AC vs. DC Charging: A Simple Breakdown

Car Charger 2

With the popularity of electric vehicles steadily increasing, it can be easy to get lost in a jumble of jargon, a miasma of misinformation, or a cloud of confusion. From vehicle charging stations to EV maintenance, there’s a lot to know.

So, begin your journey into the EV realm with something simple: the difference between AC (alternating current) and DC (direct current) charging. Whether you’re considering purchasing an EV for personal use, or manage a workplace and want to know the benefits of installing charging stations, this is essential knowledge.

In this blog post, we at Elanga Australia break down the elemental differences between these two charging types.

First things first: what does an electric vehicle run on?

Much like determining whether to pump either petrol or diesel into an ICE (Internal Combustion Engine) car, EV owners need to understand the fundamentals of what powers their vehicle.

Ultimately, all electric vehicles run on DC power. Think of an electric car like a mobile phone. Despite being charged from the power grid (where all power is AC), a phone runs on DC power. This is because DC power can be stored in a battery, allowing your device to be used independently of the grid. Thanks to a converter in your phone’s wall adapter, AC power is converted into DC. This is why your phone doesn’t need to be constantly plugged in.

The same goes for an electric vehicle, since it also runs on a portable battery. The only difference is where the converter lives. In an EV, the AC-to-DC converter lives in the vehicle itself, converting power only when the car is plugged into an AC charger.

So, why are there two different charging types, AC and DC, and what are the differences between them?

AC Charging: Conversion Slows the Process

Alternating current (AC) charging relies on AC power. To explain it simply, AC power alternates between a forward and backward flow of energy, rather than supplying a constant stream of power. This is the type that runs through our power grids, supplying homes and businesses with reliable, efficient, and inexpensive energy.

However, as previously stated, EVs run on DC power. AC car chargers supply the alternating current to an EV, which is subsequently converted to DC power inside the car. From there, the DC power is transferred to the car’s battery. The EV’s AC-to-DC convertor is, however, constrained by weight and space – it must be as light as possible to ensure optimal EV performance, and as small as possible to ensure best availability of cabin area. This means that it will be low powered and consequently slow charging.

Charging speeds will vary depending on the charger’s output and the onboard converter’s capacity, but this is generally a slower process than DC charging. So, these chargers will take longer to power your EV.

Despite their speed, however, this is the most common type of EV charger in the world today. You’ll find AC chargers in public parking spots, workplaces, and in EV owner’s homes. AC chargers are cheaper and easy to install, making them ideal for wider infrastructure changes. Not to mention, it’s also cheaper for vehicle owners to charge using AC chargers.

DC Charging: Bypassing the Converter

 This is where DC chargers have their advantage – being on the ground and not part of the EV, they don’t have size and weight limits. Therefore, they can have very large power control circuits, and convert very high AC power from a local grid utility, into very high DC power.

When plugged in, the DC power bypasses the EV’s onboard converter and feeds directly into the battery. This accelerates the charging process significantly. This is why DC chargers are also known as “rapid charging stations”; in some cases, you can bring a car to 80% charge in under twenty minutes.

So, why are these not the most common chargers out there?

Well, DC chargers suck a lot of power from the grid, resulting in higher installation and operation costs. This also means people using DC chargers must pay more per charge.

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