About a month ago I posted some questions about starting a truck with dead batteries in a building without any power. I used a generator and charger and while to took most of a day I got it started and counted it as a victory.  It prompted to to upgrade battery chargers to a Associated 6002B.  A few days later I went to start the truck (at home near an outlet) and it wouldn't start.  Charge again for a few minutes, put new charger to "boost", and truck starts.  I took it to town for new tires and they let it idle the entire time.  Next day truck wouldn't start.  Ok.  Batteries must be bad as all connections are clean and tight.  Fast forward to today.  Three new batteries......and no start.  Bad things were said.  Truck mechanic suggested tapping on starter to see if it has a dead spot.  No luck.  Get out volt meter.  Batteries have 12.25 volts.  Also have 12.25 volts at starter......but only 10.4 volts at battery disconnect that was installed two years ago.  But if I wiggle cable it has 12 volts.  5 minutes later with the cable terminal securely soldered on the truck starts.