Watch replacemnt (button) batteries?

T

terryS

Guest
Have just replaced watch button battery from a package of five bought
yesterday.
The replacement cells are SR60W 1.55 volts. (Diam 6.8mm, depth
2.15mm.)

Measured the removed battery (several years old now) open circuit,
using a high input impedance DMM, at 1.486v. Doesn't seem that low?
But that's off-load and it obviously run down because it doesn't make
the cheap 'quartz' watch tick!.

The first replacement cell was not functional at 0.948 volts. The
second replacement at around 1.5v seems to work fine.

Having introduced the topic/question can anybody comment on how much
current these button type cells provide in a typical watch? Probably
of the order of micro-amps?

Nothing important but having now got involved one wonders!

TIA. Cheers.
 
On Sun, 24 Jan 2010 10:54:08 -0800 (PST), terryS
<tsanford@nf.sympatico.ca> wrote:

Have just replaced watch button battery from a package of five bought
yesterday.
The replacement cells are SR60W 1.55 volts. (Diam 6.8mm, depth
2.15mm.)

Measured the removed battery (several years old now) open circuit,
using a high input impedance DMM, at 1.486v. Doesn't seem that low?
But that's off-load and it obviously run down because it doesn't make
the cheap 'quartz' watch tick!.

The first replacement cell was not functional at 0.948 volts. The
second replacement at around 1.5v seems to work fine.

Having introduced the topic/question can anybody comment on how much
current these button type cells provide in a typical watch? Probably
of the order of micro-amps?
Click to expand...
---
The SR60W is a 1.55V 60mAH silver oxide cell.

If it lasted "several" (3) years, then since 3 years is equal to:

24 hr * 365.25 days * 3 yr
t = ---------------------------- = 26,298 hours
1 yr

and the capacity of the battery is equal to 60 mAH,

the current supplied for 3 years will be:

C 6E-2 A H
I = --- = ------------ ~ 2.28e-6 A - 2.28 microamperes.
t 2.6298e4 H


JF
 
On Jan 24, 5:47 pm, John Fields <jfie...@austininstruments.com> wrote:
On Sun, 24 Jan 2010 10:54:08 -0800 (PST), terryS





tsanf...@nf.sympatico.ca> wrote:
Have just replaced watch button battery from a package of five bought
yesterday.
The replacement cells are SR60W 1.55 volts. (Diam 6.8mm, depth
2.15mm.)

Measured the removed battery (several years old now) open circuit,
using a high input impedance DMM, at 1.486v. Doesn't seem that low?
But that's off-load and it obviously run down because it doesn't make
the cheap 'quartz' watch tick!.

The first replacement cell was not functional at 0.948 volts. The
second replacement at around 1.5v seems to work fine.

Having introduced the topic/question can anybody comment on how much
current these button type cells provide in a typical watch? Probably
of the order of micro-amps?

---
The SR60W is a 1.55V 60mAH silver oxide cell.

If it lasted "several" (3) years, then since 3 years is equal to:

         24 hr * 365.25 days * 3 yr                
    t = ---------------------------- = 26,298 hours      
                  1 yr

and the capacity of the battery is equal to 60 mAH,

the current supplied for 3 years will be:

         C      6E-2 A H
    I = --- = ------------ ~ 2.28e-6 A - 2.28 microamperes.
         t     2.6298e4 H

JF- Hide quoted text -

- Show quoted text -
Click to expand...
Thanks for the info John:
That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr. Guess
that is what the '60' in SR60W means!
And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 = Of
the order of 2.28 x 10to minus 6.Amps.
Cheers.
 
"terryS"

Thanks for the info John:
That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr. Guess
that is what the '60' in SR60W means!
And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 = Of
the order of 2.28 x 10to minus 6.Amps.


** Shame that JF failed to say the calc gives only the AVERAGE current
drawn.

The *peak current* draw at the moment of each "tick" is up to 100 times
higher.

Has a big effect on the life span of the cell and what kind of cell ESR
value is tolerable.



.... Phil
 
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7s5mkgFeu3U1@mid.individual.net...
"terryS"

Thanks for the info John:
That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr. Guess
that is what the '60' in SR60W means!
And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 = Of
the order of 2.28 x 10to minus 6.Amps.


** Shame that JF failed to say the calc gives only the AVERAGE current
drawn.

The *peak current* draw at the moment of each "tick" is up to 100 times
higher.

