SECTION 01 / SIGNAL ROOMSIX GUIDES.
SIX GUIDES.
ONE EQUIPMENT ROOM.
Explore the repeater, six-way charger, DC backup, BDA / DAS head-end, RF distribution and alarm monitoring system.
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SERVER ROOM FIELD GUIDE
DC Backup Power for Radio Repeaters
Trace a radio repeater DC backup path from mains input to rectifier, battery, protected DC bus and alarm—and learn what runtime figures leave out.
FIELD DECISIONSpecify the load and required operating time first. Battery size is an outcome of that calculation, not the starting point.
How does repeater DC backup work?
A repeater DC backup system normally uses a rectifier or charger to supply the DC load and maintain a battery reserve while mains power is healthy. When mains fails, the protected battery path supports the repeater and selected network equipment. Runtime depends on usable battery capacity, DC load, battery age, temperature, cabling and the permitted discharge limit.
See the complete backup path
Concept illustration of AC input, a rectifier/charger, battery reserve, a fused DC bus, and radio, network and alarm loads. Actual wiring, capacity and isolation must follow the selected equipment and the manufacturer’s system design guidance.
Follow the working path
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01
AC input
A protected mains circuit supplies the rectifier and charger.
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02
Convert
The power module feeds the DC bus and maintains the battery.
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03
Store
A fused battery bank holds the reserve energy.
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04
Transfer
The DC path remains continuous when AC disappears.
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05
Report
Low voltage, battery and AC-fail contacts reach the monitoring point.
What to verify before handover
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01
List every protected load, including network switches, links and cooling controls that the radio path needs.
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02
Measure steady and peak DC current instead of relying only on nameplate estimates.
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03
Set fusing, cable size, disconnects and enclosure ventilation for the chosen battery system.
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04
Test the complete AC-fail sequence and record voltage, alarms and recovery behaviour.
Where otherwise good systems go wrong
F01
Protecting only the repeater
The RF path can still fail if a router, remote unit or alarm interface loses power.
F02
Quoting a perfect-battery runtime
Age, temperature, discharge limits and wiring loss reduce usable reserve.
F03
No live failover test
A charger showing normal does not prove the battery path will carry the actual load.
Questions teams ask before they decide
How long will a repeater run on battery backup?
There is no universal runtime. It must be calculated and then tested from usable battery capacity, total DC load, battery condition, temperature, discharge limit and conversion loss.
Should the battery power other network equipment?
Yes, when that equipment is required for the end-to-end radio service. Define the protected load list before sizing the battery system.
Which alarms matter for DC backup?
Common points include AC fail, charger fault, battery low, battery disconnected and low DC bus. The final list depends on the equipment and response plan.
Sources behind this guide
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Repeater battery-charger and alarm interface example.
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AC and battery alarm behaviour.
Product references illustrate operating principles and available equipment features. Final design, compatibility and regulatory decisions must follow the selected equipment, site survey and applicable Malaysian assignment conditions.
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