netbook doesn't finish charging

Do you have a question? Post it now! No Registration Necessary.  Now with pictures!

Threaded View
I have an Acer netbook, and the battery loses a lot of juice when it's
off.  I turned it on last night and it was down to 25%, after sitting
for 2 months or more.  

I plug in the charger and the Power Meter window says its charging,
and it slowly climbs to 90%.   About that time, I noticed that it
doesn't say  "charging" anymore, even though it says "AC power".  

Until today, I thought it always said "charging" when it said AC
power.    Unless maybe it was up to 100%.  

Does this mean the battery can only charge to 92**%?   I would have
thought the computer would think that was 100% if that was as high as
it would go, or if the current in had reached zero**.    Does this
mean the current is still going in, but somehow that doesn't make the
percentage go up?  Why not?  

***Last night the current into the camera reached zero.  But that was
USB and my USB meter worked.    I don't have one for this barrel plug.

**It finally made it to 92.  

Re: netbook doesn't finish charging

Micky wrote:

Quoted text here. Click to load it

Charge rate slows considerably at 90% to protect the lithium battery
from overheating and igniting (should the internal protection circuitry
inside the battery pack fail).  If you go online and look at charging
rates for lithium battery (and how chargers should operate with their
own protections), the charging rate slows at 90%.

Table 3 shows the charge capacity (dotted black line) tapers off at
around 90%.  The chart also shows that getting to 90% takes a lot less
time than getting the rest of the 10% top charge.

Sorry but I don't have your unidentified Acer netbook to know why their
meter software decides to stop saying "charging" at 90%.  Maybe it only
detects charging when the amperage to the battery exceeds some amount.
Charging is based on sensing the amperage rate (how resistance
increases) along with voltage and some precepts on the rate curves for
effective charging of lithium chemistries.  What the netbooks says is
92% may be 100% for an old battery (see next).  Has the netbook always
been that way or you just noticed the artifact?

Batteries are chemical and they lose capacity (storage), load handling,
and efficiency with age.  Capacity drops 80% per 2 years but this varies
with heavy load (lots of charging cycles), environment (temperatures),
and quality of construction.  After 2 years: 80% capacity.  After 4
years: 80% x 80% = 64% capacity.  After 6 years: 80% x 80% x 80% = 51%.
Many drop capacity much faster.  As the chemical composition degrades,
charge time increases but won't reach full charge anymore.  With the
safety in charging for lithium, the charger will slow down the charge
rate so you won't get a full charge any more.

You did not mention how old is the battery pack.  If over 3-4 years old,
might be time to start hunting for a replacement.  They don't last that
long.  They have a limited number of charging cycles, the chemicals
deplete, and they lose capacity so runtime wanes along with capacity
retention during storage.  How long before you replace the battery in
your car despite you drive it every day to keep it charged via

Re: netbook doesn't finish charging

[Default] On Tue, 12 Jul 2016 11:25:35 -0500, in

Quoted text here. Click to load it

This sounds reasonsable and your explanation below does also.  

At any rate it stayed firmly fixed at 90% for maybe 8 hours over
several days of use, but one day I left it on or needed it on for 6 or
8 hours in a row and I wasn't watching but i noticed at the end it was
finally at 100%

I'm going to buy another battery!


Quoted text here. Click to load it

Re: netbook doesn't finish charging

[Default] On Tue, 19 Jul 2016 02:34:04 -0400, in
microsoft.public.windowsxp.general Micky

Quoted text here. Click to load it

I said this somewhere else, but since I came across the original
thread, I'll repeat, that I left it charging for a very long time and
it made it up to 100%.  I've been using it frequently and with the
charger so it's still 100%.   But I'm still going to buy another
Quoted text here. Click to load it

Re: netbook doesn't finish charging

On 7/25/2016 2:48 AM, Micky wrote:

Quoted text here. Click to load it

Where do you get a replacement battery?
Unless the device was extremely popular and long lived, they probably
quit making batteries for it before they quit selling it.
Any battery you do find may have been sitting in a container in Arizona
for 5 years.  And the aftermarket batteries in the container in
China may have been built with crap cells in the first place.

Re: netbook doesn't finish charging

mike wrote:

Quoted text here. Click to load it

Micky, not me, probably needs a new battery.  Micky never mentioned his
model, just "Acer netbook" which gives no details on WHICH one he has to
then lookup who might have a newly manufactured battery for it.  To save
on tooling or parts costs, manufacturers continue using the same parts
for awhile even into newer models.

Micky never mentioned the model of his Acer netbook or how old it is.  
So far, only *MICKY* knows the model and age of his netbook.  (Note: I
am not bothering to hunt through his past posts in other discussions to
find that info, if present.)

Re: netbook doesn't finish charging

On 7/25/2016 10:04 PM, VanguardLH wrote:
Quoted text here. Click to load it

OK, but that still doesn't address the issue.
Some batteries have human readable date codes, some don't.
And getting a random online vendor to go look up the date code
isn't likely to happen.  Just because the manufacturer uses the
same plastic doesn't guarantee that the battery you get from
a random recycler is anywhere near new.
Storage history matters a lot.  Anecdotes
abound about people getting new, but non-working batteries off EBAY.
Quoted text here. Click to load it

Re: netbook doesn't finish charging

Once upon a time on usenet mike wrote:
Quoted text here. Click to load it

Logically this level of concern dictates that you rebuild your own batteries  
using newly-manufactured A grade cells.

Otherwise you'll always be wondering ....

"Humans will have advanced a long, long way when religious belief has a cozy  
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)  

Site Timeline