-Charge your car at work in the sun and use it to power your home at night. This doesn't make any sense. If you don't need the capacity, why do you wanna carry

-Charge your car at work in the sun and use it to power your home at night. This doesn't make any sense. If you don't need the capacity, why do you wanna carry a ton of battery everywhere with you wasting energy? Buy a smaller battery for the car. Keep another battery installed at home. The battery at home is also more flexible to draw power at the optimal time for the grid. Not to mention that this constant charging and recharging would decrease the lifetime of the battery, causing more environmentally unfriendly waste and inefficiency.