[sschueller]

Why do you need a cable? We are thinking in the realm of pumping fuel. Instead you could use a rail under the car or many other methods.

[londons_explore]

How many amps, how many volts, what will the rail be made from, how big will the pickup 'shoes' be?

[sschueller]

You can also "cheat" a bit by splitting the battery like some cellphones do now. Instead of charging one giant battery you are charging two smaller ones at the same time.

[outer_web]

You're all hired.