Battery Charger, when used in the standby application is not a standalone dedicated Battery Charger. Here battery charger along with a floating battery provides an uninterrupted DC power supply to a critical load. This is Float-cum-boost battery charger or FCBC that feeds the critical load without any break and also charges the discharged battery. Though FCBC denotes “Float-cum-Boost” which clearly means single rectifier/converter for AC to DC conversion, for higher capacity or higher load “Float-and-Boost” charger is used which has two rectifiers, one for feeding load and another for charging the battery, etc. just contact us for more information 8368018797