New Laptop -- Should I discharge the battery fully before recharge?

Dasda

Senior member
Jan 9, 2010
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I just got a new laptop, i have been keeping it on with the battery. My question is whether I should fully drain the batter before recharge or not. Thank You.
 

Dasda

Senior member
Jan 9, 2010
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76
so what should i do? take it down to about 2-3% and then recharge? i read that it is good to train the battery by letting it run out and the recharge. thanks
 

Rottie

Diamond Member
Feb 10, 2002
4,795
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81
yes drain juices and recharge battery for a better optimistic lifetime
 

Absolution75

Senior member
Dec 3, 2007
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it doesn't matter when you charge li-ion batteries in 99% of cases (1% is when the battery/charger is too stupid to realize not to charge at 99.9999% and constantly switches between charging/not charging).


li-ion batteries just degrade with time, nothing else really
 

Muse

Lifer
Jul 11, 2001
39,951
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You li-ion battery degrades faster when fully charged. So, you probably don't want to keep it in that state often or long. IOW, don't leave it attached with the adapter plugged in and the laptop configured to fully charge.

Running it all the way down is something you don't want to do. Once in a while you do want to do this to recalibrate so that what you are shown as the state of charge (e.g. 17%) is accurate. Other than for that purpose, it's not something you want to do. So, do that maybe once every couple months.
 

Throckmorton

Lifer
Aug 23, 2007
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Does your laptop have the ability to limit charging to say 80% or 50%, to make the battery last longer?
 

Thor86

Diamond Member
May 3, 2001
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You li-ion battery degrades faster when fully charged. So, you probably don't want to keep it in that state often or long. IOW, don't leave it attached with the adapter plugged in and the laptop configured to fully charge.

Running it all the way down is something you don't want to do. Once in a while you do want to do this to recalibrate so that what you are shown as the state of charge (e.g. 17%) is accurate. Other than for that purpose, it's not something you want to do. So, do that maybe once every couple months.

Do you have any references to this claim? My understanding in this day and age of Lith-Ion batteries will degrade with the number of charging, does this include leaving it plugged in to the power adapter?
 

taltamir

Lifer
Mar 21, 2004
13,576
6
76
how you treat your battery depends entirely on its chemistry. some batteries are best fully drained before a recharge... a lithium ion battery like you have in your laptop should ideally NEVER be allowed to drain below 15%... it loses a lot of its life when that happens.
AFAIK there is no harm in keepin a li-ion battery fully charged at all times, but I am not certain... you should research that battery type specifically.
 

QuantumPion

Diamond Member
Jun 27, 2005
6,010
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You li-ion battery degrades faster when fully charged. So, you probably don't want to keep it in that state often or long. IOW, don't leave it attached with the adapter plugged in and the laptop configured to fully charge.

Running it all the way down is something you don't want to do. Once in a while you do want to do this to recalibrate so that what you are shown as the state of charge (e.g. 17%) is accurate. Other than for that purpose, it's not something you want to do. So, do that maybe once every couple months.

Yes Li-Ion batteries do degrade slightly faster while fully charged or at higher temperatures, but they degrade the fastest (far more so) when deeply discharged to 0%. Each deep discharge may be equivalent to as many as 10 partial charges, and too deeply discharging can permanently reduce its capacity or damage the battery.
 

Muse

Lifer
Jul 11, 2001
39,951
9,630
136
Do you have any references to this claim? My understanding in this day and age of Lith-Ion batteries will degrade with the number of charging, does this include leaving it plugged in to the power adapter?

My favorite sites for information on this sort of thing right now are:

http://www.batteryuniversity.com/index.htm

http://www.greenbatteries.com/

I also sometimes get info at this newsgroup:

sci.chem.electrochem.battery


The issue with leaving the battery in all the time with the adapter in use is how fully charged the battery is. If you limit in your laptop's charging configuration to have charging stop at a threshold, perhaps 85% (guesstimate) then it will be a lot better. If you are using the adapter most of the time, I'd remove the battery. Mine are in my refrigerator because I seldom use the batteries and I don't want to have to buy another any time soon. I try to have them at around 40% charge when I put them in there. They will keep better that way than at, say, a charge state of 80% in a warm laptop.
 
