2004 Jeep Laredo Alternator?

This happened twice before and it was the alternator. I would be driving down the hwy and all of a sudden my battery gauge and speedometer needle goes crazy and then my car just dies. Last two times it was the alternator and everytime it happens I can start it back up and drive another 10 mins. Or so till it happens again. One place told me that was because my battery was overcharged I was able to restart it.

When it dies I do notice slight dim on my flashers.