IGH Thanks for the reply.

1. I have no daily commute.
2. My average drive is 10 miles.
3. I Live in Scottsdale Az and almost always I drive out on EV and the ICE never runs until I need a battery charge.
4. Based upon the forgoing I expect a 10% improvement or about 3+ MPG. My goal is modest and is to average 40mpg around town.
5. I do things in steps so as to make them easier and of shorter duration.
6. I will add battery capacity later after this is working well.
7. I will add battery capacity in a "baby step" by adding a single NAH battery pack so as to allow the currrent electronics to manage the system. Adding a different type (say lead acid) or an unbalance pack capacity would require a lot of electronic changes to both the onboard controller and the charger.
8. Doing a "big deal" at once and in the beginning invites an increased chance of failure IMHO.
9. A major reason for making these changes is for the enjoyment of the experience, so I want things to be as easy as possible and have educational value. When Nissan comes out with their own design Hybrid in 2010 with LI-Po batteries all this will, IMO, already be done.

So wish me luck in this first step. I am trying to identify the appropiate charger at this time. PS I am still on the first 1/2 of the first tank of gas.