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battery problem?



 
 
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  #1  
Old November 9th 11, 05:34 PM posted to microsoft.public.windowsxp.hardware
Jo-Anne[_4_]
external usenet poster
 
Posts: 1,101
Default battery problem?

Using WinXP. I have a 3.5-year-old Dell laptop as my main computer. I turn
it off and unplug it at night but leave it on and plugged in all day.
Lately, I find that in the evening the power indicator in the system tray
shows that the battery is charging. When I hover the mouse over the icon, it
says 98 or 99 percent charged. Eventually, it finishes charging and goes
back to the AC power icon. It never indicates charging when I first plug the
computer in and turn it on in the morning.

Is this likely to be a battery problem? What should I do next?

Thank you!

Jo-Anne


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  #2  
Old November 9th 11, 06:32 PM posted to microsoft.public.windowsxp.hardware
Paul
external usenet poster
 
Posts: 18,278
Default battery problem?

Jo-Anne wrote:
Using WinXP. I have a 3.5-year-old Dell laptop as my main computer. I turn
it off and unplug it at night but leave it on and plugged in all day.
Lately, I find that in the evening the power indicator in the system tray
shows that the battery is charging. When I hover the mouse over the icon, it
says 98 or 99 percent charged. Eventually, it finishes charging and goes
back to the AC power icon. It never indicates charging when I first plug the
computer in and turn it on in the morning.

Is this likely to be a battery problem? What should I do next?

Thank you!

Jo-Anne


Well, you know that the charging circuit, only responds to battery
state. If it does "98% 99% Done" kind of sequence, that means it is
topping up the battery.

The states would go something like this:

1) The charger will refuse to attempt to charge the battery,
if the battery voltage dips too low. So it doesn't pay to
leave the battery removed from the laptop forever (i.e. leave in
it's product box, for fear of "using it"). That's not a good strategy.
You have to charge it, occasionally, but not necessary 100% full.

2) If the laptop was running from battery, and the laptop switches
itself off, you know it's reached the "lower threshold". The laptop
should not run the battery below this voltage. The "lower threshold" is
still higher than the "do not charge" voltage, and perhaps the battery
could survive for some time, before self-discharge or leakage current
in the laptop, causes it to drop so low, the battery cannot be revived.
The "do not charge" voltage level is a safety feature, intended to
avoid a hazardous situation if irreversible damage was done to the
battery below the "do not charge" voltage.

3) Now, say we hit "0%", the laptop goes off. We plug in the adapter,
and it says "Charging 0%". Perhaps for the next few hours, the charger
operates in "current limited" mode. It might be pumping 2 amps into the
battery for the next couple hours. The battery voltage slowly rises
over this interval. About 80% of the charge, might be acquired in
about half the total charging interval.

4) When the charger hits the "max safe voltage", it effectively switches
from "current limited" mode, to "constant voltage mode". Now, what you'd
notice, if using lab equipment, is the current flow into the battery is
starting to drop. Moments before, we were pumping the 2 amps, and now
the current is 1.98 amps and slowly dropping. The current flow drops,
as the battery starts to approach the final state.

5) The laptop is monitoring that current flow. Once the battery voltage
is truly at the "constant voltage" value, and next to no (tapered)
charging current is flowing into the battery, it's "full". During the
tapering off of the charging process, you might see "80% ... 98% 99%"
etc. Not a lot of extra capacity is pumped into the battery during
this phase, but it's a way of achieving "maximum runtime" for the
user. When it's full, the laptop stops charging it.

6) OK, now we're in your situation. The battery is full. The laptop stops
charging the battery. The adapter powers the laptop during the day.

Depending on the age of the battery, self discharge, or basically telling
lies about charge state, means that some time during the day, the laptop
checks the battery terminal voltage and finds it too low. The laptop should
not be constantly charging the laptop, so the "I need to top this thing up"
threshold, has to be significantly below the "constant voltage mode" value.

The battery probably hasn't dipped that much. The charging circuit may
almost immediately enter and exit the current limited mode, and switch over
to tapering off again. You see "98% 99%" as it squeezes only a fraction
of the 2 amp charging current into the battery. Since only a tiny amount
of current is being used during the tapering stage, the duration of staying
on "98% 99%" can be longer than the time to get from "10% 11% 12%" etc.

