On electric vehicle you can have on-board charger. There's no need to connect the gasoline (or other fuel) unit to the traditional power train (if it exists at

On electric vehicle you can have on-board charger. There's no need to connect the gasoline (or other fuel) unit to the traditional power train (if it exists at all). The charger can run on only one optimal power setting and that's it. Therefore there's no need or reason to run the engine on wide range of engine speed at all. Either the charger is on, or off. That's it. It's only used if the battery is low and extra power is required. And of course it's possible heat emissions can be used for extra heating power.