Battery drain or faulty battery

[b3oty]

Originally Posted by bastereo

Well, I would try disconnecting the battery and leave it to sit overnight or two and test the batter then.
But there really are only 2 ways a battery dies when the car is off: there is a parasitic drain or its a bad battery.

Thank you for the reply. I think it's actually a bad battery (despite the person who tested it thinking it was ok). I tried another test I read about somewhere. I charged it up yesterday and left it for 5 minutes before checking the voltage at 12.8v. I then switched the headlights on for 1 minute, then tested the voltage again (with headlights still on) and voltage had fallen to well under 12v. I then switched the lights off and gave the battery a couple of minutes to recover and it only showed 12.34v. So I'm pretty sure it's a bad battery.