A regular rechargable battery provides no way to communicate with a charger or other device. It can be charged or discharged, old or new, overheated or cold and there are only unreliable solutions available to determine all this from the outside.

A Smart Battery System (SBS) defines a communication mechanism which lets batteries talk to their chargers and observers. The main purpose of this system is to allow a battery to control the charging parameters applied to it. In addition it allows for more accurate fuel gauges and discharge alerts.

Smart battery communication is based on the SMBus protocol. At a minimum, a smart battery system consists of a charger which is defined as a unit capable of adjusting charging parameters according to requirements received from the battery. The second obvious component of such system is the smart battery itself, which must be able to supply charging requirements and other parameters over the SMBus.

However, such system easily becomes much more complex with the appearance of additional components such as the host, which is actually powered by the smart battery, additional batteries and a battery selector to choose from different sources and optional temperature sensors. All of these components interact over the SMBus (and a third safety signal (T-Pin)). The full specification can be found at the SBS forum

There are some particularities to consider when monitoring an SBS communication. The SMBus termination may be switched off in order to save power. Compared to regular I2C or SMBus communication there are differences in slave acknowledgement of data. With Tracii XL 2.0 we provide a complete solution for Smart Battery monitoring.