Another option is to run the big battery charging wire from the alternator to the battery side of the switch so the alternator will charge the battery when the motor is running but it will not supply voltage to the electrical system when the cut off switch is turned off My car is that way, I used a #10 wire from the alternator ran directly to the battery + post connection
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
My car is that way, I used a #10 wire from the alternator ran directly to the battery + post connection 
