2014 BMW i3 REx 38-HP Range Extender Vs. 14,000-Foot Mountain: Who Wins?

Steep climbs are the enemy of electric car drivers.

While modern electric vehicles are more than capable of powering up a hill, with ample torque, the effect on a car with limited range can be significant.

It's less of a problem with a range-extended electric vehicle like the 2014 BMW i3 REx, but a trip to the 14,130-foot summit of Mt. Evans in Colorado is still a tough task.

i3 owner Don Parsons has completed just such a trip, writing about it for Tom Moloughney's BMW i3 blog.

A few weeks earlier, Parsons had completed a trip over the Loveland Pass, cresting the continental divide at 11,990 feet. On that 128-mile trip, the car managed the distance on a couple of charges and just two miles of range-extending assistance before reaching home.

Mt. Evans is tougher. As Parsons writes, the trip from his house in Denver, at 5,280 ft above sea level, involves over 12,400 ft of ascents and nearly 3,700 ft of decents.

MORE: 2014 BMW i3 REx: Range-Extended Electric Car Drive Report, By Very First Owner

Around 52 miles into the trip, the range-extender kicked in--helping ensure the i3 had enough charge in its battery to power the electric motor up the mountain.

Don notes how the engine was audible, speeding up and slowing down depending on whether he accelerated out of switchbacks or braked into them.