MBP battery behaving extremely weird

[evisa]

After having left my C2D MBP to sleep all day while I was at work, I came back to it shut down instead of sleeping. I figured the battery was probably run down and I plugged it in, everything was going fine until I noticed it stayed at 99% for a longer than usual time while it was still charging. I checked iStat Pro (which I know isn't 100% accurate but is still somewhat informing) and the battery capacity was at 71%. That alone was sketchy to me, since I calibrate my battery monthly and use it just like the Apple website says is the best (ex: unplug it, use it at work/school, plug it in when you get home). After I unplugged it to see where the battery was really at (it kept saying it was calculating how long it would take to be completely charged) and iStat Pro said the capacity was at 31%! Not only that, but it now holds at 100% with an estimated 1:02 remaining, whereas normally, i would get an initial 99% with 4:02 or something.

What could this be? A defective battery? I bought AppleCare so I'm not too worried, but this computer is my baby and I'd be so pissed off if it started to have problems so soon.

Has anyone had this kind of problem?

Edit: Right after posting, the battery seems to have leapt back up to an est. 2:13 remaining, battery capacity is at 66% but the menu bar meter still says 100%
Edit #2: If the battery meter is not registering and stays at either 0% or 100%, is it just the battery that is having problems or the software, as well? Because I have no backup methods.

 

[gunthian]

Not sure what the problem is, but you might want to try a utility called coconut battery, which seems to give fairly accurate battery stats:

http://www.coconut-flavour.com/

Don't know whether it gives better battery stats than iStatPro, but might be worth a try

 

[evisa]

Not sure what the problem is, but you might want to try a utility called coconut battery, which seems to give fairly accurate battery stats:

http://www.coconut-flavour.com/

Don't know whether it gives better battery stats than iStatPro, but might be worth a try

Thanks, I downloaded it and sadly, it gives the same battery capacity. And it's only four months old!