Electric cars bring with them a new learning curve if you’re used to fuel-driven cars – read our handy guide if you want to know your CCS from your kilowatt
If you grew up measuring cars using horsepower and mpg, electric cars can seem a little alien. So, to save you from having to ask “what’s a watt?”, we’ve put together everything you need to know about EVs in this handy guide.
Kilowatt (kW)
Kilowatts are units of measurement for power, and are commonly used to describe two areas of EV performance. The first is to measure the power output of an EV’s electric motor setup, very similar to how horsepower is used for fuel-driven engines. 100kW is the equivalent of 134hp, and carmakers will often quote both.
The second place EVs tend to use kilowatts is to describe charging speeds. For example, some of the latest EVs are able to charge at a rate of 150kW or even higher, depending on the charger used. The higher the charge rate, the faster your battery will charge. EVs will usually have a maximum kW rate of charge they’re able to accept, while the charger itself will also have a maximum kW rate it can dispense. Thankfully, your EV’s on-board systems will be able to figure out what rate to charge at automatically.
Kilowatt hour (kWh)
A kilowatt hour is a measure of power used over time. For EVs, however, you’re most likely to encounter kilowatt hours (kWh) when looking at battery pack capacities. As you’d expect, the larger the kWh figure, the greater the energy storage capacity and, as a result, the longer the range.
Don’t expect this figure across the EV industry to keep growing indefinitely, however. Already, some EVs come with huge battery packs that can weigh more than half a tonne, so we expect carmakers will try to squeeze even more miles from current battery pack sizes without simply blindly adding more kWh, which would push the cost and weight up to unacceptable levels.
Charging times
“How long will my EV take to charge?” seems like such a straightforward question, but the answer is usually a little more complicated. This is because there are several different types of EV chargers, which all put out different rates of charge, and the exact rate you’ll get also depends on factors such as ambient temperature, how many other people are using the chargers, and your battery’s level of charge.
The two most important charging time measures for most buyers, however, will be how long the car takes to charge at home – usually from a 7kW AC wallbox-style charger – and how long it takes from a DC fast charger – generally considered to be 50kW or above.
For a home charger, most EVs will charge from flat to 100% in around 12 hours or less – easily achievable if charging overnight. Charging times for DC fast chargers often measure how long it takes to reach an 80% charge, usually starting from 0 or 5%. EV chargers slow down substantially the closer they get to 100%, so it’s often better for total journey time and long-term battery health to simply keep fast charging to 80% and carrying on to the next charging point.
Range
Again, range seems like a simple measurement on the surface, but it’s important to understand what types of driving will affect how far your EV can drive. Just like a fuel-powered car’s mpg figure, an EV’s range can vary dramatically depending on how and where you drive.
Unlike most fuel-powered cars, which achieve their best efficiency figures on longer motorway runs, EVs often achieve the best range results in city and suburban settings. Here, the stop-start nature of traffic has less of an impact on an electric motor, which only uses power when it needs to, and the lower average speeds require less overall power from the battery.
For EV owners, there are two scenarios that will have a significant impact on your range figure. The first is at motorway speeds, where the greater air and rolling resistance can see range quickly drop if you stray too far above the speed limit. The other is during cold and winter months where the low temperature acts as a drag on the chemical reactions taking place inside your battery pack, limiting range and slowing recharge times.
WLTP/NEDC/EPA ratings
You might have seen an EV’s range figures advertised alongside some indecipherable acronyms. The most common are WLTP, NEDC and EPA. These refer to the ratings systems used by different nations to measure how far an EV can travel. This explains how the same car can achieve different claimed range figures depending on where it’s sold.
In Europe, by far the most common is WLTP – Worldwide Harmonised Light Vehicles Test Procedure. This replaced the older NEDC tests that were used before and was intended to give buyers a more accurate picture of how far different EVs would be able to drive.
As mentioned, the predecessor to WLTP was NEDC – New European Driving Cycle. Oddly, despite being phased out in Europe, this test is still commonly used in China, where EVs are extremely popular. NEDC testing tends to come out with the most flattering range figures compared to other systems, which can be extremely hard to replicate in real life.
