Aren't people wary about using their very expensive car batteries for the grid?
In short, no. I have a 10 year old Leaf that has been on a V2G trial for the last 3 years. (I also work for the company that built the charger.) The battery is not being deep cycled; it goes between roughly 30% and 90% state of charge. The trial has found no clear evidence that it ages the battery at all. In fact, it appears that this is better for the battery than regularly fully charging it and letting it sit. Calendar age appears to be the biggest cause of battery degradation along with deep discharging and rapid charging (which this isn't doing).
In short, no. I have a 10 year old Leaf that has been on a V2G trial for the last 3 years. (I also work for the company that built the charger.) The battery is not being deep cycled; it goes between roughly 30% and 90% state of charge. The trial has found no clear evidence that it ages the battery at all. In fact, it appears that this is better for the battery than regularly fully charging it and letting it sit. Calendar age appears to be the biggest cause of battery degradation along with deep discharging and rapid charging (which this isn't doing).