Battery Capacity after a year

[hsjC]

My z61t bought last Aug:

4 cell battery degisn capacity : 37 Wh
Actually capacity: 28Wh

What I can't believe is that, the actual capacity dropped a little bit after a battery gauge reset! From 29Wh to 28Wh...

I saw other posts complaining the short life span of batteries.
But why does a reset decreased my battery capacity?

[Harryc]

I've seen that phenomenon and experienced it first hand as well in the past. The only explanation that makes sense to me is that if you wait quite awhile to recalibrate the battery, the actual capacity remaining may be overstated and a reset brings it back in line with reality. Any manufacturers documentation I've read says that you should perform a recalibration once a month, particularly if you frequently keep the machine plugged in to A/C. By definition 'to recalibrate" means that it will return some different value in line with actual or 'spec' after it is complete. One would hope that value is higher, but that is not always the case.

[hsjC]

That makes sense. Thanks.

It's just weird that the capacity drops so fast. It's barely a year. Though I have been sort of careless...

Basicly, it means my battery is dying and there's nothing i can do?

[Harryc]

It's a disposable product. Recalibrate it once a month and enjoy it for as long as it is useful .

[LasseFJ]

I've had my Thinkpad z61m for 13 months.

The battery is 6 Cell.

Initial capacity: 56.16Wt
Current capacity: 35.55Wt