This has never happened in the world of electric bikes - 380km on a single charge! The Delfast company has made such an erower - a combination of an electric mountain bike and cross, so the bike will work well for long trips on any terrain. However, it would require some modifications - you would need to add something for panniers and you can even go on intercontinental trips. More: https://www.digitaltrends.com/outdoors/long-distance-delfast-ebike/