Charging and Infrastructure 101

The City is in the process of installing a comprehensive network of nearly 100 EV chargers throughout the City as part of a region-wide push to accommodate the increasing number of electric vehicles on the road in the Bay Area.  To make public charging even more appealing, Mayor Edwin M. Lee signed an Executive Directive in May 2011 pledging that charging stations owned by the City would be free until 2013. 

While a comprehensive, publicly accessibly charging network is critical to support EV drivers, it is expected that most charging will take place at the home and at the workplace.  If you are considering installing a charger at either location, you will need to consider which type of charging is appropriate for you.

All EVs sold in the U.S. use the same type of charging connectors, or “plugs”, governed by a uniform industry standard, the Society of Automotive Engineers’ SAE J-1772. The SAE J-1772 standard covers two “levels” of charging:

  • Level 1 Charging, at 110V, utilizes a standard wall outlet, and does not require the installation of any special charging equipment.
  • This type of charging, which is quite slow,  is most appropriate in cases where the vehicle has a smaller battery or the driver has a fairly short daily commute that allows for sufficient charging during the time available at the charger.  Depending on battery size, times for a full charge can range from 11 hours for a Chevy Volt (with a 16 kWh battery) to about 17 hours for a Nissan Leaf (with a 24 kWh battery).
  • Level 2 Charging, at 240V, is the same type of circuit used for large appliances such as clothes dryers but with a different type of plug. This type of charging requires an EVSE (electric vehicle supply equipment), more commonly referred to as a “charger” or “charging station”, which generally must be permitted and installed by an electrician. Charging times are much faster than for Level 1, and can range from 5 hours for a Chevy Volt to 7.25 hours for a Nissan Leaf.

An additional type of charging not yet covered by an SAE standard - Level 3/DC Fast Charging - utilizes 480V and can fully charge a vehicle in about half an hour.  Although an SAE standard is nearing completion, this high-voltage charging is not likely to be considered practical for residential use, except perhaps by some of the largest multifamily buildings. It will be used primarily in commercial locations.

There are a number of companies making charging stations, Level 1, 2 and 3.  Find a charger that meets your needs here. To learn about charger incentive available in the Bay Area, visit the Bay Area Air Quality Management District’s PEV Ready page.