*******

On my laptop, it is safe to operate the laptop without the battery. If I'm
running backups, doing defragmentation, or anything else with a relatively
long runtime, I may choose to shut down the laptop, pull out the battery,
plug in the adapter, and do an eight hour session on AC only.

The next time the battery is plugged in, it probably won't be 100%. And
that is only an issue, if I need "maximum runtime".

For long term storage (if you're not going to use the battery for a week
or two), you could leave it at 60% to 70% or so, rather than trying to
leave it at 100% all the time. There is no reason to be trying to keep it
fully charged, unless you really need "maximum runtime" every time you
leave the house.

The battery will wear out, whether you use it or not. So babying the
battery, really doesn't help that much. You can't even buy a spare
battery, and "put it away for a rainy day", without that battery degrading
over time. The battery is a consumable, and if you want continued
portable operation, you'll eventually have to buy a new one. But
only do so, when the actual runtime available, drops to an unacceptable
value.

When you buy a laptop battery, buy it from a "high volume" seller. With things
like laptop batteries, it's really a good idea if the things are date
stamped at the factory, so you know how "old" the thing is, when you get it.
There is one particular shop at the mall, which shall remain nameless,
that deals in fairly crusty old stock. Make sure you pick your battery
source wisely, to get "fresh" stock with max life.

*******

In conclusion, you can fret about what you're seeing, but even if you
change how you use the thing, it's still going to be dead after a
few years anyway. It's a consumable. And unlike some battery types,
being careful in this case, doesn't stretch the life that much.

Paul
  #3  
Old November 10th 11, 07:53 PM posted to microsoft.public.windowsxp.hardware
Jo-Anne[_4_]
external usenet poster
 
Posts: 1,101
Default battery problem?

"Paul" wrote in message
...
Jo-Anne wrote:
Using WinXP. I have a 3.5-year-old Dell laptop as my main computer. I
turn it off and unplug it at night but leave it on and plugged in all
day. Lately, I find that in the evening the power indicator in the system
tray shows that the battery is charging. When I hover the mouse over the
icon, it says 98 or 99 percent charged. Eventually, it finishes charging
and goes back to the AC power icon. It never indicates charging when I
first plug the computer in and turn it on in the morning.

Is this likely to be a battery problem? What should I do next?

Thank you!

Jo-Anne


Well, you know that the charging circuit, only responds to battery
state. If it does "98% 99% Done" kind of sequence, that means it is
topping up the battery.

The states would go something like this:

1) The charger will refuse to attempt to charge the battery,
if the battery voltage dips too low. So it doesn't pay to
leave the battery removed from the laptop forever (i.e. leave in
it's product box, for fear of "using it"). That's not a good strategy.
You have to charge it, occasionally, but not necessary 100% full.

2) If the laptop was running from battery, and the laptop switches
itself off, you know it's reached the "lower threshold". The laptop
should not run the battery below this voltage. The "lower threshold" is
still higher than the "do not charge" voltage, and perhaps the battery
could survive for some time, before self-discharge or leakage current
in the laptop, causes it to drop so low, the battery cannot be revived.
The "do not charge" voltage level is a safety feature, intended to
avoid a hazardous situation if irreversible damage was done to the
battery below the "do not charge" voltage.

3) Now, say we hit "0%", the laptop goes off. We plug in the adapter,
and it says "Charging 0%". Perhaps for the next few hours, the charger
operates in "current limited" mode. It might be pumping 2 amps into the
battery for the next couple hours. The battery voltage slowly rises
over this interval. About 80% of the charge, might be acquired in
about half the total charging interval.

4) When the charger hits the "max safe voltage", it effectively switches
from "current limited" mode, to "constant voltage mode". Now, what
you'd
notice, if using lab equipment, is the current flow into the battery is
starting to drop. Moments before, we were pumping the 2 amps, and now
the current is 1.98 amps and slowly dropping. The current flow drops,
as the battery starts to approach the final state.

5) The laptop is monitoring that current flow. Once the battery voltage
is truly at the "constant voltage" value, and next to no (tapered)
charging current is flowing into the battery, it's "full". During the
tapering off of the charging process, you might see "80% ... 98% 99%"
etc. Not a lot of extra capacity is pumped into the battery during
this phase, but it's a way of achieving "maximum runtime" for the
user. When it's full, the laptop stops charging it.

