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Battery for smoke alarm: Zn-Cl or Mn-alkaline?
While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. Both have PP3 batteries currently showing about 8.5 volts, so I've still no idea which one it was, but I'll replace both to be on the safe side.
Although manganese alkaline batteries are better value for most things, I have a vague memory that zinc chloride ones actually last longer for very low consumption tasks, such as door bells and smoke alarms. Is this right? -- Clive Page |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
In article ,
Clive Page writes: While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. Both have PP3 batteries currently showing about 8.5 volts, so I've still no idea which one it was, but I'll replace both to be on the safe side. Although manganese alkaline batteries are better value for most things, I have a vague memory that zinc chloride ones actually last longer for very low consumption tasks, such as door bells and smoke alarms. Is this right? For smoke alarms on PP3's, I use alkaline, and replace annually. They last longer than a year, but not 2 years, but it's easy to nominate a date, such as your birthday, or Christmas, when you routinely replace them. I did buy some of the long life lithum PP3 cells, and they worked for a year or two, but then the detectors started bleeping. However, the batteries are 11V, so I presume this is due to too high voltage, although I'm not sure why they worked for some time before that. Most of mine run off the burglar alarm supply, so there are no batteries to change in them, but I look after various battery ones around the family. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
Over voltage is not a problem. the problem is internal resistance, ie they
may measure high on small loads, but when they do a test they momentarily take more current, ie with the bleeper and hence their voltage starts to drop due to the internal resistance. Brian -- ----- - This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please! "Andrew Gabriel" wrote in message ... In article , Clive Page writes: While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. Both have PP3 batteries currently showing about 8.5 volts, so I've still no idea which one it was, but I'll replace both to be on the safe side. Although manganese alkaline batteries are better value for most things, I have a vague memory that zinc chloride ones actually last longer for very low consumption tasks, such as door bells and smoke alarms. Is this right? For smoke alarms on PP3's, I use alkaline, and replace annually. They last longer than a year, but not 2 years, but it's easy to nominate a date, such as your birthday, or Christmas, when you routinely replace them. I did buy some of the long life lithum PP3 cells, and they worked for a year or two, but then the detectors started bleeping. However, the batteries are 11V, so I presume this is due to too high voltage, although I'm not sure why they worked for some time before that. Most of mine run off the burglar alarm supply, so there are no batteries to change in them, but I look after various battery ones around the family. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
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Battery for smoke alarm: Zn-Cl or Mn-alkaline?
Clive Page wrote:
While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. Both have PP3 batteries currently showing about 8.5 volts, so I've still no idea which one it was, but I'll replace both to be on the safe side. Although manganese alkaline batteries are better value for most things, I have a vague memory that zinc chloride ones actually last longer for very low consumption tasks, such as door bells and smoke alarms. Is this right? I remember that being the received wisdom, but the specified shelf life of alkaline batteries seems so long ahead nowadays that I wonder if it is (still) true? -- Roger Hayter |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
On 16/03/2018 14:10, Clive Page wrote:
While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. It's temperature. During the night the battery gets colder and the terminal voltage drops. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
On 16/03/2018 16:13, Roger Hayter wrote:
I remember that being the received wisdom, but the specified shelf life of alkaline batteries seems so long ahead nowadays that I wonder if it is (still) true? Fresh Duracell Industrial (formerly Procell) alkaline batteries are dated 2024. -- mailto : news {at} admac {dot} myzen {dot} co {dot} uk |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
On Fri, 16 Mar 2018 15:37:10 +0000, Scott wrote:
I did buy some of the long life lithum PP3 cells, and they worked for a year or two, but then the detectors started bleeping. However, the batteries are 11V, so I presume this is due to too high voltage, although I'm not sure why they worked for some time before that. How can they be too high a voltage? Are batteries not 12 Volts nominal? The PP3 is a 9 volt battery. -- My posts are my copyright and if @diy_forums or Home Owners' Hub wish to copy them they can pay me £1 a message. Use the BIG mirror service in the UK: http://www.mirrorservice.org *lightning surge protection* - a w_tom conductor |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
On 16 Mar 2018 16:33:57 GMT, Bob Eager wrote:
On Fri, 16 Mar 2018 15:37:10 +0000, Scott wrote: I did buy some of the long life lithum PP3 cells, and they worked for a year or two, but then the detectors started bleeping. However, the batteries are 11V, so I presume this is due to too high voltage, although I'm not sure why they worked for some time before that. How can they be too high a voltage? Are batteries not 12 Volts nominal? The PP3 is a 9 volt battery. Good point. Apologies for introducing fake news to this discussion :-) |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
