A system for automation of measurement of backup batteries capacity in the telecommunication power station, comprising a control device (TBA-BN), where the system positive bus (+) is directly connected to positive terminals of the rectifying units, loads and batteries, and the system negative bus (-) is directly connected to negative terminals of rectifying units and loads, and where first input (-B) of the control device (TBA-BN) is connected to first terminal (b) of the battery, second input (-S) of the control device (TBA-BN) is connected to second terminal (s) of the rectifying units, and third input of the control device (TBA-BN) is connected to the system positive bus (+), and where the control device (TBA-BN) connects negative pole (-) of each of the batteries (B1-Bn) to negative bus (-) of the set of the rectifying units (PR1-PR2), and comprises a control system, characterized in that the control system is configured to control four electronic connectors (T1-T4) directly and individually through four dedicated I/O connections coupling the control system to each of said four electronic connectors (T1-T4) directly and individually, and where the control device (TBA-BN) comprises an additive-subtractive converter (DC/DC), separate from said four electronic connectors (T1-T4), to effect in normal mode of operation a connection of the batteries (B1-Bn) to negative bus of a set of rectifying units (PR1-PR2) through an electronic contactor, and in a capacity measuring mode of operation to effect a constant current charge/discharge of the batteries (B1-Bn), wherein connection of negative pole (-) of each of the batteries (B1-Bn) to negative bus (-) of the set of rectifying units (PR1-PR2) is realized through the circuit comprising the terminal (b), first input (-B) of the control device (TBA-BN), the electronic contactor and second input (-S) of the control device (TBA-BN), and where the electronic contactor comprises a series of two electronic connectors controlled by the control system, first electronic connector having first diode in parallel, and second electronic connector having second diode in parallel, and both electronic connectors first and second are connected serially by the respective other diode's cathode, and where first input (-B) of the control device (TBA-BN) is also connected through third resistor connected in parallel to third electronic connector, and further connected to negative terminal of first capacitor and first input of a bidirectional additive-subtractive converter (DC/DC), whereas second input of the bidirectional additive-subtractive converter (DC/DC) is connected to negative terminal of second capacitor and fourth electronic connector, connected in parallel to fourth resistor connected to second input (-S) of the control device (TBA-BN), and where third input of the control device (TBA-BN) is internally connected to third input of the bidirectional additive-subtractive converter (DC/DC), to positive terminal of first capacitor and to positive terminal of second capacitor, and where the circuit comprising the electronic contactor is connected in parallel to the circuit comprising third electronic connector connected in parallel to third resistor, the bidirectional additive-subtractive converter (DC/DC), and fourth electronic connector, connected in parallel to fourth resistor.