Detection of false reporting in a smart battery system

An energy storage and supply system has a tank 101 containing a plurality of smart battery units 100 randomly packed within the tank 101. The connections between the smart battery units 100 are programmed automatically. Depleted smart battery units 100 may be emptied and replaced by fresh ones. To prevent false state information reported by a battery unit 100, a comparison is made between data reporting energy extracted or supplied to the battery unit 100 and data of the actual measured energy extracted or supplied to the battery unit 100. Other ways to determine false state information are also claimed: a log of state information reported by the battery unit 100 is inspected in order to determine whether or not there is a change in state information which is inconsistent with normal operation of the battery unit 100. These methods ensure that the battery unit value is not fraudulently manipulated when making an exchange of battery units 100.