The Nissan Leaf once again outsold General Motors’ Chevy Volt in July after GM slowed production of its electric car last month, giving Nissan a nearly 2,000-car edge in total sales.

Nissan sold 931 all-electric battery-powered Leafs in July, bringing the total number of electric cars the company has sold to 4,806. General Motors only sold 125 Volts after shutting down its Detroit-based plant to retool it, bringing its total vehicles shipped to 2,870. General Motors expects to sell around 16,000 Volts by the end of the year now that the plant has re-opened.

The Volt is an extended-range electric car that recharges its battery with a gas-powered engine. The car can run around 35 miles off battery power before the internal combustion engine kicks in, giving the car a total range north of 300 miles on a full charge and full tank of gas. That means consumers don’t have to radically change their driving behaviors, which will give extended-range electric vehicles the edge in sales in a few years, Pike research analyst John Gartner told VentureBeat.

“We expect that the Leaf is likely to maintain the lead in sales in North America at least through 2012,” said Gartner, who added that he expects the Volt and other pure-hybrid and extended-range vehicles to start selling better than battery-powered vehicles in 2013.

Most electric car buyers are more concerned about how long it takes to charge the car and how far it is able to drive than the actual price of the electric car, according to a report by Accenture. Pure plug-in electric cars are typically limited in how far they will go on a charge. They can also take a long time to recharge.

The Leaf is a pure plug-in electric car that can travel around 100 miles on battery power before it needs to recharge. Nissan has taken the lead in the small but fiercely competitive low-end electric car market. Nissan has now sold 3,875 Leafs compared to GM’s 2,745 Volts sold in the first half of the year. The Volt’s sales likely didn’t grow as quickly as the Leaf because GM said it was pulling back on its Volt supply to issue more demonstration cars to dealerships.

While the cars operate in very different ways, they’re both designed to attract mainstream car buyers looking for a more environmentally friendly option or a way to save money on gas. The Volt has an equivalent fuel efficiency rating of 93 miles per gallon while it is running on pure electric power, and the Leaf has an equivalent fuel efficiency rating of 99 miles per gallon.

General Motors recently slashed the price of the Volt to around $40,000 to make it more competitive with the Nissan Leaf. The 2011 Nissan Leaf sells for $32,780, while the 2011 Chevy Volt cost around $41,000 prior to the price cut. Electric car buyers can apply for a federal tax credit that can bring the price down by $7,500.

Nissan recently went on the offensive by taking a shot at the Volt in a television advertisement. Sales of both electric cars were neck-and-neck for several months and only differed by around 17 cars shipped at the end of May.