2011 Chevrolet Volt plugged into Coulomb Technologies 240V wall charging unitEnlarge Photo
Just how do electric car owners use their cars? It's the question everyone is trying to answer, as it could shape how electric cars of the future are developed.
Virtually every manufacturer with an electric car runs its own field trials or keeps data on its users' driving habits, but the EV Project aggregates data from different makes and models, and thousands of owners, who use the charging stations that are monitored by the program.
Most recently, the EV Project has revealed its fourth quarter 2012 results, and with over 60 million miles logged it's building an increasingly thorough picture to help answer that question.
Most of the survey's data concentrates on Chevrolet Volts and Nissan Leafs--as the two most prolific electric vehicles on sale. However, Smart Electric Drive models also feature.
Volt versus Leaf
It's comparison between the Volt and Leaf that proves most interesting, though.
The data fluctuates from quarter to quarter, but by the end of 2012, Volt owners charged more at home than their Leaf counterparts, at 81 to 76 percent respectively. Overall, the Project suggests that around 80 percent of charging is done at home.
At the same time, Volt drivers also charge more frequently--an average of 1.4 times per day compared to 1.1 per day for the Leaf.
This is interesting, not for its frequency (perhaps obvious given the Volt's shorter electric range), but the fact that Volt drivers must consciously be charging so they can drive using the car's electric power alone--rather than doing any extra distance on the gasoline range-extender.
At around 40 miles, Volt drivers actually travel around ten miles further than Leaf drivers per day, though drivers of each tend to recharge after a similar number of miles, on average--around 30 miles. This again suggests that Volt drivers really are making the most of the car's electric range, backed up by previous data showing around two thirds of all Volt miles are on electricity.
How important is public charging?
With all that home charging, just how widely-utilized is public charging?
That depends on where you are. For 240-volt Level 2 charging stations, there's significant variety between charging time and number of charging events per day. Notable immediately is that on average, stations are used less than once per day, and most for only a few hours at a time.
Some cities break the trend, however. Chargers in Oregon are used for 9 hours per day on average, but also only around once every five days. San Diego and San Francisco's chargers are used much more frequently, around 0.6 times per day, and for shorter periods.
The EV Project notes that San Diego's high figure is influenced by a car-sharing project there, car2go. Over half of all charging events at level 2 chargers are from the city's fleet of Smart Electric Drives.
Other notable numbers
So what else has come from the Project so far? Plenty, it seems. You can read all the data in the Project's fourth-quarter 2012 report (an enormous pdf file) and read other quarterly reports from the full list--but certain numbers stand out.
Among these are the 1.6 million charging events recorded to date, and the 1.9 million gallons of gasoline avoided by EV Project vehicles, instead using over 14,100 megawatt-hours of electricity.
By the end of 2012, the Project had also seen nearly 6,700 residential level 2 chargers installed, over 2,500 commercial chargers, and 56 DC fast chargers.
We expect all those numbers have climbed further over the first few months of 2013, and look forward to the next report.
With every passing month, we're learning more about how thousands of real-world electric car users drive their vehicles--and it'll directly influence the ones we'll be buying in the future.