Jaylec - Sensitive Relay 140 Amps 12 Volts In 13.3 Volts Out 12.8 VoltsJaylec Voltage Sense Relay 12 Volt 140amp. Cut in at 13. 7 Volt and Cut out at 12. 8 Volt. Module for simultaneous dual battery charging (start and auxiliary). Allows charging of the starting battery until the preset voltage is reached. Engages when the engine is started and the start battery reaches 13. 7 Volts. It then disengages when the voltage drops below 12. 8 Volts. Eliminates the possibility of draining the start battery. Protects electronic