But the 4 terminal (correctly called DPST, or "Double Pole Single Throw") have two large studs to put in the main battery circuit, and two smaller ones. The two smaller ones are normally NOT rated to pull full alternator current, which means if you have a "one wire" you need to use the small terminals to operate a relay or solenoid (continuous duty) which will break the battery AND alternator feed to the ignition, OR use the solenoid to break the charging line
Breaking the charging line MAY indeed generate a spike, but the worst it will kill will be the regulator in the alternator. I look at this as a small expense if it saves your life and keeps the car from burning.
