Radar and ECDIS backup power on a 220 V shipboard system
Last updated 2026-11-07
A vessel that trades between 50 Hz and 60 Hz ports cannot rely on frequency alone to decide whether its backup power will work. When radar and electronic chart displays are the load, the requirement is continuity first and portability second.
Project background
A Shanghai-based shipping company needed backup power for two categories of navigation equipment on a 220 V shipboard system: the radar installation and the electronic chart display and information system (ECDIS).
Both are safety-critical. Losing the radar during an approach, or losing the chart display during a pilotage, is not an inconvenience — it changes the bridge's ability to keep the passage safe.
What made this harder than a shore installation
Frequency changes with the port. Shipboard and shore power in different regions run at 50 Hz or 60 Hz. Equipment that locks to one frequency either refuses to accept the other or runs at the wrong speed. Any backup unit that assumes 50 Hz is a liability on a vessel that trades internationally.
Shipboard supply is electrically noisy. Bow thrusters, winches, pump motors and refrigeration start and stop continuously. Voltage dips during a thruster start are normal, not a fault, and equipment that trips on them will trip constantly.
Space and mounting. Bridge and radio-room space is fixed at build. Backup equipment has to fit the space that exists, with no possibility of adding a battery room.
No technician on passage. Anything installed must be operable by the crew, with an interface that reports state without requiring interpretation.
Configuration
The installation split the two loads by criticality rather than putting both on one device:
ECDIS — offline (line-interactive) unit with internal battery. The chart display is a modest, well-behaved load with its own internal supply. An offline unit with integrated battery provides ride-through for dips and short outages, deploys without external battery wiring, and keeps the bridge console uncluttered.
Radar — online double-conversion unit with integrated battery. Radar magnetrons and their power supplies are less forgiving: a dip during transmission can drop the magnetron and force a warm-up cycle that takes minutes. An online unit holds the output steady through the dip, so the radar never sees it.
Both units are frequency-adaptive across 50 Hz and 60 Hz, which means the same hardware works in a European or an Asian port without a configuration change or a step-down transformer.
Why internal batteries rather than an external bank
On a vessel, an external battery bank means a cable run, a DC protection scheme and a mounting arrangement that must survive vibration and inclination. Internal batteries remove the DC wiring entirely: the unit mounts, connects to the 220 V circuit, and is operational.
The trade-off is runtime. Internal batteries give minutes, not hours — which is the correct objective on a bridge, where the requirement is to ride through a dip, cover a generator changeover, or allow a controlled transition to emergency supply, not to keep the radar running for an hour.
Results
- Radar and ECDIS both hold through shipboard voltage dips and short interruptions.
- Frequency adaptation means no reconfiguration when the vessel moves between 50 Hz and 60 Hz regions.
- Internal batteries removed external DC wiring, reducing both installation time and inspection scope.
- Crew operation is limited to reading the panel and pressing one button, which matters on a bridge at night.
What transfers to other marine and transport projects
- Split by load behaviour, not by convenience. Putting a sensitive magnetron supply and a chart display on one oversized UPS works, but costs more and gives the crew a single point of failure.
- Treat frequency adaptation as a hard requirement for any vessel trading internationally, and confirm it in writing — many units accept a frequency range on input but deliver a fixed output frequency.
- Runtime on a bridge is minutes by design. Spending capacity on hours of runtime usually serves a specification number rather than an operational need.
- Internal batteries win on vessels unless the load justifies a proper DC system with marine-rated protection and mounting.
Scope boundary
This arrangement suits bridges, radio rooms and small craft where the load is instrumentation. Larger vessels with class-society requirements for emergency power, or installations feeding navigation equipment from an emergency switchboard, fall under a survey-and-class regime that starts from the distribution design rather than from the UPS.
Product references: C series high-frequency online UPS, LT series offline lithium UPS, 110V marine UPS guide, and wide input voltage UPS.