Smart Battery System (SBS) is a specification for determining accurate battery capacity readings. It allows operating systems to perform power management operations based on remaining estimated run times. Through this communication, the system also controls the amount the battery is charged. Communication is carried over an SMBus two-wire communication bus. The specification originated with the Duracell and Intel companies in 1994, but was later adapted by several battery and semiconductor makers. [1]
The Smart Battery System define the SMBus connection, the data that can be sent over the connection (Smart Battery Data or SBD), the Smart Battery Charger, and a computer BIOS interface for control. In principle, any battery operated product can use SBS, but in practice only laptop computers use the system.
A special integrated circuit in the battery pack monitors the battery and reports information to the SMBus. This information might include battery type, model number, manufacturer, characteristics, discharge rate, predicted remaining capacity, an almost-discharged alarm so that the PC or other device can shut down gracefully; temperature and voltage to provide safe fast-charging.