Buying your first EV? Read this before you do to understand all about EV charging
Shaun · Jun 10, 2023 10:00 AM
0
0
Almost every electric vehicle (EV) on sale has two methods of charging - alternating current (AC) and direct current (DC). Why is it so? Well, let’s dive into each and dissect its advantages and applications.
AC vs DC
Regardless of AC or DC charging, batteries can only be charged and discharged using DC power. The key difference lies in where the conversion from AC to DC occurs - either at the charging station before the power reaches the vehicle, or within the car’s onboard charger once the power has been received.
AC is commonly used in households due to its efficiency and the ability to easily transform it to different voltages over long distances with minimal energy loss. Given the considerable distances between power stations and households, the choice of AC for power transmission becomes apparent.
In AC charging, the electric power from the grid is supplied to the vehicle's onboard charger, which converts the AC power into DC power to charge the vehicle's battery. The charger adjusts the charging current and voltage to match the vehicle's requirements.
DC charging, oftentimes referred to as fast charging or rapid charging, involves a direct connection between the charging station and the high voltage battery. Instead of converting AC power to DC power on-board the vehicle, DC charging stations provide high-power DC electricity directly to the vehicle's battery, bypassing the onboard charger.
CCS Combo 2 connector
This allows for much faster charging speeds compared to AC charging. DC charging is typically used for long-distance travel or when the vehicle needs to charge quickly. However, DC charging requires specialised infrastructure, which is more expensive, complex, and takes up more space.
Charging port types
There are also the types of charging ports to take note of but to make it easier to understand, there’s only one type of AC charging port you need to know - Type 2. Since the launch of the Nissan Leaf facelift, every EV and even plug-in hybrids (PHEVs) sold here use a Type 2 port.
CHAdeMO connector
When it comes to DC charging, there are two types you should know: CHAdeMO (less prominent, usually on Japanese makes only) and CCS Combo 2 (most prominent and essentially an enhanced version of the Type 2 port). We’ve previously elaborated on the types of EV charging, click here to read more about it.
Also of note is the power supply, which there are two main types: single-phase and three-phase. These terms refer to the way electricity is delivered to the charging point and impact the voltage, current (amps), and total power output available for charging.
Single-phase charging is the standard power supply found in most homes and buildings. It involves a single alternating current (AC) waveform. Three-phase, as its name suggests, involves three alternating current waveforms that are out of phase with each other.
Three-phase charging provides higher power capacity and faster charging rates and a more consistent, steady supply that is more accommodating to higher loads compared to single-phase charging. It is commonly used in commercial and industrial settings, though households can convert from a single-phase to a three-phase power supply.
The voltage for three-phase charging is typically higher, often around 400V (single-phase is 230V for Malaysia). The current for three-phase charging can range from 16 amps to 100 amps, depending on the charging infrastructure, which means the total power output available for charging an EV in three-phase charging is significantly higher compared to single-phase charging.
Home charging for EVs
A home EV charger or EVSE - electric vehicle supply equipment - typically have a charging rate from 3.7 kW to 22 kW. Single-phase chargers are usually rated at either 3.7 kW or 7.4 kW based on the single-phase formula, which is current multiplied by voltage (either 16 amps or 32 amps multiplied by 230V).
Not an EV, but this PHEV can utilise an 11 kW AC charger
Three-phase chargers triple the ratings of the single-phase chargers - 11 kW or 22 kW, which again, depends on the current (16 amps or 32 amps), multiplied by the voltage (400V) and square root of three (around 1.732), using the three-phase formula. You’ll also need a suitable three-phase charging cable in order to utilise three-phase chargers.
EV spec sheets don’t give you the full picture
Let’s take the BYD Atto 3 as an example. Its onboard charger is rated at 7 kW (at 32 amps, single-phase) but if you plug an 11 kW (three-phase, 16 amps) charger to it, you’ll only get 3.7 kW as the charger is limited to 16 amps and the onboard charger only takes single-phase charging.
So, if you notice that the car isn’t charging at the capacity its spec sheet says it can, don’t be alarmed. Neither the car nor the charger is at fault, it’s just the way power supply works.
Conclusion
To wrap up, EVs can be charged using either AC or DC methods. AC charging provides a convenient and widely available charging option for daily charging needs and slower charging sessions, while DC charging offers faster charging speeds for long-distance travel and situations where quick charging is necessary.
Different types of charging ports exist for AC and DC charging, with Type 2 being common for AC charging, while CHAdeMO and CCS Combo 2 used for DC charging.
When it comes to AC power supply, there are two types - single-phase and three-phase. Understanding these charging methods and power supply types helps ensure efficient and effective charging for EVs.
The quest for automotive knowledge began as soon as the earliest memories. Various sources information, even questionable ones, have been explored including video games, television, magazines, or even internet forums. Still stuck in that rabbit hole.
