1. When the engine is running and the charging source raises the voltage of the start battery to 13.4 volts* (cut in threshold), the True Smart Battery Isolator (SBI) engages and connects the two batteries to charge simultaneously. The SBI's internal LED will glow blue.
2. When all voltage sources drops below 12.9 volts* (cut out threshold) the SBI will disengage and the blue LED will go out.
3. When the SBI LED is out the batteries are separated thus preventing the power of your start battery from being drained by use of the accessories powered from the second battery.
4. When the vehicle is restarted and the start battery has recharged to 13.4 volts* the SBI engages, the LED will illuminate and the second battery is connected to receive charging.
*The True SBI is programmed with a 10 second delay before engaging or disengaging.
1. 12V,140A 2. Designed for multiple battery systems 3. Suitable for all types of 12V charging systems 4. Works will all types of batteries 5. Provides ignition surge protection 6. Unique design provides simple installation
True part number
Cut in voltage
Cut out voltage
On: Isolator engaged Off: Isolator disengaged Dimensions 2.7(L) x 2.7(W) x 1.95(H) inches