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Changed CMOS battery



 
 
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  #1  
Old August 12th 17, 07:52 PM posted to alt.comp.hardware.pc-homebuilt
John B. Smith
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Posts: 124
Default Changed CMOS battery

I changed my CMOS battery today - on suspicion. It measured 3.1 volts
after 9 years. The EverReady 2032 I put in measured 3.3v (it's a 3
volt battery). I'm wondering, does the motherboard keep the battery
topped off while the machine is on, even though it's not a
rechargable? This seems an incredibly long time for battery life. I
kinda think the flakiness on boot I've experienced lately had nothing
to do with the battery. But I eliminated it from consideration.
  #2  
Old August 12th 17, 09:12 PM posted to alt.comp.hardware.pc-homebuilt
VanguardLH[_2_]
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Posts: 1,190
Default Changed CMOS battery

John B. Smith wrote:

I changed my CMOS battery today - on suspicion. It measured 3.1 volts
after 9 years. The EverReady 2032 I put in measured 3.3v (it's a 3
volt battery). I'm wondering, does the motherboard keep the battery
topped off while the machine is on, even though it's not a
rechargable? This seems an incredibly long time for battery life. I
kinda think the flakiness on boot I've experienced lately had nothing
to do with the battery. But I eliminated it from consideration.


Voltage is meaningless except under load. A battery that has no load
will read its highest voltage. You would have to measure voltage when
the battery was in-circuit using a voltmeter with high resistance, like
10 mega-ohms, or more, so as to not affect the circuit. Those freebie,
giveaway, or cheapie meters are only useful as an indicator, not for
measuring. Meters need recalibration every 2-5 years, too. Rare few
consumers spend that money (on a good meter and then recalibration).

The CR-2032 lithium coin cell battery is not rechargeable.
  #3  
Old August 12th 17, 09:37 PM posted to alt.comp.hardware.pc-homebuilt
Paul[_26_]
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Posts: 538
Default Changed CMOS battery

John B. Smith wrote:
I changed my CMOS battery today - on suspicion. It measured 3.1 volts
after 9 years. The EverReady 2032 I put in measured 3.3v (it's a 3
volt battery). I'm wondering, does the motherboard keep the battery
topped off while the machine is on, even though it's not a
rechargable? This seems an incredibly long time for battery life. I
kinda think the flakiness on boot I've experienced lately had nothing
to do with the battery. But I eliminated it from consideration.


You're not allowed to charge a CR2032.

It's the LR2032 used in some laptops, that recharges.
That's a different battery type, and not interchangeable
with CR2032. An LR2032 only lasts for a few days, when
the main battery pack is removed. It doesn't have a lot
of amp-hours in it.

The shelf life of a CR2032 is roughly ten years.
If you keep the back of the PC switched on, then
no power is drawn from that battery. So instead of
nine years, you get ten.

If you switch off the PC at the back every night, then
the CR2032 battery life will drop. When a PC is disconnected
from the mains (it's sitting in the garage), the predicted
CR2032 lifespan is slightly less than three years. You can
work out this value for yourself, by dividing the A-h
rating of the battery in its spec sheet, by the 10uA
load coming from the CMOS/RTC circuit. And that gives a number
slightly less than three years.

And it's amazing how many companies make CR2032 batteries,
and all with the same (more or less) nominal rating.

*******

The "flakiness on boot", you don't want to know what
horrible design ideas lurk on those motherboards. The
digital part of the designs are normally quite robust.
The analog tricks in backflow cutoff and reset and
power sequencing, some of them make no sense at all.
Every motherboard designer seems to have their own
style and quirks they bring to the job. The Intel reference
schematic, you'd think it would be a "teaching tool",
but the motherboard designers just seem to ignore it.

As an example of weirdness, there was a case in the past,
where some current would flow down the LCD monitor cable
when the PC was off. It would get into the RESET circuit
(follow some leakage path), and the RESET circuit would
not cycle properly and bring the system up. If the user
unplugged the monitor cable, the PC would start :-(

There have been other cases, where the analog designs
seem to be temperature sensitive. Maybe a particular
motherboard won't start reliably, if room temperature
is 50F or less.

And you have no way of knowing, if you build your own
PC, what you're going to get. Some of these deficiencies
might only be noticed a year or two later. When a bunch
of people talk in a thread, and all share the "exact
same issue".

Paul
  #4  
Old August 13th 17, 01:43 AM posted to alt.comp.hardware.pc-homebuilt
John B. Smith
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Posts: 124
Default Changed CMOS battery

On Sat, 12 Aug 2017 16:37:52 -0400, Paul
wrote:


You're not allowed to charge a CR2032.

It's the LR2032 used in some laptops, that recharges.
That's a different battery type, and not interchangeable
with CR2032. An LR2032 only lasts for a few days, when
the main battery pack is removed. It doesn't have a lot
of amp-hours in it.

The shelf life of a CR2032 is roughly ten years.
If you keep the back of the PC switched on, then
no power is drawn from that battery. So instead of
nine years, you get ten.


