150kW charger can manage. It’s serious business too, having attracted investors including Daimler and BP. StoreDot’s batteries are still lithium-ion, which means they still bear the issue of range and particularly weight. Nevertheless, it represents a promising intermediary that will make EVs more attractive to buyers while a better battery solution is developed.  

StoreDot is far from alone in its quest for improved battery technology. All the world’s car makers are reorganising themselves to focus on EV R&D. In addressing people’s environmental and humanitarian concerns over the use of cobalt in lithium-ion batteries, Panasonic revealed its new low-cobalt batteries early in 2021, with the intention of not using the rare mineral at all in its batteries within the next couple of years. This will make car batteries not only more eco-friendly, but cheaper too. New and improved batteries are a case of when, not if. 

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