Care & feeding of laptop battery

Life Technology
1

I just bought my first laptop (IBM R40 Thinkpad). I’ve been hearing contradictory things about when and how much to charge my battery these first few days to help ensure optimum battery performance.

One person told me to run the battery down and then to charge it for about 10 hours. Repeat twice. Then just charge it for about three hours each time subsequently.

Another said, "No, that’s not the way to do it at all. You should keep it plugged in all the time for the first few days whenever you have it on.

IBM’s documentation wasn’t helpful.

Suggestions?

2

In general, I think the advice for rechargeable batteries is to use up the charge completely, then recharge them completely each time (not only the first few times). When recharging, I think you’re supposed to have the appliance switched off.

Sorry I can’t be more specific; hope others can help.

3

Don’t ask me, I blew it on this one. I bought a nice Compaq laptop and used it plugged in all the time for the first few months, so when I finally unplugged it and tried to use it I found the battery no longer works. Grrrrr. And no one told me that would happen. At least not in English. :imp:

4

Most new computers have Lithium batteries

batteryuniversity.com/parttwo-34.htm

should tell you all you need to know.

5

Great link. Thanks.

Especially useful was the “Do and don’t battery table.”

6

Wow. I always thought it was best to fully discharge all batteries! I guess not, nice post guys!

7

I had a similar experience with my first laptop, also a compaq. Not only do they not give you any clear advice in the user manual, they don’t give much help at their website either. At least, they didn’t a few years back.

The guy I bought my new machine from gave me quite a lecture about not doing that, which is one of the refreshing things about sales people in Taiwan. Mostly I get good advice when buying new toys, instead of the uninformed crap I got used to in certain other countries.

Would it be too hard for the manufacturers to build a little switch into their devices that cuts off the charge to the battery when it is full? Or do they have a vested interest in selling more batteries?

Very useful link, that one. Thanks.

8

This one is important

My computer has being saying there is no power in the battery when there was plenty. Turn it off - turn it on - things are sometimes fine again.

With lithium batteries it is hard to know the state of charge from measuring - so your computer tries to do it by counting - so much in - so much out - this is not a very exact process - but the computer can say - “hey you are out of charge” when it is not true. The suggestion about running it down is difficult because your computer may think the battery is empty - when it is not - I am not sure how to get about this problem. Repeatedly turning it off and on seems to be a solution - but I am about to uninstall the manufacturer’s power management and again use what came with Windows 98se instead - installing the manufacturers power management (Toshiba) seems to be about the start of my problems - try to run on battery and often after less than 5 minutes - beep beep beep - computer seems convinced I have no power. Let it charge all night with power off - no problem.

If the computer is not guessing I get about 3 to 5 hours on battery, depending on what I am doing

Start of quote - above in my possibly flawed opinion:)

Although lithium-ion is memory-free in terms of performance deterioration, engineers often refer to “digital memory” on batteries with fuel gauges. 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.)

Opinion again - but if the computer “thinks” the battery is flat - It will not complete the discharge.

9

Unfortunately it is difficult for the computer to know the battery is full - the idea of letting the man do it is great - I think most laptops have not be fully tested - power on - no battery - which is what your switch would do - but GREAT idea

If the battery is really f**ked - this is normal start rutine - drop battery - start computer - reinstall battery

10

Yes, great link rian; very interesting.

In my post above I was writing what I’d heard about ni-cad batteries, but it seems that lithium batteries are very different.

11

either ways a laptop battery will be good for a year only, then 100% -90%-> suddenly 0%
it is best to replace them every year.

12

The price some companies ask for replacement battery - just buy a new laptop - If the battery is dead your laptop is probably out of date.

Yours faithfully

Troll

13

The battery of my Acer Travelmate was suddenly dead after less than 2 years use. I went to their service centre today at noon and they just gave me a new one for free without me bitching around. Wow, that was very surprising!
So no I’m going to treat my battery according to the link above and hope that it lasts longer than the old one…

Does it? Anybody has some reflection on the advise in the link?

