Various agencies in the United Kingdom are running eight long-term studies on electric vehicle usage and owner behavior. One group, known as CABLED, has released some preliminary data for the Coventry and Birmingham area in the English Midlands.
For background, remember that all of England is roughly the size of the U.S. state of Louisiana, and the Birmingham-Coventry region has about 5.3 million population. Birmingham itself is a fairly large city, perhaps the size of Dallas or San Jose. The study fully acknowledged that the cars in question are designed for urban and suburban commuter and run-about use. They did not expect to find any long distance use of the vehicles.
In this case, the vehicles were 25 Mitsubishi i-Mievs and 20 Smart ForTwo electric drives in the hands of private citizens. The vehicles covered nearly 150,000 miles in the first 12 months of the survey. Most of the data is mundane; the average trip lasted less than 20 minutes and the car was at rest more than 23 hours per day. 98 percent of the trips used less than 50 percent of the battery capacity, meaning that a return trip could be made without recharging.
They did find however that users treated the cars as they do cell phones and laptops, plugging them in at any opportunity even when charging wasn’t necessary. Monitors showed the cars often being connected with more than 80 percent battery charge remaining. Peak charging times were seen at 7-9 a.m., 6-7 p.m., and after 11pm to take advantage of off-peak electrical rates.
The average “on-charge” time was between two and three hours which typically restored the car to at least the 50 percent charge point. However, since the UK standard voltage is about double that of the U.S (220 vs. 110 VAC), their standard connection is what we would call “Level 2” charging.
Researchers did note a drop in the frequency of plugging-in as users became more confident of the car’s capacity and began to lose their “range anxiety.” The initial report noted that this data could affect the number and placement of public charging facilities. This study will continue for at least another year and organizers anticipate adding 25 more cars to the program.