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The world of EV charging can be complex – and things aren’t always as they first appear. For example, a charge point may advertise speeds of 22 kWh – but this doesn’t necessarily mean this is what you’ll receive. Your real charging speed can be determined by your vehicle model, battery capacity and even the weather…
There are 3 main types of chargers used to power EVs in the UK: ‘Slow’ ‘Fast’ and ‘Rapid/Ultra Rapid’.
Slow chargers charge up to 3.6 kWh, can take between 6-12 hrs for a full charge and are most commonly used at home.
Fast chargers charge between 7-22 kWh in 3-5 hrs and are the most common type of public charging points for now.
Rapid and ultra-rapid DC chargers can handle power outputs of 50kWh up to 300 – 350kWh, allowing drivers to get an 80% charge in as little as 20 minutes. With a 50 kWh rapid charger, many EVs are capable of adding 100 miles of range in less than 35 minutes. These types of chargers are usually found at large shopping centres, car parks or motorway service stations.
You can read more about ultra-rapid charging in our recent blog.
It’s possible to charge an EV from 20 – 80% in as little as 20 minutes with a rapid charger. But it can take 12 hours + with a slow charger. And if you’re using a domestic socket – some vehicles can even take 24+ hours.
Essentially your charge time will change based on the size of your EV battery and the speed of the charge point you use.
It’s important to note too that most electric vehicles will usually charge to 80% at a faster rate, but then slow the speed, to protect the battery life.
And most of the time, you won’t be charging your vehicle from empty so it won’t take as long. The majority of drivers will charge their vehicles at home overnight and then top up using the public charging network when on the go.
A useful way to work out a rough estimate of how long it will take you to charge your EV is to use the following calculation:
Charging time (hours) = battery energy added (kWh) ÷ charger power (kW)
ZapMap has made it even easier by creating a calculator for working out the time and cost of charging on public EV charging networks in the UK.
And to help drivers understand how many miles can be added to a battery range per 15 minutes at various charging speeds, Drive Electric have calculated the below:
| 3kW Slow (3-pin plug) | 7kW Fast (home charger) | 50kW Rapid (motorways etc.) | 120kW Tesla (supercharger) | |
|---|---|---|---|---|
| 15min | 3 miles | 6 miles | 45 miles | 105 miles |
| 30min | 5 miles | 12 miles | 90 miles | 210 miles |
| 45min | 8 miles | 18 miles | 130 miles | 315 miles |
| 1h | 11 miles | 25 miles | 175 miles | 420 miles |
According to HeyCar (source) the fastest charging EVs on sale in the UK at the moment are:
Electric vehicle charge times can be dictated by a range of factors, such as:
Your vehicle charge rate: each electric vehicle has a maximum charge rate – and you won’t be able to charge beyond this – even if you use a charger capable of faster speeds.
Your car’s battery: EV batteries have set a set capacity (kWh). If you have a large battery capacity, meaning your vehicle is capable of taking you further, then naturally, it will take longer to charge it up to capacity.
The charge point: your charge time is going to be impacted by the charge point you’re using, and whether you’ve chosen a slow, fast, rapid/ultra-rapid charger. You might have a car that can charge at a very fast rate, but if you’re using a charger with a slower maximum rate, you will be capped at that slower rate. EVs also need to be charged via Direct Current (DC) so if you are using a standard socket to charge (AC) the vehicle will use a converter to transform the power into DC. There are limits on how much AC power you can get into an EV via a converter and so this type of charging reaches its maximum capacity at around 22kWh – in some vehicles – and at speeds as low as 3.7 kWh in others.
Your starting point: naturally if your battery is empty, it will take longer to charge than if you start with some charge left.
Grid availability: you will also sometimes be at the mercy of the grid – and the availability of power. For example it may not be efficient to charge at peak times.
No. of EVs competing for power: if you are using a station at the same time as many other EVs, you may find your charge speed is reduced.
Extreme weather: When temperatures are colder, your charge rate may be slower – and your range may be impacted. And research shows that extreme heat can also have an adverse affect on battery capacity over time (source).
The driving range of an EV given by manufacturers is often based on efficient driving in fairly reasonable conditions. In the real world, ‘true’ driving range can depend on:
Topography: driving up hills of any size will impact range
Weather: the temperature can have the biggest impact on range – with both extreme heat and cold reducing the number of miles you can achieve. Heating or cooling the car cabin as a result of these extremes, will also impact the range adversely.
Speed and driving style: driving fast, and aggressive braking and accelerating can use more electricity and reduce range.
However ‘regenerative braking’ is possible with EVs – a process of taking the wasted energy from slowing down a car and using it to recharge the car’s batteries.
Making use of dynamic EV load management will ensure that you can get the most out of your site’s electrical capacity – use it however needed and charge as fast as possible – all without causing strain.
Every property has a maximum electrical capacity, and EV chargers will certainly put that space capacity to the test. This is where dynamic load management controlled via smart EV chargers comes into play. EV charging load management allows you to efficiently distribute the electrical load across chargers – making sure that each charge point is able to supply each vehicle with the correct level of energy. Energy demand can be balanced through the day, and lowered during peak times – to reduce strain but also energy rates. Be aware – you can be fined for putting strain on the grid!
With ‘regular’ load balancing, when more than one EV is being charged, a charging station will distribute the maximum electrical power available across both vehicles – either charging both at a lower speed, or charging the cars at full power and alternating every 15 minutes.
With ‘full’ or ‘active’ dynamic load balancing, the power from the building to the chargers is regulated and efficiently prioritised.
When a second EV is connected and the requested charge capacity is higher than the maximum power available, the charging speed will be reduced on the first vehicle and power will be evenly distributed between the users. And when an EV is fully charged, the other connected vehicles will be given more power.
Get in touch with one of our advisers to find out more about load balancing.
Vehicle-to-grid (V2G) is a pioneering technology that enables specially designed electric vehicle batteries to store up unused electrical energy and send it back to the grid at peak times of the day.
EV owners will even be able to make money off the electricity sent back to the grid. Additionally, the technology will empower consumers to control when their vehicle charges so they can take advantage of the lowest energy rates.
The National Grid’s 2020 ‘Future Energy Scenarios’ reports predict that by 2050 up to 45% of households will actively provide V2G services.
V2G will not only reduce the demand on the grid, but it will enable EV drivers to use greener, cheaper electricity, and is seen as an important step in the journey towards Net Zero.
With that said, there is still some way to go before this technology really takes off. At present V2G only works via CHAdeMO chargers used by the Nissan LEAF and the Nissan e-NV200 in the UK. And won’t be available with CSS chargers (the most commonly used) until at least 2025.
The complete guide for workplace EV charging: The benefits it brings to businesses and how best to develop a charging strategy.
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