AC and DC Charging: What’s The Difference?
There are two criteria that determine the usefulness of an electric vehicle: range on a single charge and how quickly said battery can be recharged to 80% or to full capacity. The common terms used to describe EV charging are AC and DC chargers. But what are they and how do they differ from one another?
AC stands for alternating current. It describes the periodic alternating flow of electricity at a rate of 50Hz (for Malaysia). When viewed on an oscilloscope, the flow forms a sinusoidal wave that has a peak and trough, which make up a sideways-like S pattern.
AC is the most convenient way of transmitting electricity across long distances. Using transformers, you could step up and step down the AC voltage, and in turn minimize energy losses. It’s what’s supplied by TNB to our homes and offices.
Basics of Voltage And Current
But before we go into the details, it’s important to understand the difference between current measured in Amperes or A and Voltage measured in V.
Current is the rate of flow of electrons from one side of a closed circuit to the other. Voltage is the electromotive force between two points or in layman terms, it’s the force used to make electrons flow across a closed circuit.
How AC Is Produced
Alternating current is created with electromagnetic induction. The simplest way to explain this is by moving a permanent magnet through a wire coil, repeatedly. This movement creates a magnetic field of changing intensity. This in turn, induces a voltage in this circuit.
It’s a similar principle used by an ICE vehicle’s alternator. It uses the rotational movement of the engine’s crankshaft to create alternating current. This will need to be converted to DC or direct current to be usable for a car’s electrical systems, which includes charging the 12V battery.
How DC Is Produced
Unlike AC, DC stands for Direct Current and consists of a constant, unidirectional flow of electricity. It’s what’s generated by batteries, including EV batteries. Every EV’s battery pack consists of thousands of batteries that are not dissimilar from what’s in your flashlight or TV remote.
When operating in a closed circuit, the chemical reaction within a battery causes the flow of electrons from one terminal to the other. It’s a constant, unidirectional flow from a negative part of the circuit to the positive side. This describes the behavior of direct current.
How Does This Apply To Electric Cars?
Now, when it comes to charging an electric car, you can use electricity from either AC or DC power sources. This is why you can use both an AC charger and DC charger. The former is usually supplied from domestic power outlets whereas the latter is usually provided by dedicated chargers from commercial facilities.
AC chargers are slower than DC ones. That’s because an AC charger’s electricity will need to be converted to DC by the vehicle’s onboard charger (OBC) before it can be used to charge the battery pack.
DC chargers on the other hand can supply power to the battery pack directly without the need for any conversion work. This allows for quicker charging and at high delivery rates from 22kW to 300kW in the case of high-powered charging stations.
This allows a vehicle to be charged from 10% to 80% in a mere 30 minutes. DC chargers are large and clunky and make them impractical to be installed in residential areas. In addition to this, they require a much higher cost to operate compared to an AC one.
AC chargers supply much less power compared to their DC counterparts. This is why they offer absurdly long charging times that can reach 17 hours to top up a vehicle’s battery.
I hope this feature helped shed some light on the differences between AC and DC chargers. Expect to see more of such features in the coming days. Till then, check out our website for informative news on gadgets and their respective prices.
