The REDARC Smart Start(R) battery isolator used as a solenoid priority system to protect that start battery from excessive discharge while the auxiliary battery is supplying non-essential loads. The Battery Isolator provides 12 Volt DC incorporating 200 Ampere of continuous ratings, the battery isolator is designed for extremely heavy-duty operations. Primarily used in commercial vehicle dual battery systems, it incorporates electronic components that will prevent the solenoid from generating high voltage transients. It is better than a diode battery isolator due to the voltage drop associated with diode type isolation.