EPA stands for the Environmental Protection Agency – a division of the US government responsible for many functions including setting the country’s standard for EV range ratings. As such, EPA ratings are most commonly used in North America and tend to come out slightly more conservative than WLTP ratings.
Dual motor vs single motor
We’re all familiar with the old adage that bigger is better and, when talking about fuel-driven engines, that’s certainly the case – a bigger engine will make more power than an equivalent smaller one. However, for EVs, when carmakers want to offer more power, simply slapping a bigger electric motor under the bonnet isn’t the only option.
In fact, it’s much more common in the EV world to offer the option of more motors rather than simply a larger motor. Commonly, entry-level EVs will have one motor powering either the front or rear axle. To make this setup more powerful for customers who want it, car makers usually add a second motor to the other axle.
This substantially increases the total power available and also brings all-wheel drive, improving traction and acceleration. Manufacturers will have different brand names for their various motor options but some, including Tesla, will make it obvious from the car’s model name if it’s equipped with more than one motor.
Two motors certainly isn’t the limit, however. Some more extreme EVs such as the Tesla Model S Plaid, Rivian R1T or Rimac Nevera, use three or even four electric motors – one per wheel – to achieve power figures normally reserved for the likes of Formula 1 cars.
Regenerative braking
If you deliver power to an electric motor, it’ll turn, but if you physically turn an electric motor, you can also use it to generate power. This is exactly what most EVs and hybrid cars do when you brake or ease off the accelerator – use the momentum of the car to turn its electric motors, generating a charge, which is fed back into the battery, increasing overall range.
The level of regeneration can be adjusted in most EVs. With maximum regeneration, you get what some call ‘one-pedal driving’, where it’s possible to drive an EV simply by coming on and off the accelerator, with the car slowing to a stop if you’re not pressing the pedal. With minimum regeneration, this effect will be substantially reduced and allow the EV to feel more like it’s coasting when you come off the accelerator – this can be helpful on longer motorway runs with more sustained speeds.
V2G
This stands for vehicle-to-grid. The latest EVs now include on-board chargers that can output power from the battery as well as manage incoming charge. This, in effect, can turn your EV into a giant battery that’s plugged into your house’s mains supply.
There are a wealth of benefits that could be unlocked by adding more of these ‘distributed storage’ points to the energy grid, especially if you have solar or other renewable energy generation methods already installed. However, one of the best features might be that the vehicle is able to supply electricity to your house in the event of a power cut.
Types of EVs
Depending on who you ask, EV could stand for electric vehicle or electrified vehicle, with the latter often referring to a car that has some level of electric power, working in concert with a traditional engine. Several acronyms have been invented to mark out different varieties of electrified vehicle, and we’ll explain each here:
BEV
BEV stands for Battery Electric Vehicle and is what most people are talking about when they say “EV”. The ‘battery’ part refers to the large battery pack, which is the sole source of power for the vehicle. As such, you’ll only find batteries and electric motors in a BEV, with no fuel-driven engines in sight.
HEV
HEV stands for Hybrid Electric Vehicle. The ‘hybrid’ part of the name denotes that these models rely on both an electric motor and battery setup, and a fuel-powered engine. Hybrids usually automatically swap between the two power sources depending on driving conditions. Unlike PHEVs covered below, HEVs cannot be externally charged and recover all the energy they use directly from the car’s engine or from regenerative braking when the car’s slowing down.
PHEV
This acronym stands for Plug-In Hybrid Electric Vehicle. These are similar in spirit to HEVs, but they usually come with a larger battery and more powerful electric motor – making them something of a halfway house between HEVs and full BEVs. Crucially, a plug-in hybrid can be charged using an external charger, making it more feasible to complete shorter journeys without using the fuel-powered engine. Read our guide to PHEVs for more information.
RxEV
This acronym is relatively uncommon and refers to range-extender electric vehicles. These can be thought of as battery electric vehicles with an on-board fuel-powered generator to recharge the batteries. Unlike PHEVs, the fuel-driven generator is usually not strong enough to power the car on its own so cannot be directly connected to the wheels. Modern black cabs built by LEVC are probably the most common vehicle to use an RxEV setup.
