Thinkpads Forum

Hi,

I've been using the Windows 7 RC on my T400 since the summer, and today I finally installed W7 Professional. Since the OS is fresh, it's taken a liking to giving me all sorts of popups and information until I quiet them down. I got my T400 last January (so it's been about a year now) and I've noticed for a while that the battery life has been short, but maybe in the back of my mind I attributed it to using non-official OSs or something like that. I don't use it on battery power too much, but do sometimes. I have a 6-cell battery, and when fully charged, if I unplug and go to battery power, it says I get about 1:30 out of it. Regarding the popup notifications that I mentioned, the first time I went to battery after installing W7 Pro, I got a popup above my battery gauge in the taskbar saying something like "Your battery currently performs at 55% of its capabilities. Click here to learn more ..." or something like that. I haven't been able to get that exact popup back. It makes sense, though, since 1:30 is about 50% of what I should get using my discrete graphics card and on full brightness and everything.

I've read a couple things about trying to gain some battery life back, but I've never really understood them. So my question is: if my battery is in fact performing at 55% of what it could do when it was new, and is giving me only 1:30 of battery life, is there anything I can do to bump it back up to 3+ hours? How did it get this low in the first place, and so quickly? I was under the impression that these batteries were not the type that would require me to fully discharge them once on battery power before returning to AC power.

Any thoughts?
Thanks.

Install all of the Lenovo utilities, especially the Power Manager and related drivers (perhaps via System Update 4). This will give you more detailed numbers on how your battery is performing and what kind of wear it has.

If a 6-cell did get you only 1:30, then it would suggest a high rate of power drain on the battery, which I'm pretty sure Li-ion batteries don't like. (Both from theory and personal experience; my battery capacity would almost certainly decrease if I played Crysis on battery.)

I have also heard reports that performing the Battery Reset on a Li-ion battery further degrades the battery life. I haven't run a battery reset yet, but after 37 charge cycles on my 6-cell, my full-capacity is still 57.61 Wh, a bit above the manufacturer's design capacity of 56.16 Wh. Unfortunately, when battery life degrades, you can't really do much to get the battery back to its original capabilities without replacing the battery. (Unless you just have driver issues, then you're in luck! )

Thanks for the reply. I'm actually still under warranty so I just requested a new battery.

One last question to sum up though: with these batteries, what is the best way to use them in order to preserve battery life over time? If I have to use battery power for, say, 10 minutes, should I then just keep using battery power until it's drained, and then plug it back in? Or should I just go on battery, back to AC, back to battery, back to AC, etc. without worrying about fully draining the battery?

The general consensus seems to be to avoid fully discharging the battery... But I've been doing full discharges almost all the time and doing full charges, and still have more than a watt-hour above design capacity.

The most important factor that affected my battery personally is high current draws; by sticking to low-power tasks on the integrated Intel chipset when on battery power, I'm pretty sure it keeps power draw at a minimum. The greatest loss of capacity I had was during the one time I played Crysis for the entire life of the battery; that cost almost half a watt-hour of capacity

If you have the Lenovo Power Management program installed click on Battery Maintenance in the advanced view. It will give you discharge/recharging options you can set to your liking. You can set a start charging percentage to a stop charging so you do not continually have the battery charged to full. It seems that keeping your battery charged 100% all the time decreases cell life.

I plan on getting me a nine-cell battery for sure in the future! I think I have the four-cell battery which gets me a little over two hours right now- depending on usage!