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Muse

Lifer
Jul 11, 2001
39,951
9,630
136
Yes Li-Ion batteries do degrade slightly faster while fully charged or at higher temperatures, but they degrade the fastest (far more so) when deeply discharged to 0%. Each deep discharge may be equivalent to as many as 10 partial charges, and too deeply discharging can permanently reduce its capacity or damage the battery.
I think there's circuitry in there to prevent the battery from discharging beyond a certain level for just this reason. Even so, going down to the threshold wouldn't be good. Even so, it's recommended to do so once in a long while to recalibrate the system that tells you what the estimated capacity is, if you care about such things. I don't figure it's worth it to me particularly.
 

Muse

Lifer
Jul 11, 2001
39,951
9,630
136
how you treat your battery depends entirely on its chemistry. some batteries are best fully drained before a recharge... a lithium ion battery like you have in your laptop should ideally NEVER be allowed to drain below 15%... it loses a lot of its life when that happens.
AFAIK there is no harm in keepin a li-ion battery fully charged at all times, but I am not certain... you should research that battery type specifically.
I don't think so. I try not to charge mine above 90% and if I do so inadvertently I try to drain it to where it's not so high. For instance, I'll leave my cell phone on if it's highly charged before turning it off. It's because of things like this that I prefer NiMH when I'm making choices. AFAIK, there's no issue with them being maximally charged as long as you don't overcharge them. That's up to your charger! Also, NiMH don't suffer from being run down too far. There's also no issue with charging them at any stage of discharge, which isn't always true with NiCd. My favorite sites for information on this sort of thing right now are:

http://www.batteryuniversity.com/index.htm

http://www.greenbatteries.com/

I also sometimes get info at this newsgroup:

sci.chem.electrochem.battery
 
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fffblackmage

Platinum Member
Dec 28, 2007
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How do you keep the battery charged at, say 80%, instead of 100%?

I'm looking through the power options but dont see anything like limiting battery charge levels....

BTW, what is "Reserve battery level?" It's set to 7% by default.
 

Emulex

Diamond Member
Jan 28, 2001
9,759
1
71
the modern laptop systems attempt to avoid self destruction by not fully charging nor fully discharging 90% of the time - like your it will let you do destructive behaviour because it will sell more cars :) - but it protects itself from some stupidity to avoid warranty issues - the key factor here is to break as soon as out of warranty for maximum profit lol.

you can go to EVERY manufacturer of laptops and they have the same instructions since all modern laptops use LI-ION batteries. the story is the same apple,dell,hp,gateway, yadda.

follow the guidelines and you are cool - like everything moderation is key :)
 

taltamir

Lifer
Mar 21, 2004
13,576
6
76
the modern laptop systems attempt to avoid self destruction by not fully charging nor fully discharging 90% of the time - like your it will let you do destructive behaviour because it will sell more cars :) - but it protects itself from some stupidity to avoid warranty issues - the key factor here is to break as soon as out of warranty for maximum profit lol.

this is why they don't just set the thing to never go over 90% or under 15%... they could make it treat 15% as an empty battery and 90% as full and stop charting / lose power when that happens. but then what will keep people buying more?
Also, they insist on using weird proprietary shaped batteries for max incompatibility... you know the first mobile systems from decades ago used AA baterries? dozens of them... but they worked. (this reminds me, some guy is making an electric car with hundreds of rechargable AA batteries at a fraction of what it costs to buy specialized batteries)
 

OCedHrt

Senior member
Oct 4, 2002
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I think there's circuitry in there to prevent the battery from discharging beyond a certain level for just this reason. Even so, going down to the threshold wouldn't be good. Even so, it's recommended to do so once in a long while to recalibrate the system that tells you what the estimated capacity is, if you care about such things. I don't figure it's worth it to me particularly.

