User Guide

T
Mount Climie: Helios Power Solutions
SR250C
Power Supply System
By John M Wysocki ZL2TWS
Mount Climie is a high elevation site north of the capital city of Wellington,
New Zealand. The altitude above sea level is 867 meters or 2845 feet.
Mount Climie is exposed to weather from the Southern Ocean with an
unobstructed view towards Antarctica. During the winter freezing conditions
leaves the backup batteries and equipment at zero degrees for many days.
Access to Mount Climie is often difficult after a southerly snow storm.
DC backup charger made by Helios
Power Solutions in Auckland. It is
one
in the range of No-Break DC
UPS units which range in size
from the
100W SR100C to the
750W SR750C.
The Mount Climie application
is a 12 V system which keeps the
mains fail audio alarm and discon-
nects when mains power is restored.
This feature has will keep communi-
cations going for weeks if needed as
operators are alerted to keep traffic
use to a minimum.
Due to the power cycle restart
he amateur radio club Upper
Hutt Branch 63 (NZART), while
maintaining the Mount Climie site,
had been plagued with battery faults
for many years.
The radio equipment requiring
backup power are:
1) A Tait T800 45 Watt 147.300 MHz
VHF FM Repeater.
2) Two ICOM D-STAR (Digital
Smart Technology for Amateur
radio) DV (Digital Voice) 25 Watt
repeaters on the frequencies of
145.425 MHz and 438.600 MHz .
The battery problems occurred
during long power outages, in some
cases as long as fourteen days. (The
longest recorded outage to date was
2013 for thirty days!)
Batteries on the Tait T800 would
eventually run flat. There was no
alarm or low power setting during
a mains failure. Batteries would run
down to a low level and eventu-
ally lockup the repeater controller.
Repeater trustees would need to
visit with a laptop PC and restart
the controller. The batteries were
also being deeply discharged with
consequent reduced capacity and
shortened life.
Our solution was to use a SR250C
batteries float charged at 13.8 V (at
20C) but output voltages of 24, 30,
36 and 48 are also available in the
SR No-Break DC range.
A SR250C12TFSL model was pur-
chased for the first Tait VHF system
which had two parallel banks of 180
Ah maintenance free batteries, giv-
ing a total of 360 Ah. The SR250C
has two alarm outputs (‘Mains Fail’
and ‘Battery Low’) which could be
interfaced to the Tait T800. When
the input mains fails, there is a 30
second delay before the SR250C
mains fail relay closes a circuit.
This circuit is wired to the T800
issue with the Tait T800 it was the
preference of Branch 63 to have an
early warning alarm. This alarm is
sent via a descending two-tone audio
tone on the repeater transmitter
while a QSO is in progress. Three
seconds on and twenty seconds off.
The SR250C has a battery discon-
nect at 10.0 V and alarm at 11.0 V as
shipped from the factory. We have
found from experience that these
default settings are too low for the
Tait T800 system.
At the radio club’s request, Helios
Power Solutions-adjusted these to
10.8
V and 11.6 V respectively.
Figure 1: SR250C fitted to T800 VHF repeater 147.300 MHz.
NEW ZEALAND ASSOCIATION OF RADIO TRANSMITTERS