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British Columbia Frequency Modulation Communications Association
Emergency Power System
In efforts for emergency preparedness, all of the BCFMCA's repeaters and support equipment operate on a battery backed DC power plant. This allows continued operation in the event of AC failure. There are also provisions to allow for the connection of an emergency generator to keep the system operating through an extended outage.
In late 2012, using funding provided through a BC Gaming Grant, the DC power system was renewed. This included changing out the batteries, rectifier (charger), inverter, and some distribution fuse/breaker panels.
You can see near-realtime telemetry from the power plant here
The DC battery plant comprises of a bank of eight, 115AH, 12 volt, valve regulated, sealed lead acid batteries. The cells are manufactured by C&D Technologies, and are model TEL12-115FNG.
The advantage of these batteries is that four of them can be stacked side by side in the bottom of a standard 19" equipment rack. This reduces the footprint required in the room by using normally wasted space (normally equipment isn't installed down that low because it is a pain to work on, unless you absolutely have to).
Some further information on the battery plant:
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| Battery Plant |
Each of the batteries is terminated on the battery termination bus with #2AWG welding cable. Note that the cables between the batteries and the termination bus are all EQUAL LENGTH. This is important to ensure that all batteries are floated at same voltage and discharge at the same rate (milliohms make a difference!)
The battery termination bus is connected to the Alpha rectifier shelf with parallel runs of #6AWG cables. This is the maximum size that fits the lugs in the rectifier shelf.
The rectifier shelf is manufactured by Alpha Technologies. It is their 12V Cordex Modular Rectifier System. Our unit is equipped with all four 250W rectifiers, providing up to 83A of charge/supply current, and N+1 redundancy.
The Cordex rectifier shelf also has a low voltage disconnect built-in to protect the battery plant by disconnecting it if the voltage drops to 10.5V (adjustable). The built-in CXCI controller is web accessible and allows you to view the current operation of the shelf, including current draw. It supports SNMP for remote monitoring system interfacing, and also supports sending out email alerts on alarms.
By hooking this shelf in to BCWARN (our internet connection at the site), we get real-time notification when trouble crops up, such as loss of AC, rectifier module failure, fuse alarms, etc.
Some further information on the rectifier shelf:
- Cordex 250W Rectifier Shelf Datasheet
- Cordex 250W Rectifier Module Datasheet
- Cordex CXCI Controller Datasheet
- 1kW 19" Shelf Manual
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| Cordex Rectifier Shelf |
The battery plant is floated by the rectifier shelf all the time and the equipment is powered directly from the battery bank. With AC, all power for the equipment is supplied by the rectifier shelf. In the event of AC failure, the equipment keeps on operating on battery power.
Power distribution is by means of high current breakers and low current intelligent fuse panels. The equipment (like PA's) that require high current are fed from an Alpha breaker panel. The smaller loads are supplied through ICT Power remote controlled fuse panels. We chose the ICT180-12IRC because it offers an all in one solution for remote power control and monitoring.
The ICT180-12IRC is connected to BCWARN, and it allows us to remotely monitor current consumption on each connected device, it lets us remotely power cycle any of the ports, and lets us remotely power off equipment if we need to load shed (to extend battery run time). The fuse panel also monitors each fuse and will send an email notification if there is a blown fuse.
Some further information on the ICT Intelligent Fuse Panel:
- ICT180-12IRC Datasheet
- ICT180-12IRC Instruction Manual
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| Alpha Breaker Panel and ICT180 | Distribution Panel Rear | ICT180-12RC |
To power the AC loads on site (ethernet switches for BCWARN and the like), we have installed two ICT300-12SNV inverters. The inverters are true sine output, and are each capable of 300W. One is used to supply power to equipment that is inside the radio shack, the other feeds equipment that is mounted on the tower.
Some further information on the ICT Inverters:
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| Inverter Shelf Front | Inverter Shelf Rear |
With about 800A of battery plant capacity, we should be good for about 24-36 hours of run time under present load conditions. That could be extended based on load shedding to maintain critical components.
We also own a Honda EU3000i generator that has been converted to run dual fuel (propane or gasoline). It can be deployed easily if someone can get to the site to power all of the equipment for extended periods without AC, or to recharge the batteries to extend run time.
The dual fuel option gives us the ability to store fuel (propane) on site without having to worry about it going stale or needing to be cycled/used. We still retain the option to run on gasoline for ease of availability and transportation.