96 ranger will not start just clicks at starter reley on fender well?

96 Ford Ranger will not start it just clicks at starter relay on fender well. I have cleaned and tightened the battery post. And
replaced the starter relay. I also put the battery on a charger to make sure it was good. After finding it charged I turn on the
lights and turned over the ignition,it did not seem to pull the lights down. It is a stanard transmision. It push starts
easy. When I do and drive it the amp meter ( stock +/- ) stays right in the middle were it always is. help please