no low battery warning

I replaced the battery in my MBP which wouldn't charge or run for more than 1 hour. Now, with the new battery, I have 2 issues:

1--battery status in menu bar does not change. It shows it's at 28% all the time

2--I not longer get a warning that my battery is about to run out.

Any fixes??? This is a drag since the computer keeps going to sleep on me because it's run out of juice unbeknownst to me. Thanks.