Battery problem

[GeoffG]

I have a Macbook that is about 5 years old. Lately when I have taken my laptop out without the power cord it is fine for about 15 minutes. Then out of nowhere it shuts off with no warning and won't turn back on. When I plug the power cord back in, it says it's at 0% and then like after 30 minutes it just changes back to near 100%.
It has done this the past two times I have taken it out without the cord. What's wrong with my computer? Is it a battery issue?

 

[djackmac]

What's wrong with my computer? Is it a battery issue?

Sounds like that's the original battery and it is toast! Time for a new battery and should probably keep the AC adapter plugged in until you get a new one. All those sudden shut offs are eventually going to really hose out the directory structure on your drive and then you will have 2 problems.

 

[GeoffG]

I keep it plugged in at all times. I haven't had to use it much without the power source lately, so that's not an issue. How much will a new battery cost?

 

[djackmac]

They are $129 for an Apple battery.