Laptop Battery Question

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I just got a new laptop about a week ago. My concern is this. I am
mostly using it as another desktop. The battery hardly ever gets used.
I leave the laptop plugged into wall outlet all the time. So I guess
the battery is constantly getting a charge. Should i remove the
battery or just leave it in while laptop is plugged into outlet?

I'm just concerned that I will mess up my battery, and not sure what
proper methods I should be following.

Re: Laptop Battery Question

valid concern.

If used mainly on AC, pull the battery out.


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Re: Laptop Battery Question

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After some research, I came to the following conclusion:
1) Don't use it when you don't need it.
2) Keep it charged at 50% and store it away. Check every couple of
months to make sure it's not under 15%.

What I don't know is whether you should charge it (when charge is
<15%) to 100% and use it up to 50% or just stop when it reaches 50%.
Charge to 100%, you lose one cycle of the total charge cycle. Will
charging to 50% every time make the battery losing its total capacity
after a long time? I suspect that it will lose its capacity after 2 to
3 years no matter what.

Thanks for any suggestions,


Remember that new laptop batteries generally arrive in a discharged
state; you must charge them up for at least four hours before their
first use. Keep your laptop battery cool, but do not put it in the
refrigerator or freezer Don't use the notebook battery if you don't
have to! Many people keep their laptop plugged in most of the time.
They can preserve their notebook battery life by storing the battery
outside the laptop in a cool place. Try to avoid running your laptop
battery all the way to zero Don't charge your notebook battery before
long periods of inactivity Much as we'd like to sell you more laptop
batteries, don't buy spare notebook batteries for later use. The
longer you hold them, the less useful life they provide
If you don't plan on using your notebook for more than six months,
Apple recommends that you remove and store the battery with a 50%
charge. If you store a battery when it's fully discharged, it could
fall into a deep discharge state, which renders it incapable of
holding any charge. Conversely, if you store it fully charged for an
extended period of time, the battery may experience some loss of
battery capacity, meaning it will have a shorter life. Be sure to
store the ejected battery at the proper temperature.

Re: Laptop Battery Question

It's best to give the battery a bit of "exercise" every 2-3 months.

Don't run it down (or let it get run down) as low as 15%, that's too
low.  25% would be a better number, but one advantage to charging it
much more (and leaving it that way), even 100%, is that if you happen to
completely forget about it, it will last longer (a LOT longer) than if
you had let it continue to self discharge to destruction.

liu wrote:
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Re: Laptop Battery Question

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I keep reading this bit about not allowing a Li-ion battery to run down to
low charge levels.  However, I have never found any reliable references that
back up this assertion.  The manufacturers all claim that these batteries
are useable over their entire charge range without problem.   Do you have a
reliable cite for this claim?

I myself have 3 Li-ion batteries that were bought in 1994 that have been
regularly discharged to cut-off (actually Walkman batteries rather than
Laptop, but the technology is essentially the same).   My laptop battery is
also run to 5% fairly regularly (now 4 years old and still has the original

Here we use experimental UAVs with Li-ion batteries (admittedly fairly
modern ones) that not only get discharged to 0% (that is 3.0 volts), but get
discharged very quickly (like 15 minutes or so).  They also get charged in a
similar time scale.  None of these batteries has exhibited the slightest
evidence of a reduction in life or charge retention.

Your points about storing with higher charge levels and periodic exercise is
quite valid.  The manufacturers claim that 40% charge is the prefered charge
level for storage, but I have never stored a battery so cannot comment

SONY claim that their latest type of Li-ion batteries should be completely
discharged before any periods of non use.  I don't think they have found
their way into laptops yet because their electrical characteristics are
completely different (the average voltage is only 3.4 volts for as start).
I have 3 examples of differing capacities and the only observation that I
have on them so far is that the self discharge rate is incredibly high (they
self discharge to 70-50% charge in a month).

Re: Laptop Battery Question

In the situation that you describe, you should remove the battery and
get a small (350VA) UPS (about $30, maybe less, maybe even "free after
rebate" if you shop carefully).

The battery should be exercised every few months, charged up and then
used a bit.  The battery makers say that lithium batteries last longest
if stored at a 40% to 60% charge, but personally I have not seen much
difference between that and storing them at 100%, and I repair laptops
and have dozens of ten-year old batteries that still work well.  [you
will also see recommendations to store them in a refrigerator; nothing
wrong with that, certain, and in theory it too should help, but, again,
I don't think that it makes much if any real difference compared to room
storage in an air-conditioned environment.]

However, leaving the battery in the laptop will almost certainly destroy
it in 6 to 24 months.

Scott wrote:
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Re: Laptop Battery Question

hi Scott,

Also remember to use common sense precautions to protecting your
battery. ie.
don't expose it to extreme hot and cold, and make sure to
unplug it every once
and a while.

Here is a good additional reference for this about battery power:

Hope that helps!

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