The BOAC is a device that performs the various task required to manage a 12VDC alarm system that has an alarm strobe light and horn that must be powered by a 12V backup battery. The BOAC charges the backup battery, provides a Power Loss Alarm (when required), has a repeat cycle timer for the horn, a system push-to-test button and indication of the battery charging mode.

During an alarm condition the alarm strobe light and horn are powered by the battery. After an alarm condition and with 120VAC applied/restored, the BOAC will recharge the 12V backup battery. During an alarm condition battery power is conserved by operating the horn intermittently, on for 2 seconds, and then off for 2 seconds.

Upon closure of an alarm contact across pins 3 and 10 the strobe light and horn will be activated. Also, upon the loss of 120VAC power, the Power Loss Alarm (if enabled) will activate the strobe light and horn. The Power Loss Alarm may be enabled/disabled by setting the Power Loss Alarm Mode switch to the desired setting.

The push-to-test button is provided to verify system operation. When pushed, the battery charger is turned off so that the strobe light and horn may be powered solely by the battery during the test.

The BOAC utilizes a battery Charge Controller IC chip that was specifically designed to manage the charging of sealed lead-acid batteries. This chip carefully controls the charging current and voltage during the charging process to maximize battery capacity and life. The Charge Controller has two charging modes, “Cyclic Charging” and “Float Charging”. During an alarm event, the strobe light and horn will slowly run down the battery. As long as the battery voltage stays above 12.1V (50% charged), the Charge Controller will stay in the Float Charging Mode. In the Float Charging Mode, the battery will be recharged to 13.6V ± 1% @ 25°C, when the alarm clears. If the alarm where to be turned on often enough (or stay on long enough) to run the battery down below 12.1V (50% charged), the Charge Controller will toggle into the Cyclic Charging Mode and recharge the battery to 14.6V ±1% @ 25°C. After a period of time in the Cyclic Charging Mode with no alarm events, the charging current will drop below 25 mA, and the Charge Controller toggles back to the Float Charging Mode. Battery manufacturers typically recommend this dual voltage charging regiment to ensure the optimum capacity and life of their batteries. To accommodate lead-acid battery chemistry, the Charge Controller also adjusts the charging voltage to account for changes in the ambient temperature (-20.7mV/C° or -11.5mV/F°).