Propulsion+Convenience Battery

The EV should have 2 batteries. One large 100 mile battery for everything involved in the propulsion of the car, and another smaller battery for convenience features like air conditioning/stereo/power windows, heated seats, etc.

This way the miles/range per charge are not impacted by convenience accessory usage.

Regenerative breaking and the panoramic roof solar panel would charge both with priority toward which batter is more critical at the moment.

So turning on the air conditioner/heater, heated seats, blasting the stereo would not impact the driving range. And when the convenience battery got low, the driver would be given the option to switch to a more eco mode for air conditioning, turn it off, turn off heated seats, or even choose to pull energy from the propulsion battery for convenience accessories. But driving range is not impacted, unless the driver makes it so. And at the same time, the convenience battery is available as a backup for the primary propulsion battery.

This way the driver can be more confident that he will make it to their destination, based on the charge/range available when he started. With no surprises based on his actions not directly related propulsion.