6) OK, now we're in your situation. The battery is full. The laptop stops
charging the battery. The adapter powers the laptop during the day.

Depending on the age of the battery, self discharge, or basically
telling
lies about charge state, means that some time during the day, the
laptop
checks the battery terminal voltage and finds it too low. The laptop
should
not be constantly charging the laptop, so the "I need to top this thing
up"
threshold, has to be significantly below the "constant voltage mode"
value.

The battery probably hasn't dipped that much. The charging circuit may
almost immediately enter and exit the current limited mode, and switch
over
to tapering off again. You see "98% 99%" as it squeezes only a fraction
of the 2 amp charging current into the battery. Since only a tiny
amount
of current is being used during the tapering stage, the duration of
staying
on "98% 99%" can be longer than the time to get from "10% 11% 12%" etc.

*******

On my laptop, it is safe to operate the laptop without the battery. If I'm
running backups, doing defragmentation, or anything else with a relatively
long runtime, I may choose to shut down the laptop, pull out the battery,
plug in the adapter, and do an eight hour session on AC only.

The next time the battery is plugged in, it probably won't be 100%. And
that is only an issue, if I need "maximum runtime".

For long term storage (if you're not going to use the battery for a week
or two), you could leave it at 60% to 70% or so, rather than trying to
leave it at 100% all the time. There is no reason to be trying to keep it
fully charged, unless you really need "maximum runtime" every time you
leave the house.

The battery will wear out, whether you use it or not. So babying the
battery, really doesn't help that much. You can't even buy a spare
battery, and "put it away for a rainy day", without that battery degrading
over time. The battery is a consumable, and if you want continued
portable operation, you'll eventually have to buy a new one. But
only do so, when the actual runtime available, drops to an unacceptable
value.

When you buy a laptop battery, buy it from a "high volume" seller. With
things
like laptop batteries, it's really a good idea if the things are date
stamped at the factory, so you know how "old" the thing is, when you get
it.
There is one particular shop at the mall, which shall remain nameless,
that deals in fairly crusty old stock. Make sure you pick your battery
source wisely, to get "fresh" stock with max life.

*******

In conclusion, you can fret about what you're seeing, but even if you
change how you use the thing, it's still going to be dead after a
few years anyway. It's a consumable. And unlike some battery types,
being careful in this case, doesn't stretch the life that much.

Paul



Thank you, Paul, for your excellent information about batteries! I won't
worry for the time being. One more question: Regarding new laptop batteries,
any recommendations for good places to get them? I've used Batteries Plus a
lot for other batteries, since we have a store in my town. I don't know,
though, if laptop batteries are a high turnover item for them.

Jo-Anne


  #4  
Old November 11th 11, 12:37 AM posted to microsoft.public.windowsxp.hardware
Paul
external usenet poster
 
Posts: 18,278
Default battery problem?

Jo-Anne wrote:
"Paul" wrote in message
...
Jo-Anne wrote:
Using WinXP. I have a 3.5-year-old Dell laptop as my main computer. I
turn it off and unplug it at night but leave it on and plugged in all
day. Lately, I find that in the evening the power indicator in the system
tray shows that the battery is charging. When I hover the mouse over the
icon, it says 98 or 99 percent charged. Eventually, it finishes charging
and goes back to the AC power icon. It never indicates charging when I
first plug the computer in and turn it on in the morning.

Is this likely to be a battery problem? What should I do next?

Thank you!



In conclusion, you can fret about what you're seeing, but even if you
change how you use the thing, it's still going to be dead after a
few years anyway. It's a consumable. And unlike some battery types,
being careful in this case, doesn't stretch the life that much.

Paul



Thank you, Paul, for your excellent information about batteries! I won't
worry for the time being. One more question: Regarding new laptop batteries,
any recommendations for good places to get them? I've used Batteries Plus a
lot for other batteries, since we have a store in my town. I don't know,
though, if laptop batteries are a high turnover item for them.

Jo-Anne


I don't know the answer to that.

If the item is a "special order" at that store, try discussing with the
staff to see what they say about their stock.

Maybe someone else here, knows of a more trustworthy source.

