If they have an in-house battery bank and aren't just using net metering to offset their power usage with their power back-feed during the day when they aren't home. To fully charge a 90kWh battery within a reasonable timeframe with solar panels would require far more than what could fit on your typical house and of course requires you do it while it is sunny, so during the day when you'd be using the car, unless you have a battery that's larger than 90kWh at home that you can use to both feed the house and charge the car when you are actually home. Somehow however, I doubt that's the scenario you were alluding to.
Originally Posted By: JeffKeryk
Many people use solar panels to charge their cars, as well as to power their houses.