I bought the ASUS UL50VT laptop at the beginning of 2010. At the end of last year, the original battery that came with the laptop had some issues and I bought a new 12-cell battery for my laptop.
Now, my laptop always just cut off whenever my battery has a remaining of roughly 50% juice. Since it has only been 10 months since I got this battery, I doubt that it is no longer capable of holding charge. From what I experienced with battery that doesn't hold charge is that the battery indicator will just drop to 0% real fast, unlike mine which just cuts off at ~50%.
I did some research online and I came across some discussions talking about how the ACPI is not reading the battery charge correctly and a calibration has to be done in the BIOS. I tried doing that but realized that my laptop's BIOS doesn't have the battery calibration option in it.
I also came across other discussions which says that calibration can be done by just allowing the battery to drain off while on the BIOS screen. Then followed by a full charge of the laptop. This also did not seem to work (unless I am doing something wrong).
For the moment, I have disabled the ACPI and just checking if my laptop will last longer than 50%. Before disabling the ACPI, the windows battery meter was reading ~7-8 hours and it was at 93%. So if my laptop doesn't just cuts off at ~3-4 hours, then I was thinking that I could conclude that it is indeed the ACPI misreading my battery level.
In the mean time, I was wondering if any of you could help me diagnose this problem and tell me if it is indeed a dying battery issue or is the ACPI reading my battery level wrongly?
Btw, when I mentioned that my laptop just cuts off, I do not mean that it goes through shut down, sleep or hibernate process. I believe it is the same as disconnecting the ac cable when your laptop is not connected to the battery.
