AC Charging vs DC Charging: What’s the Difference?

By
Keith Berger, CEO
September 30, 2022

The acronyms AC and DC both refer to different types of current flow in an electrical circuit. These two types of current flow power our world, but what are the differences between the two? Is one better than the other? Stick around and find out.

What is AC?

AC stands for alternating current. An AC charger, then, sends power to an EV on an oscillating basis. The energy in an AC charger goes forward a bit, then flips back on itself, then goes forward a bit more, etc. 

While this might seem counterintuitive to fast charging, there’s a reason for this oscillation: It makes it much easier to change the voltage of the current, which is why most power grids utilize AC. The same grid can power residential homes and commercial buildings without losing a lot of power changing voltages (as the former would require much less power than the latter). 

What is DC?

DC stands for direct current, meaning exactly what its name suggests: Current flows directly and consistently from one point to another with no oscillations. Batteries, like the ones EVs have, can only store their power as DC power, which is why every EV has a converter that turns the AC power that comes from power grids into storable DC power.

The Difference Between AC Charging and DC Charging

The difference between AC charging and DC charging is where AC power gets converted into DC power. With AC charging, the power gets converted to DC power using the converter inside an EV itself. With DC charging, however, the charger has a converter, so the power is already DC power when it flows into the car, significantly reducing the job of the converter inside of the car.

Pros and Cons of a DC Charger

Advantages of DC charging include the fact that a DC charging station can serve more cars with the same amount of equipment, fully charging a car in around 20 minutes to an hour. Because a DC charging station can charge cars so quickly, multifamily complexes don’t have to invest in as many chargers as those that choose AC chargers.

In the end, a DC charger has a lower cost of ownership and lower demand charges than an AC charger does. However, a DC charger is also more expensive, costing anywhere from $6,000 to $250,000. 

Pros and Cons of an AC Charger

An AC charger costs less up-front than a DC charger, costing around $1,800 to $4,500. However, an AC charger will require more servicing, which means the monthly upkeep costs will be higher than that of a DC charger. Plus, an AC charger charges cars slower than a DC charger, so buildings typically need more of them in their parking lots to support resident EV charging.

Is AC Better or DC Better?

AC charging and DC charging both have their place in the world of EV, but there are situations and cases in which one can be more advantageous over the other.

For complexes that have the overhead to pay for DC and expect many of their occupants to utilize Charging as a Service (CaaS), then we would recommend installing DC chargers. For those that estimate a smaller portion of residents as the primary users of EV charging, we would recommend AC chargers, because although they are less efficient, they are less expensive.

It is important to keep in mind that these recommendations are general, and that we always tailor specific recommendations to our partners’ differing needs. Additionally, getting a custom recommendation is crucial to EV charging success as properties and their power needs/abilities are unique and require different solutions for optimal performance.

Looking to Install an AC Charger or a DC Charger?

Reach out to us if you are looking to install an AC or DC EV charging station, or if you have any more questions about AC and/or DC charging. We look forward to speaking with you!

EV Charging FAQs

Are Cars AC or DC?

It’s decently common knowledge that EV cars are not the first cars to have a battery. Regular cars also have a battery alongside their combustion engine, and that battery, just like EVs, can only store DC energy.

Are Electric Cars AC or DC?

EV car batteries can only store DC energy, but they can take a charge from either AC or DC chargers; the difference is in how long it will take to charge that vehicle. When using an AC charger, the current conversion happens inside of the car, which means it will take more time to charge. With a DC charger, the energy is already in the form of a direct current, so the car doesn’t have to convert it, which saves time.

Is House Electricity AC or DC?

Houses are connected directly to power grids and run off of AC energy, seeing as the different things one plugs into their wall demand varying levels of electrical current.

So when you plug your toaster into the wall, AC energy from your local grid flows into your bread-crisping device, not DC, because the energy to run said toaster is a lot different than that needed to run your washing machine.

Where is DC Current Used?

Direct current is used in any device that runs on a stored amount of energy, AKA a battery.

Why is AC Used Over DC?

Whether AC is used over DC depends on where it is used. For power grids, AC is used because it is easier to change the voltage of an alternating current. DC is used in things that have batteries, although batteries can be charged with an AC power source as long as an AC/DC converter is used (and we’re not talking about the famous rock band). 🎸

Get in touch with our team today.

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