Here's an update to my original post #1. Thank you for all the excellent replies and advice! I neglected to state the type of electrical system on my car. It is 6 volt, positive ground, original generator, original cut out with the diode upgrade. I have the generator set at 2 amps at cruising speed. I checked the water in the battery and it was ok.
I had stated that the battery was completely dead at 0 volts. The only charger I have at this time is a Schumacher SC - 1200 A – CA and when I hooked it up to the battery it would not charge. It turns out that this is a safety feature for the charger. After logging on to Amazon (where I bought it) and looking through some of the reviews I discovered some interesting details on this charger. This is an inverter based microprocessor controlled charger.
https://www.amazon.com/gp/product/B0...ustomerReviews
First, the safety feature can be overridden by pressing the two buttons before plugging it in, but don't let it charge for over 5 minutes. Also, the charger has an automatic desufating mode during charging. Please read the reviews if you have this charger or thinking about getting one. Some of them are very informative.
Anyway, the battery is now fully charged. And – I discovered what caused it to go dead. The ignition switch was left on.
The car has the original pop-out ignition switch, and I would have had to push it in to kill the engine when we got home. Maybe it popped back out on its own. I was afraid this may have burned the points (haven't looked at them yet), but the engine starts right up and runs fine.