On 15/02/2019 14:58, DerbyBorn wrote:
For some reasone I have a Burglar Alarm serviced every year - it is
wireless.

The guy usually puts a voltmeter on the various batteries and usually
declares them okay for another year.

I would thing the no-load voltage is a poor indication of likely life. Am I
right?


Poor indication.

In my mains powered alarm base unit a "failed" battery will still show
the correct terminal voltage. What it will fail to do is provide enough
instantaneous power in the event of a power cut. The mains will cut out,
the backup battery will not cut in fast enough and the alarm will
trigger. The battery will then recover enough to leave the alarm in the
triggered state with the strobe flashing and the horn sounding.
Unfortunately you may not realise that the battery is on its way out
until you get a power cut.

I stick a label on my alarm box detailing when I last changed the
battery and I replace it after around 3 years.

Is there a reason for getting your alarm serviced this way each year?
As this a DIY group I'm sure that you could have a routine to replace
the batteries every so often.
The money saved by declaring an alarm on for insurance is minimal.





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