A 12 volt system is not the point. The old generators don't produce the current of your 100 amp alternator. Put 100 amps through your 30 amp meter and most likely you will send it to the old car grave yard.
The ohm's law formula of P(watts)=I(current) X E(volts) where for a constant P and you double E (6 to 12) then I will be cut in half. It doesn't work in this case. Boy, my head is starting to hurt.
Also, sending 100 amps through a wire which should carry no more than 30 and you will let the smoke out if you don't burn your ride up.
