On average, it's like 800W. My current home charger and cars support up to 7.7 kW. It's something like 4 hours to go from near empty to full for one, and about twice that for the other one (very different sized batteries). But what that really means is that the charger will click on for a relatively short time, then sit idle for the rest of the day. It's likely that most home chargers won't exceed 40A for a while, as past that needs hard wiring. Though I suspect V2H capable chargers will all be hard wired.