Alarm battery issues
BATTERY INFORMATION FOR ALARM SYSTEMS: When the AC power (building power) goes out for any reason the Fire Alarm or Security batteries may become drained and show a low battery message on the keypad/annunciator and then normally charge backup within 48 hours. If they do not charge back up then your charging circuit may be bad. You can test this by putting a meter on DC volts and testing the two wires that go from the panel to the battery. These are normally RED and BLACK and most panels will show that the charging circuit is sending about 13.5 volts to the batteries. If you have 0 on this then there is a problem. It is best to have a professional do these things because if you mix up the wires you could cause problems that may require you to have to purchase new equipment. Some panels take in AC voltage from the transformer and some take in DC volts from the transformer so you have to know before hand.
If the power is out too long or if the batteries drop below 12 Volts sometimes they won't charge backup and you need to install new batteries. Normally these batteries last 3 to 5 years unless they are in an area with power bumps or issues, in that case you may need to replace your batteries more frequently or put the system on a UPS (Uninterrupted power supply- another battery backup or generator)
Most of the Alarm batteries are the 12 volt sealed gel cell sometimes they are the 7, 7.5, 8, 8.5 amp hour. Some panels have larger 18 amp hour batteries. Batteries & alarm components are somewhat like cars, they come in different qualities depending on the price so not all 7 amp hour batteries are the same and it also depends how long they have been on the shelf as to how long they will end up working for you. The higher quality batteries are made much better and do cost a bit more so if you end up paying $20 for a battery it may not be the same quality as the $30 dollar battery.
Testing batteries is not always cut and dried because using a normal VDC meter will tell you the volts but it will not test the load and many times a battery can test at 12 volts and still be bad. It is best to replace the batteries every 3 to 5 years. Just because they are still working after 6 years does not mean they will function when the power goes out and you really need the fire alarm to notify occupants to evacuate.
The batteries we are talking about here are not the batteries inside the residential smoke detectors. These batteries are quite large about 4 inches in depth, 4 inches high and 7 inches long. The 18 amp hour batteries are much larger than that. These batteries are normally found in a metal enclosure in an electrical room. The cans are normally locked so having your alarm contractor service these items normally is your best bet.
Many Fire Marshals will require a 24 hour battery test on your Fire Alarm Systems and if they don't the alarm contractor is supposed to do it. What you do is turn the AC (building power) off to the main Fire Alarm panel 24 hours before your test and the annunciator should indicate that the power has been turned off. The next day you should set the alarm off and allow the horn/strobe noise and light makers to be active for 5 minutes and if they all function the full 5 minutes then you pass your 24 hour battery test. If they do not pass then there is a good chance you will need larger batteries or that you might need to replace the batteries if they are old. Your alarm contractor will most likely do the batteries calculations before the test to make sure he or she has enough amp hours to handle all the appliances on the circuits.
Larry the author has been with American Security & Fire, Inc. in Salt Lake City 1998 to 2014 and is now with Peak Alarm Larry@PeakAlarm.com 801 428 1384 www.PeakAlarm.com