[JoeGengsta]

the small battery is NOT a practical choice, for instance, lets look at Kirchhoff's law that states
L(dI/dt) +RI + (1/C)Q = E(t) where voltage drop across the resistor is IR, voltage drop across the capacitor is Q/C, and lotage drop across the inductor is LdI/dt, comined you have the relationship of 1 volt * 1 ampere = 1 coulomb/1 farad = 1 henry * 1 ampere/1 second. The comibination of all of this resembeles the electrolytic behavior of your circuity within the car. Now, take something with 1/3 the electrolytic capacity, the small battery would certainly power the car, run the radio, and your sparks for the plugs.. but wait... what would happen if you plugged in something that requires 12 volts and a few amps, or perhaps what do you think would happen if your car didn't have the electrolytic potential to power the cominbation of your highbeams, your factory stereo and what not.. oh i guess intra charge < forced charge which means that your car may not be able to make it home. anyway, electrical physicts and ciruit board engineers created a BIGer battery for a reason, why mess with it? anyway, my name is Joe and i fart a lot.