How do I charge an electric car?
Written by Larry Thompson
The short answer
Approximately 80% of electric vehicle owners charge their cars at home or at their workplace.
For home charging, an electrician is usually required to install an electrical outlet or the manufacturer’s home charging system, including the charging cable, in the garage or on the exterior of the house. When the owner wants to charge the car they simply connect the cable to the car and the car will charge automatically.
In most cases, the electrician will install a 30 or 40 amp, 240-volt circuit. Charging times vary from car to car but a good rule of thumb is 20-25 miles of charge per hour for a 30 amp circuit. It’s also possible to plug the car into a standard 120-volt outlet but this will generally be limited to 4-5 miles of charge per hour, less when the ambient temperature drops into the 30-degree range. Many owners use this option when visiting friends. Fortunately, most EV’s have a phone app that allows scheduled charging during off-peak hours if you have a peak/off-peak plan.
Public charging stations also have a cable that is simply plugged into the car and the car will charge automatically. Charging times vary widely depending on the capacity of the charging station.
Tesla’s have access to Tesla Supercharger stations generally located on or just off main highways. Charging speeds vary depending on the capacity of the particular station, how many Tesla’s are simultaneously charging and ambient and battery temperature. A good rule of thumb is to expect speeds between 150 and 360 miles of charge per hour but charging speeds decrease as the battery becomes more fully charged.
There are several categories of EV charging stations in use today.
Level 1 Charging is provided from a standard 120 volt AC circuit sometimes referred to as a “household circuit”. Charging times are generally between 3 and 5 miles of charge per hour.
Level 2 Charging is provided from a dedicated 30 – 40 amp, 240 volt AC circuit similar to the circuit powering a household clothes dryer. Level 2 systems generally require an electrician to install the circuit and charging equipment in a garage or on the exterior of the house. Charging times are generally between 20 and 25 miles of charge per hour for a 30 amp circuit
Level 3 charging is provided from public charging stations and will vary considerably in terms of charging speeds depending on the kilowatt (kW) capacity of the station. Level 3 charging equipment is commercial quality and generally not installed in residential applications and may not be compatible with all EV’s. Level 3 charging is sometimes known as DC Fast Charging (DFC) or CHAdeMO charging but may require an adapter from the vehicle manufacturer. Additionally, there is the Combined Charging System (CCS) which provides for both AC and DC charging capability from a single plug.
Tesla recently announced and are installing Version 3 Tesla Superchargers with a capacity of 250kW per car and can, under optimal conditions, charge at the maximum rate of 1,000 miles per hour. Tesla reports* a total of 18 Supercharger stations with 124 outlets and 7 additional stations planned.
EV’s other than Tesla’s cannot currently use the Tesla Supercharger stations as the Supercharger will recognize only Tesla’s.
It should also be noted that charging speeds become slower as the battery becomes more fully charged. This is especially true as the battery reached full charge. Fortunately, the rate of charge can be monitored using a phone app.
There is a plug at the end of the charging cable which connects to the car but not all plugs are compatible with all cars. EV’s other than Tesla use a standard connector referred to as a J-Plug or SAE J1772 connector.
Telsa charging cables have plugs that are compatible only with Tesla’s. However, Tesla supplies an adapter allowing their cars to charge at public charging stations with J-Plug connectors.