How EV charging works – EQ Mag Pro
To charge an EV, the vehicle is parked and attached to the charging point connection or socket by a charge point cable.
EV charge points generally fall into 2 categories: standard charging and fast charging. Otherwise known as AC and DC charging. There are 2 types of AC charging: single phase or three phase. When charging, AC electricity is supplied by the charge point to the vehicle. The onboard charger on the vehicle detects the maximum power available from the charge point. The vehicle converts this AC power into DC power and manages the charging of each cell in the vehicle’s battery pack.
DC charging is largely associated with faster speeds of charging. DC charging can quickly charge the battery pack of the vehicle. In this case, the DC charge point converts AC electricity into DC electricity which it supplies to the vehicle which is channelled directly to the battery.
The process is controlled and managed via the battery management system within the vehicle which communicates with the DC charger via the connecting cable and tells the charger how much power to supply at any given point during the process and controls the start and stop of the charging process.
| Charge point speed and type | Power rating | Approximate time to charge * |
| Home (single-phase AC) | 3-7 kW | 7-16 hours |
| Standard (three-phase AC) | 11-22 kW | 2-4 hours |
| Fast (DC) | Up to 50 kW | 30 minutes |
| High Powered (DC) | > 50 kW | 30 minutes or less |
*Also depends on the vehicle’s charging capability, the state of charge at commencement of charge and other factors such as battery pack and ambient temperatures.
The power level (in kW) of a charge point indicates the maximum amount of energy which could be supplied to a battery pack over the course of 1 hour. The actual amount of energy transferred to the battery will be a factor of the battery internal resistance, the maximum rate which the pack can sustain at the given charge level on commencement of charge, battery cooling system and so on. Also, with top-up charging, particularly when using higher-powered fast charge points, EV users often do not need to fully charge their EVs and can instead plug in and charge the battery just enough to get them to their destinations.
AC electricity can be used by all speeds of charge points, while DC electricity can only be used by fast or high-powered charge points. In most residential areas, single phase AC electrical power supplies are most common, as this type of supply system is suited to relatively low electrical loads, such as lighting and heating, with a few large electric motors. For larger industrial or commercial buildings, a higher power three-phase AC system is often used. The type of available AC supply determines the type of charge point that can be installed as charge points that supply electricity significantly above 7kW (such as 11kW to 22kW) generally require a three-phase AC supply.
Additionally, most electric cars currently on the market either are unable to accommodate more than c. 7kW on a single-phase AC supply, or if they can take higher AC charges of up to 11kW have been designed so that if a single-phase AC electricity supply is involved, they will not charge above 7kW. This means that in residential areas, the most effective types of charge points are the lower wattage 7kW-11kW charge points that work best over longer charging timeframes, such as overnight. AC charge points also tend to be more compact in size, meaning that they fit better in domestic contexts where space for charging infrastructure may be limited.
EVs also have different types of connectors for different speeds of charge, and can only be plugged in to charge points with the same type of connector unless an adaptor is used.
Types 1 and 2 connectors: For AC charging (standard/fast), EVs typically use a Type 1 or Type 2 connector. Type 2 connector technologies are more common in newer EVs, and the use of this charge point type has been supported as a way to achieve standardized, interoperable charging across the EU.
Combined Charging Standard (CCS) or CHAdeMO connector types: Some charging stations contain more than 1 connector type (for example: both CCS and CHAdeMO), allowing the charging of a range of different EV models. In practice, this means that most EVs will be able to use most publicly accessible charge points.
