# Are there any electric car designs that use a generator engine to charge the battery? **URL:** \ **Category:** Factual Questions\ **Created:** [January 4, 2022, 6:59pm UTC](https://boards.straightdope.com/t/are-there-any-electric-car-designs-that-use-a-generator-engine-to-charge-the-battery/957213 "2022-01-04T18:59:54Z")\ **Posts on this page:** 1\ **Showing post:** 12
**Author:** ![Heracles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/heracles/32/487_2.png) [@Heracles](https://boards.straightdope.com/u/Heracles)\ **Post date:** [January 4, 2022, 7:30pm UTC](https://boards.straightdope.com/t/are-there-any-electric-car-designs-that-use-a-generator-engine-to-charge-the-battery/957213/12 "2022-01-04T19:30:19Z")
The BMW i3 REX was exactly as the OP described: a pure electric drivetrain with a small gasoline-powered generator that kicked in to generate electricity once the battery was near empty. As I understand it, the generator was based on a BMW motorcycle engine. This was not quite sufficient to keep the vehicle moving at highway speeds, uphill, with a full load, once the battery was empty; and when it couldn’t keep up, the car slowed to a crawl very suddenly. There were lawsuits. See [previous thread on this subject](https://boards.straightdope.com/t/series-hybrids-they-make-paper-sense-why-arent-they-more-common/787808) (2017). ETA: In general, at stable highway speeds, it makes more sense energy-wise for the gasoline engine / generator to drive the wheels directly (like a Chevy Volt). But this doesn’t scale well to a larger car, and people in North America want trucks, so GM stopped offering the Volt. It’s a pity, because a concept like the Volt is exactly what’s needed to fight range anxiety. --- _[View the full topic](https://boards.straightdope.com/t/are-there-any-electric-car-designs-that-use-a-generator-engine-to-charge-the-battery/957213)._