🚀 go-pugleaf

My opinion...and worth what you paid for it:

First, smoke detector batteries are replaced so infrequently (1-2 times per
year) that it will take you a while to make up any price differential.

Also, some rechargable batteries have different voltage ranges than their
"regular" counterparts (as you state below) - which may be okay for
household electronics but could, theorectically, adversly affect the
operation of smoke detectors (I'm theorizing only, I have never tried this.)
E.g., if the voltage is sufficiently different towards the low side, the
smoke detector could produce low battery warning chirps even with a freshly
charged battery.

Also, the power curve over time for rechargables such as NiCads is different
than regular alkalines, which could affect the performance of the low
battery warning system. I seem to recall that NiCads hold very near their
stated voltage, and then drop off like a rock to 0v when they die. This
could mean that the low battery warning doesn't have time to warn you before
the voltage drops so low that it can no longer produce an audible chirp.

Lastly, but probably most importantly, safety devices, IMO, are not the
place to scrimp just to save a few cents - go with whatever the manufacturer
of the smoke detector recommends. I mean, what are you going to save...a few
dollars over the next 10 years. Better safe than sorry.

---JRE---



Bhoot Nath <bhoot@my-deja.com> wrote in message
news:867o75$i3q$1@nnrp1.deja.com...
> Three of the six smoke alarms in began chirping a few days back. I
> presume that this means that the 9 volts batteries must be replaced.
>
> So, we thought, rather than buying alkaline batteries, why not buy
> rechargeable ones. We already have a recharger that works with
> AA/AAA/9V etc. After a few searches at yahoo.com, excite.com &
> mysimon.com we found out that cheapest mail order is about $7, about
> the same as the nearest Walmart.
>
> 1. Should we get Nickel Cadmium (NiCad) or Nickel Metal Hydride (NiMH)
> batteries for a smoke alarm? Is there a reason to prefer one vs other?
>
> 2. We looked at an EVEREADY pack and it was marked "9 volts (Use 7.2
> volts)" ... Does this mean it would deliver only 7.2 volts? If so, is
> it safe to use it for a smoke alarm? If not, are there any rechargeable
> 9 volt batteries that deliver 9 volts?
>
> 3. On a web site, I also saw a reference to "Super long lasting,
> industrial strength 9 volt alkaline batter"  for $20, about 10 times
> what a regular 9 volt battery costs. Any one has any experience with
> this kind of battery? WOuld it last 10 years in a smoke alarm?
>
> Thanks for your feedback.
> --
> Bhoot Nath
> Email: bhoot@my-dejanews.com
>
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.

Bhoot Nath wrote:
> 
> Three of the six smoke alarms in began chirping a few days back. I
> presume that this means that the 9 volts batteries must be replaced.
> 
> So, we thought, rather than buying alkaline batteries, why not buy
> rechargeable ones. We already have a recharger that works with
> AA/AAA/9V etc. After a few searches at yahoo.com, excite.com &
> mysimon.com we found out that cheapest mail order is about $7, about
> the same as the nearest Walmart.
> 
> 1. Should we get Nickel Cadmium (NiCad) or Nickel Metal Hydride (NiMH)
> batteries for a smoke alarm? Is there a reason to prefer one vs other?

Neither.

> 2. We looked at an EVEREADY pack and it was marked "9 volts (Use 7.2
> volts)" ... Does this mean it would deliver only 7.2 volts? If so, is
> it safe to use it for a smoke alarm? If not, are there any rechargeable
> 9 volt batteries that deliver 9 volts?

A fully charged, fresh 6-cell Nicad will deliver about 6*1.4V=8.4V.
After the initial charge wears off (a week or two) it'll be down to
6*1.2V=7.2V.

Ni-Cad batteries will typically have a few months of shelf-life
between charges.  This means that you'll have to charge the batteries
every few months even if there were no drain.  Typical "9V"
Nicads have a capacity of 100 mAH or so, compared to several
hundred mAH for a alkaline 9V, so you might not even go a few
months between recharges.

Typical *overall* life of the Ni-Cads in this sort of use will be
a few years.  Knowing that an alkaline 9-volt will last 6 months
or a year, are you really saving any money by going to Ni-Cads?

Ni-Cads are a real winner in high-drain frequent cycle applications,
like portable audio equipment, flashlights, cellphones, kids toys, etc.
Here their short (a few weeks to a few months) charge retention and high
peak current capacity make them suitable.  For a low drain application
like a smoke alarm they're poor choices.

> 3. On a web site, I also saw a reference to "Super long lasting,
> industrial strength 9 volt alkaline batter"  for $20, about 10 times
> what a regular 9 volt battery costs. Any one has any experience with
> this kind of battery? WOuld it last 10 years in a smoke alarm?

There are lithium batteries in a 9-volt package that offer excellent
shelf life and more capacity than an alkaline.  These are sold under
Kodak and a few other brand names, and indeed they cost a lot more
than alkalines.

I would stick to the manufacturer's recommended alkaline batteries
if I were you... and don't forget to regularly test the alarms!

Tim.

