Hi and thanks for the post.
The Main Battery is 360V DC. It of course can be charged by 110V AC or 240V AC (level 2 charger).
It also powers the 12V DC battery that is used for the traditional accessories like radio and lights, DC to DC converted from 360:12.
The power for driving comes from the Main Battery, the 360V DC is inverted to AC to run the electric drive motor. I've been surprised how quick and responsive the car is for how heavy the batteries make the Focus Electric. It accelerates from the merge lane onto the interstate much quicker than I used to do or could do with my Saturns.
Input for charging the main battery is AC. Solar panels output around 17V DC to charge 12V DC batteries, or a bank of batteries. To charge an electric car using solar panels one would have to have a bank of Deep Cycle 12V batteries to accept the output of the Solar Panels, then run through an inverter to make it AC voltage to plug the charging cable into the Electric Vehicle. This would have to be an inverter rated for quite high amperage, similar to what one would have to use if trying to run a house on stand alone alternative power off the grid.
I won't take time to run the numbers although I could later if you wanted to size the solar panels and all. The reality of solar is that to reach a level anywhere near what the grid offers requires a large number of panels, and even a partial cloud cover greatly reduces if not outright stops all charging. You can do two things with solar panels. As a stand alone system, like a cabin in the woods, you have to dump into a large bank of DC batteries, and invert that back to AC for household appliances (like an Electric Car
). The alternative is to wire the Solar Panels through an inverter and into the local power grid at your meter, if allowed ("grid tie-in"). That way you can allow that you are helping to offset the energy consumed by using alternative sources. It wouldn't be much compared to what the EV uses unless you had a large number of 125 watt panels, for instance.
The EV battery runs through a large amount of electricity per day for an average commute, 8, 10, 15 Kilowatt Hours per day, or more. This cannot be provided by a small collection of solar panels even if you have El Paso sun.
Hope this helps some. I do not know of anyway to charge the Focus Electric directly from a DC source such as solar panels, and I can't speak for the Leaf. At any rate, any small solar panel on the roof or set beside while parked would not provide any sizable amount of charging.