Originally Posted by 98CoupeV6

You need to take a voltmeter to it and find out what peak voltage it has when the car is running.

If you don't have one or can't procure one, you can pop off one of the little thick plastic covers on the top to check the battery acid level. It should be above the metal plates.

Or you could just buy a new battery since they're not that expensive. Did they charge it?