Laptop battery will not charge all the way any advice?

My mother-in-law gave us her laptop a few weeks ago. She got it from QVC a few years ago and took excellent care of it. Its a Gateway NV59C and it runs very well. The only problem we seem to be having is the battery only charges to anywhere between 45%-85% and even though its still plugged in it will quit charging. Sometimes if i unplug it wait a few seconds and than plug it back in I can get it to charge a little bit more before it stops. This is my first go around with a laptop so i dont know if there is a setting I need to change or something else. If I would need to get a new battery would I want 6 cell or would a 9 cell one be better or worth getting. I cant get a "cell" rating on the current battery. Any help or advice on this would be a great help and thanks in advance for any input.

Thanks,

Anthony

Batteries in laptops will not last forever no matter how well they are taken care of.  Over time, just like what you are seeing, they won't fully charge.  Mine stays plugged in almost all the time but since it is a few years old the max it gets is around 90% now.

If it really bothers you, get a new battery.  Otherwise, just realize it is what it is.  Unless you need it to last a long time when not plugged in, there is absolutely no need to get a new battery.  If you do and want to go long stretches without a plug, the more cells the longer it should last.  Realize that the larger cell count also means that it will be heavier.

Have you tried taking the battery out and putting it back in? I had problems with my laptop battery only lasting a minute unplugged. I waited a few minutes after taking it out, put it back in place, and haven't had a problem ever since. 

For the record, the laptop is 8 years old.