alan_m wrote:
On 16/03/2018 14:10, Clive Page wrote: While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. It's temperature. During the night the battery gets colder and the terminal voltage drops. That would explain why the clock in my garage lost time when it was very cold and was fine when it got warmer. I am enlightened. |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
On 16/03/2018 15:37, Scott wrote:
On Fri, 16 Mar 2018 14:36:27 -0000 (UTC), (Andrew Gabriel) wrote: In article , Clive Page writes: While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. Both have PP3 batteries currently showing about 8.5 volts, so I've still no idea which one it was, but I'll replace both to be on the safe side. Although manganese alkaline batteries are better value for most things, I have a vague memory that zinc chloride ones actually last longer for very low consumption tasks, such as door bells and smoke alarms. Is this right? For smoke alarms on PP3's, I use alkaline, and replace annually. They last longer than a year, but not 2 years, but it's easy to nominate a date, such as your birthday, or Christmas, when you routinely replace them. I'm sure mine last far longer than two years. If you buy ones that don't have replaceable batteries I thought they lasted five years. Why would quality batteries be any different? Because they are not alkaline batteries. Mine are supposed to last 10 years, I will let you know in 6 years if I remember. |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
On Friday, 16 March 2018 14:10:46 UTC, Clive Page wrote:
While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. Both have PP3 batteries currently showing about 8.5 volts, so I've still no idea which one it was, but I'll replace both to be on the safe side. Although manganese alkaline batteries are better value for most things, I have a vague memory that zinc chloride ones actually last longer for very low consumption tasks, such as door bells and smoke alarms. Is this right? I don't think so. ZnC/Cl leak when flat too. NT |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
In article ,
Scott writes: On Fri, 16 Mar 2018 14:36:27 -0000 (UTC), (Andrew Gabriel) wrote: In article , Clive Page writes: While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. Both have PP3 batteries currently showing about 8.5 volts, so I've still no idea which one it was, but I'll replace both to be on the safe side. Although manganese alkaline batteries are better value for most things, I have a vague memory that zinc chloride ones actually last longer for very low consumption tasks, such as door bells and smoke alarms. Is this right? For smoke alarms on PP3's, I use alkaline, and replace annually. They last longer than a year, but not 2 years, but it's easy to nominate a date, such as your birthday, or Christmas, when you routinely replace them. I'm sure mine last far longer than two years. If you buy ones that don't have replaceable batteries I thought they lasted five years. Why 10 years I think, which is because they have built-in non- recharable lithium cells. would quality batteries be any different? I did buy some of the long life lithum PP3 cells, and they worked for a year or two, but then the detectors started bleeping. However, the batteries are 11V, so I presume this is due to too high voltage, although I'm not sure why they worked for some time before that. How can they be too high a voltage? Are batteries not 12 Volts nominal? They're 9V labeled, but they have 3 non-rechargable lithium cells in them which are nearly 4V each, so they're well over 9V. It does amuse me that it says "do not incinerate" on them ;-) Most of mine run off the burglar alarm supply, so there are no batteries to change in them, but I look after various battery ones around the family. I assume your burglar alarm system has a battery to cover power failures. Yes, 12V. The smoke alarms are standard 9V PP3 battery alarms, but instead of the battery, there's a PP3 sized module which drops the 12V to 9V and measures the current. When the current increases due to the sounder, the module signals back to the alarm panel that the smoke sensor has triggered. -- Andrew Gabriel [email address is not usable -- followup in the newsgroup] |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
On 16/03/2018 16:16, alan_m wrote:
On 16/03/2018 14:10, Clive Page wrote: While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. It's temperature. During the night the battery gets colder and the terminal voltage drops. I thought it might be. It's surprising that a degree or two would make that much difference though. -- Clive Page |
Battery for smoke alarm: Zn-Cl or Mn-alkaline?
On 16/03/2018 22:52, Clive Page wrote:
On 16/03/2018 16:16, alan_m wrote: On 16/03/2018 14:10, Clive Page wrote: While lying awake last night I heard short beeps at long intervals, almost certainly a smoke alarm trying to tell me its battery was low, but I couldn't be bothered to get up to find which one (of two) it was. In the morning, by some variant of Murphy's Law, the beeping had stopped but both worked perfectly well when I pressed their test buttons. It's temperature. During the night the battery gets colder and the terminal voltage drops. I thought it might be.Â* It's surprising that a degree or two would make that much difference though. It only happens when the batteries are on their last legs. But you made the right decision by deciding to swap the batteries in both smokes and not **** about deciding if one battery is better than the other one. -- Adam |
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