On Thu, 20 Jan 2000 19:38:16 GMT, Bhoot Nath <bhoot@my-deja.com> wrote:

>3. On a web site, I also saw a reference to "Super long lasting,
>industrial strength 9 volt alkaline batter"  for $20, about 10 times
>what a regular 9 volt battery costs. Any one has any experience with
>this kind of battery? WOuld it last 10 years in a smoke alarm?

now here in oregon all smoke detectors have to have lithium batteries. these
give about 10 years service. they are about 10.00 each. or about 15.00 to 18.00
for a smoke detector with one. the only way to go.




Knight's Toolworks & Custom Furniture Galoot Made Products-
Custom made wooden planes at reasonable prices
See http://home.pacifier.com/~stevek/webpics 
For prices and ordering instructions.

Records and tapes turned into CD's Save your vinyl and still enjoy it
Visit Http://www.pacifier.com/~stevek/ for details.

You need to use an Alkaline or better battery anyway in some
detectors. This is due to the battery discharge curve. They need to
maintain the full 9 volts as long as possible to be effective.

Alkalines keep their voltage right up to the end.

I agree, the detector with a lithium for $15 to $18 is a good way to
go.

On Thu, 20 Jan 2000 15:13:35 -0800, Steve Knight <stevek@pacifier.com>
wrote:

>On Thu, 20 Jan 2000 19:38:16 GMT, Bhoot Nath <bhoot@my-deja.com> wrote:
>
>>3. On a web site, I also saw a reference to "Super long lasting,
>>industrial strength 9 volt alkaline batter"  for $20, about 10 times
>>what a regular 9 volt battery costs. Any one has any experience with
>>this kind of battery? WOuld it last 10 years in a smoke alarm?
>
>now here in oregon all smoke detectors have to have lithium batteries. these
>give about 10 years service. they are about 10.00 each. or about 15.00 to 18.00
>for a smoke detector with one. the only way to go.
>
>
>
>
>Knight's Toolworks & Custom Furniture Galoot Made Products-
>Custom made wooden planes at reasonable prices
>See http://home.pacifier.com/~stevek/webpics 
>For prices and ordering instructions.
>
>Records and tapes turned into CD's Save your vinyl and still enjoy it
>Visit Http://www.pacifier.com/~stevek/ for details.

Bhoot Nath wrote:

> Three of the six smoke alarms in began chirping a few days back. I
> presume that this means that the 9 volts batteries must be replaced.
>
> So, we thought, rather than buying alkaline batteries, why not buy
> rechargeable ones. We already have a recharger that works with
> AA/AAA/9V etc. After a few searches at yahoo.com, excite.com &
> mysimon.com we found out that cheapest mail order is about $7, about
> the same as the nearest Walmart.

I agree with everyone else that says this is not a good idea.  At 7.2
volts, they may chirp all the time.

> 3. On a web site, I also saw a reference to "Super long lasting,
> industrial strength 9 volt alkaline batter"  for $20, about 10 times
> what a regular 9 volt battery costs. Any one has any experience with
> this kind of battery? WOuld it last 10 years in a smoke alarm?

Well, according to the packaging on the last smoke alarm that I bought, the
Duracell that came with it is supposed to last 2 years, and I can get those
for under $2, so I would think that good alkalines would be a better bet
than a $20 battery (or 3).

I can't see why one would change the battery every six months, even though
lives and property are at stake.  The alarm lets you know when the battery
is dying, and the alarm will still sound in the event of a fire.  I don't
enjoy changing out batteries where a ladder is involved, so a 2 year
changing schedule makes a lot of sense to me.

Just my $.02.

JK

John Kostecki <jkost@execpc.com> wrote:
>Bhoot Nath wrote:
>
>> Three of the six smoke alarms in began chirping a few days back. I
>> presume that this means that the 9 volts batteries must be replaced.
>> So, we thought, rather than buying alkaline batteries, why not buy
>> rechargeable ones. We already have a recharger that works with
>> AA/AAA/9V etc. After a few searches at yahoo.com, excite.com &
>> mysimon.com we found out that cheapest mail order is about $7, about
>> the same as the nearest Walmart.
>
>I agree with everyone else that says this is not a good idea.  At 7.2
>volts, they may chirp all the time.
>
>> 3. On a web site, I also saw a reference to "Super long lasting,
>> industrial strength 9 volt alkaline batter"  for $20, about 10 times
>> what a regular 9 volt battery costs. Any one has any experience with
>> this kind of battery? WOuld it last 10 years in a smoke alarm?
>
>Well, according to the packaging on the last smoke alarm that I bought, the
>Duracell that came with it is supposed to last 2 years, and I can get those
>for under $2, so I would think that good alkalines would be a better bet
>than a $20 battery (or 3).
>I can't see why one would change the battery every six months, even though
>lives and property are at stake.  The alarm lets you know when the battery
>is dying, and the alarm will still sound in the event of a fire.  I don't
>enjoy changing out batteries where a ladder is involved, so a 2 year
>changing schedule makes a lot of sense to me.
>JK

Ditto.  Alkalines last a very long time in smoke alarms.  You can put
the date on one with a permanent marker and find out.  They last so
long that buying only one or two at a time probably is best, unless
you have another use for them.  I just test the smoke alarm from time
to time and wait for it to tell me (chirp) when to change the battery.
C ya, 
LShaping

In article <867o75$i3q$1@nnrp1.deja.com>,
  Bhoot Nath <bhoot@my-deja.com> wrote:
>Three of the six smoke alarms in began chirping a few days back. I
>presume that this means that the 9 volts batteries must be replaced.
>
>So, we thought, rather than buying alkaline batteries, why not buy
>rechargeable ones. We already have a recharger that works with
>AA/AAA/9V etc.

