Best way to configure battery charging..

I had read on here somewhere that there is a prefered way of charging your battery so that it keeps its maxium lifespan. It had to do with setting the battery up to start charging at a certian percentage I believe. I can't find the thread where I originally found that information, does anyone know a good way to configure it, I guess if you are plugged in its bad to keep it at 100% constantly?

 

There's a setting in power manager that charges the battery in such a way as to maximize battery longevity.

 

When I went to that power manager and chose "battery stretch" (or something worded that way), it turned off various devices including my optical drive, without my knowledge (I was going to post about the info of my DVD drive and it had disappeared from device manage, until I unchecked "battery stretch"). I'm trying to find a way to stretch battery life without turning off the DVD drive.

 

1) Press the blue Thinkvantage button
2) Open "Thinkvantage Technologies -> Power Manager"
3) Open the tab "Batteries -> Battery Maintenance"

Then select "custom" from the options, and configure the min/max charge thresholds. For my main battery, I set it to start charging only if it falls below 70%, and then charge to 100%. (The actual settings here are up to you, I haven't found any guides or evidence for better settings.) You can set up different values for your ultrabay battery if you have one, and it is called Battery 2.

I can leave my T61 plugged in to the AC as long as I want and the battery will absolutely not charge unless it falls below 70%. The battery also doesn't discharge at all while I'm plugged in. It looks like there's not even a trickle charge, since the battery detail says "no activity." The AC adapter thus makes the machine behave just like a desktop with this setting, ie. the power supply just powers the machine without affecting the batteries. The batteries don't register any more charge cycles when doing this, they feel cool to the touch - I don't think they are being charged behind my back.

So, I feel comfortable leaving my machine plugged in all the time when I'm not carrying it with me. I see no point in pulling the battery out of the machine every time I plug it in! I have a laptop only because it makes my life more convenient. I don't care what battery university says - I think their info is either a little out of date or else it is so generic that it doesn't take into account special power management SW like that of the Thinkpad.

With linux you can even set the low threshold for discharging (eg. don't discharge below 10%), but I haven't tried that yet. The only real use for this feature would be to protect my ultrabay battery from going completely empty.

 

There is also an option of "maximize performance", something like automatic. Wonder how that works.

Does it matter if we unplug the AC adapter while the computer is in use (turned on)?

 

I think you guys are confusing battery runtime with battery lifetime. It's my understanding that "battery stretch" etc only allow you to run longer on the juice that's already in there, and it's got nothing to do with how many years your battery will last which I think was the point of the OP's question.

The default profile charges when the battery when it goes below 95%. It doesn't look like the charging profile changes with the runtime options. The runtime option only affects things like CPU speed, CDROM speed, and screen brightness.

 

I've had a different experience with the thinkpad Power Manager settings to maximize battery life. I've set it to that in the past, and no matter how run down my battery was (90% charge, etc), it would always continue to charge to 100% when the AC adapter was plugged in.

Because of that, i just manually set the upper and lower limit threshold now. What Power Manager version do you have installed?

 

Ok, are you talking about the Power Plans or the Battery stretch here? If so, neither of those has anything to do with the Battery charge levels. The default charge threshold is 96%, and perhaps that's why you're always seeing it charging.

I think that's the same thing I was talking about in my post. I was referring to the "Battery Maintenance" section of PM, where you can select the battery charge thresholds. Again, this has nothing to do with actual battery runtime on your computer, which is a function of your CPU speed and screen brightness rather than when the battery charges.

I don't know what version of PM I have - all I know is that I downloaded it and installed it on 8/2/07. (There doesn't appear to be a version number in the SW, and Vista doesn't show the version number in the installed SW list.)

Here's a pic of the screen I use for the battery charge setting:
(EDIT: now I also see what Zaz was talking about - the "lifespan" setting. I've never used it, and probably never will, since the custom setting seems to work best. YMMV...)

 

Here's a pic of the main "Power plan" tab - here I have configured a custom profile called "Adaptive." This sets how fast my machine will run and how much battery it will consume, but it doesn't affect the charge thresholds:

 

Nope, i'm neither talking about the battery power plans or battery stretch.

The threshold limits are located within the Thinkpad Power Manager- Battery Information tab, Battery Maintenance button.

Edit: Just to double check, i changed the Battery Maintenance from Custom to Optimize for battery life span at 94% charge. With the Optimize for battery life span setting, the battery has begun to charge. *I have the latest Power Manager utility installed as well.

I'm sorry, i was actually looking at the wrong post when i originally posted. I was referring to ZaZ's post about the thinkpad Power Manager Optimize Battery Life Span setting. I misread your post and thought you stated the Optimize battery life span had a lower threshold of 70%. I apologize.

Edit: I'm guessing the Optimize Battery for Life Span setting constantly charges the battery pack in order to reduce the number of full cycles?