There are two types of chargeable EVs:
- Battery Electric Vehicle (BEV): Fully electric, no backup engine
- Plug-In Hybrid Electric Vehicle (PHEV): Has a large electric battery that can be charged externally, but also has an engine
While Hybrid Electric Vehicles (HEV) have a battery, they are unable to be charged by an EV charger.
A watt is a unit of measurement of power of a device – in this case, a charger. Power is the rate at which energy flows, and tells you how fast electrons are moving. The more powerful the device, the higher the wattage will be, and in turn means that the charger will deploy electricity at a faster rate.
Chargers typically use kilowatts when measuring their speeds. A kilowatt is equal to 1,000 watts.
- Kilowatt hours (kWh) is the cumulative amount of energy transferred from one device to another – in this case, from a charger to an EV. The amount of kWh in a charging session is calculated by the charger’s power (kW) multiplied by the total time in hours. So, a charger providing power at a rate of 50kW will give you 50kWh in 60 minutes, 25kWh in 30 minutes, and 100kWh in 120 minutes.
Level 1 charging consists of a nozzle cord plugged into a standard 120V electrical outlet (a standard outlet in your house). EV drivers can purchase a nozzle cord, called the emergency charger cable or the portable charger cable (in some cases this included with the purchase of an EV). This cable is compatible with the same type of outlet in your house used to charge a laptop or phone.
The majority of passenger EVs have a built-in SAE J1772 charge port, also known as the J plug, which allows them to use standard electrical outlets for Level 1 charging or Level 2 charging stations. Tesla owners have a different charging port but can purchase a J-plug adapter if they want to plug it into an outlet at home or use a non-Tesla Level 2 charger.
Level 1 charging is affordable and requires no special setup or additional hardware or software, making it a convenient choice for residential use. However, it takes over 24 hours to fully charge a battery, which makes Level 1 charging impractical for drivers that log a lot of miles on a daily basis.
Level 2 charging stations use 240V electric outlets, which means they can charge an EV much faster than Level 1 chargers due to higher energy output. Level 2 charging station power ranges from 7kW to around 22kW. An EV driver can connect to a Level 2 charger with the attached nozzle cord using the integrated J plug built into most EVs. For single-family residential owners who want a faster charge than a level 1 can provide, level 2 is a great option.
Level 2 chargers are often equipped with software that can intelligently charge an EV, adjust power levels, and bill the customer appropriately. They’re an ideal option for apartment complexes, retail spaces, employers, and university campuses that want to offer EV charging stations as a perk while also tracking usage and performance.
There are many Level 2 charger options on the market, so resellers and network owners who want maximum flexibility may want to consider hardware-agnostic EV charging station management software that works with any OCPP-compliant charger and allows them to manage their devices from one central hub.
A Level 3 charger uses direct current (DC) to charge EVs much faster than both Level 1 and Level 2 chargers. Level 3 chargers are often called DC chargers, DCFCs, or “superchargers” due to their ability to fully charge an EV in under an hour. A typical DCFC will have a power between 30kW to 500kW. As of 2023, the majority of vehicles can only take up to 150kW (some up to 350kW), so the faster available speeds are future-proofing for future EVs.
DCFCs are not as standardized as Level 1 and 2 chargers, and an EV requires special components like a Combined Charging System (CCS or “Combo”) plug, a CHAdeMO plug used by some Asian automotive manufacturers, or a Tesla connector to connect to a Level 3 charger.
You’ll find Level 3 chargers alongside main thoroughfares and highways because while most passenger EVs can use them, DC chargers are primarily designed for commercial and heavy-duty EVs. A fleet or a network operator can mix and match a selection of Level 2 and Level 3 chargers on-site if they’re using compatible open software.
The SAE J1772, also known as J plug or Type 1 connector, is the standard charging connector in North America. All electric vehicles sold in North America use a socket that supports this plug type, except for Tesla. However, Tesla owners may purchase an adapter to use these connectors.
The J1772 connector supports alternating current (AC) charging rates. It can connect to a standard household outlet and Level 2 chargers.
The Combined Charging System (CCS) is a standard for direct current (DC) charging and can come in two types – CCS1 and CCS2. In North America, the Combo 1 (CCS1) is currently found on the widest variety of electric vehicles as of 2023.
