Alarm unit battery

Mike Ge · Jun 28th, 2013, 21:14

I have the "Alarm need Service" message, and with the help of other threads, have removed the siren unit, cut it open and removed a rather "juicy" battery. The circuit looks ok, so I have nothing to lose by trying to replace the battery - but what voltage does it need. I had in mind to externally mount however many NiMH AA cells (1.2V each) it takes and wire back to the original connector. One thread linked me to a Farnell page with a 3.6V battery, another reply suggested it was 7.2V. The battery removed appears to be three units spot welded together - but are the units individual cells or are they 2.4V double cells? Does anyone have a definite answer? Thanks for looking.

Marmitespreader · Jun 28th, 2013, 21:55

The alarm voltage is 7.2.
The 3 units you pulled are 2.4v made up of 2@1.2 (total 3x2x1.2=7.2)
I don't think large capacity batteries (AAA NImh) will be necessary, but I don't think would cause any adverse effects. Farnell is a reputable place to get the batts if you go that route.

Mike Ge · Jun 28th, 2013, 22:43

Marmitespreader - Thanks for your help, it will give me a bit of confidence to have a go. I know AA cells exceed the capacity needed, but I have quite a few sitting around, and also have AA battery holders that I can strap to the outside of the siren unit. Any further advice welcome!

Marmitespreader · Jun 28th, 2013, 23:18

I think youve got it covered, you could always get some sanyo XXX eneloops.
Once charged these batts can be left on a shelf for a year & still retain 80% of their capacity. But I would save the expence & use what you have, being externally mounted, will be an easy fix when/if batts fail

Robs74 · Jul 1st, 2013, 22:52

I too have just got the alarm service message but even if i remove fuse 38 everything (including sound) still works. I was thinking the battery needs replacing so would something like this http://bit.ly/17PwAv3 be any good to replace the alarm battery if I mount it outside the alarm box?

Marmitespreader · Jul 1st, 2013, 23:25

Anything to make up the 7.2v

mrfixer · Jul 2nd, 2013, 03:40

not to steal this thread but i removed my alarm module removed battery and subsequently lost old battery can anyone tell me what side of the double pin is positive please.
thanks in advance Joe

Gazzza · Jul 2nd, 2013, 12:09

Just put a volt meter on it

Rutz · Jul 2nd, 2013, 12:50

Or if you've not got a voltmeter there's some good images on this thread c/o Blunders http://www.volvoforums.org.uk/showthread.php?t=139588

Mike Ge · Jul 2nd, 2013, 18:14

mrfixer - don't worry about stealing the thread - you've generated some interesting extra replies, from which I expect you've found the answer to your wiring question. If not, I can say that on my unit the red wire is nearest the transformer. Thanks for the link to photos, rutz, I had some dark staining on my circuit board, and on trying to clean it a piece flaked away. Unfortunately, I see from one of the photos that this was a rather fried "C19", so that's probably the end of my repair attempt. The damage looks more thermal rather than chemical burn, I wonder if it was a failed component that caused ohmic heating and demise of the battery?
Does anyone know if I can just buy a circuit board? Or - where's the best (i.e. cheapest) place to buy the whole module?

Jun 28th, 2013, 21:14	#1
Mike Ge New Member Last Online: Jun 10th, 2015 15:28 Join Date: May 2012 Location: Redhill	Alarm unit battery I have the "Alarm need Service" message, and with the help of other threads, have removed the siren unit, cut it open and removed a rather "juicy" battery. The circuit looks ok, so I have nothing to lose by trying to replace the battery - but what voltage does it need. I had in mind to externally mount however many NiMH AA cells (1.2V each) it takes and wire back to the original connector. One thread linked me to a Farnell page with a 3.6V battery, another reply suggested it was 7.2V. The battery removed appears to be three units spot welded together - but are the units individual cells or are they 2.4V double cells? Does anyone have a definite answer? Thanks for looking.

Jun 28th, 2013, 21:55	#2
Marmitespreader Master Member Last Online: Mar 24th, 2024 09:34 Join Date: Jun 2012 Location: Wales	The alarm voltage is 7.2. The 3 units you pulled are 2.4v made up of 2@1.2 (total 3x2x1.2=7.2) I don't think large capacity batteries (AAA NImh) will be necessary, but I don't think would cause any adverse effects. Farnell is a reputable place to get the batts if you go that route. __________________ Last edited by Marmitespreader; Jun 28th, 2013 at 22:02.

Jun 28th, 2013, 23:18	#4
Marmitespreader Master Member Last Online: Mar 24th, 2024 09:34 Join Date: Jun 2012 Location: Wales	I think youve got it covered, you could always get some sanyo XXX eneloops. Once charged these batts can be left on a shelf for a year & still retain 80% of their capacity. But I would save the expence & use what you have, being externally mounted, will be an easy fix when/if batts fail __________________

Jul 1st, 2013, 23:25	#6
Marmitespreader Master Member Last Online: Mar 24th, 2024 09:34 Join Date: Jun 2012 Location: Wales	Anything to make up the 7.2v __________________

Jul 2nd, 2013, 12:09	#8
Gazzza Senior Member Last Online: Apr 27th, 2021 10:17 Join Date: Jul 2011 Location: Leicester	Just put a volt meter on it __________________ D5 2003 V90 XC AWD 2.4T3

Jun 28th, 2013, 22:43	#3
Mike Ge New Member Last Online: Jun 10th, 2015 15:28 Join Date: May 2012 Location: Redhill	Marmitespreader - Thanks for your help, it will give me a bit of confidence to have a go. I know AA cells exceed the capacity needed, but I have quite a few sitting around, and also have AA battery holders that I can strap to the outside of the siren unit. Any further advice welcome!

Jul 1st, 2013, 22:52	#5
Robs74 Member Last Online: Jan 26th, 2017 15:11 Join Date: Mar 2013 Location: Nr York	I too have just got the alarm service message but even if i remove fuse 38 everything (including sound) still works. I was thinking the battery needs replacing so would something like this http://bit.ly/17PwAv3 be any good to replace the alarm battery if I mount it outside the alarm box?

Jul 2nd, 2013, 03:40	#7
mrfixer Member Last Online: Apr 23rd, 2024 12:35 Join Date: Nov 2008 Location: Livingston	not to steal this thread but i removed my alarm module removed battery and subsequently lost old battery can anyone tell me what side of the double pin is positive please. thanks in advance Joe

Jul 2nd, 2013, 12:50	#9
Rutz Junior Member Last Online: Nov 19th, 2022 12:45 Join Date: Apr 2013 Location: Manchester	Or if you've not got a voltmeter there's some good images on this thread c/o Blunders http://www.volvoforums.org.uk/showthread.php?t=139588

Jul 2nd, 2013, 18:14	#10
Mike Ge New Member Last Online: Jun 10th, 2015 15:28 Join Date: May 2012 Location: Redhill	mrfixer - don't worry about stealing the thread - you've generated some interesting extra replies, from which I expect you've found the answer to your wiring question. If not, I can say that on my unit the red wire is nearest the transformer. Thanks for the link to photos, rutz, I had some dark staining on my circuit board, and on trying to clean it a piece flaked away. Unfortunately, I see from one of the photos that this was a rather fried "C19", so that's probably the end of my repair attempt. The damage looks more thermal rather than chemical burn, I wonder if it was a failed component that caused ohmic heating and demise of the battery? Does anyone know if I can just buy a circuit board? Or - where's the best (i.e. cheapest) place to buy the whole module?

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