Paul

  #5  
Old November 14th 11, 10:30 AM posted to microsoft.public.windowsxp.hardware
rjk
external usenet poster
 
Posts: 478
Default battery problem?


"Paul" wrote in message
...
Jo-Anne wrote:
"Paul" wrote in message
...
Jo-Anne wrote:
Using WinXP. I have a 3.5-year-old Dell laptop as my main computer. I
turn it off and unplug it at night but leave it on and plugged in all
day. Lately, I find that in the evening the power indicator in the
system tray shows that the battery is charging. When I hover the mouse
over the icon, it says 98 or 99 percent charged. Eventually, it
finishes charging and goes back to the AC power icon. It never
indicates charging when I first plug the computer in and turn it on in
the morning.

Is this likely to be a battery problem? What should I do next?

Thank you!



In conclusion, you can fret about what you're seeing, but even if you
change how you use the thing, it's still going to be dead after a
few years anyway. It's a consumable. And unlike some battery types,
being careful in this case, doesn't stretch the life that much.

Paul



Thank you, Paul, for your excellent information about batteries! I won't
worry for the time being. One more question: Regarding new laptop
batteries, any recommendations for good places to get them? I've used
Batteries Plus a lot for other batteries, since we have a store in my
town. I don't know, though, if laptop batteries are a high turnover item
for them.

Jo-Anne


I don't know the answer to that.

If the item is a "special order" at that store, try discussing with the
staff to see what they say about their stock.

Maybe someone else here, knows of a more trustworthy source.

Paul


FWIW ... I had a bit of a read up on laptop batteries a while ago, when a
friends old HP nx9005 !! laptop battery died, we got a replacement on ebay,
but, spotted on the web, a popular belief that if the laptop is used mostly
on mains power, that removing the battery from laptop would prolong its'
life. ...put it back in every two or three months to top it up etc.. I
remember thinking whilst reading those views, "fat lot of good that is
unless it's on a UPS."
....so it was nice to read some sense from Paul on the topic of laptop
batteries ! :-)

regards, Richard


  #6  
Old November 19th 11, 12:20 PM posted to microsoft.public.windowsxp.hardware
Yousuf Khan[_2_]
external usenet poster
 
Posts: 2,240
Default battery problem?

On 09/11/2011 11:34 AM, Jo-Anne wrote:
Using WinXP. I have a 3.5-year-old Dell laptop as my main computer. I turn
it off and unplug it at night but leave it on and plugged in all day.
Lately, I find that in the evening the power indicator in the system tray
shows that the battery is charging. When I hover the mouse over the icon, it
says 98 or 99 percent charged. Eventually, it finishes charging and goes
back to the AC power icon. It never indicates charging when I first plug the
computer in and turn it on in the morning.

Is this likely to be a battery problem? What should I do next?

Thank you!

Jo-Anne


I wouldn't worry about it, my laptop thinks it needs a recharge as soon
as I unplug it (even if it isn't running). It's just an inaccuracy of
the charge circuitry to distinguish between 99% full and 100%.

Yousuf Khan
  #7  
Old November 19th 11, 05:49 PM posted to microsoft.public.windowsxp.hardware
Jo-Anne[_4_]
external usenet poster
 
Posts: 1,101
Default battery problem?

"Yousuf Khan" wrote in message
...
On 09/11/2011 11:34 AM, Jo-Anne wrote:
Using WinXP. I have a 3.5-year-old Dell laptop as my main computer. I
turn
it off and unplug it at night but leave it on and plugged in all day.
Lately, I find that in the evening the power indicator in the system tray
shows that the battery is charging. When I hover the mouse over the icon,
it
says 98 or 99 percent charged. Eventually, it finishes charging and goes
back to the AC power icon. It never indicates charging when I first plug
the
computer in and turn it on in the morning.

Is this likely to be a battery problem? What should I do next?

Thank you!

Jo-Anne


I wouldn't worry about it, my laptop thinks it needs a recharge as soon as
I unplug it (even if it isn't running). It's just an inaccuracy of the
charge circuitry to distinguish between 99% full and 100%.

Yousuf Khan



Thank you, Yousuf! My concern was that this has just started happening. I
won't worry about it now.

Jo-Anne


 




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