General Motors says the ’13 Chevrolet Volt extended-range electric vehicle now will travel three miles (4.8 km) farther in EV mode, admitting the improvement represents an “incremental” gain but one its enthusiasts clamored for the most.

“The No.1 thing our customers have been telling us is more is better in this particular case,” says Andrew Farah, chief engineer of the Volt.

“It is incremental,” he tells WardsAuto during a conference call today to discuss changes to the Volt for ’13. “But it’s still in the right direction.”

The ’13 Volt will drive an average 38 miles (61.2 km) on a single charge, whereas the current model travels 35 miles (56.3 km).

Three more miles makes for a particularly significant improvement among commuters traveling less than 40 miles (64.4 km) per day, the target customer for the Volt, Farah says.

“It will enable another number of people to go gasoline-free in their daily driving,” he says, adding the increased range still may not make the Volt a sensible choice for those traveling long distances each day.

“(The gain) will show up for those people who regularly deplete their battery. It’s an extra three miles every day, and that adds up over a week.”

The Volt also improves its miles-per-gallon equivalent, moving to 98 MPGe from 94 MPGe.

GM’s announcement comes on the heels of news the all-electric Honda Fit will achieve 118 MPGe, the best in the industry, according to the Environmental Protection Agency.

However, the ’13 Volt beats the 87 MPGe of arguably its principle competitor, the ’12 Toyota Prius plug-in EV that launched in March.

“I always like it when our number is bigger” compared with Toyota’s, Farah says.

Three other fully electric cars, in addition to the Fit, rank ahead of the Volt and Prius PHEV in terms of MPGe.

The EPA rates the newly launched Mitsubishi i at 112 MPGe for its 62 miles (3.8 L/100 km) of all-electric range, second best in the industry.

The Ford Focus EV, also newly launched, achieves 105 MPGe with an all-electric range of 76 miles (3.1 L/100 km), followed by the Nissan Leaf at 99 MPGe from its 73 miles (3.2 L/100 km) of all-electric range.

Unlike those full EVs, the Volt features a small internal-combustion engine that acts as a generator to provide electricity after the battery becomes depleted, giving drivers a full range of up to 382 miles (615 km) before they need to recharge or fill up with more gasoline.

The Volt’s battery capacity for ’13 increases to 16.5 kWh from 16.0 kWh, and GM engineers expand the usable charge to 10.8 kWh from 10.3 kWh. Reducing some of the battery’s “buffer” zone, which is necessary to maintain performance in extended-range mode, helps increase the useable charge.

Bill Wallace, battery systems director for the Volt, tells WardsAuto GM determined its battery chemistry was not as sensitive as the auto maker first thought, giving engineers the opportunity to withhold less electricity.

He does not say how much more of the buffer GM might consider releasing in the future to improve the Volt’s EV range even further. “We are always looking at ways to wring out as much (electricity) as possible.”

However, the extra range comes at a price, as the Volt’s industry-leading recharging time grows to 10.5 hours using a standard 120V outlet from eight hours previously. Use a 240V outlet most EV makers recommend, and the charge for a ’13 Volt is 4.25 hours, up from four hours previously.

Total range for the Volt remains roughly 380 miles (611.5 km), because the EPA wants the number rounded to the tenths, GM says.

Other new items for ’13 include a “Hold” mode, allowing a Volt owner to switch on the ICE range-extender at the push of a button.

“We think it will make people happy, being able to control their EV miles,” Farah says.

A Volt driver, for example, might want to save some EV range for when traveling in cities, rather than on the highway, because stop-and-go traffic consumes the most fuel.

The ’13 model also adds a “Power Gauge” to its information center, which shows how much energy is being consumed to move the Volt down the road and the ratio of power output between the battery and the ICE when the vehicle is operating in extended-range mode.

New colors, forward-collision warning, sport alloy wheels and a center armrest for the rear passengers also mark standard and optional equipment new for ’13.

The Volt’s base price for ’13 stays unchanged at $39,995 before available consumer tax credits.

The market remains lukewarm to the 4-passenger Volt. In 2011, the car’s first full sales year, it sold 7,671 units and fell short of GM’s goal of 10,000 deliveries.

A federal safety inspection last year crimped sales in early 2012 and compelled GM to idle the Volt’s assembly plant for three weeks before the government declared the vehicle safe. In March, the Volt sold a monthly record 2,289 units, and in May it posted its second-best performance with 1,680 deliveries, according to WardsAuto data.

GM says demand for the car has risen now that technical tweaks make the Volt eligible for high-occupancy vehicle lane use in California, where drivers can travel alone during rush hour and save time on their commutes.

However, Volt inventories remain relatively high at 5,759 units, or an 89-days’ supply to close May, WardsAuto data shows. The industry typically likes inventories of a particular car or truck at about 60 days’.

jamend@wardsauto.com