Yep, the switch in back is always on. In fact turning it off gave me
problems getting the PS to turn back on a while back, so best leave it
alone. Good thing to have the battery changed then, don't have to
worry about it. Have went thru BIOS and got it mostly back to the way
it was at this point.


If you switch off the PC at the back every night, then
the CR2032 battery life will drop. When a PC is disconnected
from the mains (it's sitting in the garage), the predicted
CR2032 lifespan is slightly less than three years. You can
work out this value for yourself, by dividing the A-h
rating of the battery in its spec sheet, by the 10uA
load coming from the CMOS/RTC circuit. And that gives a number
slightly less than three years.

And it's amazing how many companies make CR2032 batteries,
and all with the same (more or less) nominal rating.

*******

The "flakiness on boot", you don't want to know what
horrible design ideas lurk on those motherboards. The
digital part of the designs are normally quite robust.
The analog tricks in backflow cutoff and reset and
power sequencing, some of them make no sense at all.
Every motherboard designer seems to have their own
style and quirks they bring to the job. The Intel reference
schematic, you'd think it would be a "teaching tool",
but the motherboard designers just seem to ignore it.

As an example of weirdness, there was a case in the past,
where some current would flow down the LCD monitor cable
when the PC was off. It would get into the RESET circuit
(follow some leakage path), and the RESET circuit would
not cycle properly and bring the system up. If the user
unplugged the monitor cable, the PC would start :-(

There have been other cases, where the analog designs
seem to be temperature sensitive. Maybe a particular
motherboard won't start reliably, if room temperature
is 50F or less.

And you have no way of knowing, if you build your own
PC, what you're going to get. Some of these deficiencies
might only be noticed a year or two later. When a bunch
of people talk in a thread, and all share the "exact
same issue".

Paul

  #5  
Old August 13th 17, 02:01 AM posted to alt.comp.hardware.pc-homebuilt
Flasherly[_2_]
external usenet poster
 
Posts: 1,880
Default Changed CMOS battery

On Sat, 12 Aug 2017 14:52:06 -0400, John B. Smith
wrote:

I changed my CMOS battery today - on suspicion. It measured 3.1 volts
after 9 years. The EverReady 2032 I put in measured 3.3v (it's a 3
volt battery). I'm wondering, does the motherboard keep the battery
topped off while the machine is on, even though it's not a
rechargable? This seems an incredibly long time for battery life. I
kinda think the flakiness on boot I've experienced lately had nothing
to do with the battery. But I eliminated it from consideration.


Amazing little creatures, those 2032 batteries. Seems they go on
forever, maybe 10 years until something surfaces, which, by then, may
not entirely be of CMOS issues. Although that is the quickest reason
for why not changing it would be inexcusable. Did so with one of mine
not long ago, about 10 years old, when substituting a CR2025;- they'll
also work in a pinch for a 2032 (lower voltage ratings). Something or
another aberrant, I noticed, had occurred after frequent brown and
blackouts in the boot sequence. Thus and therefore an obligatory
change of CMOS batters seemed most indicative, as a matter of course.

Never mind after 10 years usage, I couldn't resist any longer and
bought a new MB/CPU/Mem and "cored" it;- it's now sitting on a shelf,
tiptop shape, making me feel guilty about not coming up with a better
reason for putting it in another box for another decade's usage.
Probably not even long enough a time with certitude for saying beyond
a doubt, I'd rather not indulge, whether any more boot and CMOS
aberrances actually might occur.

I also bought a 10-pack, for $4/US, of CR2032 as an afterthought. I
believe they've a 6-year shelf-life stated somewhere on the packaging.
Indeed, does make one wonder how simply amazing a MB should manage to
extend that out and limp along for 10-years' usage.
  #6  
Old August 13th 17, 04:16 AM posted to alt.comp.hardware.pc-homebuilt
VanguardLH[_2_]
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Posts: 1,190
Default Changed CMOS battery

Paul wrote:

And it's amazing how many companies make CR2032 batteries,
and all with the same (more or less) nominal rating.


There are a lot of counterfeits. I've seen some trying to sell themself
as Sony but their packaging exposes their fraud. They go cheap on the
blister packaging or it doesn't match Sony's. The conterfeits don't
last anywhere near as long for shelf life or usage life. Sometimes they
are re-labeled expired batteries. They may not even be the correct
chemistry inside.

When I bought at eBay, I had to do some research so I could steer clear
of the counterfeits.

http://www.microbattery.com/counterf...#counter-img-7
  #7  
Old August 13th 17, 06:32 AM posted to alt.comp.hardware.pc-homebuilt
Larc[_3_]
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Posts: 306
Default Changed CMOS battery

On Sat, 12 Aug 2017 22:16:41 -0500, VanguardLH wrote:

| Paul wrote:
|
| And it's amazing how many companies make CR2032 batteries,
| and all with the same (more or less) nominal rating.
|
| There are a lot of counterfeits. I've seen some trying to sell themself
| as Sony but their packaging exposes their fraud. They go cheap on the
| blister packaging or it doesn't match Sony's. The conterfeits don't
| last anywhere near as long for shelf life or usage life. Sometimes they
| are re-labeled expired batteries. They may not even be the correct
| chemistry inside.
|
| When I bought at eBay, I had to do some research so I could steer clear
| of the counterfeits.
|
| http://www.microbattery.com/counterf...#counter-img-7

CR2032 batteries don't cost much and I don't need to buy them often, so don't usually
bother looking for bargains when I do. Usually a single or double pack of Duracell
from a reliable local store. Duracells have never let me down.

