A class action suit against BMW was filed in US District Court in Los Angeles on Tuesday. The suit alleges that the i3 REx can suffer a dangerous loss of performance when operating in reduced power mode. As most i3 owners know, the range extender gasoline engine is prevented from turning itself on until the battery state of charge has fallen below 5%.

BMW i3 REx operation

Screenshot of BMW i3 owner’s manual explaining range extender behavior

While it is capable of keeping the vehicle speed constant on level ground, it does not produce enough electricity to power the car normally if it is climbing a hill, has 4 passengers on board, or is bucking a substantial headwind. In a press release, the attorneys for the plaintiff, Edo Tsoar, state BMW failed to inform customers that the car may slow to a maximum of 45 mph suddenly and without warning when operating in reduced power mode.

“The lawsuit centers around the BMW i3 ‘Range Extender’ feature. This option, called REx, outfits the vehicle with a two-cylinder gasoline engine producing 34 horsepower that switches on when the battery charge depletes to five percent, giving the vehicle another 70 miles of range. BMW claims that the Range Extender ‘doubles your electric driving range’ from the vehicle’s standard 81-mile range.”

“The lawsuit alleges that in practice, however, when the gasoline engine kicks in, it doesn’t produce enough power to prevent a dramatic decrease in the vehicle’s performance. As alleged, if the car is under any kind of significant load (such as going up a hill, or loaded with passengers), the speed of the car will dramatically decrease as the battery charge diminishes. The lawsuit alleges that this can result in the car slowing to speeds of 45 miles per hour on the freeway, without warning.”

The problem is one that North American customers who own a BMW i3 REx are familiar with. Many have hacked the software in their cars to make the range extender engine come on before the battery state of charge falls to 5% or less. Instructions for how to hack (aka “code”) the car’s software can be found easily online.

“The lawsuit seeks to have the vehicles redesigned and repaired at BMW’s expense, and to halt the sale of all i3 vehicles until repairs can be made. The claim also seeks compensation for all the owners of the vehicles, who were not told of the serious safety defect.”

What the lawsuit doesn’t say is that the restrictions placed on the i3 REx were demanded by the EPA and CARB in order to certify the car as eligible for zero-emissions treatment under state and federal regulations. In all other markets, the range extender engine is set up to be activated much sooner. Perhaps the attorneys should be suing the EPA and CARB for insisting on stupid regulations that end up putting members of the public at risk.

Source: Inside EVs