I have a battery that was used maybe twice that was discharged completely (unused for a few weeks) and has been dead since. It is not chargeable. I do not recommend ever discharging li-on's completely. I don't even bother charging them fully before using new systems and still have a 5 year battery going strong at full capacity.
 

Muse

Lifer
Jul 11, 2001
39,951
9,630
136
I have a battery that was used maybe twice that was discharged completely (unused for a few weeks) and has been dead since. It is not chargeable. I do not recommend ever discharging li-on's completely. I don't even bother charging them fully before using new systems and still have a 5 year battery going strong at full capacity.

Maybe your battery that went dead was "fully discharged" (discharged to the point where the internal controls kicked in and stopped the process because the charge was getting dangerously low) and then leaving it sit for a couple of weeks caused further discharge that killed it.

I have not personally had to replace any of my li-ion batteries, but I've gone through all kinds of hoops in an effort to keep them alive and vibrant. In doing so, I've developed an antipathy for them and in researching to get my next camera, I have to think it a cool thing if it uses rechargable AAs. Li-ion are lighter, but babying the batteries is a turn off. I know, a lot of people just use them and figure when they don't perform they'll buy replacements. Right now, my favorite rechargables in terms of not having to worry about screwing them up are NiMH. I have my best NiMH AA's fully charged in the freezer. Yes, I need to warm them up before inserting in my camera, etcetera but that only takes a few minutes. They keep their charge far better than at room temperature when stored in the freezer. These particular batteries aren't Eneloops or other slow discharge batteries, however they are high capacity (Powerex's).
 
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OCedHrt

Senior member
Oct 4, 2002
613
0
0
Maybe your battery that went dead was "fully discharged" (discharged to the point where the internal controls kicked in and stopped the process because the charge was getting dangerously low) and then leaving it sit for a couple of weeks caused further discharge that killed it.

I have not personally had to replace any of my li-ion batteries, but I've gone through all kinds of hoops in an effort to keep them alive and vibrant. In doing so, I've developed an antipathy for them and in researching to get my next camera, I have to think it a cool thing if it uses rechargable AAs. Li-ion are lighter, but babying the batteries is a turn off. I know, a lot of people just use them and figure when they don't perform they'll buy replacements. Right now, my favorite rechargables in terms of not having to worry about screwing them up are NiMH. I have my best NiMH AA's fully charged in the freezer. Yes, I need to warm them up before inserting in my camera, etcetera but that only takes a few minutes. They keep their charge far better than at room temperature when stored in the freezer. These particular batteries aren't Eneloops or other slow discharge batteries, however they are high capacity (Powerex's).

I read somewhere that Li'ons were recommended to be stored at 60% in the freezer ;)

Regarding maintaining Li'ons: for me, don't leave them discharged has been sufficient. This means, don't leave them out of the laptop either, because they drain. And, don't use your laptop on the bed with the battery as they tend to run hot.
 

Emulex

Diamond Member
Jan 28, 2001
9,759
1
71
no - 40% in a cool sealed environment (throw in some silica gel). but that is only for short periods - like summer vacation.

1% deviance in charge voltage/watt can kill a battery twice as fast :) so think twice before using aftermarket or generic chargers!
 

Brian Stirling

Diamond Member
Feb 7, 2010
3,964
2
0
My 2.6 year old Thinkpad can be configured to stop charging when the charge level reaches, say, 90% to prevent overcharging which is the fastest way to kill a Li-Ion battery. I have not run the Thinkpad down all the way in a while to confirm capacity but it looks to be over 90 minutes at least. My new HP dv8t does NOT have such a charge limiting feature but I don't know if that isn't built into the charge controller -- anyone know?

I have a Dell laptop that's a few months older than the Thinkpad and BOTH the batteries I have for it are dead and have been dead for more than a year. The Dell did not have any charge limiting option like the Thinkpad, but it's also likely that Dell just goes the cheap route on everything and don't care about battery life. In fact, could be a profit center for them to either sell you new batteries or new laptops sooner than otherwise necessary.


Brian