My Honda Accord 1995 will not start. One day the engine decided to only sluggishly turn (wouldn't crank) - then suddenly took off, turned over quickly and started straight away. I charged the battery overnight - just in case and the next morning it started fine. But only 8 hours later I tried to start it again and the battery was flat. I tired to jump start and I couldn't even get it to turn over - just clicking. I recently replaced one of the battery connections with a good brass fitting and I had Vasaline all over one battery connection. Could there be something draining the battery? Or could it be the alternator (brushes?) Or something else?

When the alternator doesn't supply current, the battery light on the dash would light up. (assuming the battery lightbulb is working) Next would be to doubt the voltage regulator not doing a proper job, but usually its either dead or working.

Ghost consumers can be tracked when the engine is off and removing / attaching the battery lead causes quite a bit of spark. Measure the Amps with a multimeter when turned off. When it's in the 2 Amps and upwards region - remove one fuse group after the other to see where most of it goes. Then go through all the separate consumers in that group.

If it's a low current preferably below the 1 Amp - the battery might not be as healthy anymore as suspected.