this is the Smart Version of the Victron Battery Protect. Programming is made easier using a Bluetooth link to your phone or tablet. This also allows incremental voltage values to be entered so you are not confined to the standard values. The Bluetooth can be disabled once the values are set if desired. This can be used as a stand alone device or as part of a control system for a Lithium Ion battery bank. The Victron Battery protect is a solid state relay and is used to disconnect the load from a battery when it is becoming over discharged. It is controlled internally by programmable parameters for low and high voltage or when used with Lithium Ion batteries it is controlled remotely by the the VE Bus Battery Management System