MacBook Pro battery problem

I've recently been having a problem where my computer simply shuts off when running on battery. The battery itself is relatively new (~2 years) and still holds a charge fine but regardless of what that charge might be, the computer still shuts off as though the battery were suddenly removed. I now just keep my computer plugged in all the time with the battery removed but obviously that defeats the purpose of having a laptop. Occasionally I do forget and the computer runs fine on battery power for up to an hour and then there's the sickening click of the hard drive shutting down and that's that. I'm not exactly sure what's going on but it's really starting to become a problem.

The battery is 2 years old and may be failing. You didn't tell us how many cycles of charge - re-charge that it has gone through.

Why don't you download the free cocoanutBattery application and see what it says about the battery. It could be that you just need a new battery.

I thought that as the battery capacity diminished due to age or heavy-use (which is my case, it's at 34% of original capacity, which is pretty bad) the amount of time I was able to spend on it would diminish gradually with it. I didn't expect it to be reporting a charge of 86% and still suddenly cut-out. Even if it is 86% of 34% of the original capacity, shouldn't it just go down really quickly?

Not necessarily. Batteries also develop internal faults over time due to normal wear and tear. Did you download the application I recommended? Let us know what it says.

I agree with checking with cocoNut battery. My own battery has 45% (sometimes it reports even less) of its original charge and also shut down randomly when running on battery. My best bet would be to try to get a new battery (I have the MBP 4,1) but I can't afford it as of now, so I'm always plugged in.

Hope this helps

Rubén

I did download the program and there're 285 loadcycles on the battery and it's at 37% of design capacity (2370 mAh of 6300 mAh). I'm afraid I'm in the same boat as Ralvr though, can't afford a new battery right now so I guess my computer's grounded until further notice.

Maybe not...
I understand that if a battery has a defect BEFORE it has 300 cycles Apple can replace it for free. I don't know the veracity of that, since by the time my battery started malfunctioning it was already beyond the 300 cycle limit and thus I didn't ask directly.

Hope this helps.
Rubén

Apple's battery replacement policy for user-removable batteries is 300 charge cycles or 1 year, whichever comes first. Since the battery is more than 1 year old, Apple will probably not replace it for free.

For batteries that are not user-removable, Apple will cover them for 1 year, or with the purchase of AppleCare, will cover them for the full three years or 1000 charge cycles, whichever comes first.