Auto Isolator I

Product Code: 091-139-2-12


  • System consists of a controller that detects when a vehicle's alternator is charging the main battery and then closes a solenoid to tie-in charge to an auxiliary battery
  • When the engine is stopped or charge voltage is no longer present, the solenoid opens to isolate the batteries
  • Uses a solenoid rather than an isolation diode which typically causes a 0.7 volt drop, thus auxiliary battery receives full charge voltage installation
  • 3 year warranty
Warranty 3 years
Weight 3 lbs
Output Current 3 Amps Max
Battery Load 000125 Amps
Volts to Parallel 13.0 Vdc, Field Adjustable

Volts: 12 Vdc

Coil Current: .45 Amps

Contact Rating: 200 Amps Continuous, 600 Amps Surge

Weight: 2 lbs

Warranty: 3 Years

The Auto Isolator I detects when a vehicles alternator is charging the battery and then closes a solenoid operated switch to additionally charge an auxiliary battery. When the engine is stopped, the solenoid opens to isolate the batteries. Upon "cranking" the engine with a charged auxiliary battery, the solenoid is energized to parallel the batteries and provide a starting boost. If the auxiliary battery is low, the batteries are not paralleled.

Since the auxiliary battery is charged through a solenoid-operated switch rather than an isolation diode, the auxiliary battery is fully charged. The .7 volt diode drop is eliminated, as is the power dissipation in the diode. The system therefore is more efficient. The starting boost provided by the parallel batteries is especially useful in cold weather, or when the main battery is low.