Run laptop on battery or keep it plugged in?

Question

Run laptop on battery or keep it plugged in?

Anonymous

A tech person at Best Buy warned me against "overcharging" my battery, and suggested deliberately discharging it "once a week."

I have observed that the charger's adapter becomes warm during charging, but when the battery becomes fully charged, even if not unplugged, the adapter goes cold. This seems to indicate that the battery will not "overcharge."

My instinct tells me to reserve the battery for those times when I'm not near an AC outlet, but otherwise to keep my laptop plugged in.

After reading many posts on this question, I am more confused than ever. I thought I had understood that with lithium ion batteries it was safe to keep the laptop plugged in, to save battery life. However, to my dismay, I found this on the MICROSOFT web site:

http://windows.microsoft.com/en-US/windows7/Taking-care-of-your-laptop-battery

"Don't keep your computer plugged in all the time. It's a good idea to discharge and then recharge your laptop battery about once a month. Also, you should let your battery run down before you recharge it."

What do the best minds here recommend?

Thanks a million.

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Answer 1

FWIW, here's what my Toshiba User's Guide has to say on the subject. I have a Satellite L755 I bought 6 months ago.


To ensure that the battery maintains its maximum capacity,

operate the computer on battery power at least once a month. The

Lithium-Ion battery has no memory effect so it is not necessary to

let the battery fully discharge each time. However, for better

accuracy of the battery meter, it is helpful to fully discharge the

battery periodically. Please see 

"Maintaining your battery" on

page 134 

for procedures. If the computer is continuously operated

on AC power, either through an AC adaptor or a port replicator (if

applicable to your system), for an extended period (more than a

month), the battery may fail to retain a charge. This may shorten the

life of the battery, and may cause the battery meter to be inaccurate.

Maintaining your battery

Fully discharging your battery pack will allow better accuracy of

the battery meter.

To fully discharge your battery pack:

❖ 

Periodically, disconnect the computer from a power source and

operate it on battery power until the battery pack fully

discharges. Before doing so, follow the steps below:

1 

Turn off the computer’s power.

2 

Disconnect the AC adaptor and turn on the computer’s

power. If it does not turn on, go to step 

4.

3 

Operate the computer on battery power for five minutes. If

the battery pack has at least five minutes of operating time,

continue operating until the battery pack is fully

discharged. If the battery light flashes or there is some

other warning to indicate a low battery, go to step 

4.

4 

Connect the AC adaptor to the computer and the

power cord/cable to a power outlet. The DC-IN or AC

power-light should glow white, and the battery light

should glow amber to indicate that the battery pack is

being charged. If the DC-IN or AC power-light indicator

does not glow, power is not being supplied. Check the

connections for the AC adaptor and power cord/cable.

5 

Charge the battery pack until the battery light glows white.

❖ 

If you have extra battery packs, rotate their use.

Mobile Computing 

135

Disposing of used batteries

❖ 

If you will not be using the system for an extended period,

more than one month, remove the battery pack.

❖ 

If you are not going to use the computer for more than eight

hours, disconnect the AC adaptor.

❖ 

Store spare

Answer 2

Most newer batteries today are rated for charge/discharge cycles - you can run it down so many times and then when you reach that limit, the battery will stop taking charges. Most laptop manufacturers recommend just leaving it plugged in. Have you checked with your laptop manufacturer to see what they have to say on the subject?

Answer 3

I think it's like the age old opinions on whether to turn a computer off at night. There are lots of opinions around, but here's mine. I've read and have the belief that if you have your battery in the computer and are on external power for a week or more, it's probably a good idea to use the battery for a few hours. However I also believe that the more you charge and discharge your battery, the less time it will last. They all wear out in a few years, just like new car batteries. I got a tip once from a guy in the computer business who says when he's going to need the battery for a week or more, he powers the laptop down and removes the battery; and that enables the battery to last more than the 2 years they had been doing. Some laptops won't power on without the battery in, but my Toshibas don't have that problem. Anyway I tried that in my last Toshiba laptop and got 4 years use out of the battery. When it was new, it would last just over 2 hours - after 4 years it would last 1 1/2 hrs. which I thought was pretty good for a 4 year old battery. Obviously if you're on the road a lot, you can't always do that, but I'm retired and it worked for me. YMMV

I'd be surprised if you don't get a variety of opinions about this subject. Remember opinions are like rear ends - everybody has one. :-)

I hope this helps. Good luck.

Answer 4

I don't know why it did not occur to me to check my own Users Guide.

My face is appropriately red.

Thanks to you and the other Good Samaritans at this forum, I am gratified to understand that my original "feeling" was correct. Don't use the battery when I don't have to.

Regards

Answer 5

On Mon, 18 Jun 2012 00:37:44 +0000, Grandpa Jim wrote:

A tech person at Best Buy warned me against "overcharging" my battery, and suggested deliberately discharging it "once a week."

The so-called "tech person" at Best Buy is wrong. I strongly recommend
against taking their advice or having them service your computer. The
same goes for any other big box store. Avoid them all.

Ken Blake, Microsoft MVP

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Run laptop on battery or keep it plugged in?

6 additional answers