More electrics than electronics, perhaps, but what might cause a 1.5
button cell battery (such as used in watches, calculators, car keys
with remote capabilities etc ) to change polarity after a month or
two? Only one of four batteries (in a car key in this instance) seems
to be affected.

Terry wrote:
More electrics than electronics, perhaps, but what might cause a 1.5
button cell battery (such as used in watches, calculators, car keys
with remote capabilities etc ) to change polarity after a month or
two? Only one of four batteries (in a car key in this instance) seems
to be affected.


The cell failed then was reverse charged by the other cells in the battery

RonUK

On Fri, 21 Mar 2008 14:38:43 +0000, "Ron(UK)"
wrote:

Terry wrote:
More electrics than electronics, perhaps, but what might cause a 1.5
button cell battery (such as used in watches, calculators, car keys
with remote capabilities etc ) to change polarity after a month or
two? Only one of four batteries (in a car key in this instance) seems
to be affected.


The cell failed then was reverse charged by the other cells in the battery

OK, could this in any way be the fault of the key itself, or is it
more likely to be a cheap battery?

Terry wrote:
On Fri, 21 Mar 2008 14:38:43 +0000, "Ron(UK)"
wrote:

Terry wrote:
More electrics than electronics, perhaps, but what might cause a 1.5
button cell battery (such as used in watches, calculators, car keys
with remote capabilities etc ) to change polarity after a month or
two? Only one of four batteries (in a car key in this instance) seems
to be affected.

The cell failed then was reverse charged by the other cells in the battery

OK, could this in any way be the fault of the key itself, or is it
more likely to be a cheap battery?


If all the cells are just in series, then cheap battery

Ron

Terry wrote:

On Fri, 21 Mar 2008 14:38:43 +0000, "Ron(UK)"
wrote:

Terry wrote:
More electrics than electronics, perhaps, but what might cause a 1.5
button cell battery (such as used in watches, calculators, car keys
with remote capabilities etc ) to change polarity after a month or
two? Only one of four batteries (in a car key in this instance)
seems to be affected.


The cell failed then was reverse charged by the other cells in the
battery

OK, could this in any way be the fault of the key itself, or is it
more likely to be a cheap battery?

Its a natural phenomena ! You are never going to get four batteries to
have identical voltages and deliver identical currents ! So at some
point, one of the batteries is going to become depleted first. Then
the current through it causes it to become charged in reverse.

This also applies to rechargeable batteries as well. Its a particular
problem with the sort of battery packs used in things like electric
drills ! Never let them become completely discharged for this reason !

This is why you will see manufacturers warnings to replace all the
batteries at once with new ones.

I have a remote control that uses four AA cells and at some point it
stops working. I then test the cells that I take out, throw the bad
one away and use the other three in things like my wall clock or other
remote that uses only two batteries.
--
Best Regards:
Baron.

On Fri, 21 Mar 2008 15:36:38 +0000, Baron
wrote:

Terry wrote:

On Fri, 21 Mar 2008 14:38:43 +0000, "Ron(UK)"
wrote:

Terry wrote:
More electrics than electronics, perhaps, but what might cause a 1.5
button cell battery (such as used in watches, calculators, car keys
with remote capabilities etc ) to change polarity after a month or
two? Only one of four batteries (in a car key in this instance)
seems to be affected.


The cell failed then was reverse charged by the other cells in the
battery

OK, could this in any way be the fault of the key itself, or is it
more likely to be a cheap battery?

Its a natural phenomena ! You are never going to get four batteries to
have identical voltages and deliver identical currents ! So at some
point, one of the batteries is going to become depleted first. Then
the current through it causes it to become charged in reverse.

This also applies to rechargeable batteries as well. Its a particular
problem with the sort of battery packs used in things like electric
drills ! Never let them become completely discharged for this reason !

This is why you will see manufacturers warnings to replace all the
batteries at once with new ones.

