A battery-powered system includes a battery pack (10; 71; 81) connected to an electrical equipment (30; 50; 76; 86). The battery pack includes a first positive electrode terminal (11), a first negative electrode terminal (12), a first communication terminal (13), a first data input circuit (23), and a first limiting circuit (D11; D72; D82) that limits a flow of electric current in a direction from the first negative electrode terminal to the first communication terminal via the first data input circuit. The connected equipment includes a second positive electrode terminal (31; 51), a second negative electrode terminal (32; 52), a second communication terminal (33; 53), a second data input circuit (43; 63; 77; 87), and a second limiting circuit (D31; D51; D77; D87) that limits a flow of electric current in a direction from the second negative electrode terminal to the second communication terminal via the second data input circuit.