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prolonging battery life Andy Fish 01-24-2008
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Posted by Mike S. on January 24, 2008, 11:43 am
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http://batteryuniversity.com/parttwo-34.htm

Posted by Dave Martindale on January 24, 2008, 8:47 pm
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>from what I can tell, it's a bad idea to run it on the mains all the time
>unless the battery is removed (which I don't want to get into). so therefore
>I could presumably maximise the battery life when i'm in the office by
>running it on batteries for a while, then turning on the mains power until
>it charges up to nearly 100%, then using it on batteries until it gets low
>again and so on.

>is this true? anyone tried it?

No, that's a really bad idea. It will shorten the battery life even more.
LiIon batteries are good for a few hundred charge/discharge cycles
total, and you're going to be using up one of those cycles every few
hours of operation.

Basically, you'll get the best life from a LiIon battery by using it
only when you need battery operation (to minimize charge/discharge
cycles), removing it from the laptop when you're using the laptop on AC
(unless the battery needs charging) to avoid exposing it to higher than
room temperatures, and leaving it partially charged (instead of 100%
charged) if you store it for long periods.

If you're not willing to install and remove the battery when you
switch from portable to AC operation, your second best choice is just
leave the battery in all the time, and use AC power whenever that is
available. This will shorten battery life somewhat compared to the
ideal case.

But what you suggest, charging and discharging the battery repeatedly,
is likely to give *shorter yet* life by simply exhausting the battery's
charge/discharge life. Also, while charging or discharging it gets *even
warmer* than just sitting in the laptop without charging.

>if this idea really works, presumably it would be possible to write a piece
>of software which worked a bit like a thermostat enabling and disabling the
>mains input to keep the battery charge always between (say) 70 and 90%.

Really bad idea. You're proposing to avoid something moderately bad by
doing something that's even worse.

Why don't you want to remove the battery when operating from AC, other
than the inconvenience?

        Dave


        Dave

Posted by Andy Fish on January 25, 2008, 4:47 am
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Thanks Dave for a very comprehensive and considered reply. I was assuming
that, since laptop makers have a vested interest in the battery degrading,
they might have chosen not to implement the best solution

i'm left with the conclusion that the only way to keep my battery in tip top
condition if i'm using the mains most of the time is to take it out every
time i'm not using it and leave it in the fridge at 40 percent charged :-)

the reason i don't want to take it out is (a) simply hassle, and (b)
protection from power glitches (though these are very rare)

Andy

>
>>from what I can tell, it's a bad idea to run it on the mains all the time
>>unless the battery is removed (which I don't want to get into). so
>>therefore
>>I could presumably maximise the battery life when i'm in the office by
>>running it on batteries for a while, then turning on the mains power until
>>it charges up to nearly 100%, then using it on batteries until it gets low
>>again and so on.
>
>>is this true? anyone tried it?
>
> No, that's a really bad idea. It will shorten the battery life even more.
> LiIon batteries are good for a few hundred charge/discharge cycles
> total, and you're going to be using up one of those cycles every few
> hours of operation.
>
> Basically, you'll get the best life from a LiIon battery by using it
> only when you need battery operation (to minimize charge/discharge
> cycles), removing it from the laptop when you're using the laptop on AC
> (unless the battery needs charging) to avoid exposing it to higher than
> room temperatures, and leaving it partially charged (instead of 100%
> charged) if you store it for long periods.
>
> If you're not willing to install and remove the battery when you
> switch from portable to AC operation, your second best choice is just
> leave the battery in all the time, and use AC power whenever that is
> available. This will shorten battery life somewhat compared to the
> ideal case.
>
> But what you suggest, charging and discharging the battery repeatedly,
> is likely to give *shorter yet* life by simply exhausting the battery's
> charge/discharge life. Also, while charging or discharging it gets *even
> warmer* than just sitting in the laptop without charging.
>
>>if this idea really works, presumably it would be possible to write a
>>piece
>>of software which worked a bit like a thermostat enabling and disabling
>>the
>>mains input to keep the battery charge always between (say) 70 and 90%.
>
> Really bad idea. You're proposing to avoid something moderately bad by
> doing something that's even worse.
>
> Why don't you want to remove the battery when operating from AC, other
> than the inconvenience?
>
> Dave
>
>
> Dave



Posted by tc on January 25, 2008, 5:08 am
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Power glitches won't hurt the battery.
Terry

> Thanks Dave for a very comprehensive and considered reply. I was assuming
> that, since laptop makers have a vested interest in the battery degrading,
> they might have chosen not to implement the best solution
>
> i'm left with the conclusion that the only way to keep my battery in tip
> top condition if i'm using the mains most of the time is to take it out
> every time i'm not using it and leave it in the fridge at 40 percent
> charged :-)
>
> the reason i don't want to take it out is (a) simply hassle, and (b)
> protection from power glitches (though these are very rare)
>
> Andy
>
>>
>>>from what I can tell, it's a bad idea to run it on the mains all the time
>>>unless the battery is removed (which I don't want to get into). so
>>>therefore
>>>I could presumably maximise the battery life when i'm in the office by
>>>running it on batteries for a while, then turning on the mains power
>>>until
>>>it charges up to nearly 100%, then using it on batteries until it gets
>>>low
>>>again and so on.
>>
>>>is this true? anyone tried it?
>>
>> No, that's a really bad idea. It will shorten the battery life even
>> more.
>> LiIon batteries are good for a few hundred charge/discharge cycles
>> total, and you're going to be using up one of those cycles every few
>> hours of operation.
>>
>> Basically, you'll get the best life from a LiIon battery by using it
>> only when you need battery operation (to minimize charge/discharge
>> cycles), removing it from the laptop when you're using the laptop on AC
>> (unless the battery needs charging) to avoid exposing it to higher than
>> room temperatures, and leaving it partially charged (instead of 100%
>> charged) if you store it for long periods.
>>
>> If you're not willing to install and remove the battery when you
>> switch from portable to AC operation, your second best choice is just
>> leave the battery in all the time, and use AC power whenever that is
>> available. This will shorten battery life somewhat compared to the
>> ideal case.
>>
>> But what you suggest, charging and discharging the battery repeatedly,
>> is likely to give *shorter yet* life by simply exhausting the battery's
>> charge/discharge life. Also, while charging or discharging it gets *even
>> warmer* than just sitting in the laptop without charging.
>>
>>>if this idea really works, presumably it would be possible to write a
>>>piece
>>>of software which worked a bit like a thermostat enabling and disabling
>>>the
>>>mains input to keep the battery charge always between (say) 70 and 90%.
>>
>> Really bad idea. You're proposing to avoid something moderately bad by
>> doing something that's even worse.
>>
>> Why don't you want to remove the battery when operating from AC, other
>> than the inconvenience?
>>
>> Dave
>>
>>
>> Dave
>
>



Posted by John Doue on January 25, 2008, 7:39 am
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tc wrote:
> Power glitches won't hurt the battery.
> Terry
>
snip


Terry,

I suspect this very considered reply will help a lot the OP make a
decision in the way he intends to use his battery ...!!!

--
John Doue

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