Electrical Basics: Part 1
With so many new EV charging business development opportunities, the EV infrastructure industry is seeing an explosion in the growth of new people entering the space. However, the ecosystem of EV fast charging sites can be complex and overwhelming to understand for those new to it.
This series is designed to introduce the intricacies of the electrical infrastructure required for DC fast charging sites, aiming to quickly bring newcomers up to speed and navigate the complexities of this rapidly evolving industry.
The Difference Between Power and Energy
To charge their batteries, EVs need to connect to a power source that can deliver a certain amount of energy over a certain period of time. But what is the difference between power and energy, and why does it matter for EV charging?
Power: The rate at which energy is transferred or converted. Power is used in EV charging to describe the maximum charging speed of the charger, which is measured in kilowatts (kW).
Energy: The capacity for doing work. Energy is used in EV charging to describe the amount of electricity transferred to the vehicle’s battery, which is measured in kilowatt-hours (kWh).
HOW DOES THIS APPLY TO EV CHARGING?
EV charging involves the transfer of electrical energy from a power source to the battery of an EV. The amount of energy transferred is measured in kilowatt-hours (kWh), while the rate at which energy is transferred is measured in kilowatts (kW). For example, if a 10 kW charger is used to charge an EV for 1 hour, then the total energy transferred would be 10 kWh.
The power and energy requirements for EV charging depend on various factors, including the type of charger, the battery capacity of the EV, state-of-charge, battery and environmental temperature, and the desired charging time.
The Difference Between AC and DC Current
Alternating Current (AC)
A type of electrical current that periodically reverses direction and magnitude continuously.
AC power is typically presented in Volts AC (VAC). The main advantage of AC is that it can be easily transformed to different voltages using transformers, which are devices that increase or decrease the voltage of electricity. This makes AC suitable for long-distance transmission, as higher voltages reduce the power loss and lower voltages are safer for end-users.
DIRECT Current (DC)
A type of electrical current that flows in only one direction.
DC power is typically presented in Volts DC (VDC). The main advantage of DC is that it can deliver more power to the load. This makes DC suitable for high-power applications that require stable and reliable power.
AC power can be found in common applications like:
DC power can be found in applications like:
HOW DOES THIS APPLY TO EV CHARGING?
Electric vehicles use DC batteries to store energy and provide power to the vehicle. However, most chargers use AC electricity from the grid. This means that there is a need for a device that can convert AC to DC involved in the charging process. This conversion can be made inside the EV with an onboard converter that does it automatically. There is also a category of chargers that can do this conversion and provide direct DC power to the EV.
What's Next?
Part 2 of the series will focus on the distinction between between Single-Phase and Three-Phase Power, while also exploring the various levels of VAC power that are commonly used with EV charging.
