Jeff Layman wrote:

Might be simplest to charge for 4 or 5 hours, then turn
off the charger and turn the headlights on for a minute:
1. Headlights don't come on - battery buggered. Replace asap.
2. Headlights come on and stay on - battery ok. Continue charging.
3. Headlights come on and slowly fade - battery on the way out. The car
might start and get you from A to B, but I wouldn't guarantee getting
back from B to A! Replace battery asap.

Thanks for that. Sounds like a good scheme.