When you buy a BMW i3 electric vehicle, you have the option to include a range-extending gas motor. The REx, as it’s known in car-geek parlance, is a 34-horsepower, two-cylinder engine that provides juice to the battery to boost range from about 80 miles to somewhere around 150. But in certain conditions, engaging the REx can get…hairy, as one lawsuit alleges.
MLG Automotive Law filed a national class-action lawsuit against BMW’s US arm over this REx. “[W]hen the gasoline engine kicks in, it doesn’t produce enough power to prevent a dramatic decrease in the vehicle’s performance,” MLG wrote in a statement.
As our own editor Chris Paukert has experienced firsthand, it takes a special set of circumstances to create this decrease in power. Essentially, when you’ve got a heavy load (such as long uphill stretches or if the car’s filled with passengers), the electric motor can’t produce enough juice to keep the vehicle moving while the REx attempts to charge the battery. Thus, its net output is reduced to produce a net gain on charge, extending the vehicle’s range.
