Ford f350
My f350 has had the alternator replaced and batteries replaced truck still only runs for a short amount of time. Took the alternator off and retested and it was bad, the batteries tested good.Put the new alternator on and started the truck for a few minutes. The next day not enough power to start took the batteries in to get recharged they both came back bad. What can be causing this problem. Ford f350 2005 super duty 4 wheel drive 6.0L