Use a MOSFET as a switch that turns the load on/off. Use an opamp/comparator to detect the battery voltage. When battery voltage ≧ 7V, the opamp/comparator keeps the MOSFET on and load is run from battery. When battery voltage falls below 7V, opamp/comparator shuts off the MOSFET to shut off the load. Add some hysteresis so that the load isn't turned on until battery voltage reaches (for example) 8V.
Use an op amp as a comparator. In the inverting input make a reference voltage of 7V and on the non inverting input feed in the voltage of the battery so that when the battery fall below 7V the output of the op amp will be zero. Then you can use a transistor to switch ON and OFF a relay which can knock OFF th circuit as desired.
Use a MOSFET as a switch that turns the load on/off. Use an opamp/comparator to detect the battery voltage. When battery voltage ≧ 7V, the opamp/comparator keeps the MOSFET on and load is run from battery. When battery voltage falls below 7V, opamp/comparator shuts off the MOSFET to shut off the load. Add some hysteresis so that the load isn't turned on until battery voltage reaches (for example) 8V.
Please mention your battery type. If your battery is leadacid battery means it doesn't fall below 10.5 volts.for every low voltage below 10.5V it reduces the battery life.
Please mention your battery type. If your battery is leadacid battery means it doesn't fall below 10.5 volts.for every low voltage below 10.5V it reduces the battery life.