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Possible Duplicates:
Is it better to use laptop on battery or on AC power?
What is it that kills laptop batteries?

I've heard that using a laptop computer on battery mode on a regular basis (at least two hours a day) Can prolong the battery's lifetime.

I'm not talking about increasing its duration per charge cycle, but its years of usefulness.

Is this true?

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marked as duplicate by Daniel Beck, Arjan, BloodPhilia, Sathya Feb 11 '11 at 7:11

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

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Another duplicate –  Daniel Beck Feb 10 '11 at 20:41
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This is also relevant. –  Daniel Beck Feb 10 '11 at 20:41
    
wow look at all the dupes. –  Kyle Feb 10 '11 at 20:46
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How embarrassing. Thanks for the links. –  overmann Feb 10 '11 at 20:47
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Not true, a lion battery only has so many charge cycles before it dies....h10025.www1.hp.com/ewfrf/wc/… –  Moab Feb 10 '11 at 21:18

3 Answers 3

up vote 3 down vote accepted

This reminds me of a recent Slashdot article, watch the video and it should become pretty apparent why constant charging it is not a good idea. So to answer your question if you have a lithium ion batter which most laptops have (I can't think of any laptops with nicad) it is not good to constantly charge and discharge the battery.

from the article:

As lithium ions flow from the positively charged cathode into the 200-nanometre diameter wires of tin oxide that make up the negatively charged anode, the nanowires writhe and bulge, causing them to expand up to 2.5 fold. The wires also change structure from a neatly ordered crystal to a disordered glassy material.

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And I'd figure that a good charger will stop charging when done. So, leaving it plugged in at that time, one would be running the device directly from the mains power. –  Arjan Feb 10 '11 at 20:59

Today's laptops use Lithium batteries instead of nickel, but there's a lot of incorrect information out there about how to charge or drain your batteries, so let's set the record straight: Nickel batteries required being fully drained before a recharge to optimize your battery life, but Lithium batteries are the opposite—you do not need to fully discharge it before recharging, and in fact, if you fully deplete a lithium battery and don't recharge for a while, it can become incapable of holding a charge.

You'll also want to make sure that your battery is not always fully charged—Wikipedia points out that if your lithium battery is fully charged all the time, you will lose up to 20% of your capacity every year, no matter what you do. Make sure to discharge the battery sometimes, and if you spend most of your time plugged in at a desk, you would be better off running the battery down to half, and then simply removing the battery and storing it in a cool place. You can use Hibernate mode to save exactly what you were doing while still shutting down the laptop completely.

Found in: http://lifehacker.com/#!5566020/how-to-maximize-the-battery-life-of-your-windows-laptop

I think this sets it straight for me. Thank you all for your answers.

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On a Mac, do NOT remove the battery while using the MacBook. –  Arjan Feb 11 '11 at 7:23

My thinkpad t410s has a feature that I can set the min charge level before recharging. I've got it set at 90%, so the battery has to drain down to at least 90% before it will recharge. My old T43 would charge whenever the battery level dropped to 99% and this has made the battery basically useless at this point (30% it's original charge capability).

Most battery manufacturers (li-on) also recommend that you discharge the battery fully about once a month, if you use it every day. This will help (I'm not sure why) to maintain a healthy battery. NiCad bats required this treatment more regularly, but Li-On bats also need it sometimes, apparently.

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This contradicts other advices. I've read a lot that draining a battery is actually harmful and can render it useless. Unless I read wrong of course. My compy is an acep aspire one, with a lithium ion battery with six cells. –  overmann Feb 11 '11 at 0:06
    
I think you've misread my advice. All batteries slowly drain their charge even when not in use. A major battery killer is having your battery recharge when it loses even 1%. While a laptop is plugged into AC power, it loses 1% of charge, as is normal. The charger powers it back up to 100%. This happens all the time without your knowing it and will eventually cause major battery life reduction. By setting charging to only occur when below 90% you reduce this "churn" significantly prolonging your battery's effective lifespan. The first post also states "constant charging is not a good idea." –  stevemidgley Mar 24 '11 at 14:47

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