FIELD: electrical engineering. SUBSTANCE: type of external power supply is to be determined to change charging process of internal battery considering type of power supply and data on battery. External intermediate power supply is used to feed battery-powered facility as well as to provide battery with charging current controlled by internal battery charger. Microcontroller incorporated in facility controls battery charging current. Preferable type of controller is that incorporating analog-to- digital converter connected to step-up resistor which is internal relative to facility and to step-down resistor inside external intermediate power supply. Voltage built up by resistive divider circuit that has step-up resistor and step-down one is used to determine type of external intermediate power supply. Varying value of step-down resistor in external power supply to determine type of the latter enables microcontroller to determine optimal rate of charge for battery basing on type of charger and battery characteristics. EFFECT: improved reliability. 8 cl, 4 dwg, 2 tbl
