HELIOS SR250C Power Supply System User Guide

: June 9, 2024
: HELIOS

Table of Contents

Installation
Battery temperature sensor
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

HELIOS SR250C Power Supply System User Guide

Installation

MountClimieisahighelevationsitenorthofthecapitalcityofWellington, NewZealand.Thealtitudeabovesea levelis 867metersor 2845 feet.
MountClimieis exposedtoweather fromtheSouthernOceanwithan unobstructed view towards Antarctica. During the winter freezing conditions leaves thebackupbatteriesand equipmentat zerodegrees formanydays. AccesstoMountClimieisoftendifficultafterasoutherlysnowstorm.

The amateur radio club Upper Hutt Branch 63 (NZART), while maintaining the MountClimie site, hadbeenplaguedwith batteryfaults for many years.

The radio equipment requiring backup power are:

A TaitT800 45 Watt 147.300MHz VHF FM Repeater.
Two ICOM D-STAR (Digital Smart Technology for Amateur radio)DV(DigitalVoice)25Watt repeaters on the frequencies of 145.425MHzand438.600MHz.

The batteryproblems occurred during long power outages, in some cases aslong as fourteen days.(The longest recorded outage to date was 2013 for thirty days!)

Batteries on the TaitT800 would eventually run flat. There was no alarmorlowpowersetting during amainsfailure.Batterieswould run down to a low level and eventuallylockupthe 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.

Oursolution was to use a SR250C
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 batteries float chargedat13.8V(at 20C) butoutputvoltagesof24,30, 36 and 48 are also available in the SR No-Break DC range.

A SR250C12TFS Lmodel was purchased for the first Tait VHF system
which hadtwo parallel banks of180 Ahmaintenance free batteries, giving a total of 360 Ah. The SR250C hastwo alar moutputs(‘MainsFail’ and ‘Battery Low’) which could be interfaced to theTaitT800.When the input mainsfails, there is a 30 second delay before the SR250C mainsfailrelay closes a circuit.

This circuit is wired to the T800 mains fail audio alarm and disconnects when mains power is restored.
This feature has will keep communications going for weeks if needed as operators are alerted to keep traffic use to aminimum.

Due to the power cycle restart issue with the TaitT800 it was the preference of Branch 63to have an early warning alarm. This alarm is sentvia adescending two-toneaudio tone on the repeater transmitter while a QSO is in progress.Three seconds on and twenty seconds off. TheSR250 Chasa battery disconnectat 10.0V and alar mat11.0Vas shipped from the factory.Wehave found from experience that these default settings are too low for the Tait T800 system.

At the radio club’srequest, Helios Power Solutions-adjusted these to 10.8 V and 11.6 V respectively.
Sensor
Figure 1: SR250C fitted to T800 VHF repeater 147.300 MHz.

Sensor
Figure 2: ICOMD-Star radio equipment

Sensor
Figure 3: HPS SR250C 12 TFSL

Energies also extended the battery remote temperature sensor cable to nine metres asthe batteries are located in an outside battery box.

Battery temperature sensor

This is an excellentide a that gives the SR250C a ‘SMART” control of the battery. As mentioned above, the batteries are often at 0Corjust above zero for many days on end during the winter months.

When ambientair temperatures are this cold the SR250C charges at around14.3V,droppingto 13.85V at 18C. The batteries are always charged to maximum capacity. With normal fixed output voltage float chargers’ batteries are always undercharged when operating at very lowambient temperatures.

Battery disconnect feature:

The SR250C has an Electronic Circuit Breaker (ECB) which protects the battery circuit against overload and also incorporatesa Low Voltage Disconnect (LVD) that will disconnect the battery at 10.8 V during a prolonged outage. Based on the above criteria, after mains fail the SR250C sends out two signals ‘Mains Fail’ followed by ‘Battery Low’ alarm (not currently in use) and finally disconnects the load to prevent battery damage.

Because this system was so successful we requested a quote for a second SR250C to powerthe D-STAR digital radiosystem, kindly donated by ICOM Auckland New Zealand.
Helios Power Solutions were interested to hear ICOM had given a high level of support to this new Digital Smart Technology for Amateur Ra- dio (D-STAR). Helios Power Solutions then also donated a SR250C for the ICOM repeater equipment. Total current with both VHF and UHF digital repeaters is 11 amps DC.

Helios Power Solutions SR models include convenient stepped feet for side mounting as seen in the pictures. This made installation very straight forward. Crimp /Solder lugs are also included in the installation kit making for positive connections when using 6 mm to 10 mm cables. Note that the ‘positive’ terminal is the common connection with ‘negative’used for these parateload and battery connections.

The pictures show the D-STAR installation. The SR250C is mounted
behind the Duplexer seen in the lower front of the cabinet. With two Helios Power Solutions power supplies Branch 63 was able to standardise on battery charging equipment extend- ing the life of the batteries.

Helios Power Solutions are easy to contact with the online Skype phone available. I used this a couple of times to discuss special options for the Mount Climie installation. Helios Power Solutions were also able to reprogram the SR250C for our10.8 V low voltage disconnect, temperature sensor extension and 11.6 V low battery warning alarm modifications. Quick turnaround time and a very professional twenty four month warranted product.

References:

For information on how to get involved in the new D-STAR Technology contact Branch 63 Upper
Hutt <http://www.zl2vh.org.nz/>.