the eye will be green if the battery is charged, but it wont tell you if the battery will hold the charge. you can take it to the nearest place with a load tester to see if it's good. It has to be fully charged to test it. Autozone should have one, or any service center. they basically put half the rated CCA load on it to drop it down to about 9.5 volts for a few seconds, wait about a minute for it to climb back up to 12.5v, and do it again. if it wont climb back up on its own, it's bad.
