Mac laptops forum: Can anyone help me with a battery problem?

These batteries wear out after around 300 charge/discharge cycles. When they wear out, it's no different from any other kind of rechargable battery. Except they're a whole lot more expensive of course. So what you need to do is go out and buy yourself a new battery. When you get a new battery, you can prolong its life by plugging into the A/C whenever possible, but the more you use a battery, the sooner it wears out.

Even the best battery Apple used and this was only for a specific model was 1,000 cycles. The rest were 300 cycle rated and given the age (batteries do get old too) is well past the 18 month rating (yes they can last longer) so all it tells me is the battery is gone.

I'd replace that for a few reasons.

An old battery can tax the charger and the motherboard and cause deeper damage. Some folk learn this first hand. A few learn it from others.
Bob

I too did have battery problems with my 2009 MBP. I have upgraded to Mountain Lion.
Do checks before replacing battery, such as: activity monitor, battery monitoring, is your MBP getting hot, fan takes long time to go off when put to sleep. Could be a fault is software program.

Have you recalibrated your battery ? Fully charge the battery, then disconnect the AC power & let the computer run until it forces a shutdown. You'll want to adjust the energy preferences for the battery power source so that the display does not dim & all the sliders are to the right, so display & computer sleep won't occur for hours. The battery % in the menu bar (activate if not already) may reach near 0% & then display recalibrating, or the computer may force a shutdown at 5% remaining. The point is that the controller chip in the battery gets out of sync & needs a full charge & discharge cycle to reset itself. The computer has to run until it goes into battery save mode; ie the computer will protect the lithium ion battery by shuting down before it ruins the battery by completely discharging it

If you work on battery power heavily, then it could be that your battery has reached it's max recharge cycles. At that point, the battery can only hold @ 80% of it original charge & will degrade from there

Another option could be excessive use of an internal device. Besides the 2 external USB ports, the hard drive, optical drive, keyboard, track pad, Bluetooth, iSight camera & other components are attached via internal USB ports. So if anything is heavily used while on battery power or possibly a 3rd party software is running that uses a component, could be the culprit. Check your user ID in System Preferences and review any software that is listed to automatically activate at login. Make sure that it is all necessary

Cheers !