FCEV
FCEV stands for fuel cell electric vehicle – these are not currently sold in the UK. This setup is quite different to those already discussed here because it features an on-board fuel cell that generates power by oxidising a fuel source – almost always hydrogen. This is distinct from a BEV’s battery pack, which simply stores power that’s generated elsewhere. The power from the fuel cell can directly drive an electric motor, or can be stored in an on-board battery pack for later use.
Types of charger
There are two common types of charger EV owners will need to familiarise themselves with:
DC fast chargers
These chargers are commonly found at motorway services or public EV charging stations. They send direct-current (DC) power straight to your battery pack and are generally the fastest way to charge your EV. Depending on the rate of the charger and the rate your EV can accept, it's sometimes possible to recover an 80% charge in as little as half an hour.
To be considered ‘fast’, a DC charger usually needs to be capable of outputting 50kW of charging power. Some more recent fast charger designs can handle rates of up to 150kW or even higher, although these usually need high-tech additions such as liquid-cooled charging cables to achieve this.
It’s important to note that, while your car and the charger you’re using might be capable of a 150kW charge rate, for example, you probably won’t see that rate for the full duration of your charge. Typically, you’ll get the highest rates with a fairly empty battery pack but, as you get closer to fully charged, rates will drop substantially to prevent overheating and damage.
AC chargers and wallboxes
These chargers – sometimes called wallboxes – are usually found in homes or offices and draw power from the building’s existing alternating-current (AC) electricity supply. The charging rates AC chargers can achieve are quite a lot lower than those found at DC fast chargers – usually around 7kW – although some designs can go as high as 22kW if you have access to a beefed-up three-phase AC power supply.
Between the lower charging rates and the fact that your EV’s on-board charger will need to convert the incoming AC power into DC for the battery pack, AC chargers take a lot longer to charge an EV. Typical charge times can be 12 hours or longer for a full 100% charge from flat, but these rates will usually be plenty for EV owners that can charge at work, or overnight at home.
You can also charge an electric car using a normal household plug socket, but this is regarded as a last-resort option by many carmakers because it takes such a long time. EVs with medium-sized or large batteries can take 24 hours or more to fully charge from a three-pin plug. Make sure you don’t use an extension cable, as this could be unsafe.
Types of charging connector
Different charging connector standards have sprung up around the globe which, annoyingly, means EVs from certain parts of the world might not be able to charge if they’re imported to another country. Thankfully, some standardisation has begun to take hold and, in the UK, you’ll probably only encounter CCS 2 type connectors. Connector types include:
CCS 2
CCS 2 stands for Combined Charging System 2 and this connector has become the de-facto standard in the UK and Europe. All new EV models sold here will come with this connector as standard. It has two elements – the upper part can be used for AC charging, while the lower section must also be connected to allow for DC fast charging.
Type 2 (Mennekes)
A Type 2 or Mennekes connector – after the German company that invented it – is the predecessor to CCS 2. Type 2 connections don’t have the DC fast charging portion of the connector so can only handle slower AC charging rates.
CHAdeMO
This somewhat mangled brand name stands for Charge de Move. The connector was developed in Japan and was, at one point, the most viable competitor to CCS 2 charging in Europe. This connector is most commonly found on Nissan Leaf models, as an early pioneer of the EV segment, but is rapidly falling out of favour in Europe and the UK.
CCS 1
CCS 1 is, like its European counterpart, becoming the de facto charging standard in North America. The upper portion of the CCS 1 connector is essentially the same as the J1772 connector covered below, with the same DC fast charging lower connector as found on CCS 2 sockets.
J1772
J1772 is a connector standard that was used in North America before DC fast charging necessitated the upgrade to CCS 1. As such, J1772 can only handle AC charging.
Tesla
As a pioneer in the EV world, charging standards didn’t really exist when Teslas began appearing in greater numbers from 2012 onwards. As a result, the US company opted to create its own connector standard to facilitate its Supercharger high-speed charging network, and this remains the connection standard used for Teslas sold in North America. All Teslas sold in the UK and Europe come with CCS 2 connectors so they’re compatible with most charging points.
GB/T
GB/T connectors are most commonly used in China, where it has become the nation’s connection standard. This standard supports both AC and DC charging, although you’re unlikely to ever encounter it beyond China.
Fancy an electric car?
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