Alarm going off after power cut
F
were out and the alarm was set. Neighbours have said that the alarm has
gone off each time the power has come back on. While the power was off
none of the panel lights were lit and when the power came back on and we
reset it 'Day' and both zones were lit.
Is this expected behaviour?
I thought the battery in the control panel and the one in the bell box
were supposed to deal with power cuts. Could it be that one or both of
the batteries needs to be changed?
The alarm is a Scantronic 9448.
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F
Owain
> We've had a couple of power cuts recently (up to two hours) while we
> were out and the alarm was set. Neighbours have said that the alarm has
> I thought the battery in the control panel and the one in the bell box
> were supposed to deal with power cuts. Could it be that one or both of
> the batteries needs to be changed?
Suggests that the battery in the panel is dead and the one in the bell
isn't.
Owain
F
Should have added that, according to the neighbours, the sounder sounds
fairly 'wheezy' and underpowered.
--
F
Bob Minchin
Bob
Phil L
I bought new batteries about 12 months ago, they were about �12 each IIRC,
yours won't be much different in price.
Word to the wise, don't order them off the internet - the P&P doubles the
overall cost - any decent electrical outlet will have them in stock
--
Phil L
RSRL Tipster Of The Year 2008
Al
> the batteries needs to be changed?
Sounds like the panel one needs replacing, and possibly the bellbox too.
They are *supposed* to be changed regularly, whne the system is 'serviced'.
Frankly, nobody bothers ;-)
Al.
Alan
<news@nowhere.?.invalid> wrote
When this happened to my alarm it was the battery at fault, even though
it was still giving a 12v reading. The batteries don't last forever and
after a few years should be changed.
I suspect that old batteries don't hold a full charge and while they can
maintain the alarm for a short period whilst the mains is off they drag
down one of the power supply lines when the mains comes back on. This
glitch on the internal supply line triggers the alarm. You can test this
yourself by switching off your mains power at the 'fuse' box for a
couple of minutes.
The battery in the bell is used to sound the alarm when someone cuts the
wires to the main control unit.
--
Alan
news2009 {at} admac {dot} myzen {dot} co {dot} uk
Andrew Gabriel
Battery life depends heavily on the quality of the charging circuit,
and the number of times you've had it run too flat. (A larger capacity
battery is less likely to run flat during a typical power cut.)
Commercial alarms often include a daily battery test cycle, and can
include circuitry to protect against running the battery too flat.
I don't know if these features are found in domestic alarms, but I
suspect certainly not cheaper ones. It could also be that commercial
alarms may have better quality charging circuits.
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Stuart Noble
Are they easy to change without triggering the alarm?
Andrew Gabriel
Stuart Noble <stuart...@ntlworld.com> writes:
> Phil L wrote:
>> I bought new batteries about 12 months ago, they were about �12 each IIRC,
>> yours won't be much different in price.
>> Word to the wise, don't order them off the internet - the P&P doubles the
>> overall cost - any decent electrical outlet will have them in stock
IME, they are vastly more expensive in local electrical outlets than
on the Internet. Just make sure you order enough to get free postage.
> Are they easy to change without triggering the alarm?
I suspect that depends heavily on the alarm.
On mine, I have to put it into Engineer Test Mode so I can
open the box without it going off, and then doesn't care
about you disconnecting the battery, as long as the mains
stays on. (If left disconnected, it generates a dead battery
alert, but continues working fine otherwise.)
Might want to be careful and check instructions though. I
could imagine a cheap charging circuit might rely on the
battery for voltage stablisation, and the internal electronics
supply voltage might go out of range if the battery is
disconnected.
Frank Erskine
Gabriel) had this to say:
>In article <3wC8m.58247$OO7....@text.news.virginmedia.com>,
> Stuart Noble <stuart...@ntlworld.com> writes:
>> Phil L wrote:
>>> I bought new batteries about 12 months ago, they were about �12 each IIRC,
>>> yours won't be much different in price.
>>> Word to the wise, don't order them off the internet - the P&P doubles the
>>> overall cost - any decent electrical outlet will have them in stock
>
>IME, they are vastly more expensive in local electrical outlets than
>on the Internet. Just make sure you order enough to get free postage.
>
I got a replacement battery locally (an auto electrical factor)
cheaper than anywhere I'd seen on the 'net. It was a decent quality
one too - not some unnamed brand. He didn't have the exact size one I
wanted, but it took only a day or two to get the right one.
Sadly the proprietor died a while ago and the business is closed down.
--
Frank Erskine
Alan
Noble <stuart...@ntlworld.com> wrote
>
>Are they easy to change without triggering the alarm?
The battery is easy to change - it will have two pull off spade
terminals, perhaps with the aid of a pair of pliers.
Access to the alarm panel will trigger the alarm. It will have an anti
tamper switch.
If you turn off the mains and then remove the battery the alarm may/will
forget all of it's settings so have all the instructions to hand.
Otherwise, leave the mains supply on, remove the case of the panel
(triggering the alarm), quickly change the battery, refit the cover with
one screw and reset/disable the alarm in the normal way.
Stuart Noble
Thanks. We don't actually set the alarm any more (inherited a cat and
can't be bothered to change the sensors) but I gather it may still go
off in the event of a power cut if the battery is naff
Mike Harrison
Probably not what you're seeing, but I once had a faulty PIR which false-triggered when its supply
voltage dropped slightly when the panel switched over to battery power. Took 2 Police callouts
before tracing this one....!
Dave Plowman (News)
Andrew Gabriel <and...@cucumber.demon.co.uk> wrote:
> Might want to be careful and check instructions though. I
> could imagine a cheap charging circuit might rely on the
> battery for voltage stablisation, and the internal electronics
> supply voltage might go out of range if the battery is
> disconnected.
At the cheaper end aren't most backup batteries an option?
--
*He's not dead - he's electroencephalographically challenged
Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.