It's dangerous to charge alkalines in a charger designed for nicad or
NiMH batteries becuase the pressure can build up to well over 50 PSI
internally and cause rupture.  Also, alkalines just don't recharge well
unless they're designed for that purpose (like Renewals), but even
those are good for only 10-20 recharges.

>1. Should we get Nickel Cadmium (NiCad) or Nickel Metal Hydride (NiMH)
>batteries for a smoke alarm? Is there a reason to prefer one vs other?

>2. We looked at an EVEREADY pack and it was marked "9 volts (Use 7.2
>volts)" ... Does this mean it would deliver only 7.2 volts? If so, is
>it safe to use it for a smoke alarm? If not, are there any rechargeable
>9 volt batteries that deliver 9 volts?

UL approved smoke alarms are required to contain circuitry to warn when
the battery is low and to continue operating normally for at least 30
more days.  This circuitry measures the voltage, and nicad and NiMH
batteries in this size are too low in voltage even when fully charged,
either 7.2V or 8.4V.  And unlike alkaline and lithium batteries, nicad
and NiMH batteries put out a nearly constant voltage until the end,
meaning the low-battery warning may not be noticed because the battery
will go completely dead so quickly.

>3. On a web site, I also saw a reference to "Super long lasting,
>industrial strength 9 volt alkaline batter"  for $20, about 10 times
>what a regular 9 volt battery costs. Any one has any experience with
>this kind of battery? WOuld it last 10 years in a smoke alarm?

Duracell makes some high-capacity alkalines with about 70% more energy
capacity than normal alkalines, but they don't last any longer in
storage.  Because smoke detectors draw very little power, their
batteries are more likely to run down from normal spoilage than
anything else, in about 2-3 years.  But there are lithium batteries
with not only 3 times the energy capacity but also 3 times the shelf
life, and they will last 10 years in a smoke detector.  In fact some
detectors with them are guaranteed for 10 years.  Kodak Ultralife is
one brand of lithium 9V battery, and it's also sold under the brand
name of one smoke detector.


Sent via Deja.com http://www.deja.com/
Before you buy.

Said jkost@execpc.com (John Kostecki) in misc.consumers:
>I can't see why one would change the battery every six months, even though
>lives and property are at stake.  The alarm lets you know when the battery
>is dying, and the alarm will still sound in the event of a fire.

That's true in theory.

It's not a bad idea to go around on the first of every month and 
test each smoke detector. I used to own one that never chirped 
when the battery was low, so testing it was the only way to know 
when the battery needed changing.

Also make sure you use a strong enough battery. Not all 9V 
batteries can deliver the needed current, as I found out by 
reading the fine print in the leaflet that came with my detector. 
A fresh silver Eveready would not make the alarm sound, but some 
other brand (Duracell, maybe? I can't rememeber) did.

-- 
Stan Brown, Oak Road Systems, Cleveland, Ohio, USA
                http://www.mindspring.com/~brahms/
My reply address is correct as is. The courtesy of providing a correct
reply address is more important to me than time spent deleting spam.

In article <MPG.12f41ed6cb6344bf98a9d2@news.mindspring.com>,
  brahms@mindspring.com (Stan Brown) wrote:

>It's not a bad idea to go around on the first of every month and
>test each smoke detector. I used to own one that never chirped
>when the battery was low, so testing it was the only way to know
>when the battery needed changing.
>
>Also make sure you use a strong enough battery. Not all 9V
>batteries can deliver the needed current, as I found out by
>reading the fine print in the leaflet that came with my detector.
>A fresh silver Eveready would not make the alarm sound, but some
>other brand (Duracell, maybe? I can't rememeber) did.

While it's bad to use those silver batteries (carbon-zinc) in a smoke
detector, a fresh one that really was fresh (shelf life is terrible,
especially at high temperatures) should be able to sound the alarm
because I've seen them do so, and that was with very old detectors
with  mechanical buzzers that drew 150 milliamps.  Today's detectors
instead usually use piezoelectric whistles that draw far less current.


Sent via Deja.com http://www.deja.com/
Before you buy.

We use UltraLife 10-year smoke alarm batteries in our Fire-X built in
smoke detectors (which specifically allow the use of a 10-year
battery).  Some of the detectors are hard to reach for yearly battery
replacement.  I had originally seen these batteries at a very high
price in a catalog -- as noted by another poster in this thread; I did
some calling around, and found them for $6.99 at a local ServiceStar
hardware store.  Obviously, at this price they are extremely
economical as well as convenient.  Your mileage may vary.  -- KM