Quote Originally Posted by Mike Henderson View Post
It actually makes sense that the battery would not be recharged by the engine. You want to store cheap power in the battery, which you get from the electric power grid. If you used the engine to charge the battery, you would lose the "space" to put the power from the grid, and you'd use more expensive gas power to charge the battery and produce more pollution. On the Volt, if you don't have any power in the battery, the engine/generator provides motive power so you are never without motive power unless you run out of gas. When you get home, plug in and load up with cheap power.

Mike
Point well taken. I had not thought of it in those terms. Since my post above replying to Jim, I did a little re-reading and found the following:
"The drivetrain permits the Volt to operate as a pure battery electric vehicle until its battery capacity has been depleted to a defined level, at which time it commences to operate as a series hybrid design where the gasoline engine drives the generator, which keeps the battery at minimum level charge and provides power to the electric motors. The full charge of the battery is replenished only by loading it on the electrical grid."
Minimum level is normally 30% or 45% in mountain mode. So, Jim is between 30% and 45% correct .