Has a big effect on the life span of the cell and what kind of cell ESR
value is tolerable.
Click to expand...
I suppose there might be a capacitor in there to handle the peaks.

Paul
 
On Jan 24, 8:54 pm, terryS <tsanf...@nf.sympatico.ca> wrote:

 That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr.
Click to expand...
*cringe* No, it's 60 mA-hr! Monsieur Ampere capitalized his
surname, and so do we. Gratuitous use of the '/' character
where multiplication is appropriate is also ... points off. Correct
those units!
 
terryS wrote:
Have just replaced watch button battery from a package of five bought
yesterday.
The replacement cells are SR60W 1.55 volts. (Diam 6.8mm, depth
2.15mm.)

Measured the removed battery (several years old now) open circuit,
using a high input impedance DMM, at 1.486v. Doesn't seem that low?
But that's off-load and it obviously run down because it doesn't make
the cheap 'quartz' watch tick!.

The first replacement cell was not functional at 0.948 volts. The
second replacement at around 1.5v seems to work fine.

Having introduced the topic/question can anybody comment on how much
current these button type cells provide in a typical watch? Probably
of the order of micro-amps?

Nothing important but having now got involved one wonders!

TIA. Cheers.
Click to expand...
http://data.energizer.com/PDFs/364-363.pdf

23mAh nominal rating.

The problem is the increased ESR as the battery ages, it can't supply the
higher current pulses required to kick the hands.
No such current pulse issue with the same battery in a digital watch, unless
you turn on the backlight or something.

Dave.

--
================================================
Check out my Electronics Engineering Video Blog & Podcast:
http://www.eevblog.com
 
"Paul E. Schoen" <paul@peschoen.com> wrote in message
news:rem7n.2262$1m3.1738@newsfe11.iad...
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7s5mkgFeu3U1@mid.individual.net...

"terryS"

Thanks for the info John:
That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr. Guess
that is what the '60' in SR60W means!
And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 = Of
the order of 2.28 x 10to minus 6.Amps.


** Shame that JF failed to say the calc gives only the AVERAGE current
drawn.

The *peak current* draw at the moment of each "tick" is up to 100 times
higher.

Has a big effect on the life span of the cell and what kind of cell ESR
value is tolerable.

I suppose there might be a capacitor in there to handle the peaks.

Paul
Click to expand...
Good catch Paul.
 
"Charles the Anencephalic Troll"
"Paul E. Schoen"
"Phil Allison"
"terryS"

Thanks for the info John:
That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr. Guess
that is what the '60' in SR60W means!
And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 = Of
the order of 2.28 x 10to minus 6.Amps.


** Shame that JF failed to say the calc gives only the AVERAGE current
drawn.

The *peak current* draw at the moment of each "tick" is up to 100 times
higher.

Has a big effect on the life span of the cell and what kind of cell ESR
value is tolerable.

I suppose there might be a capacitor in there to handle the peaks.

Paul

Good catch Paul.
Click to expand...

** There is never any such cap in a watch or battery wall clock

- you ASD fucked, parroting fuckwit.



..... Phil
 
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7sc0fcFpp4U1@mid.individual.net...
"Charles the Anencephalic Troll"
"Paul E. Schoen"
"Phil Allison"
"terryS"

Thanks for the info John:
That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr. Guess
that is what the '60' in SR60W means!
And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 = Of
the order of 2.28 x 10to minus 6.Amps.


** Shame that JF failed to say the calc gives only the AVERAGE
current drawn.

The *peak current* draw at the moment of each "tick" is up to 100 times
higher.

Has a big effect on the life span of the cell and what kind of cell
ESR value is tolerable.

I suppose there might be a capacitor in there to handle the peaks.

Paul

Good catch Paul.


** There is never any such cap in a watch or battery wall clock
Click to expand...
At the microampere level, it does not require much of a capacitor to smooth
out (supply) current peaks. And you will (of course not) supply
documentation that there are no such smoothing/leveling capacitors in
clocks/time pieces? Jackass.
 
"Charles the Anencephalic Troll"

At the microampere level,
Click to expand...

** But it is not a few microamps.

FUCKWIT !!

Go DROP DEAD YOU STINKING LIAR !
 
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7sc1eeFuk8U1@mid.individual.net...
"Charles the Anencephalic Troll"
Click to expand...
You have earned the first PLONK of 2010! Congratulations.
 
"Charles the Anencephalic LYING Troll"

At the microampere level,
Click to expand...

