My wagon refused to start last Saturday. I hitched it to the charger and it started after about a 5-minute charge. So I took it to a trustworthy battery shop
, where they put it on the tester and assured me that there was not a thing wrong with the battery, regulator, alternator or starter.
After ten minutes more I shut it off and came back ten minutes later: it refused to start.
I took off the terminals and roughed them up good inside and out. They were plenty tight before I did this, and there was no obvious corrosion (white or black deposits).
It has not failed again for the past week.
My advice: clean the terminals. A bad contact can keep it from passing enough current to start. The probable cause was a 20-degree F dip in the temperature, I suspect.
I had not cleaned the terminals for about a year. They had a bit of Vaseline and a pair of those "magic" felt circles
around each, for what that is worth.