In a test of the Ford F-150 Lightning truck, AAA found that heavy loads restrict its driving range.

Heavier loads tax electric trucks, making them work  harder, the study found.

When AAA loaded a Lightning with 1,400 pounds of sandbags, 110 pounds short of its maximum capacity, it found that its range fell from 278 miles between charges to 210 miles, a 25% decrease.

AAA pointed out that such a load isn’t typical. “Most buyers will likely use their Lightning with a lighter load, resulting in a much smaller range reduction,” it said, adding that all electric and gas-powered vehicles’ driving ranges are effected by the weight they carry.

It said the Lightning’s unloaded range is significantly less than its gas-powered counterpart, whose range is more than 500 miles per tank.

AAA urged prospective electric truck buyers to think about the driving they’ll typically do so they choose the right model for their needs. Currently, it pointed out, it’s easier to go the gas route than electric.

LEARN MORE: F-150 Lightning MotorTrend's Truck of the Year