hardware failure - Detection of battery status totally messed up

I already posted this question in the Ubuntu forum and stackOverflow. I forward it here with the hope to find some different opinions about the problem.

I have an Acer TravelMate 5730, which is 3 y.o., running Ubuntu 10.04 LTS. One year ago I changed the battery because the old one died. Since then, everything worked like a charm.

A week ago I was using my laptop running on battery; it was charged up to 60%. Suddenly it shut down and for about 24h it was like the battery was totally broken: it didn't charge anymore and the 'upower --dump' said

    state: critical.

I was kind of resigned to buy a new battery, when suddenly the orange light became green: battery was charged and actually working; strangely the battery indicator was stuck to 100%, even after 2 hours running.
I tried again with 'upower --dump' or 'acpi -b' commands and it kept saying battery is discharging, though maintaining the percentage to 100%.
Thus, battery working fine up to 3 hours, without any warning when it was almost empty, likely to result in a brute shut down.

Today something different. the 'upower --dump' command says:

    ...
    present:             yes
    rechargeable:        yes
    state:               fully-charged
    energy:              0 Wh
    energy-empty:        0 Wh
    energy-full:         65.12 Wh
    energy-full-design:  65.12 Wh
    energy-rate:         0 W
    voltage:             14.481 V
    percentage:          0%
    capacity:            100%
    technology:          lithium-ion

I tried to boot WinXP and the problem is pretty much the same, with the battery fully-charged, percentage equal to 0% and no way to fix it.

While writing, the situation has changed again:

    present:             yes
    rechargeable:        yes
    state:               charging
    energy:              0 Wh
    energy-empty:        0 Wh
    energy-full:         65.12 Wh
    energy-full-design:  65.12 Wh
    energy-rate:         0 W
    voltage:             14.474 V
    percentage:          0%
    capacity:            100%
    technology:          lithium-ion

...charging, but it does not charge up. (Recall, the battery lasted 3 hours until yesterday!).

So, the big question is: is it an hardware issue, like a dedicated internal circuit is broken? or maybe it is just the battery that must be changed. Or, rather, some BIOS problem that could be fixed in some way.

I'd appreciate every help that can shed some light on this annoying problem