What is Level 1 Charging?


Level 1 charging is the slowest method of charging an EV and uses a regular 120-volt outlet to deliver electricity to the battery in the form of AC.

It’s considered the simplest, most affordable, and most basic charging option available and requires no additional infrastructure beyond what’s typically found in most homes.

Here’s a brief look at what you’ll learn about level 1 charging:

1️⃣ You can expect about 3 to 5 miles of range per hour by plugging into a standard 120-volt household power outlet.

2️⃣ The power output of Level 1 chargers is around 0.7 to 1.9 kilowatts (kW), making it a cost-effective option for cars with small battery capacities or for slow charging.

3️⃣ Charging efficiency is influenced by factors such as battery size, energy consumption rate, and available power supply, with higher amperage supplies leading to increased efficiency.

What is Level 1 EV Charging?

Understanding what Level 1 charging is goes hand in hand with knowing how long it takes. So let’s explore that now.

Charging Time

As an entry-level charging option for EVs, Level 1 charging typically provides about 3 to 5 miles of range per hour. 

While it may not be as fast as other charging methods, it’s important to remember that it’s also the most accessible option for many EV owners. 

I can easily plug my EV into a standard 120-volt household power outlet, which can be found in most homes and parking areas.

This convenience allows overnight charging or during extended hours when the car is parked.

Power Output

Level 1 chargers can supply a power output of around 0.7 to 1.9 kilowatts (kW), the lowest of EVs’ charging levels. 

But the upside of low power output is that it makes Level 1 a cost-effective option. Especially for a car with a small battery capacity or if I don’t need to add a significant amount of range during a short charging window.


In terms of efficiency, Level 1 charging can, in some rare cases, be pretty practical for slow, overnight charging or for keeping my EV topped off during the day. 

Charging efficiency is influenced by various factors, such as the battery size, energy consumption rate, and the available power supply. For example, if you access a 15-amp power supply, the charging efficiency would increase compared to a 12-amp supply.

If you wonder why I’ve just mentioned amps, the equivalent kilowatt output is 1.8 kW. 

Overall, Level 1 charging isn’t really a practical approach for meeting the daily charging needs of many EV owners.

As batteries continue to get bigger, their demands will increase and need to be met with more efficient methods.

How Level 1 Charging Works

Alternating Current

Level 1 charging primarily relies on alternating current (AC) power to recharge an electric vehicle (EV). 

This charging method uses the same current in standard household outlets, making it the most accessible option for most American homes and those without access to 240-volt outlets at home chargers.

Household Outlets

For me, one of the biggest advantages of Level 1 charging is the accessibility. In most cases, simply plugging in your EV directly into a regular 120-volt household outlet will work. 

This means that homeowners don’t need to install additional hardware or worry about compatibility issues with charging stations. Here are a few key aspects of Level 1 charging from a household outlet:

  • Voltage: 120 volts
  • Amperage: 6-16 amps
  • Power: 0.7-1.9 kW (depending on the amperage)

Onboard Charger

The onboard charger (OBC) of an EV plays a critical role in converting AC power (power from the grid) into direct current (DC) for storage in the car’s battery.

The efficiency and capacity of the OBC can affect charging times. Here are some common variations in onboard chargers:

OBC RatingTypical Charging SpeedCharging Time Estimate (for 100 miles)
3-3.3 kW12-16 miles of range per hour6-8 hours
6.6-7.2 kW25-30 miles of range per hour3-4 hours

Remember that these times are approximate and can be influenced by temperature and battery capacity.

Additionally, the onboard charger’s maximum capacity must be compatible with the charging station’s output to achieve optimal charging speed.

Level 1 Charging Connectors and Compatibility

SAE J1772

The most common and widely used connector is the SAE J1772 or the J-plug. This is the most universally compatible connector available today, except for Teslas, which have their unique connector. 

If an EV has a J1772 charging port, Level 1 charging can be conveniently done at home using a simple 120V outlet. This charging method can be painfully slow, but it’s an option when you don’t need a rapid charge.

Tesla Connector

For Tesla owners, the Tesla Connector is unique to their EV lineup. Charging via Tesla’s proprietary connector works similarly to the J1772 connector in terms of charging speed and ease of use, plugged into a standard 120V household outlet. 

Even though their connector looks different, Tesla vehicles can still utilize adapters to charge on J1772 Level 1 charging stations if needed.

Key Takeaways

In summary, Level 1 charging provides a slow method for EV owners to recharge their vehicles overnight or during extended parking periods. 

Connectors like the SAE J1772 and the Tesla Connector enable compatibility across most EVs available today, ensuring accessibility and ease of use for charging your car at home or elsewhere.

1️⃣ Level 1 charging primarily relies on Alternating Current (AC) power and is the most accessible option for many American homes lacking access to Level 2 home chargers.

2️⃣ The onboard charger (OBC) plays a critical role in converting AC power into Direct Current (DC) for storage in the car’s battery, affecting charging times.

3️⃣ Connector types vary, with the SAE J1772 (or “J-plug”) being universally compatible, and Tesla having its unique connector. These connectors allow for home charging using a standard 120V outlet.