What AC charging is and why it matters

AC charging is the slower, more common way to charge an electric car at home or at public stations. Your car's onboard charger converts the alternating current (AC) from the wall outlet or charging station into direct current (DC) that the battery can store. Most electric car owners do 80 percent of their charging this way because it costs less to install and operate than DC fast charging.

The speed depends on three things: the power available at the outlet, the capacity of your car's onboard charger, and the battery's ability to accept charge. A standard 120-volt household outlet charges slowly — roughly 3 to 5 miles of range per hour. A 240-volt home charger, which is what most owners install, adds 25 to 30 miles of range per hour. Public AC chargers at workplaces and shopping centers typically deliver the same speed or slightly faster.

Key Takeaways

  • AC charging converts household or public AC power into DC power your battery stores, and is slower but cheaper than DC fast charging.
  • A 120-volt outlet charges at roughly 3 to 5 miles per hour; a 240-volt home charger adds 25 to 30 miles per hour.
  • Installing a 240-volt home charger costs between $500 and $2,500 depending on your electrical panel and distance from the garage, and usually takes a licensed electrician.
  • Most electric cars come with a Level 1 cable for 120-volt outlets, but you will need to buy or install a separate 240-volt charger for faster home charging.
  • Public AC chargers are often free or cost $1 to $3 per hour, and are common at workplaces, apartment buildings, and retail locations.

The difference between Level 1 and Level 2 AC charging

The electric vehicle industry uses two terms for AC charging: Level 1 and Level 2. Level 1 is any standard 120-volt household outlet — the same outlet you plug a lamp into. Level 2 is a 240-volt circuit, the same voltage that powers a clothes dryer or electric range in most homes.

Level 1 is convenient because the cable comes with your car and works anywhere, but it is impractical for daily use. Charging a 60-kilowatt-hour battery from empty takes roughly 24 to 48 hours. Level 2 is the standard for home and workplace charging because it cuts that time to 8 to 12 hours overnight, meaning you wake up with a full battery most mornings.

There is no Level 3 in the AC world. What the industry calls DC fast charging (sometimes labeled Level 3) is a different technology entirely — it bypasses your car's onboard charger and feeds DC power straight to the battery, which is why it charges in 20 to 45 minutes but costs more and stresses the battery faster.

Installing a 240-volt home charger

A 240-volt charger requires a licensed electrician to run a dedicated circuit from your electrical panel to the garage or parking location. The cost varies widely based on the distance from your panel to the charger location and whether your panel has spare capacity. Most installations fall between $500 and $2,500. If your panel is full or far from where you park, the cost can climb higher.

Before calling an electrician, check your home's electrical service. Most homes built in the last 20 years have a 200-amp service, which is sufficient. Older homes with 100-amp service may need a panel upgrade, which adds $1,000 to $3,000 to the project. Your electrician can assess this in a brief site visit.

You will also choose between a hardwired charger, which is permanently installed and slightly cheaper, and a plug-in charger, which you can unplug and move if you relocate. Plug-in models cost $100 to $300 more but offer flexibility. Both deliver the same charging speed once installed.

What comes with your car and what you need to buy

Every electric car includes a Level 1 charging cable in the trunk or frunk. This cable has a standard household plug on one end and a connector that fits your car's charging port on the other. It works when ready and costs you nothing, but as noted, it is slow enough that most owners treat it as an emergency backup rather than a daily tool.

For Level 2 charging at home, you have two paths. You can buy a portable Level 2 charger (sometimes called a mobile connector) for $300 to $600 and have an electrician install a 240-volt outlet where you park. You then plug the charger into that outlet the same way you would plug in a lamp. Alternatively, you can buy a hardwired Level 2 charger for $400 to $1,200 and have the electrician wire it directly to your panel. Both approaches require the same electrical work; the difference is whether the charger itself is portable or fixed.

