A guide to EV charging

Charging your Electric Vehicle is a vital part of ownership, but getting to know the different plug and inlet types can be confusing. This guide has been put together by the Drivenergy team to help make the process a little easier. It may seem confusing now, but if you buy or lease an EV you'll get the hang of it in no time.

Charging - the basics

Both EVs and Plug-in Hybrid Electric Vehicles (PHEV) have built-in batteries which need to be recharged from an external mains supply. The vehicles have inlets for connecting a charging cable, but they are not all the same. Vehicles often have two charging inlets; one for AC charging and one for DC. The inlet(s) on the vehicle will depend on the vehicle brand and age.

 

The vast majority of electrical grids around the world use Alternating Current (AC) to distribute power. UK and European homes are almost exclusively fed with AC power. Batteries use Direct Current (DC) so charging requires converting the AC power to DC power. AC electricity is used for 'slow' and 'fast' charging and DC is used for 'rapid' charging. These terms have become commonplace in the UK, but their meaning varies around the world (e.g. in North America, 'fast' is used to mean 'rapid!').

Slow and Fast Charging (AC)

When AC electricity is used for charging, an onboard charger integrated into the vehicle converts the incoming AC to DC to be sent to the battery. AC charging occurs using one of two types of charging plug, simply known as Type 1 and Type 2.

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The Type 2 charging plug

The Type 2 charging plug is a European standard (IEC 62196) for all new electric car models produced from 2017. The plug was designed in 2014 by MENNEKES, and so is commonly referred to as the MENNEKES plug.

 

The connector contains seven contacts, 2 more than the Type 1 plug. The top row contains 2 small signalling contacts, the middle row consists of a central earth contact and two outer contacts used for power supply, and the third row has two more contacts which, if connected, can be used for three-phase charging (these are absent in the above photo, which is a single-phase AMTRON charging point).

The Type 1 charging plug

The Type 1 plug is a Japanese and American standard for EV charging. The plug has a rounded housing and a latch which stops the plug moving in the socket.

 

The connector contains 5 contacts. Much like the Type 2 plug, the Type 1 contains 2 small signalling contacts, an earthing contact and two contacts for power supply. The main difference between the Type 1 and Type 2 plugs is the presence of the 2 extra power contacts on the Type 2 coupler.

Power transfer and speed

AC charging can transfer up to 22kW of power, but this depends on the charging point and the onboard charger (inside the vehicle) which converts AC to DC. The capability of the onboard charger is key to the speed of charge; for example, if the vehicle was manufactured with a 3.7kW onboard charger, then the vehicle will be limited to charging at 3.7kW or less, even if plugged into a higher rated charge point, i.e. if plugged into a three-phase 22kW charging point, it will still only charge at 3.7kW. If the charge rate is limited by the onboard charger, then DC charging is required to recharge the battery at a faster speed.

Rapid Charging (DC)

For faster charging, DC must be used. Just as with AC charging, the vehicle battery must be fed DC electricity, so a conversion from AC to DC must occur. The key difference is the location of this conversion; for rapid DC charging, AC is converted to DC within the charging station and the current is then fed through the cable and straight into the vehicle battery. There are two types of DC charging; Combined Charging System (CCS) and CHAdeMO.

CHAdeMO

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CHAdeMO is a rapid DC charging standard designed by Japanese vehicle manufacturers in 2010. The name is said to stand for CHArge de MOde, but is also derived from the Japanese phrase "O cha demo ikaga desuka", meaning "How about a cup of tea?" hinting at the time it would take to charge a vehicle.

 

CHAdeMO is capable of charging vehicles at to 62.5kW, and CHAdeMO 2.0 is capable of up to 400kW.

 

Currently, CHAdeMO is the only standardised charging protocol that has been verified for Vehicle-to-Grid (V2G) charging.

CCS

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Combined Charging System, or CCS, is a competing rapid DC charging standard designed by Germany vehicle manufacturers. The CCS connection combines the inlets for AC and DC using shared communication pins, so the vehicle coupler is formed of a Type 2 plug with 2 DC pins below.

 

When AC charging, only the top part of the inlet is used. The 2 DC pins are normally covered. When using the CCS system, the larger coupler uses the whole inlet.

 

CCS is capable of charging vehicles at 80-350 kW.

Rapid AC

Rapid AC charging does exist, but it is not commonly used. Rapid AC chargers provide power at up to 43kW and use the Type 2 charging plug as a standard. DC charging is generally favoured over rapid AC charging as it can now extend to 150kW or even 350kW on performance vehicles.

Charging Modes

Charging methods are also commonly referred to by 'mode'. There are four categories, simply referred to as Mode 1, Mode 2, Mode 3, and Mode 4. Although this seems like another layer of jargon, the four categories are an easy way of categorising charging types.

Mode 1

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This is the simplest method of charging. The vehicle is connected to the power grid using a standard 3-pin socket in a home or building with a simple cable. Mode 1 charging is generally only used to charge vehicles with minimal power requirements, such as scooters/mopeds. Mass vehicle manufacturers no longer allow this method of charging to be used on large vehicles because the cable is live at all times, even when the vehicle is unplugged. Alongside this, there is no communication between the plug and vehicle to monitor a charge.

Mode 2

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Mode 2 charging is similar to Mode 1, but a cable with an incorporated protection device is used. Charging is again done through the use of a 3-pin plug or 'commando' plug, but the cable has a built-in protection device (often a box in the cable) which monitors power draw and temperature. The protection device greatly improves saftey over Mode 1, although it is not intended as a permenant solution. You may be provided with a Mode 2 cable when purchasing a vehicle, although the number of vehicles being supplied with a Mode 3 cable is increasing.

Mode 3

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Mode 3 charging can be seen as a 'step up' from Mode 1 and 2. Instead of using a cable with 3-pin plug, Mode 3 charging uses a fixed charging point containing the protective device with a dedicated socket or permanently attached cable. This method is much safer than Mode 1 or Mode 2 charging as the charging point is wired on a separate electrical circuit. Mode 3 charging is AC, so the charger within the vehicle converts AC power to DC.

Mode 4

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Mode 4 charging is much the same as Mode 3, but charging uses DC power not AC. Like Mode 3, a fixed charging point with its own dedicated circuit and control electronics is used. The AC to DC conversion happens in the charging station itself, not within the vehicle, then the DC power is sent directly to the battery. A large separate cabinet often houses the AC to DC converter. Due to the high voltage and current, the charging cable is always tethered to the charge point (like at a fuel station) - you cannot use your own cable to charge.

Other Plugs

Commando Plug

'Commando' plugs (IEC60309-2) are often used on commercial or industrial sites where more power is required than a normal UK 3-pin plug. The commando plug and socket is more flexible than the 3-pin plug. Most people would associate a 'commando' plug with a caravan site, where they are used as a robust way to hook up caravans. Mode 2 cables are avaliable with a 16A commando plug.

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Thanks to our wealth of automotive, electrical and sustainable consultancy experience, we can advise you on all things EV.