This manual sets out an operating overview for Intelligent Energy’s 802 and 804FCMs. The 802 and 804 FCMs are part of the 800 Series products, which also feature aFCM 801 which can provide power up to 1.2kW.The FCM-802/804 provides regulated DC at nominal output voltage, which can bedefined by the user at a nominal 24V or 48V. The FCM-802/804 will hold the DC outputat the nominal voltage while connected to an external battery or power supply sothat the system will act as a hybrid system. In the hybrid system, the battery is usedto provide power whilst the fuel cell starts, supports the load during the fuel cellPerformance Optimisation Cycle (POC) and in the standby state. Hydrogen gas must beprovided at a regulated pressure to the module inlet. The FCM-802/804 will generatepower when it is given both Enable and Run signals (see Section 7.1 & 7.2).During normal operation, the FCM-802/804 will conduct a POC where powerdelivery is briefly interrupted. In this period, the fuel cell will hybridise with theexternal battery (see Section 8.3 Performance Optimisation Cycle (POC)). If duringnormal operation the load drops to a low level (e.g. less than 6A, as default forFCM-804), the fuel cell will enter a standby state (see Section 8.4 Standby State). Thisis designed to optimise fuel consumption. If the DC Bus voltage then dips below apre-set voltage, the fuel cell will restart.During normal operation, the FCM-802 or 804 will periodically conduct an optimisationcycle which improves the performance of the fuel cell. Power production is reduced orsuspended for up to 12 seconds during the cycle so an external power source may beneeded to briefly provide power to the load, for more details see section 8.3.