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Chuck Husick:
Techno-Talk, September 2006 from BoatUS Magazine -
EPIRB Batteries
An Emergency Position
Indicating Rescue Beacon (EPIRB), or the smaller but equally effective
Personal Locater Beacon (PLB) can save your life, but only if it
has the energy to operate its transmitter when you activate it.
This is especially important for the many boat owners who purchased
these life-saving devices in 2001 as EPIRB batteries have a five-year
service life. As the one in your EPIRB may now need to be replaced,
the job should be done by a service shop approved by the manufacturer.
The technical and performance
specifications for all EPIRBs and PLBs are government regulated
to ensure that the beacons are compatible with the worldwide satellite
monitoring system. It’s a lifesaving device, therefore the
specifications are exact. For example, the five-watt 406 MHz transmitter
must operate for at least 48 hours (24 hours for the smaller PLB)
even in the most adverse conditions — temperatures as low
as -40°C (-40°F) or as high as 55°C (131°F) —
and after five years’ storage at temperatures as low as -50°C
(-58°F) and as high as +70°C (+158°F).
At this time batteries
capable of providing the required combination of very long storage
life and assured power delivery must be assembled from carefully
made Lithium cells. The need for using only the correct type of
battery is emphasized in the paragraph about EPIRB battery replacement
that appears on the Coast Guard Navigation Center web site at www.navcen.uscg.gov/marcomms/gmdss/epirb.htm.
Recently, the battery
in my 2001 ACR RapidFix 406 EPIRB was due for replacement. Wanting
to know as much as possible about the battery replacement process,
I arranged to take the EPIRB to the ACR factory in Fort Lauderdale
where I accompanied it during the two-plus hours it took to perform
the incoming inspection, perform the same series of tests used for
new production units and install the new battery.
The beacon was logged
into the recertification process by recording the model and serial
number, NOAA number, manufacturing date code and the name of the
registered owner in the receiving log. A quick check of the test
/ activate switch (a flip lever on this model) revealed that the
tension of the spring that holds the manual activate switch in the
off position was too low and would not pass the final inspection
the unit would undergo after the service work was finished. The
spring was replaced, and an entry made on the quality control traveler
that would accompany the beacon during its voyage through the recertification
process. The digital code that identifies the unit was verified
when it appeared on the computer screen.
The Quality Control
seal on the case screw was removed, the unit opened, the battery
removed and everything examined for evidence of damage or deterioration.
All was in order. A new battery was slipped into the case and the
battery information entered into the log sheet. The beacon, less
its battery, was installed with a radio frequency shielded test
enclosure that provided a power source and a dummy load to absorb
the energy from the transmitter. It was then run through a computer
controlled 45-minute test of every aspect of its operation, including
frequency accuracy and stability, power output and overall signal
quality.
With this test successfully
concluded, the beacon was reassembled and tested to ensure that
it was totally watertight and that the circuit that would activate
the beacon when it was immersed in water was functional. The technician
who tested the unit signed off on the log and sent my beacon on
for a final review of the unit and all of the paperwork, a process
identical to that used for new production units.
The work that was done
went far beyond just replacing the battery. The companies that make
these units know that lives may depend on their product working
precisely as designed, up to five years after you put it on your
boat. The price for the service, about $300 (this will vary depending
on the type of unit; PLBs will usually cost less to service) would
be high if all that was required was a new, garden variety battery.
Considering the need for the special battery and the extensive testing
done to assure that the unit would work when needed, the price I
paid was a bargain.
By Chuck Husick
Chuck Husick is a pilot, engineer, sailor and former president of
Chris Craft Boats.
© Copyright BoatUS Magazine 2006
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