After several lackluster years, Nissan North America has sold more of its electric cars in six months than it did all of last year. More than 9,800 LEAFs were sold and it allows Nissan to stop charging so much for the battery-powered cars. A car that has no extras, like navigation, is now offered for a $199 a month lease. Company officials say moving production of the vehicles from Japan to the Smyrna plant also saved some money on shipping costs and unfavorable exchange rates. The batteries for the LEAF are produced at Nissan’s Decherd plant.