WHILE RANGE anxiety is often cited as a deterrent in people deciding to make the switch to electric cars, the prospect of waiting for hours for a battery to recharge is also a significant element that plays on people’s minds.
If you can charge at home, this isn’t too much of an issue, as the car fills up while it sits on your driveway or in the garage. After all, cars spend 96% of their life parked up, according to the RAC Foundation, which means plenty of potential to be plugged in.
But for the 45% of households without off-street parking, who will rely on the public charging network, how quickly an electric car recharges will be a significant consideration. As it will be for anyone looking to drive long distances and top up on the move.
But how long it takes depends on many factors, and perhaps surprisingly, the size of the battery isn’t the most important factor.
Think of a battery like a tank of fuel. How long it takes to fill depends on not just the size of the tank but also the rate at which fuel can flow into it.
With that in mind, let’s take a look at the three main factors affecting charging an electric car.
How quickly a car can charge depends primarily on how fast electricity can be delivered to the battery. That depends both on the car’s onboard electronics and the type of charger you’re using.
Domestic three-pin sockets
EVs can, in a pinch, be charged using a domestic 13-amp AC three-pin socket, which will mean a 3kW charge, approximately. That’s very slow by comparison to other methods, and only really suitable for trickle charging.
In a car with a 40 kilowatt-hour battery (think of kilowatt-hours as the electric equivalent of litres of fuel), it will still take around 12 hours to recharge the battery from empty using a domestic socket. A car with a much larger 75kWh battery may take more than 20 hours, and some electric cars now have 100kWh or larger batteries, meaning even longer charging times at 3kW.
It’s important to say here that most experts don’t recommend using domestic three-pin sockets not only because they’re slow, but also because they may not be designed to handle a sustained charge at the full 13 amps. Inadequate wiring could lead to overheating, melting wires and, in a worst case scenario, fire. If you must use a three-pin socket, be sure to have it checked out by a qualified electrician.
Home and office wallboxes
Most electric vehicle (EV) owners who charge their cars will do so at home or work using a dedicated AC wallbox, rated at either 7kW or 11kW.
That means a charging rate more than double that of a 3kW domestic socket, and charging times will usually be comparably halved. The 40kWh battery will thus take 6-7 hours to fully recharge while the 75kWh battery will take around 12 hours.
Fast public chargers
While some public chargers do offer 7kW charging — most currently installed at Tesco superstores, for example — many on-street charging posts now deliver 22kW or more for much faster charging compared to home set-ups.
Using a 22kW charger, a 40kWh battery will, in theory, be able to recharge from empty in three hours or so, while a full refill for the 75kWh battery ought to take around six hours.
It’s worth noting here that there may be a wait if someone else is charging when you arrive, and some charging posts can be out of order. You may also find some posts are located behind barriers or in car parks that charge per hour for parking. We advise to check Zap-Map.com for recent user comments about the charging location you’re visiting and call ahead if necessary.
Rapid and ultra-rapid public charging
Often found in motorway service areas, rapid and ultra-rapid charging points allow EV owners to top-up quickly on the move.
Chargers can range from 50kW to potentially as high as 350kW. However, some vehicles are unable to charge at these high speeds.
A Nissan leaf’s maximum charging speed is 50kW, using a DC charger (with a ChaDeMo connector instead of the CCS connector that has been made the European standard), and can be topped up to around 80% capacity in under an hour.
It’s worth noting here that most batteries are rarely charged from totally empty and that when fully recharging, the car’s onboard systems will slow the charge rate once the level reaches 80% in order to avoid damaging the cells. For that reason, most EV owners charging up on-the-go unplug when they reach 80%.
More expensive cars with bigger batteries tend to feature faster charging capability. One of the major selling points of Tesla cars, for example, is their access to the Tesla Supercharger network, which are capable of charging at up to 250kW, and cars can be preconditioned to charge at the maximum rate sooner as you approach a Supercharger using built-in navigation. Tesla claims its V3 Superchargers can work at speeds of up to 1,000 miles per hour.
The Porsche Taycan and Audi e-tron can manage 270kW charging, while the upcoming Lucid Air can support charging of up to 300kW. These ultra-rapid charging posts are very rare in the UK at present, however.
Without the capability of ultra-rapid charging, vehicles with substantially bigger battery packs would simply take too long to recharge. But with these ultra-rapid charging capabilities, it’s possible to recharge a long-range 100kWh battery from 10% to 80% quicker than a 40kWh battery with a slower charging speed.
Does battery size matter?
Of course, at a constant flow rate, the bigger the battery the longer it’ll take to refill. At 7kW charging it’ll take nearly twice as long to recharge a 75kWh battery as it will a 40kWh Leaf.
Long range EVs need bigger batteries to avoid the driver having to stop to recharge too frequently. But cars designed for use in city and suburban environments don’t need or have the room for big batteries, and so car makers will fit smaller battery packs. This has the advantage of keeping costs and weight down to a minimum.
It also means that a 50kW maximum charging speed is deemed sufficient for a smaller EV, such as a Honda e, which comes with a 35.5kWh battery, or Mini Electric, which has a 32.6kWh pack and can be charged fully in around an hour, or taken to 80% in about 30 minutes. Click here to see how we got on with a Mini Electric over an extended six month test, charging only using the public network.
At the other end of the scale, the expensive and advanced Mercedes EQS uses a 107.8kWh battery pack. Its owners will expect it to be capable of long-distance cruising and so it requires ultra-rapid charging capability.
The average battery size for an electric car on the UK market is around 55-60kWh.
How much range will I get from a charge?
That depends on the battery size, the efficiency of the car’s powertrain, and a number of other factors including how fast you’ll be driving, the ambient temperature and more.
If you fully charge the Mini Electric’s 32.6kWh battery you will get an official 141 miles of driving out of it, though if you’re using the car on motorways and A-roads, you may find you need to plug in again after less than 100 miles. Drive only in the city, at lower speeds and you’ll be able to get close to the official range, and maybe even beat it.
A Lucid Air (above) was recently rated in the USA as having a range of up to 520 miles per charge, which makes it the longest-range EV to date. It also has 900V charging capability and can potentially add 300 miles in just 20 minutes.
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