A mobile emergency charging device for a battery of a motor vehicle that is designed to charge the battery in a recuperation operation. The mobile emergency charging device has at least one fuel tank, an internal combustion engine, and at least one drive roller for driving a wheel of the motor vehicle. This at least one drive roller is connected at least indirectly to an output shaft of the internal combustion engine and, by way of this connection, the drive roller is set into a rotational movement when the internal combustion engine is running.