[The LED Artist] often found a need for a relatively high voltage (100 to 200 Volt) but low current DC power supply, and it turns out that a small HV generator that uses a single AA cell only took ...

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 ...