Thinkpads Forum

Okay, so I have a 6-cell battery for my T400, and Lenovo Power Manager says it's design capacity is 56.16 Wh. What's strange is the full charge capacity reads 59.03 Wh now... which calculates to around 12 extra minutes at 15 watts.

I've read a few battery usage guidelines, but I just use the battery until it's 3-5% left (but not usually in one continuous go) and fully recharge overnight while the computer is off.

Is this normal behavior because my battery is still relatively new? I've only had 16 charge cycles on it... I saw that the full charge capacity was at 58 Wh last time I checked.

I remember reading somewhere that this can be normal behavior for a new lithium ion battery. Mine did it for awhile, but eventually the full charge capacity drops below the design capacity.

New batteries usually show higher capacity than their "Designed" capacity. I remember with my T60s 6 cell it was 58.12 for a while and i tried to maintain it as best as i could so that it would stay higher (longer battery life). Eventually it went down and then got to 52.XX - pretty good for about 1yrs usage! I sold the thinkpad after that but i definitely didn't wanna let her go!

It's a normal behavior for a new SANYO battery in a Thinkpad. Panasonics and Sony behave differently.

My guess is that it has more to do with the way the gauge is calibrated on the different batteries than with actual capacity.

Thanks guys, now discovered why the battery in my A31 only does 40 mins at best! rather than the much longer time period that I thought it would be. So the full charge capacity decreases over time...think I might also add a brand new battery onto my project "to buy" list for my A31 restoration, had some problems with it overheating and restarting in the middle of the night!!!

Heh.. I've managed to keep mine at a nice 57.65 Wh capacity... I notice it won't even try to charge above that amount, so better make your first charge of a new battery count

I've heard things that suggest a slow continual power drain is better than a quick battery drain in terms of resetting the capacity. It was suggested that a full battery be run empty with the computer on standby, where it draws minimal current. Granted this would take a while, but it might just restore some battery capacity.

Colonel O'Neill wrote:It was suggested that a full battery be run empty with the computer on standby, where it draws minimal current. Granted this would take a while, but it might just restore some battery capacity.

What, two weeks? Hardly a problem. It's not like anyone needs to use their laptops so often.