I have a remote control that uses four AA cells and at some point it
stops working. I then test the cells that I take out, throw the bad
one away and use the other three in things like my wall clock or other
remote that uses only two batteries.
--
Best Regards:
Baron.

Thank you both. I'm glad that it's not the key that's doing it!

This happened to me a few years ago with the N cells in an HP calculator.

On Fri, 21 Mar 2008 17:58:23 -0700, "William Sommerwerck"
wrote:

This happened to me a few years ago with the N cells in an HP calculator.

The odd thing (to me, at least) is that although such button cells
can't be charged once they're dead, they can apparently be reverse
charged.

On Sat, 22 Mar 2008 04:59:56 GMT, Terry wrote:
On Fri, 21 Mar 2008 17:58:23 -0700, "William Sommerwerck"
wrote:

This happened to me a few years ago with the N cells in an HP calculator.

The odd thing (to me, at least) is that although such button cells
can't be charged once they're dead, they can apparently be reverse
charged.

Having a "charge" and having a "polarity" are pretty much two separate
things.

On 3/22/08 7:50 AM, in article ,
"Allodoxaphobia" wrote:

On Sat, 22 Mar 2008 04:59:56 GMT, Terry wrote:
On Fri, 21 Mar 2008 17:58:23 -0700, "William Sommerwerck"
wrote:

This happened to me a few years ago with the N cells in an HP calculator.

The odd thing (to me, at least) is that although such button cells
can't be charged once they're dead, they can apparently be reverse
charged.

Having a "charge" and having a "polarity" are pretty much two separate
things.

So what do YOU call it when a cell's voltage polarity becomes reversed?

Reversed Polarity.
cuhulin

On 22 Mar 2008 14:50:10 GMT, Allodoxaphobia
put finger to keyboard and composed:

On Sat, 22 Mar 2008 04:59:56 GMT, Terry wrote:
On Fri, 21 Mar 2008 17:58:23 -0700, "William Sommerwerck"
wrote:

This happened to me a few years ago with the N cells in an HP calculator.

The odd thing (to me, at least) is that although such button cells
can't be charged once they're dead, they can apparently be reverse
charged.

Having a "charge" and having a "polarity" are pretty much two separate
things.

I'd connect a resistor across the battery and monitor the voltage as
it "discharges". A quick test and measure with a 100K resistor and
then a 10K and 1K should give you a feel for how much stored charge
there is.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.

On Mar 22, 12:59*am, (Terry) wrote:
On Fri, 21 Mar 2008 17:58:23 -0700, "William Sommerwerck"

wrote:
This happened to me a few years ago with the N cells in an HP calculator.

The odd thing (to me, at least) is that although such button cells
can't be charged once they're dead, they can apparently be reverse
charged.

well, you can often recharge them in the positive direction, but
they're not designed for it, so bad things might happen, like they
build up internal pressure and leak. chemically, though, all these
electrochemical reactions are reversible unless one of the products is
a gas or something and goes away.

z wrote in
:

On Mar 22, 12:59*am, (Terry) wrote:
On Fri, 21 Mar 2008 17:58:23 -0700, "William Sommerwerck"

wrote:
This happened to me a few years ago with the N cells in an HP
calculator.


The odd thing (to me, at least) is that although such button cells
can't be charged once they're dead, they can apparently be reverse
charged.

well, you can often recharge them in the positive direction, but
they're not designed for it, so bad things might happen, like they
build up internal pressure and leak. chemically, though, all these
electrochemical reactions are reversible unless one of the products is
a gas or something and goes away.

Not just leak. Explode. Spread toxic chemicals.

This can happen if they are reverse charged, overcharged or charged too
rapidly. I stuck one into a 'universal battery charger' and forgot about
it until I hear a loud bang a few minutes later! Made one heck of a mess.

Attempting to charge a mercury cell has additional hazards because heated
mercury out-gasses enough mercury vapor to be fatal.








