In addition to the standard Power Supplies that are used for CCTV, Access Control and DVR, these 12VDC Battery Charger models have additional feature of charging the battery. These “Battery back – up Power Supplies” are used for CCTV and Access Control Systems. These are also popularly called as “Battery Back – Up Power Supplies for CCTV” OR “Battery Back – Up Power Supplies” for Access Control System”. These are also popularly known as “SMPS with Battery Charging option” OR simply “Battery Charger Power Supply”. So even in case of A/C failure recording from CCTV or storage from DVR will continue without any loss of data. In simple words it works like UPS or inverter for CCTV or Access.