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View Full Version : Is it bad idea to leave netbook plugged in majority of time?



mamamia88
April 16th, 2010, 04:50 PM
i have a netbook and i rarerly use it. but i like to leave it plugged in so when i go out i have 100% full charge. so is it a bad idea to leave my netbook in sleep mode plugged in most of the time? will it have negative impact on the battery?

nerdy_kid
April 16th, 2010, 05:37 PM
i think it does have a negative impact on the battery...not entirly sure. However, I have a laptop and my battery has lasted me ~2 years of constant use; and i always leave it plugged in when im not using it. I wouldnt be concerned about it :)

CharlesA
April 16th, 2010, 05:50 PM
I've had mine running off A/C for the last 2-3 months. I haven't really noticed any problems (yet) but it's not charging, even on A/C power.

undecim
April 16th, 2010, 06:10 PM
Yes.

It leaves the battery charged, which allows the checmicals inside to crystalize and make the battery worthless.

I intentionally let my battery drop to 30% at least once per week.

Lightstar
April 16th, 2010, 06:20 PM
Some batteries need to be emptied and refilled every now and then to stay in good health.
I can't remember if that is about nimh or lithium, but it's worth looking up, which I will... later.

FuturePilot
April 16th, 2010, 06:24 PM
Some batteries need to be emptied and refilled every now and then to stay in good health.
I can't remember if that is about nimh or lithium, but it's worth looking up, which I will... later.

nimh

Lightstar
April 16th, 2010, 06:25 PM
nimh

Thanks! XD

aysiu
April 16th, 2010, 06:26 PM
Read this:
http://www.batteryuniversity.com/parttwo-34.htm

Tristam Green
April 16th, 2010, 06:29 PM
Yes.

It leaves the battery charged, which allows the checmicals inside to crystalize and make the battery worthless.

I intentionally let my battery drop to 30% at least once per week.

I go to 15% before replugging.

If you're going to leave your netbook plugged in 100% of the time, just remove the battery. It's not like you'll miss the weight.

Dragonbite
April 16th, 2010, 06:34 PM
So leave the netbook on all of the time and plugged into one of those Christmas Tree light timers that turns it off for about 3-4 hours every day (like in the middle of the night when not using it) to let the battery drain down.

You don't see any loss as by the time you get up in the morning it should be recharged yet the battery has gone through one of its (limited?) cycles.

I know the Lenovo laptop I have for work has the battery set so it doesn't recharge until the battery gets below a certain value (like 30%) but I think that's OS-controlled because it'll recharge if it is plugged in but turned off.

mamamia88
April 16th, 2010, 07:45 PM
So leave the netbook on all of the time and plugged into one of those Christmas Tree light timers that turns it off for about 3-4 hours every day (like in the middle of the night when not using it) to let the battery drain down.

You don't see any loss as by the time you get up in the morning it should be recharged yet the battery has gone through one of its (limited?) cycles.

I know the Lenovo laptop I have for work has the battery set so it doesn't recharge until the battery gets below a certain value (like 30%) but I think that's OS-controlled because it'll recharge if it is plugged in but turned off.
that is actually a genius idea thanks

Dragonbite
April 16th, 2010, 07:49 PM
that is actually a genius idea thanks

Let me know if it actually works ;)

cguy
April 16th, 2010, 10:08 PM
Dudes, dudes, don't sweat over this! I'm sure they have a circuit (and maybe software) to stop the charging after reaching full capacity and continue to run on AC.

It's the obvious thing to do when designing such devices.

aysiu
April 16th, 2010, 10:18 PM
I'm sure they have a circuit (and maybe software) to stop the charging after reaching full capacity and continue to run on AC. They do, but that's not the issue. To optimize the battery life of a lithium ion, it's better to do regular charges and discharges (but not full discharges). Read the link I posted earlier.

sudoer541
April 16th, 2010, 11:32 PM
Read this:
http://www.batteryuniversity.com/parttwo-34.htm


Thank you for the link and we love you!!!!

aysiu
April 16th, 2010, 11:49 PM
You're welcome.

Here are some highlights:
A lithium-ion battery provides 300-500 discharge/charge cycles. The battery prefers a partial rather than a full discharge. Frequent full discharges should be avoided when possible. Instead, charge the battery more often or use a larger battery. There is no concern of memory when applying unscheduled charges.
If possible, store the battery in a cool place at about a 40% state-of-charge. Some reserve charge is needed to keep the battery and its protection circuit operational during prolonged storage. Avoid keeping the battery at full charge and high temperature. This is the case when placing a cell phone or spare battery in a hot car. Running a laptop computer on the mains has a similar temperature problem. While the battery is kept fully charged, the inside temperature during operation rises to 45C (113F).
Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns. And from the Apple website (http://www.apple.com/batteries/notebooks.html) (don't worry--these are not Mac-specific, as Macs just use lithium ion batteries, as other non-Mac laptops do):
For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her MacBook Pro on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month. So frequent small charges and discharges are good. A full discharge is okay every once in a while, but shouldn't be done too often. Keeping the charge at 100% perpetually will not maximize your battery life.

lisati
April 16th, 2010, 11:57 PM
From the instruction manual for my Toshiba Satellite M200 laptop:

To maximize the life of your battery pack:
❑ At least once a month, disconnect the computer from a power source and operate it on battery power until the battery pack fully discharges.

aysiu
April 17th, 2010, 12:05 AM
From the instruction manual for my Toshiba Satellite M200 laptop:
That seems in line with both what BatteryUniversity and Apple say:
Although lithium-ion is memory-free in terms of performance deterioration, batteries with fuel gauges exhibit what engineers refer to as "digital memory". Here is the reason: Short discharges with subsequent recharges do not provide the periodic calibration needed to synchronize the fuel gauge with the battery's state-of-charge. A deliberate full discharge and recharge every 30 charges corrects this problem. Letting the battery run down to the cut-off point in the equipment will do this. If ignored, the fuel gauge will become increasingly less accurate. (Read more in 'Choosing the right battery for portable computing', Part Two.)
Apple recommends charging and discharging its battery at least once per month. The reason I don't emphasize this as much is there is too much fear leftover from outdated Nickel Cadmium practices of discharging fully all the time for fear of losing battery life. Lithium Ion does not operate that way. Also, as BatteryUniversity explains, the full discharge is more about calibrating the accuracy of reading how much battery life is left rather than actually prolonging the battery life.

gletob
April 17th, 2010, 03:05 AM
You shouldn't discharge your battery. What the article above says that multiple short charges are better than one big charge. Lithium-ion batteries degrade because of use. So if the batteries already full, leave it in, or remove it if you prefer.

aysiu
April 17th, 2010, 07:43 AM
You shouldn't discharge your battery. What the article above says that multiple short charges are better than one big charge. Yes, generally. Every now and then (like once a month) it isn't a terrible thing to do a full discharge.
Lithium-ion batteries degrade because of use. Actually, they degrade with time even if you don't use them, which is why it's a bad idea to buy a battery "for later."

Khakilang
April 17th, 2010, 03:51 PM
Once its full it is full. Over charge them may shorten the life of the battery. I use to advice my customer whenever to take out the battery if they were to use their Notebook with power plug in once the battery is full.