The CCS1 connector is an extension of the J1772 connector. The “combo” refers to the addition of the DC contact below the existing AC and communication contacts. This DC extension allows for the EV to receive a faster charge as dispensed by Level 3 (DCFC) chargers.
A CCS1 connector can support a theoretical charging rate up to 700kW, but in practice, most cars with this connector are designed to support 50kW to 350kW charging speeds.
The Charge de Move (CHAdeMO) connector is an older standard for direct current (DC) charging. In North America, it is uncommonly used and is found on cars such as Nissan LEAFs and Mitsubishi Outlander PHEV.
In North America, most CHAdeMO chargers will dispense speeds of up to 50kW for this connector type.
The North American Charging Standard (NACS) is the connector type developed by Tesla.
NACS connectors can be used on both Level 1 and 2 (AC) charging, as well as Level 3 (DC) charging. Adapters for NACS to J1772 can also be purchased so that Teslas have access to more L2 chargers.
Originally the NACS standard was developed as a proprietary Tesla standard; however, the standard was opened for use by other manufacturers in 2022. Most other vehicle manufacturers have announced that they will be using this standard on their North American EVs starting in 2025.
- Alternating current (AC) charging takes an electrical current directly from the wall, through the charging cable, and into the car’s on-board charger. The on-board charger in the car converts the current to a direct current (DC). The current continues to flow to the battery, which is where the power is stored. The acceptance rate of the on-board charger will vary by car model and a car may take anywhere from 4 to 12 hours to fully charge using a Level 2 AC charger. The on-board AC conversion is inefficient, which is why AC charging is capped to relatively low speeds. Additionally, there is some tendency towards power leakage, meaning that not all energy leaving the wall will end up in the battery.
- Direct current (DC) charging bypasses the on-board car charger; the AC to DC conversion occurs within the charger itself. The current then flows from the charger, through the cable, directly to the battery. The acceptance rate of the battery will vary by model, and a car may take 15 to 120 minutes to fully charge using a Level 3 DC charger. Note that at 80% you’ll see speeds
Your charging speed will be affected by several variables:
Your vehicle: Your car is only able to accept a maximum charging speed on both AC (Level 2) and DC (Level 3) chargers. On Level 2 chargers, some cars will max out at accepting 7.7kW, while others can handle up to 22kW on a Level 2. On Level 3 chargers, some older cars can handle up to 50kW of power, while others can handle up to 350kW! This means that if a car that can handle a max of 50kW is plugged into a charger that can dispense 100kW of power, the car’s max charging speed will only ever get to 50kW. Check your handbook to see your car’s maximum rate of charge.
Your charger: Chargers have different power ratings. At peak charging speed, your car will charge at either the maximum kW rating of the charger, or the maximum handleable rate of your car, whichever is lower. A Level 3 (DC) charger will charge more quickly than a Level 2 (AC) charger, and both of these will charge more quickly than a Level 1 charger. Even within these categories, you will have different speeds, so make sure you check the charger rating!
Power managed charging: If your charger is part of a group of chargers in a power management group, increasing the number of chargers in its group may reduce the rate at which your car is charging.
Battery temperature: Very cold or very hot weather conditions can affect the temperature of your battery, which will cause your car to interact differently with the chargers. For instance, your car may limit the allowable power, or simply take longer to accept a charge. Expect that your car will need more time for a charge, particularly below 4 degrees Celsius as the battery may be cold. As your battery heats up in hot weather, your car will automatically slow down the speed at which the battery accepts power. The optimum temperature for EV car charging is between 10 degrees Celsius and 25 degrees Celsius.
Charging curve: You may notice that if your car above 80%, the rate of charging may slow down. This is normal behaviour! A charging curve is typically engineered by each manufacturer to protect the vehicle and battery and ensure user safety while optimizing the speed of charge. What this means is that your car may accept a charging speed at varying rates. Generally speaking, the last 20% of charging requires slowly cooling the battery. The speed of charge can decrease so drastically in this windows that it can take nearly as long to charge a battery from 85% to 100% as it does to charge from 10% to 80%. For this reason, charging etiquette suggests only charging to 80%-85% and then moving on so that a charger can be opened up quickly for the next driver.