Larc
  #8  
Old August 13th 17, 07:44 AM posted to alt.comp.hardware.pc-homebuilt
VanguardLH[_2_]
external usenet poster
 
Posts: 1,190
Default Changed CMOS battery

Larc wrote:

On Sat, 12 Aug 2017 22:16:41 -0500, VanguardLH wrote:

| Paul wrote:
|
| And it's amazing how many companies make CR2032 batteries,
| and all with the same (more or less) nominal rating.
|
| There are a lot of counterfeits. I've seen some trying to sell themself
| as Sony but their packaging exposes their fraud. They go cheap on the
| blister packaging or it doesn't match Sony's. The conterfeits don't
| last anywhere near as long for shelf life or usage life. Sometimes they
| are re-labeled expired batteries. They may not even be the correct
| chemistry inside.
|
| When I bought at eBay, I had to do some research so I could steer clear
| of the counterfeits.
|
| http://www.microbattery.com/counterf...#counter-img-7

CR2032 batteries don't cost much and I don't need to buy them often, so don't usually
bother looking for bargains when I do. Usually a single or double pack of Duracell
from a reliable local store. Duracells have never let me down.


I had to replace CR2032 batteries for: 2 garage door remotes, 2 desktop
PCs, a couple meters, a couple wireless doorbell remotes, and probably
some more. I bought a pack of 20. A week after getting them, I was
already through more than half. I paid $7.95 w/free shipping for 20.
My local Bestbuy wants $7.96 for a 2-pack. Would've been a LOT more
expensive to buy them your way. I looked for bulk sales at eBay but
wanted to make sure I did not get stuck with counterfeits. Since I
replace the coin cell batteries at 5-year intervals, and because the
ones that I got have a shelf life until 2025, I've got spares to replace
them all again.
  #9  
Old August 13th 17, 01:07 PM posted to alt.comp.hardware.pc-homebuilt
SC Tom
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Posts: 411
Default Changed CMOS battery



"VanguardLH" wrote in message
...
Larc wrote:

On Sat, 12 Aug 2017 22:16:41 -0500, VanguardLH wrote:

| Paul wrote:
|
| And it's amazing how many companies make CR2032 batteries,
| and all with the same (more or less) nominal rating.
|
| There are a lot of counterfeits. I've seen some trying to sell themself
| as Sony but their packaging exposes their fraud. They go cheap on the
| blister packaging or it doesn't match Sony's. The conterfeits don't
| last anywhere near as long for shelf life or usage life. Sometimes they
| are re-labeled expired batteries. They may not even be the correct
| chemistry inside.
|
| When I bought at eBay, I had to do some research so I could steer clear
| of the counterfeits.
|
|
http://www.microbattery.com/counterf...#counter-img-7

CR2032 batteries don't cost much and I don't need to buy them often, so
don't usually
bother looking for bargains when I do. Usually a single or double pack
of Duracell
from a reliable local store. Duracells have never let me down.


I had to replace CR2032 batteries for: 2 garage door remotes, 2 desktop
PCs, a couple meters, a couple wireless doorbell remotes, and probably
some more. I bought a pack of 20. A week after getting them, I was
already through more than half. I paid $7.95 w/free shipping for 20.
My local Bestbuy wants $7.96 for a 2-pack. Would've been a LOT more
expensive to buy them your way. I looked for bulk sales at eBay but
wanted to make sure I did not get stuck with counterfeits. Since I
replace the coin cell batteries at 5-year intervals, and because the
ones that I got have a shelf life until 2025, I've got spares to replace
them all again.


Must have gotten them from Amazon :-) Gotta love Prime!

I got a similar deal a while back since I also have a number of devices that
use them- 3 PCs, 2 ceiling fan remotes, 2 fitness trackers, 1 garage door
opener, etc. My newer Fire Stick remote uses one now instead of AAA
batteries like the old one. Seems like more and more small devices like that
are turning to CR2032's, so I have to keep an eye out for good deals.
--

SC Tom


  #10  
Old August 13th 17, 09:21 PM posted to alt.comp.hardware.pc-homebuilt
mick[_3_]
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Posts: 5
Default Changed CMOS battery

On Sat, 12 Aug 2017 21:01:59 -0400, Flasherly wrote:

Did so with one of mine
not long ago, about 10 years old, when substituting a CR2025;- they'll
also work in a pinch for a 2032 (lower voltage ratings).



Nope. The voltage rating is the same, but the capacity is smaller because
the thickness is also smaller.

On all this range the number is the size:
CR2032 is 20mm dia x 3.2mm thick
CR1625 is 16mm dia x 2.5mm thick
etc...

 




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