A range extender is a device designed to increase the operational range of electric vehicles or other battery-powered devices. It typically consists of a small internal combustion engine or generator that produces electricity to recharge the battery while the vehicle is in motion. This allows the vehicle to travel further without needing to stop for a lengthy charging session. In the context of electric vehicles, range extenders help alleviate concerns about battery life and charging infrastructure. They provide a backup power source, ensuring that drivers can complete longer trips without the anxiety of running out of charge. Popular examples include the BMW i3 and Chevrolet Volt.