The CiA 418 device profile specifies the interface for battery modules and the CiA 419 device profile specifies the interface for battery chargers. The battery module provides information to a charger, which enable it to carry out a battery charge. The smallest amount of information is the battery type, battery capacity, number of cells, maximum charge current permissible, and the battery temperature. Additionally, optional information is defined, e.g. various identifiers, charge history data, battery voltage, battery state of charge, requested current and water level status. A default TPDO is defined to send the battery temperature and status information on a timer-driven basis. Optional TPDOs are defined for transmitting battery voltage, current requests and state of charge. A default RPDO is defined to receive charger status. An optional RPDO adds the "Charge Returned" object to the data received. Optional PDOs supported by the module can be configured via SDO services. The corresponding default PDOs are implemented in the battery charger. The battery module has to support the heartbeat protocol.