A buffer PSU intended for uninterrupted supply to devices that require stabilized voltage of 12V DC (+/- 15%). The PSU provides voltage of U=13,8V DC with output current of I=3A + 0,5A for battery charging. In case of power decay, a battery back-up is activated immediately. The PSU is constructed based on the switch mode PSU, with high energy efficiency. The PSU is housed in a metal enclosure (colour RAL 9003) which can accommodate a 17Ah/12V battery. Amicro switch indicates door opening (front cover). Power supply: 176÷264VAC. Power supply output: 3A/13,8VDC. Battery charging current: 0,5A. Fitting battery:17Ah/12V. Efficiency: 76%. Protections: SCP, OVP, OLP, UVP, tamper (opening of the enclosure). Technical outputs OC and relay type: EPS - AC network failure, LoB - low battery voltage, PSU - power supply failure. Dimensions: W=280, H=292, D+D1=82+8 [+/- 2mm]. Surface mounted enclosure, locking – bolted (lock assembly possible).