This is an electromechanical device that is connected into vehicle electrical systems where auxiliary components are drawing power from the vehicle batteries, if the LVD senses the battery voltage is getting low it will disconnect the device to preserve the battery so as it still has enough power to start the vehicle engine.

Transfer switches are most commonly found internally in inverter-chargers when the inverter is also connected to AC shore power or auxiliary generators and are designed to seamlessly transfer AC loads passing through the unit to battery power if AC is no longer available. External transfer switches are also available that can be installed in line with inverters to transfer AC loads to battery power.

Battery switches isolate the potentially destructive energy in the battery banks when the boat is not in use or during emergencies, and typically, there is a selection on this manual switch between Battery A, Battery B or both.

Battery isolators are designed for vehicle charging systems with multiple battery banks—each battery bank charges independently through the isolator connected directly to the vehicle alternator. The isolator contains blocking diodes that only allow power to flow from the charging system to the battery; this prevents the batteries from sharing power.

Battery Separators - these devices are used where battery isolators once prevailed. Battery separators are designed to connect one battery pack to another so that both battery packs can be charged while the vehicle charging system is operating, if the separator senses no charge voltage at the main battery it will automatically disconnect the auxiliary battery to prevent on battery from discharging the other.