A multi-battery system includes a plurality of batteries, a first connector having a first identification unit, and a second connector having a second identification unit. Each battery includes a microcontroller, and a battery connector having a detection unit. The first connector is for electrically connecting a battery connector of a first battery of the plurality of batteries and a motor controller. The second connector is for electrically connecting a battery connector of a second battery of the plurality of batteries and the motor controller. When the first identification unit is set to a first predetermined value, and a detection unit of the first battery is electrically connected to the first identification unit, a microcontroller of the first battery sets the first battery as a master battery.