In article ,
charles writes:
In article ,
alan_m wrote:
On 25/09/2017 14:56, Dave Plowman (News) wrote:

Most false alarms are caused by sloppy installation.


Or a lack of maintenance. The backup battery in an alarm control box is
not fit and forget. The backup battery is trickle charged when mains is
present and intended to provide power when the mains drops out. After a
few years the battery cannot provide the instantaneous power to maintain
the control box when the mains fails, even for short glitches, and hence
the alarm is triggered. This can be easily tested by just turning of
the mains to the alarm at the consumer unit. A new battery every 2
couple of years stops false alarms caused by this.

I attach a label (brother tape) to the outside of my alarm control box
giving the date when the battery was changed - and the type number of
the battery. It sometimes surprises me when checking how long ago the
battery was fitted.

I understand taht the BS for this requires battery replacement every 5
years at a minimum,

My system tests the batteries every day (it switches off the
power supply and checks it can run on the battery for a while,
cutting back to mains if the battery voltage sags too much,
and generates a dead battery alert). I've never got more than
5 years from the standard 7AH SLA batteries. The battery
probably has to drop to 1/20th or less of its new capacity
before it actually reports as dead, so even long before that,
you won't get full capacity from it (just like with a UPS).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]