Communicating method for smart battery system

Various embodiments are described herein for a method of communicating between a main processor of a mobile device and a battery for providing power to the device. In general terms the method comprises providing a communication interface (132) between the main processor (102) and the battery (130) to provide communication therebetween; sending a protocol version request packet (460) from the main processor (102) to the battery (130); initiating authentication (610) of the battery (130) by the main processor (102) if the battery (130) provides (604) a protocol version response packet to the main processor (102) in response to the sending a protocol version request packet; and reading a battery ID resistor of the battery (130) if the battery (130) does not provide a protocol version response packet to the main processor (102) in response to the sending (602) a protocol version request packet.