Unexpectedly low battery life

[Myrddraal]

I'm trying to sort out someone's battery problems. Apparently the battery drains very quickly. It's an Asus Eee PC 900, which I have discovered has had very contentious battery problems from many users, however I think this problem might be even worse that that described by others.

The netbook is supposed to have a 4400 mAh battery, however, I have downloaded notebook hardware control which informs me that the battery has a full capacity of 840 mWh, and a voltage of 7.971 V. Perhaps I'm being stupid, but doesn't that mean a rating of 94.84 mAh, which is rather low?

If I'm not being stupid, I'm guessing the best bet is to replace the battery. Would the resident experts agree?

[Beskar]

It also depends on the battery has reached the end of its lifespan or not. How old is the laptop being used?

The solution would obviously be a battery replacement, if it is indeed that.

[Xiahou]

It also depends on how the battery was used. If it spent 99% of the time plugged in, that could kill it off fairly quickly too. Lithium batteries don't like being fully charged (or fully discharged) all the time. Extreme heat can also kill em quick.

[Myrddraal]

I take it from your responses that my conversion from mWh to mAh is correct then. NHC also informed me that the "wear level" is 98%. Does that mean the battery is 98% of it's original capacity, or just 2%? Surely if it was that worn it wouldn't be able to turn on for more than five minutes...

EDIT: how curious...

What does battery wear level mean?
Indicates how much Full Charge Capacity has become less compared with Designed Capacity. A battery wears gradually as it goes through charge and discharge cycles or secular charge and its capacity decreases. Battery recalibrating (you will find this function in the BIOS) mostly improves the battery wear level.

So apparently this wear level should increase as the battery gets more worn, which would indicate that there is indeed something wrong with this battery, even though it is relatively new.

More interestingly though, I have been trying to discharge this computer completely to see how long the battery lasted, and it seems to have levelled off at 20% charge for quite some time now. I wonder if the problem is in the calibration of the battery indicator rather than an actual problem with the battery...