** But it is not a few microamps.

FUCKWIT !!

Go DROP DEAD YOU STINKING LIAR !
 
Charles wrote:
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7sc0fcFpp4U1@mid.individual.net...

"Charles the Anencephalic Troll"
"Paul E. Schoen"
"Phil Allison"
"terryS"

Thanks for the info John:
That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr.
Guess that is what the '60' in SR60W means!
And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 =
Of the order of 2.28 x 10to minus 6.Amps.


** Shame that JF failed to say the calc gives only the AVERAGE
current drawn.

The *peak current* draw at the moment of each "tick" is up to 100
times higher.

Has a big effect on the life span of the cell and what kind of cell
ESR value is tolerable.

I suppose there might be a capacitor in there to handle the peaks.

Paul

Good catch Paul.


** There is never any such cap in a watch or battery wall clock

At the microampere level, it does not require much of a capacitor to
smooth out (supply) current peaks.
Click to expand...
I doubt the current spikes for an analog watch would be in the microamp
range.

And you will (of course not)
supply documentation that there are no such smoothing/leveling
capacitors in clocks/time pieces? Jackass.
Click to expand...
Can't say I've seen one in any watch I've opened.
It would be a waste of 0.1cents (or whatever) and take up space.
And no real need for it when you have a battery with 10ohms ESR or so.

Dave.

--
================================================
Check out my Electronics Engineering Video Blog & Podcast:
http://www.eevblog.com
 
"David L. Jones" <altzone@gmail.com> wrote in message
news:uw88n.15679$p66.11875@newsfe09.iad...
Charles wrote:
"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:7sc0fcFpp4U1@mid.individual.net...

"Charles the Anencephalic Troll"
"Paul E. Schoen"
"Phil Allison"
"terryS"

Thanks for the info John:
That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr.
Guess that is what the '60' in SR60W means!
And yes; if 3 years that's (60 x 10to minus 3)Ah./24 x 365 x 3 =
Of the order of 2.28 x 10to minus 6.Amps.


** Shame that JF failed to say the calc gives only the AVERAGE
current drawn.

The *peak current* draw at the moment of each "tick" is up to 100
times higher.

Has a big effect on the life span of the cell and what kind of cell
ESR value is tolerable.

I suppose there might be a capacitor in there to handle the peaks.

Paul

Good catch Paul.


** There is never any such cap in a watch or battery wall clock

At the microampere level, it does not require much of a capacitor to
smooth out (supply) current peaks.

I doubt the current spikes for an analog watch would be in the microamp
range.

And you will (of course not)
supply documentation that there are no such smoothing/leveling
capacitors in clocks/time pieces? Jackass.

Can't say I've seen one in any watch I've opened.
It would be a waste of 0.1cents (or whatever) and take up space.
And no real need for it when you have a battery with 10ohms ESR or so.
Click to expand...
There is a detailed explanation of the analog quartz watch movement at
http://www.patentstorm.us/patents/4087957/description.html
and
http://www.freepatentsonline.com/4173863.html
and a PDF of the patent:
http://www.freepatentsonline.com/4173863.pdf

Since these use CMOS logic circuits I would be surprised if there were NOT
at least one small bypass capacitor across the battery power supply.

Here is a web page with some ASCII schematics of watch circuits:
http://www.rdrop.com/~cary/html/time.html

The Bulova Accutron:
http://www.elektron.demon.co.uk/accutron.html

And details on how it works:
http://www.elektron.demon.co.uk/works.html

Note that there is a capacitor on the base of the transistor. It appears to
contribute to the current pulse through the collector, which is shown to be
16 uA, with a duty cycle of maybe 10%. But this article states that a
running movement draws about 7 uA. In that case a 60 mA-Hr battery would be
expected to last 60,000/7 = 8571 hrs = 357 days or just about a year.

Paul
 
On Mon, 25 Jan 2010 11:39:36 -0800 (PST) in sci.electronics.basics,
whit3rd <whit3rd@gmail.com> wrote,
On Jan 24, 8:54 pm, terryS <tsanf...@nf.sympatico.ca> wrote:

 That's what I was missing; the ampere hour capacity of the button
cell. Amazing something with that small a volume can be 60ma/hr.

*cringe* No, it's 60 mA-hr! Monsieur Ampere capitalized his
surname, and so do we. Gratuitous use of the '/' character
where multiplication is appropriate is also ... points off. Correct
those units!
Click to expand...
Subtraction is no more correct than division.
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top