OK, I still need to check my battery groundings (main ground was good), but I discovered the following:

- Charged battery to 100%, then let it sit overnight connected to car. Checked in the morning, battery charge was 60% (yikes!)
- So, then I charged it again to 100%, let it sit overnight disconnected from car. Checked in the morning, battery charge was 80% (still a 20% loss).

So does this likely mean that my battery is simply no good, since it loses 20% of it's charge unconnected and 40% connected (meaning that perhaps the minimal load of the car's clock, etc. was causing big drainage)?

I still need to check the wires to the starter and the starter grounding, but what I've discovered so far SEEMS to point to a bad battery.

Any thoughts from the more experienced here?