As the first mass-produced electric vehicles come closer to launch, consumers are beginning to get a better view of the range they can expect from their new cars.
This week, Nissan released details of expected ranges in various conditions which it has developed using a series of computer simulations.
The Leaf, which is officially quoted as having a 100-mile (161 km) range, can manage up to 138 miles (222 km) in ideal driving conditions according to Nissan, which means an ideal outdoor temperature - so no climate control, a flat road and a constant speed of 38 mph (61 km/h).
In the city, driving at an average of 24 mph (39 km/h) on a nice day with no climate control, the Leaf will manage 105 miles (167 km), but take it onto the highway at 55 mph (88 km/h) in the summer (and so using climate control), the range drops to 70 miles (113 km).
In the height of winter, with an external temperature of -10ºC and an urban traffic jam reducing speeds to an average of 15 mph (24 km/h), the Leaf will only squeeze 62 miles (100 km) out of its battery (which is assumed new for all of the above figures).
Although Nissan's estimations are laboratory-only, they are broadly in-line with what has been expected for electric cars and has always been the case for conventional cars - when driven economically, they'll go further.
GM was forced to clarify its position on the Volt in late September, admitting that its likely all-electric range was anywhere between 25 and 50 miles (40 - 80 km); a recent test from a panel of journalists gave a slightly more positive outcome.
A total of 24 teams of reporters on GM's media trip took part in a competition to drive the most efficiently, with the average electric range coming out at 50.2 miles (81 km) despite traffic conditions which weren't ideal and teams consisting of several people - suggesting that the Volt can perform better than was originally expected.