14

don’t load and unload the battery completely
that does only harm to its capacity
if you do read german browse heise.de
and search for an article about batteries there

15

This is interesting. I was taught that if you’re going to have your laptop plugged into the wall for any great length of time, like at work. Or like me, pretty much the moment i get home since it’s my only computer… to disconnect the battery from the laptop. I guess I should start leaving it in the laptop.

Hmmm.

16

Related to all of the above…

If you’re using Linux with kernel 2.6.7 or higher, there is a very useful utility you should be running called “powernowd”. What it does is to drop the CPU speed down to 20% of normal when the machine is idling, and boosts it back to 100% when the speed is needed. You just set it and forget it. This has two advantages:

  1. Increases the numbers of hours you can compute on battery power, and

  2. Decreases CPU temperature (which will increase the life span of the processor).

I tested powernowd on Kanotix (it’s enabled by default if you have a Centrino CPU) and found that it dropped CPU temperature by 15 degrees Celsius.

regards,
Robert

17

What’s worked for me is to never use your laptop with the AC power plugged in while the battery is inside the laptop. Use either the AC power or use the battery, not both simultaneously. When you use your battery, use it all up and then recharge it full again with the computer off.

18

[quote=“Yellow Cartman”]When you use your battery, use it all up and then recharge it full again with the computer off.[/quote]I think that’s correct for rechargable ni-cads, but not lithiums.

[quote=“rian”]Most new computers have Lithium batteries

batteryuniversity.com/parttwo-34.htm

should tell you all you need to know.[/quote]

19

[quote=“robert_storey”]Related to all of the above…

If you’re using Linux with kernel 2.6.7 or higher, there is a very useful utility you should be running called “powernowd”. What it does is to drop the CPU speed down to 20% of normal when the machine is idling, and boosts it back to 100% when the speed is needed. You just set it and forget it. This has two advantages:

  1. Increases the numbers of hours you can compute on battery power, and

  2. Decreases CPU temperature (which will increase the life span of the processor).

I tested powernowd on Kanotix (it’s enabled by default if you have a Centrino CPU) and found that it dropped CPU temperature by 15 degrees Celsius.

regards,
Robert[/quote]
Is this only a Centrino thing, or can it be done on all laptops? If neither of these is the case, how do you tell whether yours has this feature?? Many thanks.

20

[quote=“MaPoSquid”][quote=“robert_storey”]Related to all of the above…

If you’re using Linux with kernel 2.6.7 or higher, there is a very useful utility you should be running called “powernowd”. What it does is to drop the CPU speed down to 20% of normal when the machine is idling, and boosts it back to 100% when the speed is needed. You just set it and forget it. This has two advantages:

  1. Increases the numbers of hours you can compute on battery power, and

  2. Decreases CPU temperature (which will increase the life span of the processor).

I tested powernowd on Kanotix (it’s enabled by default if you have a Centrino CPU) and found that it dropped CPU temperature by 15 degrees Celsius.

regards,
Robert[/quote]
Is this only a Centrino thing, or can it be done on all laptops? If neither of these is the case, how do you tell whether yours has this feature?? Many thanks.[/quote]

If I understand correctly, the developer of Kanotix only enabled it BY DEFAULT if a Centrino or AMD64 is detected, but you can enable it for other chips. According to the Powernowd web site…

deater.net/john/powernowd.html

…it works with many different chips, even the Apple Gx PowerPC series.

To enable Powernowd on a Debian-based system, run the “rcconf” utility and choose Powernowd as a startup service. You SHOULD have rcconf installed (apt-get install rcconf) because it’s very easy to use, but if you don’t, on Debian-based systems you could enable it like this:

update-rc.d powernowd defaults

and disable it like this:

update-rc.d -f powernowd remove

With RPM-based systems, enabling startup services is done differently. On Redhat there is a utility “ntsysv”, and Mandrake does something else (can’t remember since I haven’t used it in eons).

regards,
Robert