Saturn

Saturn 98'. Twin cam. 1.9 liter wouldnt start. Checked starter. Tried to cross wire starter. No spark. We hit starter witha hammer and it started up right away. We replaced the starter. Started it up and it started right up. We let it run for a bit. When I went to drive it I noticed the battery light was dimming on and off. Then when I started to gain speed the battery light dimmed off and stayed up. I started to roll up the window and the speed gauges went to 0. And that rpm gauge went to 0. And the radio cut out.I got it home and it died immediatly and would not turn over again. It made no sound when I turned the key. No clicking or anything. I had the battery checked and they said it was good. It was only producing 20 amps less than the accurate amps.