Although less of an issue than I thought there are driving conditions where it cannot maintain speed due to lack of power, it was a big enough issue for class a

Although less of an issue than I thought there are driving conditions where it cannot maintain speed due to lack of power, it was a big enough issue for class action lawsuit to be filed over it dropping to 45mph on the highway: https://www.greencarreports.com/news/1105823_bmw-i3-rex-range-extender-owner-assesses-pros-and-cons-of-limited-power-engine https://www.greencarreports.com/news/1105823_bmw-i3-rex-rang... And again my main point was on efficiency, I would hope you agree 31mpg combined is extremely poor for a 34hp engine when much larger engines get much better mileage and have no issues with providing power when needed without battery assistance. It doesn't need much hp to maintain highway speed (probably around 34hp on flat ground) which means the engine is running full throttle to do so, vs running in it most efficient range which is not where it puts out peak power. The e-power Nissan has a full size engine, but a small battery, although would be interesting to compare it drivetrains weight with a standard one, having both a electric motor and generator of equal size is typically much heavier than a transmission.