| This article describes the procedure for replacing the battery in an External Sounder.
Introduction
Modern sounders and some older installations are fitted with an SAB/SCB module within the sounder enclosure. The module incorporates a rechargeable back-up battery and charging circuit, and is designed to sound the sounder if the connection from the control panel to the sounder is lost, e.g. if the cable is cut. As with any battery, the working life is finite and the battery will need replacing after a few (typically 5) years.
Battery Type
The majority of batteries fitted in External Sounders are Nickel/cadmium (NiCd or Nicad) or Nickel/Metal Hydride (NiMH). The two types are interchangeable. The batteries are made up of stacks of button cells each having a nominal voltage of 1.2v. Thus a 6v battery has a stack of 5 cells, a 7.2v has 6 cells and an 8.4 has 7 cells. They all have a capacity of around 300mAh. Different external sounder manufacturers use different battery types. The sure-fire way to ascertain which battery is required is to remove the sounder cover and physically inspect the battery. With luck the battery will be marked with the voltage and capacity, otherwise simply counting the cells in the stack and multiplying by 1.2 will give the battery voltage. The issue is further complicated by some manufacturers using soldered-in batteries with others using batteries with flying leads. The batteries with flying leads are generally easier to replace but the soldered-in batteries can usually be replaced with the use of a soldering iron.
Battery Replacement
WARNINGIF THE EXTERNAL SOUNDER IS FITTED WITH A STROBE UNIT, TAKE CARE NOT TO TOUCH THE STROBE CONNECTIONS AS THEY CARRY HIGH VOLTAGES
- Remove the sounder cover - the sounder should sound as the tamper switch goes open circuit. Silence the sounder by entering the user code at the control panel.
- Disconnect and remove the existing battery - note the connections and polarity.
- Disconnect the leads from the battery.
- Connect the new battery - observe polarity. If the alarm sounds, silence the alarm by entering the user code.
- Refit the sounder cover ensuring that the tamper switch(es) is/are closed.
- Reset the alarm at the control panel.
Note: the new battery may take several hours charging to reach its full capacity.
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