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8 Electrical Considerations
8.1 Battery charge limits
The battery charging rate can be set in the configuration file (see section 7.3),
battery charging functions can be set via CAN dynamically. If CAN communication
is lost battery charging settings will revert to configuration file settings.
8.2 Emergency battery usage
The 2.4kW FCPM has redundancy offered by this kind of architecture. If one SPM
has a critical fault, the remaining SPM 1.2kW and battery are still operational to
provide power.
Note The operator should monitor the data outputs so they are aware of any fuel
cell emergencies during flight.
8.3 Specifying a battery
The 2.4kW FCPM is designed to support a number of different aircraft and power
architectures. Modularising the unit gives freedom to integrators to change battery
capacity, voltage and discharge rates to suit particular applications. Batteries must
be specified that are suitable for the application. Things to check specifically are:
• Battery discharge rate (or ‘C’ rating) – the battery must be able to supply the
current requested by the load source.
• Battery voltage (or number of cells) – must be aligned with the configured
voltage of the fuel cell system.
• Battery capacity – this will affect how long the battery can discharge for and will
directly affect the batteries capability to provide peak or emergency power.
• Typical battery configurations used are 12S-16S LiPo voltage range.
Note Not correctly specifying a battery could cause sudden and immediate loss
of output power.
8.4 Specifying a hybrid battery cable
The 2.4kW FCPM is designed to support a number of different vehicles, airframes
and power architectures. Modularising the unit gives freedom to integrators to
change battery and output cables to suit particular applications. Cables must be
specified that are suitable for the application. In particular, the current specification
of the cable must be able to handle the maximum current drawn by the load source
(typically UAV motors/ESCs).
Note Not correctly specifying a cable could cause sudden and immediate
loss of output power.
If you have any questions about the electrical configuration of the
FCPM or how to customise to a particular application, please
contact [email protected].