--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap

Terry wrote:
On Fri, 21 Mar 2008 17:58:23 -0700, "William Sommerwerck"
wrote:

This happened to me a few years ago with the N cells in an HP calculator.

The odd thing (to me, at least) is that although such button cells
can't be charged once they're dead, they can apparently be reverse
charged.

Actually, they can.

I had a situation a couple of weeks ago where the button cell in a
guitarist's pickup was dead, with no spare and no real option to put a
microphone in front of the instrument, I held the dead cell across the
terminals of a PP3 until it became 'quite warm'. The resultant charge
held for the first half of the show after which I 'recharged' it again
for the second half.

Ron(UK)



--
Lune Valley Audio
Public Address Systems
Hire Sales Maintenance
www.lunevalleyaudio.com

On Mar 24, 8:11*pm, bz wrote:

Not just leak. Explode. Spread toxic chemicals.

an explosion is just a real fast leak.

z wrote:

On Mar 24, 8:11 pm, bz wrote:

Not just leak. Explode. Spread toxic chemicals.

an explosion is just a real fast leak.


With shrapnel.


--
aioe.org is home to cowards and terrorists

Add this line to your news proxy nfilter.dat file
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http://improve-usenet.org/index.html

On Mar 25, 1:41*pm, "Michael A. Terrell"
wrote:
z wrote:

On Mar 24, 8:11 pm, bz wrote:

Not just leak. Explode. Spread toxic chemicals.

an explosion is just a real fast leak.

* *With shrapnel.

--
aioe.org is home to cowards and terrorists

Add this line to your news proxy nfilter.dat file
* drop Path:*aioe.org!not-for-mail to drop all aioe.org traffic.

http://improve-usenet.org/index.html

conversely, a leak is just any explosion where you can run away from
it.

z wrote:

On Mar 25, 1:41 pm, "Michael A. Terrell"
wrote:
z wrote:

On Mar 24, 8:11 pm, bz wrote:

Not just leak. Explode. Spread toxic chemicals.

an explosion is just a real fast leak.

With shrapnel.

--
aioe.org is home to cowards and terrorists

Add this line to your news proxy nfilter.dat file
* drop Path:*aioe.org!not-for-mail to drop all aioe.org traffic.

http://improve-usenet.org/index.html

conversely, a leak is just any explosion where you can run away from
it.


Try that with a high pressure steam leak and get back to me, if they
find all the pieces.


--
aioe.org is home to cowards and terrorists

Add this line to your news proxy nfilter.dat file
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z wrote in news:a62ea883-f6a8-413c-bbfd-
:

On Mar 25, 1:41*pm, "Michael A. Terrell"
wrote:
z wrote:

On Mar 24, 8:11 pm, bz wrote:

Not just leak. Explode. Spread toxic chemicals.

an explosion is just a real fast leak.

* *With shrapnel.

--
aioe.org is home to cowards and terrorists

Add this line to your news proxy nfilter.dat file
* drop Path:*aioe.org!not-for-mail to drop all aioe.org traffic.

http://improve-usenet.org/index.html

conversely, a leak is just any explosion where you can run away from
it.

You could say that a leak is a sssslllloooooowwwww explosion.

Slow as molasses in January.

But that reminds me....

Have you heard of the 'Great Molasses Disaster'?

http://en.wikipedia.org/wiki/Boston_Molasses_Disaster





--
bz 73 de N5BZ k

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

remove ch100-5 to avoid spam trap

On Mar 25, 7:53*pm, bz wrote:

Have you heard of the 'Great Molasses Disaster'?

http://en.wikipedia.org/wiki/Boston_Molasses_Disaster

heard of it? I've actually smelled it. (did not dealt it, however)

On Mar 25, 5:21*pm, "Michael A. Terrell"
wrote:

* *Try that with a high pressure steam leak and get back to me, if they
find all the pieces.


like back in sixth grade, where i discovered that if you unscrewed the
valve on the big steam line running through the schoolroom closet far
enough, it would actually come out of the pipe. hilarity ensues.