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Laptop Battery Weird Behavior

Last response: in Laptops & Notebooks
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April 12, 2012 8:22:09 AM

Im a heavy laptop user.
I use it generally for 7 hours or more a day. Basically, Its my alternative to desktop.
Today I turned off the switch because the battery was 100% charged and a moment later it dropped to 64%
and back to 93% (right from 100% a second ago)
Is this because my battery's health is going down?
How do I prevent deterioration of my battery??

I mostly keep it plugged in even if its 100% charged.
April 12, 2012 8:25:09 AM

Or sometimes (40% of the times) I unplug it, let it discharge to about 20% and then recharge it
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April 12, 2012 1:37:43 PM

Hi Fasihxkhabit,

How old is the current battery? Sound like it is starting to loose its charge.
Connecting the battery to the computer all the time is bad for your battery - you battery will constantly absorb heat from the computer and AC-adapter. Heat is one of the worst things you can expose your battery to.

If you want to read some useful battery tips, i found some @:
http://www.laptopbatteriesplanet.com/batterytips.html

:bounce:  :hello: 
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April 12, 2012 2:55:41 PM

Well, its a year and a half old.
I use PressMark BatMon to monitor the battery.
is there some specific thing I should look at to know if my battery condition is deteriorating?
Like capacity drop and stuff
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a b D Laptop
April 12, 2012 3:27:01 PM

The best test is to run the system on battery and note How long it takes to go from 100% to "Low battery, powering Off" when this time drops to half then time to replace.

As fortuna indicated, leaving battery in when normal operation is from AC is not good for Li-ion batteries. Also store battery (ie not planing on using for a week or two) at 1/2 -> 3/4 charge, NOT dead, not 100%. This is a reversal of Nicad cells which should be stored for long periods of time the cells should be discharged to 1.00 Volts.
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April 12, 2012 3:48:19 PM

You should cycle the battery. Close all of your work and unplug the laptop. Let it run all the way down until it shuts off. Then (while leaving the computer off), let it charge back to 100%.
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April 12, 2012 4:54:10 PM

So, how do I reverse the damage that may have been caused?
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April 12, 2012 4:58:18 PM

aicom said:
You should cycle the battery. Close all of your work and unplug the laptop. Let it run all the way down until it shuts off. Then (while leaving the computer off), let it charge back to 100%.


What will that do? Reverse the damage? :) 
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a b D Laptop
April 12, 2012 5:57:39 PM

It's to "recalibrate" the battery and charge software.

It does not correct/fix a "Damaged" battery, that is depleted chemicals.
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April 13, 2012 2:11:57 AM

OK so what aicom is saying that maybe that jump from 100 to 64% was due to a software error and not a physical one
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a b D Laptop
April 13, 2012 12:23:40 PM

Possible, Would recommend doing that - discharge to point that it powers off, then recharge.

As I mentioned, it is not recommended to leave the battery in when normally you leave it plugged in to the AC.
Another comment, When On battery, Li-ion batters have a longer life if recharged at the half-way point (not always possible) and this is one of the reasons to "recalibrate". This is another diff between Li-ion and NiCd cells. NiCd should be used until the down to 1.00 volts then recharged at 1/10 rated current for 16 hrs.
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April 13, 2012 4:51:27 PM

Just a question to add:
1. How long is the battery of HP dv4-2126 supposed to last when fully charged?

and
the charge of my battery dropped from 65% to 60% when after it was turned off for an hour.
Isnt this weird?
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April 13, 2012 6:32:09 PM

RetiredChief said:
Possible, Would recommend doing that - discharge to point that it powers off, then recharge.

As I mentioned, it is not recommended to leave the battery in when normally you leave it plugged in to the AC.
Another comment, When On battery, Li-ion batters have a longer life if recharged at the half-way point (not always possible) and this is one of the reasons to "recalibrate". This is another diff between Li-ion and NiCd cells. NiCd should be used until the down to 1.00 volts then recharged at 1/10 rated current for 16 hrs.


was just going through a youtube video on recalibration and found this user comment

""Correct! Cycling a battery like this will remove a percent or two of life, it shows up in wear leveling. You never should let it go till the system shuts down. That's why windows has two alarms. TO PREVENT A COMPLETE DISCHARGE! Lithium ION batteries don't have memory effects. Nickel metal Hydride batteries don't have memory effects. Nickel Cadmium batteries HAVE memory effects. Go ahead and do this if you're interested in removing a few percent battery life!""
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a b D Laptop
April 13, 2012 9:00:39 PM

It is correct, you do not want to do this often. Would only do when you have aproblem.
If fact, with Li-ion batteries, it is best to recharge when they hit the half hay point. This is not true of niCd cells which should be discharged to 1.00 Volts per cell before recharging.

Was responding earlier, Hit the wrong key and lost my comments. Left work and just got home.
Ref #1. "How long should battery last" this is Hard to answer as manuf's claims are basted on a specific sotware application and are often MISLEADING. I've seen several post where indivduals claim that their battery only last alittle over half time when watching a DVD. My Samsung RF711 last between 1 1/2 -> 2 hrs watching a Movie (ie traveling and on a plane).

Ref #2. Also hard to say, as When you powered back on, you drained some charge. Power on has a High inrush current compared to normal idle current.

The way most electronic evaluate "time left" is based on the Voltage and a voltage curve. Most are good at 100% and say 10 %. In between values can be iffy and are highly dependent on the state of the battery. When you look at amp/hr ratings and the time to discharge, @ the rated current drops to about half, it time to start looking for a replacement.

See.
http://www.google.com/search?q=li-ion+discharge+curve&h...
and
http://en.wikipedia.org/wiki/Lithium-ion_battery
and for care:
http://batteryuniversity.com/learn/article/how_to_prolo...
NOTE: This indicates it is OK to leave battery in when mostly using AC power - I still recommend when mostly using AC, remove battery.
http://batteryuniversity.com/learn/article/how_to_prolo...

OF interest, To bad Laptop manuf do not read, but then it would increase cost of charger.
Quote
The voltage threshold of commercial chargers cannot be changed, and making it adjustable would have advantages, especially for laptops as a means of prolonging battery life. When running on extended AC mode, the user would select the “long life” mode and the battery would charge to only, say, 4.05V/cell. This would get a capacity of about 80 percent. Before traveling the user would apply the “full charge mode” to bring the charge to 4.20V/cell. This saturation charge would take about an hour and would fill the battery to 100 percent capacity. END Quote.

THIS indicates for longer life - it is best to ONLY charge the battery to 80% and ONLY charge to 100% when You need to run on battery for an extended time.

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April 13, 2012 9:11:37 PM

just used a software to find out my battery wear and it is at 18.25% after 1 and a half year of use (of which the past 4 months were intense)
So, is that a lot of wear and tear?
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a b D Laptop
April 13, 2012 9:58:53 PM

Not really a Battery expert, Just have enough Knowledge to get me introuble. Did work with an eng. that worked with NiCads.
Bottom Line - On how long they should last - proper care 3->5 yrs. Have an Old laptop, about 10 Years old and had to replace the battery about 3 or 4 yrs ago.

Also there is a big diff between Industral battery Cells and Retail Cells.
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April 14, 2012 3:00:04 AM

Best answer selected by fasihxkhatib.
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a c 244 D Laptop
April 16, 2012 8:02:49 AM

This topic has been closed by Maziar
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