From the get go, General Motors insisted that the Chevrolet Volt would use half of its battery capacity – about eight kilowatt hours – to deliver an all-electric range of 40 miles. Well, that 40 miles of range has changed to an ballpark estimate of 25-50 miles, so it shouldn't comes as a surprise to find out that the 8 kWh claim was an early guesstimate as well. Lyle Dennis, founder of GM-Volt and a member of the Volt Consumer Advisory Board, recently posted that vehicle line director Tony Posawatz revealed Chevy's breakthrough vehicle will consume "a little bit more" than 8 kWh to reach the electric range marks set by The General.
Posawatz stopped short of revealing how much "a little bit more" actually means, but another GM exec provided additional details. GM's director of global energy systems and infrastructure commercialization, Britta Gross, told Advisory Board members that up to 10 kWh of grid energy may be needed to recharge an empty Volt. Gross explained that some energy would be used to condition the battery and it's also assumed that some of the juice will be lost due to charging inefficiencies, but we'd expect the Volt to eat up somewhere in the neighborhood of 8.5 to 9 kWh to charge from a fully depleted state. Admittedly, revealing that the Volt digs deeper into its battery capacity than first thought is not as shocking as the adjusted electric range numbers or yesterday's brouhaha, but it's still surprising that The General withheld this info until recently.