The series circuit yields a 24-volt system, but the amperage does not change. 24 volts to the starter and solenoid makes it crank twice as fast as 12 volts. Photo Credit: MARLAN DAVIS ...

Install single-pole toggle switch in dash and connect one pole to the wire from the solenoid. Wire the other switch pole to a 12-volt power source, such as a circuit breaker. 4.