What's the cost to charge an electric car at a public station, and why
Every so often an electric car owner discovers a public charging station costing $3 per hour to charge their car. Their reaction isn't always positive because of the fee paid per mile of range received by charging.
The public charging stations fall into three groups. The first group is the stations in one of the two electric car charge station networks in the U.S., the Blink Network run by ECOTality, and the ChargePoint network run by Coulomb Technologies. The second group are the other public charging stations that aren't in one of those networks. The last group are the stations, in California and elsewhere, left over from 10 or so years ago when electric cars were last manufactured by the automakers.
The cost to use each electric car charging station differs based on various conditions. Sometimes the station is owned by a business, and is available for its employees. Sometimes a city will own the charging station making it available for the city employees, the city fleet, or for the public. Sometimes a parking garage owner will install a charging station, making it available for electric car owners parking in the garage. Some of these public charging stations are free, while others cost money with a fee that varies from station to station.
For the stations where users pay to charge their cars, the effective cost per mile is calculated from two factors. First is the cost per hour to use the charging station. Second is the number of miles of range the car gets per hour of charging. The electric cars with a 3.3 kilowatt on-board charger (Nissan Leaf, Chevy Volt and Mitsubishi iMiev) typically get 12 miles of range per hour hour of charging. Hence the stations that cost $3 per hour, costs $0.25 per mile of range. On the other hand the cars with a 6.6 kilowatt on-board charger (Ford Focus Electric and Coda Sedan), if charging at a station that costs $3 per hour, costs $0.12 per mile of range. To compare with gasoline, if a car gets 30 miles per gallon fuel efficiency and gasoline costs $3.50 per gallon, the cost per mile for gasoline is $0.12.