All of the above, Jerry. The problem is that everything in your car is designed to run on 6 volts. Running 8 volts through 6-volt components will put some stress on them and might shorten their lives ...

Above is a video diary of my second full day with the Volt, commuting to work here in frigid Chicago. On my first commute home a day before this video was shot, the temperature was in the high 20s, ...