Many employers and apartment buildings provide Level 2 chargers for free or as part of a parking fee, so check what is available where you work or live before spending money on home installation.

Using public AC chargers

Public AC chargers are scattered across parking lots, shopping centers, office buildings, and apartment complexes. They are slower than home charging but useful if you spend several hours in one place — a full workday, a shopping trip, or a movie. Most add 5 to 10 miles of range per hour, depending on the charger's power output.

Finding them is straightforward. Apps like PlugShare, ChargePoint, and your car's native navigation system show the location, availability, and cost of nearby chargers. Many are free, especially at workplaces and apartment buildings. Public chargers that charge a fee typically cost $1 to $3 per hour, though some charge by kilowatt-hour instead. Costs vary by network and location.

Public AC chargers do not require membership or registration in most cases, though some networks ask you to create an account or read an app to unlock the charger. The process takes a few minutes the first time and is automatic after that.

How long AC charging takes for a full battery

Charging time depends on the battery size, the charger's power output, and how full the battery already is. A typical mid-size electric car with a 60-kilowatt-hour battery charges from empty to full in roughly 8 to 12 hours on a 240-volt home charger, or 24 to 48 hours on a 120-volt outlet. Larger batteries take longer; smaller ones faster.

In practice, you rarely charge from completely empty. Most owners plug in at night and charge overnight, adding 150 to 200 miles of range by morning. If you drive 40 miles a day, you only need to replace those 40 miles, which takes 1 to 2 hours on a 240-volt charger.

Charging also slows as the battery fills. The last 10 to 20 percent of charge takes longer than the first 80 percent because the battery's chemistry requires slower power input to avoid damage. This is why many owners unplug at 80 percent for daily driving and only charge to 100 percent before a long trip.

AC charging costs compared to gasoline

The cost of AC charging depends on your local electricity rate, which varies by region and time of day. The U.S. average is roughly $0.14 to $0.18 per kilowatt-hour, though rates in some states are higher and others lower. Charging a 60-kilowatt-hour battery costs between $8 and $11 at average rates, which translates to roughly $0.03 to $0.04 per mile.

Gasoline costs vary by region and fuel price, but at current rates, driving a gas car costs roughly $0.10 to $0.15 per mile. AC charging is typically one-third to one-half the cost of gasoline per mile driven. Home charging is cheaper than public charging because you avoid the markup that public networks add to cover their equipment and maintenance.

Some utilities offer time-of-use rates that charge less during off-peak hours, usually late evening and early morning. If your utility offers this, charging overnight can cut your per-mile cost by another 20 to 30 percent.

Frequently Asked Questions

Can I charge my electric car on a regular 120-volt outlet?

Yes, every electric car comes with a Level 1 cable that works on any standard outlet. It charges slowly — roughly 3 to 5 miles per hour — so a full charge takes 24 to 48 hours. It works as a backup or for occasional use, but is not practical for daily charging.

Do I need a special outlet for AC charging, or can I use an extension cord?

For Level 1 (120-volt), a standard outlet and a heavy-duty extension cord work, though the cord should be rated for outdoor use if you are charging outside. For Level 2 (240-volt), you need a dedicated circuit installed by a licensed electrician — extension cords are not safe for this voltage and power level.

What happens if I leave my car plugged into an AC charger overnight?

Nothing harmful. Once the battery is full, the charger stops delivering power. Your car will sit at full charge until you unplug it. Some owners leave their cars plugged in all the time to keep the battery topped up, which is safe and convenient.

Is AC charging safe in rain or snow?

Yes. Charging equipment is designed to be weatherproof and safe in wet conditions. The connector and outlet are insulated, and the circuit includes safety features that shut off power if water is detected. You can charge in rain, snow, or any weather.

Can two electric cars share one home charger?

Yes, but only one car can charge at a time. You would unplug from one car and plug into the other. If you own two cars and both need daily charging, you would need two separate chargers and two 240-volt circuits, which requires additional electrical work and cost.