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?

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?

no.


--
"Strange as it seems, no amount of learning can cure stupidity, and
higher education positively fortifies it."

- Stephen Vizinczey

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.





--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

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?


I frequently test batteries for mobility scooters.I've found that a no
load voltage test isn't much help. I therefore do a discharge test. It
doesn't actually take long for a poor battery to reveal itself. But in
the case of alarms I would be inclined to replace routinely every three
years.

Bill

DerbyBorn explained on 15/02/2019 :
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?

Yes, it is pointless - even off charge it takes a while for battery
volts to fall. The proper test method is a drop test - a suitable load
is applied and then the voltage monitored, for a rough idea.

Chris Hogg presented the following explanation :
My DVM has a setting for no-load voltage measurement, and a different
setting for battery testing. In the latter case, AIUI some load is put
on the battery, i.e. current is drawn, and the voltage reading will
fall away quite quickly if the battery is on its last legs. Perhaps
your guy has such a setting on his meter.

Those good for small primary batteries, but not much use for a lead
acid battery - the tiny discharge will not really affect the voltage
much.

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.






I was conerned about my wife coping with my home installed alarm when I pop
my clogs. I did have a mains powered one I installed myself - a kitchen
extension made it necessary to change it.

alan_m wrote:
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.

Interesting theory but wrong.

Old batteries dont get €œslow€� or then recover to provide power for the
sounder etc.

When the mains goes, they fail to provide enough power for the system and
the external sounder/strobe responds to this as a €œtamper€�. The
sounder/strobe has its own battery that can keep the sounder going for ages
without any external supply. Its got nothing to do with the main battery
€œrecovering€�.


Tim


--
Please don't feed the trolls

Are they rechargeable?

I would have thought that a realistic load and voltage drop measurement
might be a good idea, certainly. I have an old laptop where the battery
reads fine after a charge, for all of five minutes in use!
Brian

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"DerbyBorn" wrote in message
2.222...
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?

On 16/02/2019 07:35, Tim+ wrote:
alan_m wrote:
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.

Interesting theory but wrong.

Old batteries dont get €œslow€� or then recover to provide power for the
sounder etc.

When the mains goes, they fail to provide enough power for the system and
the external sounder/strobe responds to this as a €œtamper€�. The
sounder/strobe has its own battery that can keep the sounder going for ages
without any external supply. Its got nothing to do with the main battery
€œrecovering€�.

Yes, the bell box may detect a a short drop of power as a tamper but
battery is still well enough to allow the control unit to be fully
working to cancel the alarm.

While the battery in the control unit may be replaced at regular
intervals I wonder how may batteries in the bell box are replaced likewise?

In an alarm system batteries tend to never go through a discharge cycle
unless there is a power cut.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On Fri, 15 Feb 2019 14:58:57 GMT, DerbyBorn wrote:

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

For a mains powered panel:

If the mains supply is still on, he's measuring the charging voltage
- pointless.

If the mains is off, he measuring the voltage under load. If he's
measures it immediatly after the mains is switched off and again 10
mins later the difference will give a reasonable indication of the
state of the battery.

For the sensors they take very little energy, what are the batteries?
Tewrminal voltage might be good enough. I'd assume that there is some
method that gives a low battery warning for a given sensor.

--
Cheers
Dave.

"Dave Liquorice" wrote in
idual.net:

On Fri, 15 Feb 2019 14:58:57 GMT, DerbyBorn wrote:

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

For a mains powered panel:

If the mains supply is still on, he's measuring the charging voltage
- pointless.

If the mains is off, he measuring the voltage under load. If he's
measures it immediatly after the mains is switched off and again 10
mins later the difference will give a reasonable indication of the
state of the battery.

For the sensors they take very little energy, what are the batteries?
Tewrminal voltage might be good enough. I'd assume that there is some
method that gives a low battery warning for a given sensor.


CR123 BATTERIES - in the sensors.

On 16/02/2019 10:28, Dave Liquorice wrote:


For the sensors they take very little energy, what are the batteries?
Tewrminal voltage might be good enough. I'd assume that there is some
method that gives a low battery warning for a given sensor.


Surely if its an expensive maintenance contract any non-rechargeable
batteries probably should be replaced yearly to ensure that the system
works reliably for a future 12 months?

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

alan_m wrote:

On 16/02/2019 10:28, Dave Liquorice wrote:


For the sensors they take very little energy, what are the batteries?
Tewrminal voltage might be good enough. I'd assume that there is some
method that gives a low battery warning for a given sensor.


Surely if its an expensive maintenance contract any non-rechargeable
batteries probably should be replaced yearly to ensure that the system
works reliably for a future 12 months?
That would be a bit of an expensive waste, especially if the likely
lifetime is about 10 years for a lightly loaded lithium primary cell.


--

Roger Hayter