User Manual

Mission Valley Radio Repeater Equipment + UpgradeUser/Maintenance Handbook
APPENDIX C Battery Backup
Handbook No. 50-078021HBKM Page 76 of 85
APPENDIX C - BATTERY BACKUP
C.1 GENERAL DESCRIPTION
The 80-209302 Battery Backup Unit is designed to complement AFL’s extensive range of Cell
Enhancers and provide for continued operation during mains power failure.
The Battery Backup Unit is mounted in a single environmentally-protected case. NOTE:
Although battery back-up units are fitted in an IP65 case, they are open to the local
environment via coarsely filtered grill apertures which are necessary to allow the escape of
gasses from the batteries when they are being charged or discharged. Handles are provided
for carrying the unit and the door is fitted with locks. All the power and alarm connections are
via rugged IP68 sealed connectors.
The Battery Backup Unit contains a switch-mode power supply module (SMPSU), the batteries,
a battery charger and the associated control circuitry. In particular a low-voltage cut-off is fitted
to shut the system down after extended operation to prevent deep discharge of the batteries.
The Battery Backup Unit is fitted as standard with two alarms, a combined power supply and
charger alarm and an intruder alarm. The intruder alarm operates when the enclosure door is
opened. Both alarm circuits are volt-free contacts which are normally closed and become open
circuit in a fault condition. The Battery Backup Unit can be fitted with a more comprehensive
alarm and monitoring alarm system if required. In these cases the Battery Backup Unit can also
be fitted with alarms for AC failure, temperature, etc. and be interfaced for use with the Cell
Enhancer remote alarm reporting system.
When the Battery Backup Unit is used as the default power source for the Cell Enhancer, the
Cell Enhancer only requires a 12V DC supply input. This has the effect of removing the power
supply from the Cell Enhancer case, therefore saving on cost, weight and most importantly
reducing heat generation within the Cell Enhancer case.
The Battery Backup Unit is designed to provide typically four hours autonomy in the event of
mains supply failure. However, this will vary depending on the load presented by the Cell
Enhancer and the size of the batteries fitted.
The circuit diagram and schematic contained in this handbook are based on the standard
model. All Battery Backup Units are capable of being customised to individual customers
requirements for battery capacity, alarms etc. and the drawings may differ from those included
in this manual.