Battery indicator and charging tips for X31

[runningman]

Hi there, I have a couple of quick questions regarding battery use on the X31.

1). When I unplug the AC cable and go to battery use I always check the battery icon in the tray so that I can gauge how much time I've got. What I can't understand is why the figures given jump around and don't always tally with one another. E.g., the battery will be stating 100% and say 2hr 30, then it will drain down down to say 95%, but the time left will increase quite quickly and significantly, sometimes up to 3hrs. I'm quite happy with the battery performance given the age, just a bit confused as it seems counter-intuitive.

2). I usually plug into AC when the battery alarm comes on (this is set at 10% for low battery and 3% for critical battery) so is this the best way, or should I be charging it before the capacity gets that low?

Any thoughts would be appreciated.

[sojourner]

runningman, your observation of battery life increasing is quite common but dependant on the laptop configuration for battery.

I believe what happens is this, your initial 'battery life' indications are based on the current operational state. The CPU frequency, video memory refresh rate, screen refresh rate, state of power for wireless, LAN, HDD power down, etc, etc are all factors in the equation for battery life. Once on battery, with a properly configured system, lots of things begin to happen:

- CPU frequency should lower (gives longer battery life)
- LCD should dim (gives longer battery life)
- if your ATI video is setup for PowerPlay refresh rate will drop, memory speed will drop (gives MUCH longer battery life)
- wireless and / or LAN should powerdown
- unused USB ports should turn off
- HDD may turn off

Well, you get the idea. As features are either turned off or tuned down less power is consumed, thus greater battery life. And BTW, some of these power saving features take a while to engage, some do not powerdown or turn off immediately upon battery operation. And BTW, I have multiple X31 (love them) and have found them to do quite well with power saving! If I recall, it's drawn as little as 9 watts on battery ... and my T41, actually got it down to <8 watts (using XP).
http://forum.thinkpads.com/viewtopic.ph ... ts#p445261

Now with a fresh install of Windows 7 RC1, power draw will not go below 12 watts ( ) on the T41.

Regarding thresholds for battery alarms; yours seem fine.

[moronoxyd]

1.) The remaining battery time jumps because it is calculated based on the current aktivity of your X31.
That is if your notebook is idling, it is using little power and the battery gauge will display a longer runtime than when your notebook is working hard and thus consumes more power.

The increase directly after unplugging the notebook is a good example:
Your X31 is probably configured to run full speed when on AC power.
Now when you disconnect power, it takes a few seconds for the system to power down into power saving mode, so you see an increase in exstimated runtime because the notebook is using increasingly less power.


2.) The basic rule here is: Reduce loading cycles.
That is: The less often the battery is loading, the longer it will last. (In theory, there are other factors.)
Using the battery until it's almost empty is doing exactly that.

I personally take a somewhat different approach.
I'm always trying to make sure that the battery is as full as possible, so that if I have to take my X32 on the road I get maximum runtime without much preparation.
To archive that I usually start loading the battery once it is below 90%, if I have the chance.

This does reduce the lifetime of the battery a little, but then again, batteries are expendable part (is that the correct erm?) anyway, so I'd rather buy a new battery a month earlier than be on the road with an empty battery.

[Subliming]

Here are some tips for keeping your lithium-ion battery in good shape:

Never completely discharge and recharge the battery... it will reduce the capacity of your battery noticiably.

If you are not going to use the battery for a long time, discharge it to about 40-50% and store it in a cool environment.

If you use battery often you wont put much wear on it (even tho your cycle count will increase) if you do not let it discarge too far below 40% or so.

I used to have an X31 and even tho the battery's cycle count neared 200 its capacity never decreased.

[tomh009]

I used to have an X31 and even tho the battery's cycle count neared 200 its capacity never decreased.

Actually ... if you are basing "capacity" on what the battery meter says, and you never discharge below 50%, you could have as little as 50% of the original capacity left. The capacity is estimated and if you never drain the battery (such as the battery gauge reset does) the battery meter can never figure out the true capacity.

[Subliming]

Actually ... if you are basing "capacity" on what the battery meter says, and you never discharge below 50%, you could have as little as 50% of the original capacity left. The capacity is estimated and if you never drain the battery (such as the battery gauge reset does) the battery meter can never figure out the true capacity.

Oh, uh... well, what I meant was the way power manager reports capacity in Watt-hours... For example, my battery reports a design capacity of 42.4Wh and a full charge Capacity of 41.8Wh. This is as it was from day one.

In real terms I get about 3.5 hours when browsing or typing, and half that when watching a video. Not bad for such an old battery...

Also, I'm not sure what you mean by battery gauge reset... the gague software only reports what the system reports to it.